Abstract: In the manufacturing industry, Augmented Reality (AR) has shown significant potential in enhancing operators’ capabilities while performing inspection and assembly activities. However, the augmented visualization of virtual models on physical components can present challenges and potential misunderstandings, as the visualization mode greatly influences the perception of components and the amount of information received. This study investigates the impact of rendering techniques on user performance during industrial assembly inspection tasks. In particular, a set of rendering techniques, suitable for industrial AR applications, have been selected and implemented through a dedicated AR tool. The selected AR rendering techniques have been compared, in terms of qualitative and quantitative metrics, in order to test their efficiency and effectiveness for industrial assembly inspection activities. 17 domain experts and 33 representative users have been involved in the experimental study which outcomes reveal that the rendering techniques play a significant role in assisting operators for identifying design discrepancies in industrial products. Furthermore, a correlation has been observed between the two AR rendering techniques best suited to support industrial inspection activities and the types of assembly errors detected.

Keywords: AR rendering techniques | Augmented Reality | Industrial assembly inspection | Industry 4.0 | Quality inspection

Abstract: The coralligenous build-ups located on the Mediterranean shelf in front of Marzamemi (SE Sicily, Italy) represent useful natural examples to use in studying the relationship between skeletal organisms and non-skeletal components in marine bioconstructions. Coralligenous build-ups are formed in open marine systems, and their comparison with coeval bioconstructions (biostalactites) of confined environments, like submarine caves, allows depicting the complex interactions between metazoans and microbial communities in the formations of recent bioconstructions in different Mediterranean settings. In this study, two coralligenous build-ups were characterized in terms of organisms and sediments involved in their formation. The framework mainly consists of coralline algae and subordinate bryozoans and serpulids. Sponges affect the general morphology of the bioconstructions both interacting with skeletonized organisms and through bioerosion activity. The micrite or microcrystalline calcite is present in minor amounts compared to other components that form the build-ups and consists of two types: autochthonous (in situ) and allochthonous (detrital). Fine autochthonous micrite mineralized directly inside the framework cavities and shows aphanitic or peloidal fabric, produced by organomineralization processes of soft sponge tissues and microbial metabolic activity, respectively. The detrital micrite occurring inside cavities derives from external sources or erosion processes of the bioconstructions themselves. This component has been classified as organic or inorganic based on the organic matter contents deduced by UV epifluorescence. A great quantity of sponges live in cavities of the coralligenous build-ups and compete with carbonatogenic bacteria for the same cryptic spaces, limiting the production of microbialites. The sharing of a similar relationship between sponges and microbial communities by coralligenous concretion and biotic crusts of particular submarine caves suggests that this competition is not habitat-specific. On the contrary, it may develop in a range of environmental settings, from open to cryptic systems, and could be used to clarify the role of metazoans vs. microbialites in palaeoecological reconstructions.

Abstract: Augmented Reality (AR) has been widespread over the years in different areas, especially in the manufacturing field, to facilitate the digitization of production processes, and increase productivity and product quality. While AR has grown in popularity, significant barriers exist to its adoption in industry, including high development costs and ineffective interoperability, which limit high flexibility and rapid adaptability required for competitive production systems. Therefore, handling interoperability properly is a key issue in this scenario, especially between AR technology and existing IT systems, widely adopted throughout the product lifecycle. Many of those challenges are related to the compatibility of data representation across these different systems, resulting in data loss or sharing of unusable information. Based on these considerations, this paper first analyzes the main issues related to the interoperability between AR and CAD systems, including data exchange, AR content authoring, and virtual data specifications. To bridge the gap between AR and CAD interoperability, a CAD automation tool is then presented that can support unskilled operators in preparing AR content for industrial applications. Preliminary experimentation is carried out to evaluate the main potentialities due to its adoption, which provides the basis for further implementation and investigation in a real industrial setting.

Keywords: Augmented Reality | CAD systems | CAD-AR interoperability

Abstract: The development of an Autonomous Underwater Vehicle (AUV) is driven by careful design choices in order to obtain the best trade-off between mission performance and cost. Currently, several companies provide off-the-shelf solutions for a wide variety of operational scenarios offering highly modular systems. This allows users to customize the AUV integrating custom payloads tailored for specific applications. The factory customization has a strong impact on time and resources due to significant precautions to be taken. In particular, some design constraints must be respected for the mechanical integration ensuring, at the same time, the overall neutral buoyancy of the module to preserve the final trim of the AUV. Therefore, without a careful approach during the design phase, the risk of impairing the integrity and operation of the AUV could be high. This paper describes a design methodology for the proper development of custom payloads aimed to be integrated in AUVs. The proposed methodology has been applied in the manufacturing of a custom payload that has been integrated in the AUV X-300 of Graal Tech s.r.l. The methodology results as a useful tool for AUVs customization by providing detailed guidelines for the development of specific payloads for a wide range of applications.

Keywords: Autonomous Underwater Vehicle | Balance Identification | Modular Payload Design | Shape Optimization

Abstract: In the realm of smart manufacturing, Augmented Reality (AR) technology has gained increasing attention among researchers and manufacturers due to its practicality and adaptability. For this reason, it has been widely embraced in various industrial fields, especially for helping operators assemble products. Despite its widespread adoption, there is a debate in the research community about how effective AR is for improving user performance in assembly tasks, particularly when using handheld devices. These disparities can be attributed to differences in experimental approaches, such as the frequent use of qualitative methods, the inclusion of non-representative users, and the limited number of comprehensive case studies. In response to this, the paper delved into the benefits of AR applications, with a specific focus on measuring user performance and the cognitive workload perceived by users during assembly activities. To this end, an AR assembly guidance tool has been developed to assist users during assembly tasks, running on a mobile device, specifically a tablet, for freedom of movement and high portability. Experimentation involved the assembly of a comprehensive case study and a diverse user group, allowing the comparison representative users and experienced industrial operators. The results were promising, indicating that AR technology effectively enhances user performance during assembly-guided activities compared to conventional methods, particularly when users are unfamiliar with the task at hand. This study brings valuable insights by addressing previous research limitations and providing strong evidence of AR's positive impact on user performance in real-world assembly scenarios.

Keywords: AR Foundation | Assembly guidance | Augmented Reality | Hand-held devices | Industry 4.0 | User performance

Abstract: In the context of Industry 4.0, the Operator 4.0 paradigm plays a crucial role in seamlessly integrating new digital technologies into smart factories. These technologies are designed to accommodate workers with varying skills, capabilities, and preferences. To promote the adoption of these innovative digital tools and ensure high user acceptance, it is essential to prioritize human factors and place workers at the heart of the development process. This can be achieved through structured design strategies, such as those employed in user-centered design approaches. Within this framework, this paper introduces an innovative Augmented Reality tool designed to facilitate and streamline real-time inspection activities performed by operators on assembled products at the workplace. The development of this tool was based on a user-centered design approach, which actively engaged end-users at different stages of design and testing phases. User studies were conducted using a real case study to evaluate the usability and user acceptance of the proposed solution. The results are encouraging, indicating a promising path forward for the effective and valid implementation of this AR tool in an industrial setting.

Keywords: Industrial augmented reality | Industry 4.0 | Operator 4.0 | Technology acceptance model | Usability | User-centered design

Abstract: Over the past few years, the manufacturing industry has increasingly embraced Augmented Reality (AR) for inspecting real products, yet faces challenges in visualization modalities. In fact, AR content presentation significantly impacts user performance, especially when virtual object colors lack real-world context. Additionally, the lack of studies in this area compounds uncertainty about visualization effects on user performance in inspection tasks. This study introduces a novel AR recoloring technique to enhance user performance during industrial assembly inspection tasks. This technique automatically recolors virtual components based on their physical counterparts, improving distinctiveness. Experimental comparisons with AR experts and representative users, using objective and subjective metrics, demonstrate the proposed AR recoloring technique enhances task performance and reduces mental burden during inspection activities. This innovative approach outperforms established methods like CAD and random modes, showcasing its potential for advancing AR applications in manufacturing, particularly in the inspection of products.

Keywords: AR recoloring techniques | Assembly | Augmented Reality | Cognitive load | Color | Image color analysis | Industrial assembly inspection | Industry 4.0 | Inspection | Three-dimensional displays | Videos | Visualization | Visualization modalities

Abstract: ugmented Reality (AR) is considered one of the key pillars of Industry 4.0 as it innovates the manufacturing process and promotes new ways of human-machine interaction. Among the main challenges influencing the implementation success of AR technology in industry, visualization modalities of AR content represent a crucial factor to be considered in relation to the application domain. In this regard, previous studies evaluating different AR-based content visualizations have demonstrated significant implications on worker performance and, in particular, specific factors such as colors applied to virtual information and uncontrolled environmental conditions, which can hinder the correct perception of AR content by users. Based on these considerations, the paper proposes a context-aware recoloring approach for AR-assisted maintenance applications for both indoor and outdoor environments. More specifically, the proposed approach is used to recolor virtual information on the basis of real work conditions in order to improve distinctiveness and visibility of virtual objects with respect to the real ones. By way of example, a use case is presented for exploring the benefits of the proposed solution in the field of maintenance activities. The outcomes provide the basis for further improvement and experimentation in a real industrial setting.

Keywords: Augmented Reality | Industrial Augmented Reality | Maintenance | Visualization modalities

Abstract: Survey missions in the underwater environment are key activities in several application fields, but the physical properties of such a harsh environment make it challenging for both navigation and data collection. In particular, in the field of underwater photogrammetry, optical sensors are mainly installed on remotely operated vehicles (ROVs). The maneuvering is performed remotely by expert pilots who can only rely on bidimensional visual feedback from one or more camera streams. Additional navigation data can aid pilots in assessing if the mission meets the requirements while undergoing it. To this end, the paper presents a SLAM-based solution that can be used to compute parameters in support of ROV pilots during photogrammetric surveys, when a stereo-camera is equipped. In order to assess the performance of the proposed solution, different tests were conducted. These tests involved comparing the parameters derived from SLAM with the data computed by the navigation system of a professional-grade ROV. The focus of this comparison was on three key parameters: position, velocity, and distance from the target.

Keywords: Multi-camera System | Underwater 3D Reconstruction | Underwater Photogrammetry | Underwater SLAM | Underwater Survey

Abstract: The Marine Strategy Framework Directive (MSFD, 2008/56/EC) was adopted to achieve a Good Environmental Status (GES) in the EU's marine waters and to protect resources and ecosystem services, including the deep-sea waters and seafloor. The deep sea (below 200 m) is the largest biome on Earth, and its biodiversity plays a key role, despite being strongly threatened by several anthropogenic stressors, potentially affecting some ecosystem functions. Among the main deep-sea structuring species, the habitat-forming cold-water corals (CWCs) are known to form Vulnerable Marine Ecosystems (VMEs). In the Mediterranean Sea, in the last two decades, a significant effort has been devoted to unveiling the distribution, extension and ecological role of scleractinian CWCs (Madrepora oculata and Desmophyllum pertusum), but quantitative data on their conservation status are very limited. Because of their ecological importance and vulnerability, Italy has extended the implementation of the MSFD to the deep sea, carrying out specific monitoring programmes on these scleractinian CWCs. In this regard, this study established, for the first time, an extensive standardized baseline for national monitoring programmes focusing on two recently discovered upper bathyal areas dominated by scleractinian CWCs (Dohrn Canyon and Corsica Channel). The goal was to evaluate the ecological status of the bathyal biogenic reefs using traditional diversity and impact variables as well as the innovative photogrammetry tool. In both areas, the investigations have increased the knowledge about the extent of the habitat and new CWC assemblages in good health conditions were discovered. The pressure extent is limited with respect to the total extent of the CWC habitat, accounting for approximately 32% and 63% of the fishing-related items entangled on structuring species. The photogrammetric approach showed a deviation of about 33% in the measurement of the population size structures. Moreover, the use of a standardized operative protocol has been proposed to obtain reliable, coherent, and comparable data for future monitoring activities. This approach improved scientific knowledge for the two studied areas and it is pivotal in defining long-term monitoring activities useful to assess the effectiveness of specific protection measures, for these VMEs

Keywords: Cold-water corals | Fishing impact | Marine strategy framework directive (MSDF) | Mediterranean sea | Photogrammetry | ROV-Imaging

Abstract: Editorial - [No abstract available]

Abstract: In the frame of the project FISR_04543 “CRESCIBLUREEF - Grown in the blue: new technologies for knowledge and conservation of Mediterranean reefs”, we present preliminary data on the ecological and depositional implications of micritic sediments in a coralligenous bioconstruction formed along the Mediterranean shelf in front of the Marzamemi village (Sicily, Italy). The framework of the buildup is mainly built by crustose coralline algae, which in turn create the substrate for a high-diversified epi- and infaunal community. Two types of microcrystalline calcite, tentatively interpreted as allochthonous and autochthonous micrite, strictly related to fine skeletal debris, have been detected. The allochthonous micrite derive from abiotic accumulation of fine sediments in the framework cavities. The autochthonous micrite is deposited in situ through organic-mediated processes. The occurrence of this component allows hypothesizing a possible contribution of non-skeletal carbonate in the strengthening of the primary framework due to its syndepositional cementation.

Keywords: bioconstruction | Coralligenous reef | Ionian Sea | micrites

Abstract: Shape Memory Alloys (SMAs) are increasingly being used in actuator technologies owing to their high reliability, advantageous specific power and fast actuation capabilities. This results from the extremely simple architecture and actuation mechanisms, which are linked to the thermally-induced shape recovery properties of SMAs. Owing to the elevated power-to-weight ratio, small diameter wires can be directly used as linear actuators, whose activation can be achieved by electric currents, exploiting the Joule effect. Fast actuation represents a design requirement in several engineering fields, ranging from aerospace to automotive applications, and it can be easily obtained by a high electric current pulse owing to the extremely small thermal inertia of SMA wires. However, dynamic effects caused by fast actuations, in terms of overloads and stroke oscillations, could represent a threat to material integrity at both structural and functional levels. For these reasons the thermal-mechanical response of the SMA wires under both static and dynamic conditions must be taken into account in designing SMA-based actuators, especially when dealing with fast actuation applications. Unfortunately, SMAs exhibit a very complex constitutive response, with intricated electro-thermal-mechanical coupling mechanisms, whose modeling represents one of the main challenges within the technical and scientific communities. Within this context, an effective multiphysics simulation model was developed combing basic underlying equations for electric, thermal, and mechanical problems. The model was implemented in MatLab/SimuLink environment and solved numerically. Experiments were also carried out, by using an ad-hoc developed testing rig, to capture the dynamic response of SMA wires during fast actuation experiments. The accuracy of the model was validated by systematic comparisons with experimental results, that is under different applied mechanical stresses and electric actuation conditions.

Keywords: Actuators | Dynamic response | Experimental | MatLab | NiTi | Shape memory alloys

Abstract: The paper presents the development of a Virtual Reality (VR) application to perform dives in the Christoforos Shipwreck. The huge wreck lies in the Panormos Bay of Skopelos island (Greece) at a depth of 45 meters. Based on a well-known methodology designed for ancient shipwrecks, the 3D reconstruction of the underwater site has been carried out by adjusting the workflow to survey modern shipwrecks. In particular, the methodology, based on photogrammetry, is capable to provide a highly detailed 3D reconstruction of the shipwreck in a few dives, considering issues like working depth, elevations, and thin elements modelling. Moreover, the paper describes the optimization of the 3D model and the software to be executed in low-performance Head Mounted Display (HMD) devices. The resulting VR application, realized for touristic purposes, recreates the exact ambient conditions inside and outside the water simulating the flora and fauna of the place, the coastline, allowing users to live a recreational and educational experience by virtual diving in the underwater site.

Keywords: computer graphics technologies | cultural heritage | modern shipwreck | underwater photogrammetry | virtual reality

Abstract: Although Jerusalem is one of the most photographed places in the world, few works have focused on the existence of its former 800-year-old Maghrebi Quarter, located in the shadow of the Western Wall. Founded in 1193 by Saladin’s son, al-Afdal ͑Ali to house Muslim pilgrims from North Africa (today Morocco, Algeria, Tunisia, and Libya), the Quarter was razed by Israeli bulldozers on the night of 10–11 June 1967. Its 1,000 or so inhabitants were forced to flee within hours. Silenced by the occupation of East Jerusalem as part of the Six-Day War, the existence of the Maghrebi Quarter faded behind the walls of history. This research paper describes how 55 years after its razing, the selection of a corpus of archives, combined with 3D technology and Interprofessional collaborations between historians and 3D designers enable making a forgotten history accessible again. Beyond a discussion on methods and technical process, this research paper aims to highlight the potential applications of the data set and the 3D model not only for scholarly research but also for pedagogical purposes, for instance.

Keywords: 3D reconstruction | archives | Jerusalem | Maghrebi Quarter | Open data

Abstract: The "An Ocean of Science" project encourages effective interventions and innovative educational paths to support the growth of knowledge and skills in schools, helping competent institutions to guarantee more inclusive cohesion policies with a high cultural and scientific impact. The project also provides innovation in education and training by providing cultural and socio-educational development opportunities in the framework of cultural heritage located in the marine environment and sea protection. The purpose of this study was to evaluate the effects and involvement of secondary school students during several educational laboratory activities, focusing on the development of their practical skills and training. With a view to active learning, which makes the students actors, responsible and aware of the learning process, this study shows an experimental work designed to demonstrate the usefulness and the validity of the scientific approach as the main pillar of the teaching of the sciences related to the marine issues, with special focus to submerged cultural heritage and sea pollution.

Keywords: Educational innovation | serious games | teaching/learning experiences | underwater cultural heritage | virtual reality

Abstract: The documentation, conservation, and preservation of underwater archaeological sites is conventionally performed by divers in shallow waters. However, when dealing with significant depths, the sites can be inaccessible for humans, presenting significant challenges and risks, making these activities hazardous. Recently, the use of robotic platform such as remotely operated vehicles (ROVs) allows to overcome the difficulty of such a harsh environment. Nevertheless, professional-grade ROVs employed for this purpose are expensive and specifically designed with integrated advanced sensor systems for data acquisition and navigation. In the context of the MSCA-RISE H2020 Technological Consortium TO develop sustainability of underwater Cultural heritage (TECTONIC) project, a solution consisting of an optical payload and an acoustic localization system for low-cost ROV, was defined in order to support ROV pilots during documentation and monitoring activities. The project aims to preserve underwater cultural heritage (UCH) encompassing the selection of a commercially available ROV and the definition of a customized hardware/software (HW/SW) architecture. After market research, a suitable commercial off-the-shelf (COTS) low-cost ROV was defined and used as the foundation for integration. Mechanical, electric, and data interface modules were designed to seamlessly integrate and manage the sensor suite. The results of the integration demonstrate the potential of the chosen algorithms and the sensor suite for improved navigation and data collection in challenging underwater environments, where high-grade and expensive sensors are not available, thereby making more accessible the field of underwater survey missions.

Keywords: Underwater 3D Reconstruction | Underwater Cultural Heritage (UCH) | Underwater Localization | Underwater Mapping | Underwater Survey

Abstract: As one of the most promising technologies for next-generation mobile platforms, Augmented Reality (AR) has the potential to radically change the way users interact with real environments enriched with various digital information. To achieve this potential, it is of fundamental importance to track and maintain accurate registration between real and computer-generated objects. Thus, it is crucially important to assess tracking capabilities. In this paper, we present a benchmark evaluation of the tracking performances of some of the most popular AR handheld devices, which can be regarded as a representative set of devices for sale in the global market. In particular, eight different next-gen devices including smartphones and tablets were considered. Experiments were conducted in a laboratory by adopting an external tracking system. The experimental methodology consisted of three main stages: calibration, data acquisition, and data evaluation. The results of the experimentation showed that the selected devices, in combination with the AR SDKs, have different tracking performances depending on the covered trajectory.

Keywords: Apple ARKit | benchmarking | Google ARCore | mobile augmented reality | simultaneous localization and mapping (SLAM) | tracking accuracy

Abstract: In the Cultural Heritage field, the choice of materials and exhibit structures is essential to properly house and support artifacts without causing damage or deterioration. This problem is even more evident in the case of finds made of stone for which, due to their weight, a proper selection and dimensioning of the relative supports is required. In fact, without adequate support, this can result in stress concentrations that could compromise the artifact's state of conservation. As a consequence, more often such exhibition supports are customized items, that are designed and manufactured to meet specific functional and artistic setup needs. In this context, the paper presents a design approach that combines topology optimization and additive manufacturing techniques to develop customized support structures which undertake the twofold purpose of preserving the artifact and making it available for the exhibition in the museum. The proposed approach has been assessed through the case study of a sandstone Ionic capital hosted in the Brettii & Enotri Museum in Cosenza (Italy). The proposed approach is therefore meant as a guideline for the design of customized exhibit supports especially in the case of sandstone artifacts with a complex shape or a conservation condition that requires specific attention.

Keywords: Additive manufacturing | Cultural heritage | Design methods | Exhibit supports | Photogrammetry | Topology optimization

Abstract: Underwater photogrammetry provides a means of generating high-resolution products such as dense point clouds, 3D models, and orthomosaics with centimetric scale resolutions. Underwater photogrammetric models can be used to monitor the growth and expansion of benthic communities, including the assessment of the conservation status of seagrass beds and their change over time (time lapse micro-bathymetry) with OBIA classifications (Object-Based Image Analysis). However, one of the most complex aspects of underwater photogrammetry is the accuracy of the 3D models for both the horizontal and vertical components used to estimate the surfaces and volumes of biomass. In this study, a photogrammetry-based micro-bathymetry approach was applied to monitor Posidonia oceanica restoration actions. A procedure for rectifying both the horizontal and vertical elevation data was developed using soundings from high-resolution multibeam bathymetry. Furthermore, a 3D trilateration technique was also tested to collect Ground Control Points (GCPs) together with reference scale bars, both used to estimate the accuracy of the models and orthomosaics. The root mean square error (RMSE) value obtained for the horizontal planimetric measurements was 0.05 m, while the RMSE value for the depth was 0.11 m. Underwater photogrammetry, if properly applied, can provide very high-resolution and accurate models for monitoring seagrass restoration actions for ecological recovery and can be useful for other research purposes in geological and environmental monitoring.

Keywords: bathymetry | habitat restoration | monitoring | multibeam | Posidonia oceanica | Structure from Motion | underwater photogrammetry

Abstract: Delicate grasping of complex diverse objects is a challenging task for underwater vehicles, such as remotely operated vehicles (ROVs). In this article, a novel controllably compliant soft robotic underwater gripper is presented, which uses two neutrally buoyant particle jamming pads to safely and securely grasp arbitrarily shaped objects, including fragile and/or massive targets. Antagonistic low-friction rolling diaphragm hydraulic cylinders are used to control the compliance of the jaw closure to passively limit the total force applied during the approach. The antagonistic hydraulic cylinders also compensate for the volume reduction of the pads during the jamming process while still enabling rigid grasp during manipulation. Soft finger-like fiber-reinforced actuators are used to maintain the shape of pads without introducing rigid elements. Force limitation is demonstrated by the ability to pick up fragile objects without breakage and to surround soft targets without excessive deformation of the object. We present the overall design, experimental setup, and in-water testing using a compact ROV-based hydraulic drive system. The resulting system has demonstrated capability for grasping a diverse range of objects that vary widely in terms of weight, size, and geometry, largely enabled by the hybrid design of soft grippers guiding jamming pads into optimal configurations.

Keywords: Actuators | Fiber-reinforced actuator | Force | Grippers | Hydraulic systems | Jamming | jamming gripper | low-friction hydraulic transmission | Manifolds | remotely operated vehicle | Shape

Abstract: Although computer vision techniques are widely and effectively used for terrestrial applications, the adoption of these techniques in underwater scenarios is often a challenging task. This is due to the water medium that degrades the quality of the acquired images requiring the use of specific methodologies for their correction and improvement. In this context, this paper presents a low-cost system for underwater 3D reconstruction and 3D measurements based on an off-the-shelf depth camera. The system consists of a Stereolabs ZED stereo camera and its waterproof housing designed to be fabricated through additive manufacturing technologies. A dedicated software has been developed to manage all the steps of the acquisition process, starting from the calibration phase and continuing for rectification, depth map computation, 3D scene reconstruction, and 3D measurement. A preliminary laboratory test has been carried out in a controlled environment to quantify system performance in accuracy of measurement.

Keywords: Calibration Techniques | Stereo Camera | Stereolabs ZED | Underwater 3D Reconstruction | Underwater Inspection

Abstract: In the context of Industry 4.0, Operator 4.0 paradigm represents a key factor when dealing with the integration of new digital technologies into smart factories that are suited for workers with different skills, capabilities, and preferences. In this regard, to encourage the introduction of these new digital solutions and achieve high user acceptance, it is fundamental to consider human factors and put the worker at the center of the development process through the adoption of structured design strategies such as user-centered design (UCD) approaches. In this perspective, the paper proposes a novel Augmented Reality (AR) tool for supporting operators at the workplace, in real-time, while performing inspection activities on built products. The proposed tool has been developed according to a user-centered design approach by involving end-users in the various design and testing stages. Preliminary tests have been conducted with representative users on a real case study to assess the usability of the proposed solution. The outcomes are very encouraging and lead us towards further investigations for effective and valid implementation of this AR tool in an industrial scenario.

Keywords: Industrial augmented reality | Industry 4.0 | Operator 4.0 | Usability | User-centered design

Abstract: Today’s Product Lifecycle Management (PLM) platforms are a fundamental strategy for the development of complex products because of their capability to integrate processes, business systems, and information getting a complete and clear vision of all the various stages of the product development process and supporting the design and management of an extensive set of requirements. Nevertheless, common PLM platforms lack efficient traceability of design requirements within the product development process. Rather than a stand-alone tool for requirements management, it is desirable to take a design method that places requirements in the spotlight of the design process. For this reason, the paper presents a method, based on the Requirement - Functional - Logical - Physical (RFLP) design approach, that ensures requirements traceability during each stage of the product development process and provides decision support in a multidisciplinary collaborative digital environment. In particular, Dassault Systèmes’ 3DEXPERIENCE platform has been adopted for the case study of the suspension and tyre systems of a vehicle to assess the efficacy of the proposed method and validate the integration within the collaborative business experience platform.

Keywords: 3DEXPERIENCE Platform | Collaborative business experience platform | Design requirements | Product lifecycle management | Requirements traceability | Vehicle suspension system

Abstract: The "An Ocean of Science" project promotes effective interventions and innovative educational paths to support the growth of knowledge and skills in schools, helping competent institutions to guarantee more inclusive cohesion policies with a high cultural and scientific impact. The project also supports innovation in education and training by providing opportunities for cultural and socio-educational development within the framework of the cultural heritage located in the marine environment and the protection of the sea.

Keywords: Cultural heritages | Education and training | Educational laboratory | Innovation in educations | Marine environment | Science projects

Abstract: The paper presents the development of a Virtual Reality application to perform dives in the Christoforos Shipwreck. The huge wreck lies in the Panormos Bay of the Skopelos island (Greece) at a depth of 45 meters. Based on a well-known methodology designed for ancient shipwrecks, the 3D reconstruction of the underwater site has been carried out by adjusting the workflow to survey modern shipwrecks. In particular, the methodology, based on photogrammetry, is capable to provide a highly detailed 3D reconstruction of the shipwreck in few dives, considering issues like working depth, elevations, and thin elements modelling. Moreover, the paper describes the optimization of the 3D model and the software to be executed in low-performance HMD devices. The resulting Virtual Reality (VR) application, realized for touristic purposes, recreates the exact ambient conditions inside and outside the water simulating the flora and fauna of the place, the coastline, allowing users to live a recreational and educational experience by virtual diving in the underwater site.

Keywords: 3D modeling | History | Image reconstruction | Ships | Three dimensional computer graphics

Abstract: In the last decades, the popularity of video games has been increasing thanks to their unique ability to engage their audience and create empathy. Among them, serious games have additional purposes besides entertainment, such as learning and behaviour change. Serious games, in fact, have been successfully applied to different fields, including education, health, tourism, and cultural heritage. In this context, the paper describes a novel serious game developed for increasing awareness and promoting the Underwater Cultural Heritage (UCH). In particular, the paper focuses on the Dive in the Past Serious Game which allows users to simulate a virtual dive into the Mediterranean Sea to explore accurate and life-sized 3D reconstructions of underwater archaeological sites. The purpose of the game is twofold: to engage diver and non-diver tourists into a virtual interactive exploration of underwater sites through digital storytelling and challenges; to increase awareness and knowledge on Mediterranean UCH. This work has been carried out in the context of the MeDryDive project, an EU co-funded under the COSME Programme, which aims to create personalized dry dive experiences for the promotion of Mediterranean UCH sites as distinctive tourism destinations.

Keywords: 3D reconstruction | Mediterranean Sea | Serious game | Underwater archaeology | Underwater Cultural Heritage

Abstract: Among the key technologies of Industry 4.0, Augmented Reality (AR) is one of the most promising and enabling technologies for supporting factory workers and engineers at the workplace. To this end, the paper proposes a novel AR tool to assist operators during the inspection activities for the detection of production and assembly errors. In fact, thanks to the superimposition of the 3D models, as designed by the technical office, a worker can easily detect the presence of design discrepancies on the final physical assembled product and report them by adding 3D annotations directly on virtual models. This AR tool has been developed by using ARCore™ libraries to ensure, in the first place, its compatibility with commonly used devices for which workers are already trained and, secondly, to take advantage of the hybrid-tracking techniques that combine vision- and sensor-based methods to improve the reliability of the AR visualization. Nevertheless, the proposed AR tool adopts multiple markers to minimize tracking errors and therefore to provide greater freedom of movement to the user, who can use the tool also for the assessment of large-size products. Field experimentations have been carried out on a real case study with end-users in order to assess its usability and perceived mental workload through the SUS (System Usability Scale) and NASA-TLX (Task Load Index) standard questionnaires, respectively. The usability study was performed taking into account also objective metrics, i.e., by analysing user performance in target acquisition tasks while interacting with the AR tool. Statistical analysis proved that the adoption of this AR tool requires low mental demand, and its usability has reached a high level of satisfaction both by the factory workers and engineers involved in the user study.

Keywords: Augmented Reality | Google ARCore | Industry 4.0 | Marker-based tracking | Operator 4.0 | Usability studies

Abstract: Marine animal forests are benthic communities dominated by sessile suspension feeders (such as sponges, corals, and bivalves) able to generate three-dimensional (3D) frameworks with high structural complexity. The biodiversity and functioning of marine animal forests are strictly related to their 3D complexity. The present paper aims at providing new perspectives in underwater optical surveys. Starting from the current gaps in data collection and analysis that critically limit the study and conservation of marine animal forests, we discuss the main technological and methodological needs for the investigation of their 3D structural complexity at different spatial and temporal scales. Despite recent technological advances, it seems that several issues in data acquisition and processing need to be solved, to properly map the different benthic habitats in which marine animal forests are present, their health status and to measure structural complexity. Proper precision and accuracy should be chosen and assured in relation to the biological and ecological processes investigated. Besides, standardized methods and protocols are strictly necessary to meet the FAIR (findability, accessibility, interoperability, and reusability) data principles for the stewardship of habitat mapping and biodiversity, biomass, and growth data.

Keywords: 3D monitoring | biodiversity | biogenic reefs conservation | semantic segmentation | underwater photogrammetry

Abstract: A major challenge in the field of Augmented Reality (AR) is the way in which augmented information is presented in a wide range of uncontrollable environmental conditions. In fact, the variability of colours and illumination conditions of the real environment makes it difficult to choose the most suitable appearance properties for augmented contents. In many AR applications, the colours of virtual objects play a crucial role in blending digital information into the real environment, therefore these colours should be selected according to the appearance of the real background. In some use cases, the colours of virtual objects need to be harmonised with the ones of the real environment; in other cases, the colours should be chosen to ensure the visibility (e.g. maximizing the contrast) of the augmented data with respect to the background. To this end, the paper presents a background-aware colourisation technique that allows for selecting virtual objects' colours in accordance with the real environment in real-time. Given an arbitrary real background, virtual objects' colours are automatically chosen according to three different strategies, i.e. harmonic, disharmonic, and balanced. The proposed AR colourisation technique was assessed with a user study that focused on three different case studies. The results were promising and suggest the potential of the proposed technique for many different application areas. In particular, disharmonic and balanced strategies ensured the distinctiveness of virtual objects according to the real background. Instead, the harmonic strategy was less effective in the case of colourful complex AR scenarios.

Keywords: Augmented reality | colour harmonisation | colourisation | image processing | user studies

Abstract: Color schemes play a crucial role in blending virtual objects with the real environment. Good color schemes improve user’s perception, which is of crucial importance for augmented reality. In this paper, we propose a set of novel methods based on the color harmonization methodology to recolor augmented reality content according to the real background. Three different strategies are proposed—harmonic, disharmonic, and balance—that allow for satisfying different needs in different settings depending on the application field. The first approach aims to harmonize the colors of virtual objects to make them consistent with the colors of the real background and reach a more pleasing effect to a human eye. The second approach, instead, can be adopted to generate a set of disharmonious colors with respect to real ones to be associated with the augmented virtual content to improve its distinctiveness from the real background. The third approach balances these goals by achieving a compromise between harmony and good visibility among virtual and real objects. Furthermore, the proposed re-coloring method is applied to three different case studies by adopting the three strategies to meet three different objectives, which are specific for each case study. Several parameters are calculated for each test, such as the covered area, the color distribution, and the set of generated colors. Results confirm the great potential of the proposed approaches to improve the AR visualization in different scenarios.

Keywords: Augmented reality | Color harmonization | Image processing

Abstract: Underwater cultural heritage sites represent an attractive and exciting experience for diving tourists, even if often it is complicated for them to understand the significance and value of the remains that are usually strongly damaged and covered by the marine organisms. Thanks to the recent advancements in technologies that overcome these problems, augmented reality is nowadays possible even in such harsh conditions, opening new possibilities for enhancing the diver's experience. However, no user study has formally evaluated the usefulness and usability of augmented reality in open sea underwater environments. This paper presents two novel solutions for underwater augmented reality: a compact marker-based system for small areas, and a complex acoustic system for large areas. Both of them were deployed at an underwater cultural heritage site and evaluated by ten divers in experiments analyzing their perception and remembrance, interests, and user experience. For comparison, the same study was also performed with non-divers assessing the marker-based system on land. Results show that both systems allow divers to encounter new and exciting moments and provide valuable insights for underwater augmented reality applications.

Keywords: Augmented reality | cultural heritage | sensor fusion | underwater | user experience | user testing

Abstract: In scientific and technical diving, the survey of unknown or partially unexplored areas is a common task that requires an accurate planning for ensuring the optimal use of resources and the divers’ safety. In particular, in any kind of diving activity, it is essential to foresee the “dive profile” that represents the diver’s exposure to pressure over time, ensuring that the dive plan complies with the specific safety rules that have to be applied in accordance with the diver’s qualification and the environmental conditions. This paper presents a novel approach to dive planning based on an original underwater pathfinding algorithm that computes the best 3D path to follow during the dive in order to be able to maximise the number of points of interest (POIs) visited, while taking into account the safety limitations. The proposed approach, for the first time, considers the morphology of the 3D space in which the dive takes place to compute the best path, taking into account the decompression limits and avoiding the obstacles through the analysis of a 3D map of the site. Moreover, three different cost functions are proposed and evaluated to identify the one that could suit the divers’ needs better.

Keywords: 3D optimal pathfinding | Dive planning | Scientific diving | Underwater surveying

Abstract: In recent years, the development in digital technologies such as Augmented Reality (AR) and Virtual Reality (VR) has evolved rapidly. These technologies are currently in the process of creating driving change in the Cultural and Creative Industries (CCIs), representing innovative means to share information, facilitating access and increasing the value and public awareness on Cultural and Natural Heritage. This is particularly relevant for underwater environments, where the most interesting cultural and naturalistic sites are accessible only to scuba divers, or not accessible at all, due to depth and/or environmental constraints. In addition, in underwater sites, guided diving tours are carried out by professionals that usually describe the area to be visited during the predive briefings; such step is needed due to the impossibility of underwater verbal communication without dedicated equipment, a practice very rarely adopted for recreational diving. So, these difficulties make it almost impossible to replicate under the sea, the guided tour approach that is usually offered in on‐land museums. Considering such limitations, several technological applications are emerging to increase the accessibility underwater and enrich users’ experience both for divers and nondivers. This work aims to identify the potential of underwater sites (either cultural or natural) to support the development of sustainable tourism (economic, environmental, cultural and social) in the Mediterranean. Moreover, it focuses on supplying local/regional authorities and stakeholders with a multidisciplinary plan for managing Underwater Museums and Knowledge Centres, by promoting innovation in the diving industry and improving users’/tourists’ experience through value‐added services and cutting‐edge technologies.

Keywords: Diving tourism | Sustainable tourism | Underwater cultural heritage | Virtual diving

Abstract: This paper presents a combined subjective and objective evaluation of an application mixing interactive virtual reality (VR) experience with 360◦ storytelling. The hypothesis that the modern immersive archaeological VR application presenting cultural heritage from a submerged site would sustain high levels of presence, immersion, and general engagement was leveraged in the investigation of the user experience with both the subjective (questionnaires) and the objective (neurophysiological recording of the brain signals using electroencephalography (EEG)) evaluation methods. Participants rated the VR experience positively in the questionnaire scales for presence, immersion, and subjective judgement. High positive rating concerned also the psychological states linked to the experience (engagement, emotions, and the state of flow), and the experience was mostly free from difficulties linked to the accustomization to the VR technology (technology adoption to the head-mounted display and controllers, VR sickness). EEG results are in line with past studies examining brain responses to virtual experiences, while new results in the beta band suggest that EEG is a viable tool for future studies of presence and immersion in VR.

Keywords: 360-video storytelling | Cultural heritage | EEG | Immersion | Presence | Virtual reality

Abstract: In this study, we present a framework for seagrass habitat mapping in shallow (5-50 m) and very shallow water (0-5 m) by combining acoustic, optical data and Object-based Image classification. The combination of satellite multispectral images-acquired from2017 to 2019, together with Unmanned Aerial Vehicle (UAV) photomosaic maps, high-resolution multibeam bathymetry/backscatter and underwater photogrammetry data, provided insights on the short-term characterization and distribution of Posidonia oceanica (L.) Delile, 1813 meadows in the Calabrian Tyrrhenian Sea. We used a supervised Object-based Image Analysis (OBIA) processing and classification technique to create a high-resolution thematic distribution map of P. oceanica meadows from multibeam bathymetry, backscatter data, drone photogrammetry and multispectral images that can be used as a model for classification of marine and coastal areas. As a part of this work, within the SIC CARLIT project, a field application was carried out in a Site of Community Importance (SCI) on Cirella Island in Calabria (Italy); different multiscale mapping techniques have been performed and integrated: the optical and acoustic data were processed and classified by different OBIA algorithms, i.e., k-Nearest Neighbors' algorithm (k-NN), Random Tree algorithm (RT) and Decision Tree algorithm (DT). These acoustic and optical data combinations were shown to be a reliable tool to obtain high-resolution thematic maps for the preliminary characterization of seagrass habitats. These thematic maps can be used for time-lapse comparisons aimed to quantify changes in seabed coverage, such as those caused by anthropogenic impacts (e.g., trawl fishing activities and boat anchoring) to assess the blue carbon sinks and might be useful for future seagrass habitats conservation strategies.

Keywords: Habitat mapping | Mediterranean sea | Multibeam bathymetry | Object-based image analysis (OBIA) | Pléiades-HR satellite images | Seafloor mapping | Seagrass | Tyrrhenian sea | UAV

Abstract: The use of modeling and ergonomic analysis software is a widespread practice in the industrial sector to effectively improve the operator’s well-being and operating comfort within the workplace. In this context, the paper proposes a Mixed Reality system for the ergonomic assessment of industrial workstations. Specifically, the proposed system integrates motion capture tools, a head-mounted display device, and ergonomic analysis software to simulate and analyse the operations to be carried out within a virtual workplace where some physical components, with which the operator interact, are prototyped through 3D printing technology in order to make the simulation as realistic as possible. The proposed Mixed Reality system in fact increases the realism of the simulation and improves the effectiveness of the ergonomics analysis thanks to the haptic feedback that the user perceives when manipulating the physical objects.

Keywords: Ergonomics | Industry 4.0 | Mixed Reality | Rapid prototyping

Abstract: In recent decades, increasing attention is being paid to the multidisciplinary approach that allows the performance of both a preventive conservation and a more invasive restoration action. In this context, the present study aims to acquire information and data from field surveys undertaken in San Domenico Church, Southern Calabria, in order to provide a tool for the recording and the inventory of damage and decay phenomena, and assess their causes and scale. The subsequent calculation of damage indices also provided useful information in order to allow the prioritization of conservation and preservation responses.

Keywords: Built heritage | Calabria | Computer graphics | Damage diagnosis | Decay | Italy | Photogrammetry

Abstract: Documentation and conservation of underwater cultural heritage (UCH) are crucial to preserving humankind's history and traditions, safeguarding tangible testimonies of past human life while ensuring its accessibility to future generations. The TECTONIC (Technological Consortium TO develop sustainability of underwater Cultural Heritage) project is promoting an intersectoral collaboration between academic and non-academic professionals (i.e., archaeologists, conservators, geologists, engineers, etc.) working on different topics related to UCHs, to find solutions to the issues still existing in the field. The overall aim is the exchange of skills for the improvement and assessment of innovative materials and techniques to develop solutions and marketable products for the conservation and management of the UCH, sustainably. To achieve its overall aim, TECTONIC is undertaking activities driven by the following objectives: (a) the study, documentation, and mapping of selected UCHs; (b) the creation of decision-support tools for UCH risk assessment in a changing environment; (c) the initiation of conservation studies and protocols for conservation activities; (d) the development of open and low-cost robotic solutions for the inspection of UCH; and (e) the raising of public awareness and knowledge about UCH. All the objectives are devoted to stimulating new sustainable ideas that would bring the growth of cultural tourism and the development of new marketable products by capitalizing on the research results.

Keywords: Archaeology | Materials | Protection | Sustainability | Tourism | Underwater cultural heritage (UCH); 3D

Abstract: This paper presents the results of an archaeometric study performed on white marbles from the shipwreck of Cala Cicala (Crotone, Calabria, Italy). The stone materials, especially the white marbles, are an excellent tool for reconstructing the trade routes of the past and studying the relationships between ancient populations. The purposes of this study were to establish the provenance of the white marbles of the shipwreck of Cala Cicala (Crotone, Calabria, Southern Italy) and to use analysis of their composition to acquire more knowledge about trade routes in the Roman imperial age. The 35 samples of white marble were studied by X-ray diffraction (XRPD), optical microscopy (OM), and isotopic analysis (δ13C and δ18O). All of the archaeometric data collected indicate that the marble blocks in the cargos are from the Greek island of Thasos, in the northern Aegean Sea.

Keywords: Archaeometric analysis | Calabria | Marble cargo | Shipwreck | Thasian marble

Abstract: The paper presents the MOLUX project which aims to design and develop a system capable of supporting the underwater operators by means of innovative technologies for the diagnosis, recovery, management, conservation, and valorization of the archaeological and naturalistic assets in the marine environment. This system allows to increase the efficiency and the safety of the operations carried out in the underwater environment thanks to its capabilities: to make the diver aware of his/her position; to acquire geolocated data (images, videos, notes, environmental parameters); to optimize and monitor the planned dive route.

Keywords: Autonomous surface vehicle | Diver operation support | Monitoring | Underwater localization | Underwater tablet

Abstract: In the context of Industry 4.0, Augmented Reality occupies an important role thanks to its unique capability to enhance the perception of the real world with virtual information. Taking advantage of this capability, the paper presents a handheld mobile Augmented Reality tool that supports manufacturing and production workers and engineers to easily check on-site the ongoing operations carried out in the manufacturing environment for the tubing and piping assembly. The tool runs on a modern tablet and performs an augmented reality visualization of the 3D models, as defined in the project plan, on the corresponding physical objects. In this manner the user can easily check the presence of assembly errors or detect design discrepancies. The level of acceptance of the proposed handheld mobile Augmented Reality tool has been assessed by means of a preliminary test carried out with representative users on a real case study. Results from the experiment are presented and discussed in the paper.

Keywords: Google ARCore | Industrial augmented reality | Industry 4.0 | Mobile augmented reality | Usability

Abstract: Autonomous Surface Vehicles are versatile marine vehicles that allow to fulfill a variety of offshore activities. Their versatility has been appreciated by the marine and aquatic science community, in fact, in the last years, a large number of ASVs have been developed in research projects and introduced in the market. In this paper, the design and simulation of a small-sized ASV for seabed mapping of shallow waters are described. The vehicle is characterized by catamaran shape, low draft, jet-drive propellers that allow its deployment from the shore, and a payload of 20 kg. The design process has been carried out with the aim to realize a vehicle characterized by ease of transportability and deployment, available payload and performance in terms of speed and endurance. Three hull types have been modelled in a computer-aided design environment and then optimized through fluid dynamics analysis for a cruise speed of 1.5 kN. The results of these simulations have been used to choose the best hull shape in terms of resistance, in order to comply with the constraints of autonomy and available payload. Finally, a scaled model of the best hull shape has been then tested in a circulating water channel to validate simulation data.

Keywords: Additive manufacturing | Autonomous Surface Vehicle | Modeling and simulation | Shape design

Abstract: Augmented Reality (AR) is one of the nine key technologies of Industry 4.0 and one of the most promising innovation accelerators that in the next years will bring smart factories to a higher level of efficiency. In this context, the paper presents an AR tool that improves and increases the efficiency of data collection and exchange of information among different professional figures involved in the design and production processes of products for the oil and gas sector. In fact, prototyping and labour-intensive activities usually require modifications and improvements to be made on-site that should be sent as feedback to the technical office. To this end, the proposed AR tool supports workers at the workplace to easily detect and annotate design variations made during their working activities and furthermore to formalize and automate the collecting and transferring of this data to the designers in order to prevent loss of information. Field experimentation has been carried out with end-users to evaluate their acceptance by means usability studies, based on objective and subjective metrics, and personal interviews. Experimental results show that the proposed AR tool provides medium-to-high levels of usability and has been positively accepted by all the participants involved in the study.

Keywords: Augmented reality | Design discrepancies | Industry 4.0 | Technical instructions

Abstract: The Mediterranean Sea has a vast maritime heritage which exploitation is made difficult because of the many limitations imposed by the submerged environment. Archaeological diving tours, in fact, suffer from the impossibility to provide underwater an exhaustive explanation of the submerged remains. Furthermore, low visibility conditions, due to water turbidity and biological colonization, sometimes make very confusing for tourists to find their way around in the underwater archaeological site. To this end, the paper investigates the feasibility and potentials of the underwater Augmented Reality (UWAR) technologies developed in the iMARECulture project for improving the experience of the divers that visit the Underwater Archaeological Park of Baiae (Naples). In particular, the paper presents two UWAR technologies that adopt hybrid tracking techniques to perform an augmented visualization of the actual conditions and of a hypothetical 3D reconstruction of the archaeological remains as appeared in the past. The first one integrates a marker-based tracking with inertial sensors, while the second one adopts a markerless approach that integrates acoustic localization and visual-inertial odometry. The experimentations show that the proposed UWAR technologies could contribute to have a better comprehension of the underwater site and its archaeological remains.

Keywords: Markerless and marker-based tracking | Underwater acoustic localization | Underwater augmented reality | Underwater cultural heritage

Abstract: Virtual Reality (VR) storytelling enhances the immersion of users into virtual environments (VE). Its use in virtual cultural heritage presentations helps the revival of the genius loci (the spirit of the place) of cultural monuments. This paper aims to show that the use of actors in VR storytelling adds to the quality of user experience and improves the edutainment value of virtual cultural heritage applications. We will describe the Baiae dry visit application which takes us to a time travel in the city considered by the Roman elite as 'Little Rome (Pusilla Roma)' and presently is only partially preserved under the sea.

Keywords: Baiae | Interactive digital storytelling | Virtual cultural heritage | Virtual reality | VR storytelling

Abstract: In underwater localization several sources of error may impact in different ways the final estimation of the position. This applies to the Long Baseline (LBL), the Short Baseline (SBL) and the Ultra-Short Baseline (USBL) localization systems. Through simulations and statistical analysis, it is possible to identify and experimentally characterize such sources of error. It could be also investigated how much these sources of error influence the estimation results of an Extended Kalman Filter (EKF). This paper presents the results of experiments designed in a virtual environment, useful to represent real localization systems. Specifically, the system used for the simulation is constituted by a surface platform equipped with four acoustic transducers used for the localization of an underwater target.

Keywords: Acoustic ranging | Error analysis | Extended Kalman Filter | Positioning systems | Transponders | Underwater localization

Abstract: The Western civilization is deeply rooted in the Ancient Greece culture; political, scientific, technological and philosophic knowledge were born in this epoch. Their diffusion was improved upon by the Greek expansionist policy in colonies of Magna Graecia in Mediterranean Basin, leaving important archaeological traces for the community. In this context, the European project “MAGNA, on the route from Greece to Magna Graecia” seeks to develop a transnational thematic touristic route between Greece and the Ionian coast of Calabria (Southern Italy), an ancient Magna Graecia colony, on the basis of cultural and historical connections between these two Mediterranean areas. The project aims to promote the touristic development of the Greek and Calabrian archaeological sites through dissemination activities. These will concern scientific subjects regarding the conservation of cultural heritage, both in sub-aerial and underwater environments; and study of the sea floor, and pollution of seawater by microplastics. This touristic product consists of cruises on a ship equipped with scientific instruments that offer unique cultural experiences, accompanied by multimedia supports. Experts drive people in the proposed activities, creating more awareness of sustainable and responsible tourism.

Keywords: Ancient pottery | Dissemination | Ecotourism | Greece | Ionian sea | Mediterranean area | Microplastics | ROV | Southern Italy

Abstract: The paper presents the digital technologies developed in the VISAS project and their application to the underwater archaeological site of Cala Minnola (Levanzo Island, Italy)that preserves the remains of a Roman ship. Following the basic principles defined by UNESCO for the protection of the Underwater Cultural Heritage the VISAS project has led to the development of innovative digital technologies for a more engaging and educational exploitation of the submerged archaeological sites. In particular, the paper describes a virtual diving system that allows users to perform, outside of the submerged environment, a virtual exploration of the Cala Minnola shipwreck site. Moreover, an augmented diving system provides, through an underwater tablet, a geolocalized multimedia guide for the divers that visit the underwater archaeological site. Both digital technologies allow users to perform an entertaining and interdisciplinary learning experience by receiving archaeological, historical, and biological information of the specific submerged site.

Keywords: Underwater 3D reconstruction | Underwater archaeology | Underwater Cultural Heritage | Virtual exploitation | Virtual reality

Abstract: The paper presents the application of some Virtual Reality technologies developed in the Horizon 2020 i-MARECulture project to the case study of the sunken "Villa con ingresso a protiro", dated around the II century AD, and located in the Marine Protected Area - Underwater Park of Baiae (Naples).The i-MARECulture project (www.imareculture.eu), in fact, aims to improve the public awareness about the underwater cultural heritage by developing new tool and techniques that take advantage of the virtual reality technologies to allow the general public to explore the archaeological remains outside of the submerged environment.To this end, the paper details the techniques and methods adopted for the development of an immersive virtual tour that allow users to explore, through a storytelling experience, a virtual replica and a 3D hypothetical reconstruction of the complex of the "Villa con ingresso a protiro".

Keywords: 3D hypothetical reconstruction | digital storytelling | Virtual Diving | Virtual Heritage | Virtual Reality

Abstract: The preservation status of an underwater cultural site can be determined as the combination of two primary factors, namely the site physical integrity, which results from the past and present interaction of the site itself with the biological/chemical agents located in the surrounding environment, and the exposure of the site to human-related threats. Methods to survey underwater archaeological sites have evolved considerably in the last years in order to face the challenges and problems in archaeological prospection, documentation, monitoring, and data collection.This paper presents a case-study of an archaeological documentation campaign addressed to study and monitor the preservation status of an underwater archaeological site by combining the quantitative measurements coming from optical and acoustic surveys with the study of biological colonization and bioerosion phenomena affecting ancient artefacts. In particular, we present the first results obtained in the survey and documentation campaign carried out during the spring - summer 2018 in the "Nymphaeum of Punta Epitaffio" located in the Marine Protected Area - Underwater Park of Baiae (Naples).

Keywords: 3D Imaging | 3D Mapping | Baiae Archaeological Park | Photogrammetry | Underwater Archaeology

Abstract: Augmented reality can be deployed in various application domains, such as enhancing human vision, manufacturing, medicine, military, entertainment, and archeology. One of the least explored areas is the underwater environment. The main benefit of augmented reality in these environments is that it can help divers navigate to points of interest or present interesting information about archaeological and touristic sites (e.g., ruins of buildings, shipwrecks). However, the harsh sea environment affects computer vision algorithms and complicates the detection of objects, which is essential for augmented reality. This paper presents a new algorithm for the detection of fiducial markers that is tailored to underwater environments. It also proposes a method that generates synthetic images with such markers in these environments. This new detector is compared with existing solutions using synthetic images and images taken in the real world, showing that it performs better than other detectors: it finds more markers than faster algorithms and runs faster than robust algorithms that detect the same amount of markers.

Keywords: Augmented reality | Cultural heritage | Generating synthetic images | Marker-based tracking | Real time

Abstract: 3D models of submerged structures and underwater archaeological finds are widely used in various and different applications, such as monitoring, analysis, dissemination, and inspection. Underwater environments are characterised by poor visibility conditions and the presence of marine flora and fauna. Consequently, the adoption of passive optical techniques for the 3D reconstruction of underwater scenarios is a highly challenging task. This article presents a performance analysis conducted on a multi-view technique that is commonly used in air in order to highlight its limits in the underwater environment and then provide guidelines for the accurate modelling of a submerged site in poor visibility conditions. A performance analysis has been performed by comparing different image enhancement algorithms, and the results have been adopted to reconstruct an area of 40 m2 at a depth of about 5 m at the underwater archaeological site of Baiae (Italy).

Keywords: 3D reconstruction | Image enhancement | Underwater Cultural Heritage | Underwater imaging

Abstract: Marine archaeologists study a large number of submerged sites of interest around the world, which require continue diving explorations and monitoring. Although technology has improved a lot the research in the underwater environment, human intervention is preferred whenever depth makes the sites accessible by divers. This paper presents the concept, the first steps and the preliminary results of the Lab4Dive project, which is co-funded by the EMFF programme of EU, that aims to design, develop, and validate an innovative, marketable and competitive product for surveying, documenting and preserving Underwater Cultural Heritage. The archaeologist will be provided with an underwater tablet equipped with environmental sensors, where a properly designed data gathering system will be accessible through a dedicated application. Lab4Dive aims also to train young researchers and to encourage multi-disciplinary cooperation through the concept of a “Blue Lab”.

Abstract: In view of the wide scope of challenges concerning Industry 4.0, a variety of enabling digital industrial technologies can support the digitization of the manufacturing sector. Among them, Augmented Reality represents one of the most promising innovation accelerators that will support human workers and bring Smart Factories to a higher level of efficiency. To this end, the paper presents an Augmented Reality tool that provides support at the workplace to easily detect and collect design changes by augmenting virtual 3D models, as defined in the project plan, on the actual design. The proposed tool runs on a consumer smartphone and adopts hybrid tracking techniques to allow workers to formalize and make more efficient the knowledge management of the design changes within the overall design process.

Keywords: Augmented reality | Industry 4.0 | Knowledge-based engineering

Abstract: 3D recording, digital surveying and mapping are efficient and manageable tools for reconnaissance, documentation and monitoring in underwater archaeology. Lab4Dive project, co-funded by the European Union's EMFF Programme, through the EASME and DG MARE call on 'Blue Labs', aims to design, develop and validate an innovative, marketable and competitive technology, which will assist underwater archaeologists in the field and will contribute significantly to the successful outcome of the survey process, documentation and preservation of submerged archaeological sites. In this article, the Lab4Dive system and its preliminary testing results, will be presented. The system is based on an underwater tablet coupled with an intelligent underwater case embedded with environmental sensors, a high-resolution camera and compatible with different commercial acoustic positioning systems, which will be integrated with a cloud data gathering system. During the dive, the tablet provides the diver with an augmented navigation interface, which guides him towards the selected targets. The cloud data gathering system allows the archaeologists to produce a 3D reconstruction of the site, which encompasses all the acquired information, enabling them to further study and analyze the data before the next mission.

Keywords: 3D documentation | 3D Reconstruction | IoT | Marine Robotics | Underwater Archaeology

Abstract: Underwater manipulation is a key technology for marine industries and exploration that can be efficiently adopted in other application fields, such as underwater archaeology, biological manipulation, scientific expedition, as well as offshore construction in the Oil and Gas industry. It is performed remotely by expert pilots thanks to the visual feedbacks provided by one or more cameras but without any information about the distance between the end-effector and the target. To this end, the paper presents a novel system based on a sensorized robotic arm, stereoscopic 3D perception and augmented reality visualization to support ROV's pilots in underwater manipulation tasks. The system, thanks to the adoption of an optical-stereo camera, provides a visual feedback of the underwater scene on which a depth map of the underwater workspace is augmented on. In particular, combining the kinematics of the robotic arm and the standard photogrammetric model of the stereo camera, it is possible to generate a depth map that shows to the pilots the distances of the surface of the scene objects from the end-effector's pose. Experimental tests carried out in the context of the CoMAS (In-situ conservation planning of Underwater Archaeological Artefacts) project have demonstrated the effectiveness of the proposed system.

Keywords: Augmented reality | Forward kinematics | Optical-stereo camera | Underwater manipulation

Abstract: Images obtained in an underwater environment are often affected by colour casting and suffer from poor visibility and lack of contrast. In the literature, there are many enhancement algorithms that improve different aspects of the underwater imagery. Each paper, when presenting a new algorithm or method, usually compares the proposed technique with some alternatives present in the current state of the art. There are no studies on the reliability of benchmarking methods, as the comparisons are based on various subjective and objective metrics. This paper would pave the way towards the definition of an effective methodology for the performance evaluation of the underwater image enhancement techniques. Moreover, this work could orientate the underwater community towards choosing which method can lead to the best results for a given task in different underwater conditions. In particular, we selected five well-known methods from the state of the art and used them to enhance a dataset of images produced in various underwater sites with different conditions of depth, turbidity, and lighting. These enhanced images were evaluated by means of three different approaches: objective metrics often adopted in the related literature, a panel of experts in the underwater field, and an evaluation based on the results of 3D reconstructions.

Keywords: 3D reconstruction | Automatic colour equalization | Benchmark | CLAHE | Colour correction | Dehazing | Lab | Non-local dehazing | Screened poisson equation | Underwater image enhancement

Abstract: Underwater augmented reality is a very challenging task and amongst several issues, one of the most crucial aspects involves real-time tracking. Particles present in water combined with the uneven absorption of light decrease the visibility in the underwater environment. Dehazing methods are used in many areas to improve the quality of digital image data that is degraded by the influence of the environment. This paper describes the visibility conditions affecting underwater scenes and shows existing dehazing techniques that successfully improve the quality of underwater images. Four underwater dehazing methods are selected for evaluation of their capability of improving the success of square marker detection in underwater videos. Two reviewed methods represent approaches of image restoration: Multi-Scale Fusion, and Bright Channel Prior. Another two methods evaluated, the Automatic Color Enhancement and the Screened Poisson Equation, are methods of image enhancement. The evaluation uses diverse test data set to evaluate different environmental conditions. Results of the evaluation show an increased number of successful marker detections in videos pre-processed by dehazing algorithms and evaluate the performance of each compared method. The Screened Poisson method performs slightly better to other methods across various tested environments, while Bright Channel Prior and Automatic Color Enhancement shows similarly positive results.

Keywords: Augmented reality | Dehazing | Image restoration | Markers | Tracking | Underwater images

Abstract: Lab4Dive project aims to design, develop, and validate an innovative, marketable and competitive product for supporting underwater archaeologists in surveying, documenting and preserving the underwater cultural heritage. These activities could be improved considerably with the introduction of new technological devices and tools, helping underwater archaeologists to collect data from the marine environment. The project will provide a solution by equipping divers with portable, low cost and relatively small sized data-gathering systems (i.e. environmental sensors, acoustic localization system, HD cameras, etc.), so they can significantly improve both the amount of data collected in a single mission and the management of time and human resources at disposal. In this paper, the preliminary developments and the tests of the Lab4Dive system will be presented, which is mainly based on two modules: Cloud Server Module and the Underwater Module. The latter is based on two systems: an underwater tablet, that supports the diver during the immersion providing an augmented navigation interface that guides the diver along the selected targets; and a Docking Station, to acquire and exchange data coming from different environmental sensors, a high-resolution camera and an acoustic localization system, physically connected to it.

Abstract: The Underwater Cultural Heritage represents a key aspect of our historical memory still little known due to a number of limitations imposed by the underwater environment. The aim of this paper is to explore the use of digital three-dimensional reconstructions to support the research about this immeasurable archaeological and historical resource. The whole virtual reconstruction process is described step by step, focusing on the iterative feedback allowing for reaching the best virtual reconstruction solutions, helping the archaeologists to better focus their reasoning through a detailed visual representation, and the technical experts to avoid misleading details in the final virtual reconstruction.

Abstract: Underwater exploration, in the last years, has evolved toward a wide adoption of increasingly smaller ROVs (Remotely Operated Vehicle). As a consequence, the need to equip these underwater vehicles with robotic arms is currently rising as well. According to this demand, the paper presents three innovative solutions achieved in the UVMS (Underwater Vehicle-Manipulator System) field. Firstly, the paper proposes a modular architecture for a lightweight underwater robotic arm, which can be mounted on small-sized ROVs. The modular concept of the arm enables several different configurations, each one characterized by the related DOFs, deployed according to the type of application to be performed. Secondly, the arm has been equipped with an adaptive gripper that, taking advantage of the additive manufacturing techniques, is able to easily grip differently shaped objects. Lastly, the underwater arm is controlled through a Master–Slave approach, designed for commercial off-the-shelf electronics, that on the one hand, entailed a significant reduction of the bill of materials, but, on the other hand, required a greater effort in the software development. Experimental tests have been carried out to measure and evaluate the gripping and manipulation capability of the robotic arm and the performance of the proposed control system.

Keywords: Flexible gripper | Master-slave control | Modular robotic arm | Underwater manipulation | Underwater vehicle-manipulator systems (UVMS)

Abstract: The paper presents a virtual diving system based on a virtual reality (VR) application for the exploitation of the Underwater Cultural Heritage. The virtual diving experience has been designed to entertain users, but its added pedagogical value is explicitly emphasized too. In fact, the ludic activities, consisting in the simulation of a real diving session from the point of view of a scuba diver, are following a storyline described by a virtual diving companion who guides users during the exploration of the underwater archaeological site. The virtual diving system provides general and historical-cultural contents, but also information about the flora and fauna of the specific submerged site to the users. The results collected through user studies demonstrate that the proposed VR system is able to provide a playful learning experience, with a high emotional impact, and it has been well appreciated by a large variety of audiences, even by younger and inexperienced users.

Keywords: Serious games | Underwater archaeological sites | Underwater Cultural Heritage | Virtual diving system | Virtual reality

Abstract: Nowadays, the adoption of virtual reality (VR) exhibits is increasingly common both in large and small museums because of their capability to enhance the communication of the cultural contents and to provide an engaging and fun experience to its visitors. The paper describes a user-centered design (UCD) approach for the development of a VR exhibit for the interactive exploitation of archaeological artefacts. In particular, this approach has been carried out for the development of a virtual exhibit hosted at the “Museum of the Bruttians and the Sea” of Cetraro (Italy). The main goal was to enrich the museum with a playful and educational VR exhibit able to make the visitors enjoy an immersive and attractive experience, allowing them to observe 3D archaeological artefacts in their original context of finding. The paper deals with several technical issues commonly related to the design of virtual museum exhibits that rely on off-the-shelf technologies. The proposed solutions, based on an UCD approach, can be efficiently adopted as guidelines for the development of similar VR exhibits, especially when very low budget and little free space are unavoidable design requirements.

Keywords: Human–computer interaction | User interface design | User-centered design | Virtual museum systems | Virtual reality

Abstract: Underwater images usually suffer from poor visibility, lack of contrast and colour casting, mainly due to light absorption and scattering. In literature, there are many algorithms aimed to enhance the quality of underwater images through different approaches. Our purpose was to identify an algorithm that performs well in different environmental conditions. We have selected some algorithms from the state of the art and we have employed them to enhance a dataset of images produced in various underwater sites, representing different environmental and illumination conditions. These enhanced images have been evaluated through some quantitative metrics. By analysing the results of these metrics, we tried to understand which of the selected algorithms performed better than the others. Another purpose of our research was to establish if a quantitative metric was enough to judge the behaviour of an underwater image enhancement algorithm. We aim to demonstrate that, even if the metrics can provide an indicative estimation of image quality, they could lead to inconsistent or erroneous evaluations.

Keywords: Automatic colour | Colour correction | Dehazing | Underwater image enhancement

Abstract: Underwater sites are a challenging environment for augmented reality. Images taken under water are degraded in several ways, most importantly they are affected by unbalanced colors due to uneven absorption of light in each color channel, blurring and desaturation caused by turbidity, or noise due to the presence of larger organisms, plants, or bubbles. In this paper, we introduce a new method based on white balancing that enhances underwater images to improve the results of detection of markers. We compare this method with several image enhancement methods, and evaluate their performance when applied to the problem of detecting markers under water. Our results show that our method improves the detection in underwater environments while keeping the computation time low.

Abstract: UCRCA - Underwater Cultural Routes in Classical Antiquity" is an eu project financed through the easme-emff fund in order to promote the creation of touristic thematic itineraries linked to the underwater archaeological heritage. It aims to enhance the sustainability of the touristic sector in coastal and maritime areas through the broadening of the cultural tourism offer, thanks to the creation of underwater itineraries for recreational diving activities. Four pilot sites bearing specific characteristics have been chosen to create and launch a new touristic product, two in Greece and two in Southern Italy. Alonissos Island (Sporades), Methoni (Peloponnese), San Pietro in Bevagna (Puglia) and Crotone (Calabria) are four popular holiday destinations in the Mediterranean Sea, whose archaeological underwater sites are still unnoticed by the greater audience. Before creating archaeological underwater itineraries, the Italian Institute for the Conservation and Restoration (MiBAC-iscr) and the Department of Mechanical and Management Engineering of the Calabria University (dimeg-unical) carried out several years of activities linked to the research and test of new methods and technologies for the in situ conservation of the underwater artifacts.

Keywords: European community | In situ preservation | Responsible tourism | Shipwrecks | Underwater archaeological heritage | Underwater archaeology | Underwater restoration | Underwater tourism

Abstract: The Underwater Cultural Heritage (UCH) represents a vast historical and scientific resource that, often, is not accessible to the general public due the environment and depth where it is located. Digital technologies (Virtual Museums, Virtual Guides and Virtual Reconstruction of Cultural Heritage) provide a unique opportunity for digital accessibility to both scholars and general public, interested in having a better grasp of underwater sites and maritime archaeology. This paper presents the architecture and the first results of the Horizon 2020 i-MARECULTURE (Advanced VR, iMmersive Serious Games and Augmented REality as Tools to Raise Awareness and Access to European Underwater CULTURal heritage) project that aims to develop and integrate digital technologies for supporting the wide public in acquiring knowledge about UCH. A Virtual Reality (VR) system will be developed to allow users to visit the underwater sites through the use of Head Mounted Displays (HMDs) or digital holographic screens. Two serious games will be implemented for supporting the understanding of the ancient Mediterranean seafaring and the underwater archaeological excavations. An Augmented Reality (AR) system based on an underwater tablet will be developed to serve as virtual guide for divers that visit the underwater archaeological sites.

Keywords: Serious games | Underwater Archaeological sites | Underwater Augmented Reality system | Virtual museums

Abstract: Underwater manipulation is an essential operation for performing a diverse range of applications in the submerged environment that, in spite of the hostile and unstructured environment, it requires high precision and reliability of the robotic arm. The paper presents the evaluation and characterization of the kinematic performances of an underwater robotic arm mounted on a light work class ROV. The arm analyzed in the study is a re-engineered version of a commercial hydraulic manipulator whose geometry and end-effector have been modified. Moreover, the arm has been equipped with a set of encoders in order to provide the positioning feedback. The test conducted in laboratory focused on the measurement of accuracy and repeatability in order to evaluate the limits of the arm architecture. This work has been carried out in the context of the CoMAS (In situ conservation planning of Underwater Archaeological Artifacts - http://www.comasproject.eu) project in which the possibility to develop a ROV able to perform maintenance operations in underwater archeological sites has been investigated.

Keywords: accuracy | forward kinematics | repeatability | robotic arm | underwater manipulator

Abstract: Virtual museum (VM) systems are a very effective solution for the communication of cultural contents, thanks to their playful and educational approach. In fact, these appealing technological systems have demonstrated their usefulness and value in science centres and traditional museums all over the world, thanks to the fact that visitors can view digitized artworks and explore reconstructed historical places by means of VM-hosted installations. This paper presents a methodology, based on user studies, for the comparative evaluation of different design alternatives related to the user interaction with VM systems. The methodology has been validated by means of a testbed related to a VM system hosted at the “Museum of the Bruttians and the Sea” of Cetraro (Italy). The results of the user study demonstrate that this methodology can be effectively adopted in the development process of VM systems to optimize its outcomes in terms of usability and potential for entertainment and education.

Keywords: User study | User-centered design | Virtual museum systems | Virtual reality

Abstract: The paper presents the application of the technologies and methods defined in the VISAS project for the case study of the underwater archaeological site of Cala Minnola located in the island of Levanzo, in the archipelago of the Aegadian Islands (Sicily, Italy). The VISAS project (http://visas-project.eu) aims to improve the responsible and sustainable exploitation of the Underwater Cultural Heritage by means the development of new methods and technologies including an innovative virtual tour of the submerged archaeological sites. In particular, the paper describes the 3D reconstruction of the underwater archaeological site of Cala Minnola and focus on the development of the virtual scene for its visualization and exploitation. The virtual dive of the underwater archaeological site allows users to live a recreational and educational experience by receiving historical, archaeological and biological information about the submerged exhibits, the flora and fauna of the place.

Keywords: Underwater 3D reconstruction | Underwater cultural heritage | Virtual exploitation | Virtual reality

Abstract: The paper describes a user-centered design (UCD) approach that has been adopted in order to develop and build a virtual museum (VM) system for the “Museum of the Bruttians and the Sea” of Cetraro (Italy). The main goal of the system was to enrich the museum with a virtual exhibition able to make the visitors enjoy an immersive and attractive experience, allowing them to observe 3D archaeological finds, in their original context. The paper deals with several technical and technological issues commonly related to the design of virtual museum exhibits. The proposed solutions, based on an UCD approach, can be efficiently adopted as guidelines for the development of similar VM systems, especially when very low budget and little free space are unavoidable design requirements.

Keywords: Human-computer interaction | User interfaces design | User-centered design | Virtual museum systems

Abstract: This paper describes a part of the contribution of the CoMAS project (“In situ conservation planning of Underwater Archaeological Artifacts”), funded by the Italian Ministry of Education, Universities and Research (MIUR), and run by a partnership of private companies and public research centers. The CoMAS project aims at the development of new materials, techniques and tools for the documentation, conservation and restoration of underwater archaeological sites in their natural environment. This paper details the results achieved during the project in the development of an innovative electric tool, which can efficiently support the restorers’ work in their activities aimed to preserve the underwater cultural heritage in its original location on the seafloor. In particular, the paper describes the different steps to develop an underwater electric cleaning brush, which is able to perform a first rough cleaning of the submerged archaeological structures by removing the loose deposits and the various marine organisms that reside on their surface. The peculiarity of this work consists in a user centred design approach that tries to overcome the lack of detailed users’ requirements and the lack of norms and guidelines for the ergonomic assessment of such kind of underwater tools. The proposed approach makes a wide use of additive manufacturing techniques for the realization and modification of prototypes to be employed for insitu experimentation conducted with the final users. The user tests have been addressed to collect data for supporting the iterative development of the prototype.

Keywords: Additive Manufacturing | Product Design | Underwater Applications | User centred design

Abstract: The paper presents an outcome of the VISAS project (www.visas-project.eu) that concerns a virtual reality application for the exploitation of the underwater cultural heritage. The VR system takes advantage of novel 3D reconstruction techniques to provide geolocated and multi-resolution textured 3D models of underwater archaeological sites. Within the virtual underwater sites users live a recreational and educational experience by receiving historical, archaeological and biological information and contents about the submerged exhibits and structure of the site. Furthermore, the VR system allows divers to make a detailed planning of the operations and itinerary that will be later performed in the underwater environment.

Keywords: underwater 3D reconstruction | Underwater cultural heritage | VR systems

Abstract: On November 2, 2001, the UNESCO Convention on the Protection of the Underwater Cultural Heritage provided a detailed state cooperation system and set out the basic principles for the protection of underwater cultural heritage. To date, the Convention has been ratified by 51 countries. One of the four main principles states that the in situ preservation of underwater cultural heritage should be considered as the first option before allowing or engaging in any further activities. In accordance with these principles and recommendations, in the last years many projects intended for developing and testing new techniques and tools to support in situ conservation of underwater archaeological remains have been funded and are now underway. This paper describes the contribution of the CoMAS project (In situ conservation planning of Underwater Archaeological Artifacts—http://www.comasproject.eu), funded by the Italian Ministry of Education, Universities and Research (MIUR) and run by a partnership of private companies and public research centers. The CoMAS project aims at the development of new materials, techniques, and tools for the documentation, conservation, and restoration of underwater archaeological sites in their natural environment. The paper describes in detail the results achieved during the project in the development of innovative materials, mechatronic tools, and armed remotely operated vehicle systems that can efficiently support the restorers’ work in all their activities for preserving underwater cultural heritage in its original location on the seafloor.

Keywords: 3D imaging | Mechatronics | ROV | Underwater archaeological restoration | Underwater archaeology

Abstract: The integration of underwater 3D data captured by acoustic and optical systems is a promising technique in various applications such as mapping or vehicle navigation. It allows for compensating the drawbacks of the low resolution of acoustic sensors and the limitations of optical sensors in bad visibility conditions. Aligning these data is a challenging problem, as it is hard to make a point-to-point correspondence. This paper presents a multi-sensor registration for the automatic integration of 3D data acquired from a stereovision system and a 3D acoustic camera in close-range acquisition. An appropriate rig has been used in the laboratory tests to determine the relative position between the two sensor frames. The experimental results show that our alignment approach, based on the acquisition of a rig in several poses, can be adopted to estimate the rigid transformation between the two heterogeneous sensors. A first estimation of the unknown geometric transformation is obtained by a registration of the two 3D point clouds, but it ends up to be strongly affected by noise and data dispersion. A robust and optimal estimation is obtained by a statistical processing of the transformations computed for each pose. The effectiveness of the method has been demonstrated in this first experimentation of the proposed 3D opto-acoustic camera.

Keywords: Optical and acoustic integration | Opto-acoustic vision | ROV navigation | Underwater 3D imaging

Abstract: The underwater cultural heritage is an immeasurable archaeological and historical resource with huge, but yet largely unexploited, potentials for the maritime and coastal tourism. In this regard, in the last years, national and international government authorities are supporting and strengthening research activities and development strategies, plans and policies to realize a more sustainable, responsible and accessible exploitation of the underwater cultural heritage. To this end, the paper presents the architecture of a new system that, taking advantage of the modern virtual and augmented reality technologies, allows diver and non-diver tourists to make a more engaging and educational experience of the underwater archaeological sites. This system has been developed and tested in the VISAS project (www.visasproject. eu) that aims to the enhancement of the cultural and tourist offer related to the underwater archaeology through innovation of modes of experience, both on site and remote, of the underwater environments of archaeological interest.

Keywords: AR systems | Underwater 3D reconstruction | Underwater cultural heritage | VR systems

Abstract: The project iMARECULTURE is focusing in raising European identity awareness using maritime and underwater cultural interaction and exchange in Mediterranean Sea. Commercial ship routes joining Europe with other cultures are vivid examples of cultural interaction, while shipwrecks and submerged sites, unreachable to wide public are excellent samples that can benefit from immersive technologies, augmented and virtual reality. The projects aim to bring inherently unreachable underwater cultural heritage within digital reach of the wide public using virtual visits and immersive technologies. Apart from reusing existing 3D data of underwater shipwrecks and sites, with respect to ethics, rights and licensing, to provide a personalized dry visit to a museum visitor or augmented reality to the diver, it also emphasizes on developing pre- and after- encounter of the digital or physical museum visitor. The former one is implemented exploiting geospatial enabled technologies for developing a serious game of sailing over ancient Mediterranean and the latter for an underwater shipwreck excavation game. Both games are realized thought social media, in order to facilitate information exchange among users. The project supports dry visits providing immersive experience through VR Cave and 3D info kiosks on museums or through the web. Additionally, aims to significantly enhance the experience of the diver, visitor or scholar, using underwater augmented reality in a tablet and an underwater housing. The consortium is composed by universities and SMEs with experience in diverse underwater projects, existing digital libraries, and people many of which are divers themselves.

Abstract: This paper presents an experimentation, which has been conducted in the underwater archaeological site of Capo Colonna, aimed to verify the joined use of optical and acoustic techniques for the generation of multi-resolution textured 3D models of underwater sites, obtained by merging the results of surveys carried out with these two types of systems.

Abstract: Seagrass meadows are complex ecosystems representing an important source of biodiversity for coastal marine systems, but are subjected to numerous threats from natural and human-based influences. Due to their susceptibility to changing environmental conditions, seagrasses are habitually used in monitoring programmes as biological indicators to assess the ecological status of coastal environments. In this paper we used a non-destructive photo mosaicing technology to quantify seagrass distribution and abundance, and explore benefits of micro-cartographic analysis. Furthermore, the use of photogrammetric tools enhanced the method, which proved to be efficient due to its use of low-cost instruments and its simplicity of implementation. This paper describes the steps required to use this method in meadows of Posidonia oceanica, including: i) camera calibration procedures, ii) programming of video survey, iii) criteria to perform sampling activities, iv) data processing and micro-georeferenced maps restitution, and v) possible study applications.

Keywords: Mapping | Photo mosaicing | Photogrammetry | Posidonia oceanica | Seagrass | Underwater photography

Abstract: Remotely Operated underwater Vehicles (ROVs) play an important role in a number of operations conducted in shallow and deep water (e.g.: exploration, survey, intervention, etc.), in several application fields like marine science, offshore construction, and underwater archeology. In this work we describe the preliminary steps in the development of the set-up of a special ROV addressed to perform the monitoring and the planned maintenance activities required to prevent the biological colonization in an underwater archeological site. In order to perform these operations, the ROV has been equipped with a custom arm and an opto-acoustic camera. To simultaneously satisfy position and force trajectory constraints, the vehicle-manipulator system is also controlled through a hybrid positionforce control scheme.

Keywords: opto-acoustic 3D camera | ROV control | sensorized arm

Abstract: In accordance to the recommendations of the 2001 UNESCO Convention on the Protection of Underwater Culturage Heritage in the last years many projects have been founded and are now underway developing and testing new techniques and tools to support in-situ conservation of underwater archaeological remains. This paper describes the contribution of the CoMAS project ('In situ conservation planning of Underwater Archaeological Artefacts' - www.comasproject.eu) in the development of innovative electromechanical devices that can efficiently support the cleaning process of submerged archaeological structures.

Keywords: electromechanical devices | restoration | underwater archaeological artefacts

Abstract: This paper describes the design process and the construction stages of a multi-fingered robot hand prototype, named GUH14, to be used in underwater environment. The prototype was developed in collaboration by the University of Calabria and the University of Girona, with the goal of designing and building an underwater robotic hand that can be implemented on robot arms. This project is aimed to develop prototype solutions for grasping and manipulation operations in a submarine environment. The hand is composed by a palm and three independent fingers, each with three degrees of freedom (hereinafter, DoF), actuated by servomotors through hybrid transmission, tendons and gearing. The design and manufacturing procedures that allowed for the operation of the prototype will be discussed. This paper summarizes the obtained results.

Keywords: AUV | Hand design | Manipulation | Robot hand | Underwater application

Abstract: Remotely Operated underwater Vehicles (ROVs) play an important role in a number of operations conducted in shallow and deep water (e.g.: exploration, survey, intervention, etc.), in several application fields like marine science, offshore construction, and underwater archeology. ROVs are usually equipped with different imaging devices, both optical and acoustic. Optical sensors are able to generate better images in close range and clear water conditions, while acoustic systems are usually employed in long range acquisitions and do not suffer from the presence of turbidity, a well-known cause of coarser resolution and harder data extraction. In this work we describe the preliminary steps in the development of an opto-acoustic camera able to provide an on-line 3D reconstruction of the acquired scene. Taking full advantage of the benefits arising from the opto-acoustic data fusion techniques, the system was conceived as a support tool for ROV operators during the navigation in turbid waters, or in operations conducted by means of mechanical manipulators. The paper presents an overview of the device, an ad-hoc methodology for the extrinsic calibration of the system and a custom software developed to control the opto-acoustic camera and supply the operator with visual information.

Keywords: 3D opto-acoustic camera | Optical and acoustic data fusion | ROV guidance | Stereovision system | System calibration

Abstract: Seagrass communities are considered one of the most productive and complex marine ecosystems. Seagrasses belong to a small group of 66 species that can form extensive meadows in all coastal areas of our planet. Posidonia oceanica beds are the most characteristic ecosystem of the Mediterranean Sea, and should be constantly monitored, preserved and maintained, as specified by EU Habitats Directive for priority habitats. Underwater 3D imaging by means of still or video cameras can allow a detailed analysis of the temporal evolution of these meadows, but also of the seafloor morphology and integrity. Video-photographic devices and open source software for acquiring and managing 3D optical data rapidly became more and more effective and economically viable, making underwater 3D mapping an easier task to carry out. 3D reconstruction of the underwater scene can be obtained with photogrammetric techniques that require just one or more digital cameras, also in stereo configuration. In this work we present the preliminary results of a pilot 3D mapping project applied to the P. oceanica meadow in the Marine Protected Area of Capo Rizzuto (KR, Calabria Region-Italy).

Keywords: 3D mapping | 3D reconstruction | Optical instruments | Posidonia oceanica | Quality status

Abstract: This paper presents some experimentations, which have been conducted in the submerged archeological Park of Baiae, aimed to identify the problems related to the underwater 3D documentation process. The first test has been addressed to verify if a dense stereo mapping technique, usually employed in terrestrial and aerial applications, might be employed in critical underwater conditions by assessing the influence of different factors on the results. In the second test, the accuracy of the 3D model obtained through this technique has been evaluated. The third test deals with the geo-localization of the 3D models, conducted by merging the optical and acoustic data, through a multi-resolution bathymetric map of the site as a reference.

Keywords: 3D documentation | 3D model accuracy | 3D reconstruction | Baiae archeological park | Optical and acoustic data merging

Abstract: Recovering correct or at least realistic colors of underwater scenes is a very challenging issue for imaging techniques, since illumination conditions in a refractive and turbid medium as the sea are seriously altered. The need to correct colors of underwater images or videos is an important task required in all image-based applications like 3D imaging, navigation, documentation, etc. Many imaging enhancement methods have been proposed in literature for these purposes. The advantage of these methods is that they do not require the knowledge of the medium physical parameters while some image adjustments can be performed manually (as histogram stretching) or automatically by algorithms based on some criteria as suggested from computational color constancy methods. One of the most popular criterion is based on gray-world hypothesis, which assumes that the average of the captured image should be gray. An interesting application of this assumption is performed in the Ruderman opponent color space lαβ, used in a previous work for hue correction of images captured under colored light sources, which allows to separate the luminance component of the scene from its chromatic components. In this work, we present the first proposal for color correction of underwater images by using lαβ color space. In particular, the chromatic components are changed moving their distributions around the white point (white balancing) and histogram cutoff and stretching of the luminance component is performed to improve image contrast. The experimental results demonstrate the effectiveness of this method under gray-world assumption and supposing uniform illumination of the scene. Moreover, due to its low computational cost it is suitable for real-time implementation.

Keywords: Color correction | Computational color constancy | Ruderman space | Underwater imaging

Abstract: The present paper describes the development of a modular and easily configurable simulation platform for ground vehicles. This platform should be usable for the implementation of driving simulators employed both in training purposes and in vehicle components testing. In particular, the paper presents a first architectural model for the implementation of a simulation platform based on the Functional Digital Mock-Up approach. This platform will allow engineers to implement different kinds of simulators that integrate both physical and virtual components, thus achieving the possibility to quickly reconfigure the architecture depending on the hardware and software used and on specific test case needs. The platform has been tested by developing a case study that integrates a motion platform, some I/O devices and a simple dynamic ground vehicle model implemented in OpenModelica. © 2013 Springer-Verlag France.

Keywords: Driving simulator | Functional Digital Mock-up | OpenModelica | Real time simulation | Virtual reality

Abstract: The Visuo-Haptic Mixed Reality (VHMR) is a branch of the Mixed Reality (MR) that is acquiring more and more interest in the recent years. Its success is due to the ability of merging visual and tactile perceptions of both virtual and real objects with a collocated approach. Like any emerging technology, the development of the VHMR systems is accompanied by challenges that, in this case, deals with the efforts to enhance the multi-modal human perception with the user-computer interface and interaction devices at the moment available. This paper deals with two of the typical problems related to VHMR systems, that are device obtrusion and tool-hand misalignment, and suggests solutions whose effectiveness has been tested by means of user studies. First, the paper analyzes the obtrusion problem and the benefits that users may gain performing task in a mixed environment with unobstructed haptic feedback, performed by means of a novel technique. Secondly, it investigates the effects of tool-hand misalignment on user perception and verifies the efficacy of a proposed misalignment correction technique by means of a comparative user test. Experimental results show that users would benefit from using the proposed unobstructed visuo-haptic approach and the misalignment compensation technique. These enhancements demonstrate the efficacy of the proposed solutions and at the same time get stronger the awareness that obtrusion and misalignment problems are fundamental issues to take into account for producing a realistic perception of a visuo-haptic mixed environment. © 2014 Elsevier Ltd.

Keywords: Haptic interaction | Occlusion handling | User evaluation | Visuo-Haptic Mixed Reality

Abstract: 3D reconstructions of small objects are more and more frequently employed in several disciplines such as medicine, archaeology, restoration of cultural heritage, forensics, etc. The capability of performing accurate analyses directly on a three-dimensional surface allows for a significant improvement in the accuracy of the measurements, which are otherwise performed on 2D images acquired through a microscope. In this work we present a new methodology for the 3D reconstruction of small sized objects based on a multi-view passive stereo technique applied on a sequence of macro images. The resolving power of macro lenses makes them ideal for photogrammetric applications, but the very small depth of field is their biggest limit. Our approach solves this issue by using an image fusion algorithm to extend the depth of field of the images used in the photogrammetric process. The paper aims to overcome the problems related to the use of macro lenses in photogrammetry, showing how it is possible to retrieve the camera calibration parameters of the sharp images by using an open source Structure from Motion software. Our approach has been tested on two case studies, on objects with a bounding box diagonal ranging from 13.5. mm to 41. mm. The accuracy analysis, performed on certified gauge blocks, demonstrates that the experimental setup returns a 3D model with an accuracy that can reach the 0.05% of the bounding box diagonal. © 2013 Elsevier Masson SAS.

Keywords: 3D reconstruction | Cultural heritage | Digital documentation | Image fusion | Macro lens | Small objects

Abstract: This paper describes the experimentation of a common multi-view stereo technique on a particularly complex test case: the "Via Colonnata" in the archaeological site of Kyme Eolica in Turkey. The study demonstrates that it is possible to create a detailed 3D model of an area sized tens of square meters without the need to use any dedicated device like laser scanners, drones or helium balloons, but just employing a digital camera and open source software. The reconstruction process implemented in this study addresses and solves some of the most relevant problems related to the reconstruction of large areas and the subsequent mapping of a texture on the geometrical model. In particular, we suggest some guidelines for the acquisition phase that help to reduce the subsequent problems related both to 3D geometry creation and texture mapping. In the pre-processing phase, we propose an automated technique for filtering of unimportant areas, based on the analysis of the disparity maps related to each image pair (the farther areas from the current point of view are masked out, in order to obtain a 3D model free of artifacts/defects). For the texture mapping process, in order to reduce the blur resulting from averaging and blending operations in overlapping areas, we propose a method that automatically identifies the most appropriate subset of images to be projected on the 3D model. © 2013 IEEE.

Keywords: Cultural Heritage | Multi-view stereo | texture mapping

Abstract: The CoMAS project aims to develop new methodologies and tools for the restoration and conservation of submerged archaeological artefacts. One of the project goals is to study the cleaning operations that are intended to remove the living organisms (algae, sponges, molluscs, etc.). These organisms cause severe deteriorations of the artefacts and their removal is crucial for the subsequent phases of consolidation and protection. In particular, the Unit of Underwater Archaeology of the Istituto Superiore per la Conservazione ed il Restauro is experimenting and comparing different cleaning techniques and tools developed in the context of the CoMAS project. This comparison requires also a precise documentation of the test cases and a quantitative measurement of the effectiveness of the cleaning procedures. This paper describes the process that has been defined in order to document and monitor the results obtained through different cleaning experiments, conducted with different tools and utensils over various types of surfaces (marble, bricks, mortar, etc.) affected by several types of biological colonization. The process includes: 1) the 3D mapping of the experimental site; 2) the planning of the tests and the choice of the areas to be cleaned; 3) the 3D reconstruction of the selected areas; 4) the execution of cleaning operations; 5) the 3D acquisition of the cleaned areas; 6) the comparison of the 3D model of the areas before and after the cleaning; 7) the analysis of the data about the cleaning effectiveness. This process has been implemented during an experimentation carried out in the "Villa dei Pisoni", located within the underwater archaeological site of Baia near Naples. © 2013 IEEE.

Keywords: 3D Reconstruction | Archaeology | Restoration | Underwater

Abstract: The validation of a product interface is often a critical issue in the design process. Virtual reality and mixed reality (MR) are able to enhance the interactive simulation of the product human-machine interface (HMI), as these technologies allow engineers to directly involve end users in the usability assessment. This paper describes a MR environment specifically addressed to the usability evaluation of a product interface, which allows the simulation of the HMI behaviour using the same models and the same software employed by engineers during the design phase. Our approach is based on the run-time connection between the visualisation software and the simulators used for product design and analysis. In particular, we use Matlab/Simulink to model and simulate the product behaviour, and Virtools to create the interactive MR environment in which the end user can test the product. Thanks to this architecture, any modification done on the behaviour models is immediately testable in MR. © 2012 Springer-Verlag London.

Keywords: Finite state machine | Functional behaviour simulation | Interactive virtual prototype | Mixed reality | Product design evaluation

Abstract: Mixed prototyping (MP) is an emerging approach for usability testing, thanks to its multimodal environment, which is able to involve sight, hearing and touch thus improving the ability to analyze the inter-relationships between the physical form and the behavior of the industrial products. This paper presents a method to perform usability tests in a mixed reality (MR) environment for analyzing human performance in target acquisition tasks while interacting with household appliances. The proposed method is based on the use of different kinds of digital and physical prototypes and, moreover, it introduces an experimental physical archetype for mixed prototyping that contributes to increase the efficiency of the usability evaluation process. Through this archetype the design of a user interface can be easily changed by the adoption of plug-and-play moving components (knobs and buttons) that allow to model in a few seconds any kind of control panel for washing machines, thus reducing the prototyping costs and enlarging the variety of MR interfaces that can be evaluated. The paper proposes also a validation of the use of the physical archetype through a case study in which three different control panel alternatives have been evaluated in a competitive usability study. The competitive testing allows to gather user behaviors with a broad range of design options before the development of a new control panel refined through iterative design. Experimental results show that the proposed method based on the physical archetype can be an effective support to improve the usability of the product interface. © 2012 Elsevier B.V.

Keywords: Design review | Interaction design | Mixed prototyping | Usability test

Abstract: In some application fields, such as underwater archaeology or marine biology, there is the need to collect three-dimensional, close-range data from objects that cannot be removed from their site. In particular, 3D imaging techniques are widely employed for close-range acquisitions in underwater environment. In this work we have compared in water two 3D imaging techniques based on active and passive approaches, respectively, and whole-field acquisition. The comparison is performed under poor visibility conditions, produced in the laboratory by suspending different quantities of clay in a water tank. For a fair comparison, a stereo configuration has been adopted for both the techniques, using the same setup, working distance, calibration, and objects. At the moment, the proposed setup is not suitable for real world applications, but it allowed us to conduct a preliminary analysis on the performances of the two techniques and to understand their capability to acquire 3D points in presence of turbidity. The performances have been evaluated in terms of accuracy and density of the acquired 3D points. Our results can be used as a reference for further comparisons in the analysis of other 3D techniques and algorithms. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Keywords: 3D reconstruction | Active and passive 3D techniques | Underwater imaging

Abstract: Multispectral imaging techniques are widely used to analyse and restore digital images of ancient documents degraded over time. In particular, acquisitions in infrared and ultraviolet bands can reveal information invisible by naked eye, which is not captured by conventional RGB imaging. Multispectral acquisitions are usually performed with filter-wheel cameras that mount a series of interference filters in front of the sensor to select the spectral band in which the document has to be acquired. Due to the use of different filters, the focus of the lens changes and it is necessary to adjust it manually for each filter, because such imaging systems are devoid of automatic focusing. Thus the acquired images may not be perfectly in-focus and have misalignments. In this work we present an automatic solution to acquire a multispectral data cube of aligned images that can be used in document analysis to extract and/or separate information through enhancement techniques. A custom-made motorized autofocus system controlled by software has been installed on a filter-wheel camera, which allows us to acquire in-focus images automatically at each filter changing, and a registration method based on Fourier-Mellin transform aligns these images. A preliminary calibration is performed to set the focusing of each filter with the working distance. As a result, the camera can capture images independently from the contrast of the scene, also in presence of documents with homogeneous texture. The proposed solution reduces considerably the acquisition time and offers a tool to acquire automatically the data cube to be used in further image analysis techniques. The results of experimentations are hereby presented and discussed. © 2012 Elsevier Masson SAS.

Keywords: Document analysis | Focusing | Image registration | Multispectral imaging

Abstract: Visuo-haptic mixed reality consists of adding to a real scene the ability to see and touch virtual objects. It requires the use of see-through display technology for visually mixing real and virtual objects, and haptic devices for adding haptic interaction with the virtual objects. Unfortunately, the use of commodity haptic devices poses obstruction and misalignment issues that complicate the correct integration of a virtual tool and the user's real hand in the mixed reality scene. In this work, we propose a novel mixed reality paradigm where it is possible to touch and see virtual objects in combination with a real scene, using commodity haptic devices, and with a visually consistent integration of the user's hand and the virtual tool. We discuss the visual obstruction and misalignment issues introduced by commodity haptic devices, and then propose a solution that relies on four simple technical steps: color-based segmentation of the hand, tracking-based segmentation of the haptic device, background repainting using image-based models, and misalignment-free compositing of the user's hand. We have developed a successful proof-of-concept implementation, where a user can touch virtual objects and interact with them in the context of a real scene, and we have evaluated the impact on user performance of obstruction and misalignment correction. © 2012 IEEE.

Keywords: haptic interfaces | image-based rendering | Mixed reality | occlusion handling | visuo-haptic mixed reality

Abstract: The importance of participatory design (PD) is progressively increasing thanks to its capacity to explore a wide variety of concepts, thus increasing the opportunity to create a successful product. In fact the design process should not be a solo activity, as designers often need inputs and other points of view, especially from end-users. According to the ultimate idea of PD, end-users are actively involved in the various activities of the product development to ensure that their needs and desires are satisfied. This paper presents a novel approach to the participatory design of product interfaces in a user-centered design (UCD) process. The approach is based on an interactive tool that allows end-users to design custom user interfaces of household appliances taking advantage of their own needs and experiences. The tool incorporates the analytical and more abstract knowledge of the designers codified in the form of aesthetical, technological and manufacturing constraints (i.e., limitations in the number and geometry of interface components, a limited number of colors, a discretization of the area where interface widgets are placed). This solution allows the end-users to directly design their favorite interface without the interference of any other subject. Through an accurate analysis of the choices done by the users, the designers are able to access to the deepest level of the usersâTM expression in order to catch their latent needs and tacit knowledge. The tool has been designed in order to make possible to immediately perform usability tests on the designed interface by using a Mixed Reality prototype. The paper describes the development of the tool and proposes a methodology that has been specifically addressed to include this tool in a design process based on UCD principles. Both the tool and the methodology are presented through the description of a case-study related to the redesign of a washing machine dashboard. Experimental results show that the proposed tool can be an effective support to design product interfaces during PD sessions. Copyright © 2012 by ASME.

Keywords: Participatory design | Usability | User-centered design

Abstract: The diagnostic analysis of decay processes on small specimens is gaining importance in the restoration and maintenance of archeological finds. In this context, the 3D reconstruction is very useful for the study and identification of the different types of decay. In this paper we present the analysis conducted on two small specimens taken from an ancient underwater pavement, using a new technique for the 3D reconstruction of small sized objects based on a multi-view passive stereo technique applied on a sequence of macro images. In order to overcome the problems related to the use of macro lenses, such as the very small depth of field and the loss of sharpness due to diffraction, each image of the sequence is obtained by merging a stack of images acquired at different focus planes by the means of an image fusion algorithm. The experimentation involves a series of preliminary laboratory tests in which we validate the system accuracy and the 3D reconstruction of specimens taken from a marble pavement located in the underwater archeological site park of Baiae (Naples, Italy). The results show that with our approach it is possible to obtain high quality textured 3D models of objects with dimensions ranging from few millimeters to few centimeters, which can be usable both for interactive measurements and virtual presentations. © 2012 IEEE.

Keywords: 3D reconstruction | Cultural Heritage | Image Fusion | Macro Lens | Small Objects

Abstract: The use of haptic devices in Virtual Reality applications makes the interaction with the digital objects easier, by involving the sense of touch in the simulation. The most widespread devices are stylus-based, so the user interacts with the virtual world via either a tool or a stylus. These kinds of devices have been effectively used in several virtual prototyping applications, in order to allow the users to easily interact with the digital model of a product. Among the several open issues related to these applications, there is the choice of the set-up and of the techniques adopted to combine the visual and the haptic stimuli. This paper presents the comparison of three different solutions specifically studied for virtual prototyping applications and in particular for usability assessment. The first is a simple desktop configuration where the user looks at a screen, and visual and haptic stimuli are presented in a de-located manner. The second is a HMD based set-up where the user has a more natural first-person immersive interaction. The third requires a video-see-trough HMD in order to augment the virtual scene with the visualization of the real user's hand. The test realized with the users on these three different setups have been finalized to study the effect of two different factors that are crucial for the effectiveness and the user-friendliness of the interaction. One is the perception of the visual and haptic stimuli in a collocated manner; the other is the visualization of his/her own hand during the interaction with the virtual product. Copyright © 2011 by ASME.

Abstract: In the field of 3D scanning, there is an increasing need for more accurate technologies to acquire 3D models of close range objects. Underwater exploration, for example, is very hard to perform due to the hostile conditions and the bad visibility of the environment. Some application fields, like underwater archaeology, require to recover tridimensional data of objects that cannot be moved from their site or touched in order to avoid possible damages. Photogrammetry is widely used for underwater 3D acquisition, because it requires just one or two digital still or video cameras to acquire a sequence of images taken from different viewpoints. Stereo systems composed by a pair of cameras are often employed on underwater robots (i.e. ROVs, Remotely Operated Vehicles) and used by scuba divers, in order to survey archaeological sites, reconstruct complex 3D structures in aquatic environment, estimate in situ the length of marine organisms, etc. The stereo 3D reconstruction is based on the triangulation of corresponding points on the two views. This requires to find in both images common points and to match them (correspondence problem), determining a plane that contains the 3D point on the object. Another 3D technique, frequently used in air acquisition, solves this point-matching problem by projecting structured lighting patterns to codify the acquired scene. The corresponding points are identified associating a binary code in both images. In this work we have tested and compared two whole-field 3D imaging techniques (active and passive) based on stereo vision, in underwater environment. A 3D system has been designed, composed by a digital projector and two still cameras mounted in waterproof housing, so that it can perform the various acquisitions without changing the configuration of optical devices. The tests were conducted in a water tank in different turbidity conditions, on objects with different surface properties. In order to simulate a typical seafloor, we used various concentrations of clay. The performances of the two techniques are described and discussed. In particular, the point clouds obtained are compared in terms of number of acquired 3D points and geometrical deviation.

Keywords: Dense reconstruction | Stereo vision | Structured-light | Underwater imaging

Abstract: Current research on underwater 3D imaging methods is mainly addressing long range applications like seafloor mapping or surveys of archeological sites and shipwrecks. Recently, there is an increasing need for more accessible and precise close-range 3D acquisition technologies in some application fields like, for example, monitoring the growth of coral reefs or reconstructing underwater archaeological pieces that in most cases cannot be recovered from the seabed. This paper presents the first results of a research project that aims to investigate the possibility of using active optical techniques for the whole-field 3D reconstructions in an underwater environment. In this work we have tested an optical technique, frequently used for in air acquisition, based on the projection of structured lighting patterns acquired by a stereo vision system. We describe the experimental setup used for the underwater tests, which were conducted in a water tank with different turbidity conditions. The tests have evidenced that the quality of 3D reconstruction is acceptable even with high turbidity values, despite the heavy presence of scattering and absorption effects. © 2011 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS).

Keywords: 3D reconstruction | Imaging in turbid medium | Photogrammetry | Structured light | Underwater imaging

Abstract: This paper presents a methodology in which CAD, a multi-body simulator and a Topological Optimisation (TO) tool are synergically employed to support the design of a suspension component. In particular, the methodology defines some guidelines and introduces two knowledge-based interfaces able to facilitate the integration of TO of the component within a standard design process. To illustrate this capability, the process is applied to the conceptual design of the Upright for a Formula SAE prototype. The results show that the integrated design approach can efficiently support the selection of the optimum conceptual design of a mechanical component with complex dynamic behaviour, in particular when very little previous experience on the system is available. Copyright © 2011 Inderscience Enterprises Ltd.

Keywords: Integrated approach | Knowledge-based engineering | Multi-body | TO | Topological optimisation | Virtual product development

Abstract: Topological optimization (TO) tools are today widely employed in several engineering fields (e.g., construction, aeronautics, aerospace, and automotive). The diffusion of these tools is due to their capacity to improve mechanical properties of products through a global optimization of the product in terms of weight, stiffness, strength, and cost. On the other hand, the adoption of TO tools still requires a sizeable organizational effort because, at present, these tools are mostly stand-alone and are not well integrated into the product development process (PDP). This paper presents an innovative methodology that supports designers and analysts in formalizing and transmitting design choices taken during project activities and in making the integration of TO tools in the PDP more efficient. The methodology clearly defines the roles, the activities, the data to exchange, and the software tools to be used in the process. Some custom computer-aided design automation tools have been implemented to improve the efficiency of the methodology. Moreover, this paper defines an original procedure to support the interpretation of the TO results. © 2010 American Society of Mechanical Engineers.

Keywords: CAD automation | knowledge management | topology optimization

Abstract: Historical documents often undergo various changes over time, that alter their original state and reduce their legibility. Digital techniques are widely applied for document preservation, archiving, analysis and dissemination over the Internet. The goal of restoration is to improve the document legibility for both human and automatic operators, to extract patterns and enhance colour reproduction. Our paper presents a framework for virtual restoration of ancient documents based on a combination of multispectral acquisition, 3D imaging and digital image analysis. The proposed framework consists of several steps. First, digital representations of the documents are acquired as multispectral images and 3D surface maps, the latter reconstructed by a structured light technique. A mul-tispectral camera and a digital projector are used in triangular configuration for 2D and 3D data acquisition. Then the multispectral images are registered against possible misalignments, and the 3D surface representation is used to correct geometrical distortions. Document flattening is then performed by 3D surface parameterization and texture mapping. Statistical techniques of decorrelation are applied to extract individual context parts of the document patterns (stamp, text, etc.) and to attenuate interferences. The processed data are then binarized by the proper segmentation technique. The entire digital object history - all the acquisition and processing steps, with the corresponding parameters - is stored in metadata files. These data can be exploited in a future evaluation of the restoration process and can be used for either the creation of an expert knowledge database or the extraction of cross-document observations and conclusions. © The Eurographics Association 2010.

Abstract: Mixed prototyping is an industrial practice that combines virtual and real components in order to realize a prototype of a product used to evaluate and assess the design choices. Recently, mixed prototypes have been also used to assess the usability of products interface. This particular application arises several problems related to the devices and the interaction techniques that, better than others, allow a natural interaction with the mixed prototype. This paper presents a mixed reality environment for usability evaluation that deals with two specific problems of this kind of application: the occlusion between real and virtual objects and the interpretation of the user's gestures while he/she is interacting with the elements of the product interface. In particular we propose a technique able to manage both the problems by using only commodity hardware and video processing algorithms, thus avoiding the use of expensive datagloves and tracking devices. The proposed approach has been validated through a user study addressed to establish whether and to what extent the augmented reality devices and the techniques proposed may distort the usability assessment of the product. Moreover, the user study compares the mixed reality environment adopted in this study with a classical virtual reality set-up. Copyright © 2010 by ASME.

Abstract: VR (Virtual Reality) is a powerful tool for the simulation of virtual prototypes, because it allows engineers to enhance the analysis and validation of the digital product before manufacturing any physical mock-up. Unfortunately, VR software tools are not able to fully simulate the behaviour of a virtual product, because they are mainly conceived to reproduce the visual appearance of the product: the functional simulation is limited to basic behaviours related to the animation of the objects in the virtual world (e.g.: part movements). This paper describes an innovative approach to create functional behaviour simulations in VR using the same models and the same software employed by the engineers in the design phase. Our approach is based on the run-time connection between the VR software and the simulators used for product design and analysis. This means that there is no need to write code for describing the product behaviour, and any modification done on the behaviour models is immediately testable in VR. It is apparent that these advantages allow to reduce the time needed to implement the virtual prototyping, thus achieving a more efficient design process. © Organizing Committee of TMCE 2010 Symposium.

Keywords: Finite state machine | Functional behaviour simulation | Interactive virtual prototype | Product design evaluation

Abstract: This paper presents a methodology in which CAD, a multi-body simulator and a topological optimization tool are synergically employed in order to support the design of a suspension component. In particular, the methodology defines some guidelines and introduces two Knowledge Based interfaces able to facilitate the integration of topological optimization of the component within a standard design process. In order to illustrate this capability, the process is applied to the conceptual design of the Upright for a Formula SAE prototype. The results show that the integrated design approach can efficiently support the selection of the optimum conceptual design of a mechanical component with complex dynamic behaviour, in particular when very little previous experience on the system is available. © Organizing Committee of TMCE 2010 Symposium.

Keywords: Integrated approach | Knowledge based engineering | Multi-body | Topological optimization

Abstract: The design review process of new products is time consuming, requires the collaboration and synchronization of activities performed by various experts having different competences and roles, and is today performed using different tools and different product representations. In order to improve the performances of the overall product design process, it would be beneficial the availability of Computer Aided tools supporting both conceptual design and analysis activities within an integrated environment based on a multi-disciplinary model paradigm. The paper presents an environment named PUODARSI that allows product designers to intuitively modify the shape of a product through haptic interaction and to test in real-time the structural and fluid-dynamics impact of these changes. The research work shows that a smooth and effective integration of modeling tools based on haptic interfaces, fluid-dynamics analysis tools, and Virtual Reality visualization systems is feasible in real-time through the use of a proper data model exchange. © 2010 Springer-Verlag.

Keywords: Design review | Haptic interaction | Interactive simulation | Multi-disciplinary model | Virtual design

Abstract: The usability of the user interface is a key aspect for the success of several industrial products. This assumption has led to the introduction of numerous design methodologies addressed to evaluate the user-friendliness of industrial products. Most of these methodologies follow the participatory design approach to involve the user in the design process. Virtual Reality is a valid tool to support Participatory Design, because it facilitates the collaboration among designers and users. The present study aims to evaluate the feasibility and the efficacy of an innovative Participatory Design approach where Virtual Reality plays a 'double role': a tool to evaluate the usability of the virtual product interface, and a communication channel that allows users to be directly involved in the design process as co-designers. In order to achieve these goals, we conducted three experiments: the purpose of the first experiment is to determine the influence of the virtual interface on the usability evaluation by comparing "user-real product" interaction and "user-virtual product" interaction. Subsequently, we tested the effectiveness of our approach with two experiments involving users (directly or through their participation in a focus group) in the redesign of a product user interface. The experiments were conducted with two typologies of consumer appliances: a microwave oven and a washing machine. © 2009 Elsevier Ltd. All rights reserved.

Keywords: Participatory design | Product interface design | Usability | Virtual reality

Abstract: The use of Mixed Reality in the product development process is emerging as a promising solution that combines the advantages of virtual and rapid prototyping. A mixed prototype is usually based on a physical mock-up on which the visual appearance of the product is superimposed thanks to the augmented reality technologies. An open issue in mixed prototyping is the reduction of time and efforts required to generate and update the behaviour model of the product. This paper presents a Mixed Reality environment in which the product behaviour is simulated using the same models and the same software employed by the engineers in the design phase. This approach guarantees the reliability of the simulation and allows a strong reduction of the time needed to develop the digital prototype. Moreover the paper presents an innovative technique, specifically studied for the simulation of electrical appliances, that aims to make the user able to naturally interact with the mixed prototype. This technique is able to manage the occlusion between real and virtual objects and the interpretation of the user's gestures while he/she is interacting with the elements of the product interface. The novelty of the technique is that it does not require any specific device like data-gloves or tracking systems. © 2010 by ASME.

Abstract: For nearly two decades, virtual reality (VR) technologies have been employed in the field of cultural heritage for various purposes. The safeguard, the protection and the fruition of the remains of the past have gained a powerful tool, thanks to the potentialities of immersive visualization and 3D reconstruction of archaeological sites and finds. VR applications based on videogame technologies are known for their realism and fluid interactivity, but the choice of the fittest technologies remains a complex task because there is an ample number of hardware devices and software development kits. Moreover the design of a VR application for cultural heritage requires several different professional skills and presents a certain complexity in coordination and management. This paper presents strategies to overcome these problems, by suggesting some guidelines for the development of VR systems for cultural heritage. It illustrates a complete methodology to create a virtual exhibition system, based on realistic high-quality 3D models of archaeological finds (reconstructed using a 3D Scanner and a high definition camera) and a low-cost multimedia stereoscopic system called MNEME, which allows the user to interact in a free and easy way with a rich collection of archaeological finds. The solution we propose is intended to be easy to transport and fully usable by different user typologies, without any external assistance or supervision. © 2009 Elsevier Masson SAS. All rights reserved.

Keywords: 3D acquisition | 3D scanner | Archaeological finds | Laser scanner | MNEME | Stereoscopic vision | Virtual archaeology | Virtual museum | Virtual reality

Abstract: Simulation and other computer aided tools are often used in automotive design, since the design process is strictly oriented to the optimization of the performances through an iterative synthesis and analysis cycle aimed to understand the effects of changes in the geometry and layout of the various components. The search for the optimal performances is at the moment carried out empirically by the "trial and error" approach because parameters and constraints are too many for a global optimization of the vehicle dynamics to be performed. Nevertheless it is possible to introduce in the current design process some optimization algorithms or tools that can guide the designer in the decision process. This paper presents a methodology, applied to the conceptual design of the upright for a Formula SAE prototype, in which a multi-body simulator, CAD and a topological optimization tool are sinergically employed in order to support the suspension design.

Keywords: Integrated approach | Multi-body | Topological optimization

Abstract: Visuo-haptic mixed reality consists of adding to a real scene the ability to see and touch virtual objects. It requires the use of see-through display technology for visually mixing real and virtual objects, and haptic devices for adding haptic interaction with the virtual objects. However, haptic devices tend to be bulky items that appear in the field of view of the user. In this work, we propose a novel mixed reality paradigm where it is possible to touch and see virtual objects in combination with a real scene, but without visual obtrusion produced by the haptic device. This mixed reality paradigm relies on the following three technical steps: tracking of the haptic device, visual deletion of the device from the real scene, and background completion using image-based models. We have developed a successful proof-of-concept implementation, where a user can touch virtual objects in the context of a real scene. ©2009 IEEE.

Keywords: H.5.1 [information interfaces and presentation]: multimedia information systems - artificial, augmented, and virtual realities

Abstract: Abstract: This paper presents some experiments on different image processing techniques combined and adapted to define a procedure aimed at improving the readability of ancient degraded documents. The focus is on documents affected by the bleed-through effect, which significantly reduces readability. The availability of the recto and verso scans of any single page is assumed. The proposed procedure is composed of three steps: recto-verso registration, image enhancement through statistical decorrelation and, finally, image segmentation. As the registration step can strongly influence the results obtained during the subsequent phases, we carried out a comparison of different registration algorithms, in order to evaluate their overall effectiveness on recto-verso processing. © 2009 IEEE.

Keywords: Ancient documents. | Binarization | Image enhancement | Registration

Abstract: The problem of integrating topological optimization tools in product development process (PDP) is becoming more and more urgent since nowadays they are widely employed in several engineering fields (civil, aeronautics, aerospace, automotive). The interest for these tools is due to their capacity to better mechanical properties through a global optimization of the product in terms of weight, stiffness, resistance and cost. In particular, there is a lack of specific tools for automatic feature recognition on voxel models generated by the topological optimization tools. Our paper presents an innovative methodology that allows the integration of topological optimizers in the product development process by means of a wise and rational knowledge management and an efficient data exchange between different systems. The target has been reached through the implementation of CAD automation modules which decrease the working time and give the possibility to effectively schematize the designer's knowledge. Copyright © 2008 by ASME.

Abstract: Virtual reality (VR) became a very common mean during the development of the industrial products. One of the main applications of VR in the industrial field is the validation of virtual prototypes (VP). A virtual prototype should be able to reproduce, as realistically as possible, the behaviour of the product from any point of view. In this paper we propose an unexploited approach to the simulation of a VP in VR. A high level software library for the inter-process communication has been developed to let the multi-body solver communicate with the VR environment. Such approach allows the designer to use different software frameworks for the simulation and the visualisation. The test case provided regards an excavator machine. It is possible to simulate the action of the actuators to move arms and bucket, and also perform visibility analyses discovering the viewing volume of the operator. © 2008 Springer-Verlag London Limited.

Keywords: Multi-body analysis | Numerical analysis | Virtual reality | Visibility analysis

Abstract: The aesthetic impact of a product is an important parameter that makes the difference among products technologically similar and with same functionalities. Product shape, which is strictly connected to the aesthetic impact, has different meanings if seen from the design and the engineering point of view. The conceptual design of shape of aesthetic products is usually performed by designers at the beginning of the product development cycle. Subsequent engineering design and studies, such as structural and fluid-dynamic analyses, lead to several design reviews where the original shape of the object is often modified. The design review process is time consuming, requires the collaboration and synchronization of activities performed by various experts having different competences and roles, and is performed using different tools and different product representations. Then, computer aided tools supporting conceptual design and analysis activities within the same environment are envisaged. The paper presents the conceptual description of an environment named PUODARSI that allows designers to modify the shape of a product and evaluate in real-time the impact of these changes on the results of the structural and fluid dynamic analyses in an Augmented Reality (AR) collaborative environment. Main problems in integrating tools developed for different purposes, such as, haptic interaction, FEM and CFD analyses, AR visualization concern the feasibility of the integration, the data exchange, and the choice of those algorithms that allow all that while guaranteeing low computational time. The paper describes the main issues related to the choice of hardware and software technologies, and the PUODARSI system implementation. © The Eurographics Association 2008.

Abstract: The aesthetic impact of a product is an important parameter that makes the difference among products technologically similar and with same functionalities. The shape, which is strictly connected to the aesthetic impact, has different meanings if seen from the design and the engineering point of view. This paper describes an environment based on an integration of Mixed- Reality technologies, haptic tools and interactive simulation systems, named PUODARSI whose aim is to support designers and engineers during the phase of design review of aesthetic products. The environment allows the designer to modify the object shape, through the use of haptic devices, and the engineer to run the fluid-dynamics simulation on the product shape. The paper describes the main problems faced in integrating tools, originally developed for different purposes and in particular issues concerning data exchange, and the choice of those algorithms that guarantees low computational time as required by the application.

Keywords: Design review | Fluiddynamics analysis | Haptic interfaces | Mixed-Reality

Abstract: The problem of integrating topological optimization tools in product development process (PDP) is becoming more and more urgent since nowadays they are widely employed in several engineering fields (civil, aeronautics, aerospace, automotive). The interest for these tools is due to their capacity to better mechanical properties through a global optimization of the product in terms of weight, stiffness, resistance and cost. In particular, there is a lack of specific tools for automatic feature recognition on voxel models generated by the topological optimization tools. Our paper presents an innovative methodology that allows the integration of topological optimizers in the product development process by means of a wise and rational knowledge management and an efficient data exchange between different systems. The target has been reached through the implementation of CAD automation modules which decrease the working time and give the possibility to effectively schematize the designer's knowledge. Copyright © 2008 by ASME.

Abstract: The efficacy of virtual reality (VR) as a design support technique is widely recognised by industries. However, the efficiency of the routine employment of VR into the product development process (PDP) still finds an obstacle in the poor integration of the tools employed. The use of VR still needs long and quite hard procedures to work effectively; the models have to be converted into a format that is compatible with VR systems and each task requires an effort to prepare the virtual environment or to post-process the results that depend on the complexity of the task. This work analyses some VR applications into the PDP and describes some ideas to effectively support the operator that prepares the virtual environment. These ideas have been tested by developing four software interfaces, able to create an easy data exchange link between VR and other design tools like CAD, CAE and computer aided control engineering (CACE). © 2007 Springer-Verlag London Limited.

Keywords: CACE | CAD | CAD-VR integration | CAE | Virtual prototyping | Virtual reality

Abstract: During the development of complex industrial products, several physical and engineering domains are involved. Mechatronic products, for example, are the result of the synergy among mechanical engineering, electronics and computer science. Therefore, the development of such products requires a constant and continuous cooperation among the designers responsible of the different fields of knowledge. Further, to prevent possible design errors before the building of the physical mock-up, there is the need of a simulation environment able to perform analyses in several physical domains. A possible solution to this need is the employment of a software package able to compute multi-domain simulations. However, the existent solutions do not allow engineers to employ their own solver or to choose the best combination among the available simulation software. This paper describes the development of an experimental middleware that supports the communication among different synchronously running simulations, solving interrelated problems and integrating a graphical interactive environment to support the interdisciplinary team in the design review and decision taking.

Abstract: The design methodologies traditionally employed to develop mechatronic products are articulated in a sequence of phases: mechanical design, choice of actuators, sensors and other devices, design of the control system. Traditional methodologies usually end with the realisation of the physical prototypes used to perform the tests that are needed to optimise the product, and to verify the effectiveness of the design solutions adopted in the previous phases. The realisation of the physical prototypes is, usually, a complex and expensive task in which design errors and non-optimal solutions, related to the design phase, cause lateness in product launch and development costs increase. The present paper describes a design methodology devoted to the development of mechatronic products supported by an integrated and interactive co-simulation. This methodology, in fact, allows designers from different domains (mechanical, electronic and software engineers) to follow a classic top-down approach in which, starting from the conceptual phase, they can check, at each milestone of the project, the functionality of the product at different stages and for different levels of detail. At the end of the design process the engineers can directly interact with the mechatronic model by using the product interface implemented in the control system. The actions of the user are processed by the electronics simulation software that dialogues with actuators, motors and sensors placed in the multi-body model inside another specific simulator. So the 3D model in the multi-body software interactively responds to the actions performed by the user.

Keywords: CACE | CAE | Co-simulation | Design methodology | Mechatronics | Top-down design

Abstract: Design for Usability (DFU) is a well known concept in computer science, since it refers to an important topic for the Human-Computer-Interaction research community. In the industrial design field this term is not so widely employed although the product usability is considered one of the most important factors for a product to be successful on the market. The importance of usability addresses the relationship between the interface of a product and its users. The success of several products on the market depends on complex interfaces, which require the user's intense interaction. Often such devices, which the designer sees as being extremely efficient, are too complex and incomprehensible to the user. Usability should be one of the peculiar aims of the design, and thus assessed throughout the design itself. It should work on the assumption that final users should be involved during all the phases of the development of a product. The present study proposes a methodology of participatory design based on the user-product interaction in a virtual environment, and developed by involving users in the definition of the interface of an interactive product for household use.

Keywords: Participatory design | Usability | Virtual reality

Abstract: In the last ten years many Augmented Reality (AR) applications for Scientific Visualization have been developed, attesting the effectiveness of this technique for data visualization and interaction. In all these applications, a software framework for scientific visualization was used to process data to be visualized, while an AR system was employed to display these data within an AR context. Hence, everyone who intended to approach the development of such applications should become necessarily familiar with the scientific visualization framework and the augmented reality one. This is of course an hurdle for the applications development, and the idea behind this work is exactly to provide a software framework that simplifies the development of such applications. With this in mind, we extended an existing and powerful open source library for scientific visualization (VTK) with few but useful classes for the interfacing with an existing AR library (ARToolKit) to easily handle the video see-through and the video-tracking functionalities. The resulting software tool, called VTK4AR, can be considered as an all in one software framework specific for scientific visualization in AR. Moreover, since it is built on top of VTK, it will be possible to employ a wide range of visualization techniques in many application fields. In particular, it has been tested in two AR applications: one for displaying data relative to a CFD simulation of a flow past a helmet, and another for displaying the forming error obtained prototyping an ankle support with the incremental forming technique. © 2006 The Eurographics Association.

Abstract: Virtual Reality (VR) technologies are becoming commonly used tools in the product development process, starting from the styling review in the conceptual design phase, until to the Digital Mock-up (DMU) validation in the advanced stages of the design process. What has not yet been sufficiently investigated is the possibility to interact with the DMU directly inside the CAD environment using 3D input devices. Although few CAD systems, like CATIA V5, have an additional module to support VR devices, in most cases it is still necessary to customize the application to obtain the functionalities desired by the user. The present paper discusses difficulties and advantages related to the integration of VR techniques and 3D input devices in CAD systems. The work has been conducted analyzing and testing the potentialities of the Unigraphics NX3 CAD environment and implementing a software plug-in that allows the user to perform such interaction tasks employing 3D input devices. © 2006 The Eurographics Association.

Abstract: The paper describes an industrial application of VR techniques in the field of Digital Mock-Up (DMU) analyses, reporting the results obtained with the development of a software application that allows Elasis engineers to evaluate important design parameters in the serviceability studies. These analyses can be conducted during the early stages of the design process using DMUs and finding the difficulties related to the serviceability tasks. Using VR techniques it is possible to simulate the entire operative context in which the human operator works during the assembly/disassembly task. In this way a designer can directly verify some potential difficulties in component reachability, in posture and visibility.

Keywords: Automotive | Design for maintenance | Serviceability | Virtual reality

Abstract: This paper presents an innovative application of Augmented Reality (AR) techniques in the field of industrial engineering in which the user explores data from numerical simulations or the results of measurements and experiments, superimposed to the real object that they refer to. The user observes the object through a tablet PC, used as a video see-through handheld display. Data are visualized superimposed to the real object that represents a spatial reference relative to which the user can refer to, so the exploration is more natural compared to a traditional visualization software. Moreover, we have developed a new framework, called VTK4AR, that provides a set of useful software classes for the rapid development of AR applications for scientific visualization. VTK4AR is built on top of VTK (an open source API for scientific visualization), so it will be possible to employ a wide range of visualization techniques in many application fields, and moreover, it is possible to interactively manipulate data-sets in order to achieve a more effective way of visualization. © 2006 The Visualization Society of Japan and Ohmsha, Ltd.

Keywords: Augmented reality | Interaction techniques | Scientific visualization

Abstract: In the recent past several studies have been conducted, and several methodologies have been set up to aid the designer in product design development. Another useful development in this field would be tools able to support the designer when he/she is manipulating abstract elements that roughly approximate their final shape and placement in the definitive layout. The paper describes a methodology and a prototype software to support the designer during the conceptual phase. It is based on the creation of a 3D environment, the "design space", where the functional representation of the problem, that the designer has outlined, is increasingly clarified and solved in an architectural lay out of a product.

Keywords: Conceptual design | Creative design | Early phases of design