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: 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: In a competitive market, where engineering design skills are mandatory, the capacity to be creative, and make innovative forms, represents the distinctive element that can offer the added value for that specific product. The product’s aesthetics, in fact, play an ever more decisive role especially where different products have similar functions and performances. In this context, the paper investigates the adoption of Generative Design (GD) as a tool for creating new concepts and encourage creativity in product design. Since GD automatically explores a large number of solutions in search of the best functional forms, this could offer designers the opportunity to focus on the aesthetic aspects by using its results as a trigger to explore new forms. To this end, the paper presents a pilot experiment in which, using generative design tools, some conceptual furniture design solutions have been generated. In particular, the paper compares the design concept of stools made, with and without the support of generative design, by students enrolled in the last year of the Master’s Degree in mechanical engineering. The concepts have been evaluated in terms of design creativity, with particular reference to novelty and aesthetics, by involving the general public and a group of experts.

Keywords: Conceptual design | design creativity | engineering creativity | form innovation | generative design

Abstract: Coralligenous (C) include calcareous build-ups of biogenic origin, formed since the Holocene transgression. Peculiar columnar-shaped C outcrops were documented offshore Marzamemi village (SE Sicily, Ionian Sea), although the actual extension and distribution were not assessed. Project ‘CRESCIBLUREEF’ produced a new, 17 km2 high-resolution bathymetric map, leading to good knowledge about their extent in this area. C bioconstructions are largely distributed along two depth ranges 36–42 m and 86–102 m water depth. By coupling the documented uplift rate in this region and the Holocene sea-level curve, we were able to interpret the distribution of C outcrops over terraces. However, additional investigation is required to understand: (1) the role of the inherited continental shelf landscape, in creating a favorable substrate for the settlement and growth of C habitats during the Holocene, and (2) the extent to which C bioconstructions can impact the evolution of present-day continental shelf landforms and landscapes.

Keywords: biogeomorphology | Calcareous build-ups | Mediterranean sea | sea-level changes | seascape | submarine geomorphology

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: Along the Mediterranean Sea shelf, algal reefs made of crustose coralline algae and Peyssonneliales are known as Coralligenous. It ranks among the most important ecosystems in the Mediterranean Sea because of its extent, complexity, and heterogeneity, supporting very high levels of biodiversity. Descriptive approaches for monitoring purposes are often aimed at assessing the surficial ephemeral canopy, which is sustained and controlled by the occurrence of the long-lasting rigid structure at the base. This practice led to the non-univocal definition of Coralligenous, sometimes indicated as “animal Coralligenous” because of the surficial dominance of these components. The quantitative assessment of the builders that actively build up the persistent structure through geological time is therefore a fundamental topic. We collected two discrete coralligenous samples in front of Marzamemi village (Sicily, Ionian Sea), the first from an area of a dense coralligenous cover (- 37 m) and the second one from an area with sparse build-ups (- 36 m). By using image analysis and computerized axial tomography, we distinguished and quantified the different components both on the surface and inside the framework. In both cases, our results confirm the primary role of crustose coralline algae as major builders of the Mediterranean Coralligenous, this aspect matching with the evidence from the Quaternary fossil record. We suggest that the role of encrusting calcareous red algae in the Coralligenous should be considered in conservation and management policies.

Keywords: algal reef | bioconstruction | crustose coralline algae | framework | Marzamemi

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: The advent of Additive Manufacturing (AM) is uncovering the limits of the current CAD systems and, at the same time, is highlighting the potentials of the Topology Optimization (TO) and Generative Design (GD) tools that had not been fully exploited until now. Differently from the traditional design approach in which designers occupy a predominant role in each stage of the design process, the introduction of such tools in the product development process pushes toward simulationdriven design approaches which imply a significant change in the role of the designer. To this end, the paper presents a comparison of two different design methods for Additive Manufacturing based on the adoption of TO and GD tools. The comparison aims to offer a reflection on the evolution of the traditional approach when TO and GD tools are used, and to highlight the potential and limitations of these optimization tools when adopted in an integrated manner with the CAD systems. Furthermore, this comparative study can be a useful and practical source for designers to identify the most appropriate approach to adopt based on their needs and project resources. The comparative study is carried out through the design study of a prototype of a rocker arm and a brake pedal for the Formula Student race car. Their results, compared in terms of mechanical performances, show that both TO and especially GD tools can be efficiently adopted early in a design process oriented to AM to redesign components to make them lighter and stronger.

Keywords: Additive Manufacturing | CAD systems | Design methods | Generative design | Topology optimization

Abstract: During field 3D reconstruction activities and indoor reverse engineering processes, there is often a need for a portable and easy-to-deploy system that can autonomously conduct a full 3D scanning operation, aligning and registering point clouds even in a low-light environment and considering different target sizes. Currently, this process can be obtained through various technological solutions, such as photogrammetric systems and laser scanners, that come with some limitations like portability, affordability, and degree of automation. In this context, the paper presents a feasibility study of a low-cost solution that, by integrating a commercial depth camera into an easy to unfold frame design, autonomously operates to perform a fast 3D scanning and reconstruction of small and medium-sized objects. In particular, the proposed system features a rotating two-dimensional light detection and ranging system and integrates an Inertial Measurement Unit sensor to automatically performs a pre-alignment and registration of the acquired scan data. According to the experimental results, this system may become a cost-effective solution for fast 3D scanning when high levels of accuracy are not required.

Keywords: 3D acquisition | Depth camera | LiDAR | Product development

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: 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: 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: This work proposes an approach to fabricate micro patterned surfaces on PA2200 polyamide in order to improve its performance in terms of wettability and adhesion. In more detail, the present work aims to change the wettability of the surface and decrease their bacteria adhesion tendency. The experimental procedure consists of imprinting a set of different micro patterned structures over the polymer in order to verify the effectiveness of the methodology to change the contact angle of the surface, and in turn, reduce the occurrence of bacteria adhesion. Four different surface patterning were produced by laser ablation of a commercially pure titanium alloy, and then imprinted over the polyamide by surface stamping. The resulting surfaces were analyzed by topographical characterization and scanning electron microscopy. The wettability was probed by contact angle measurements while the bacteria adhesion was analyzed by adhesion test. The experimental results demonstrate the effectiveness of the method to modify the surface characteristics and to obtain a reliable patterned surface without using chemical hazardous material; opening to the possibility to replicate more complex structures and to obtain graded engineering surfaces.

Keywords: Adhesion | Laser | PA2200 | Surfaces | Textures | Titanium | Wettability

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: Purpose: The purpose of this study is to investigate the feasibility of using additive manufacturing (AM) technique to produce an efficient valve manifold for hydraulic actuator by redesigning valve blocks produced by conventional methods. Design/methodology/approach: A priori, a computational fluid dynamics (CFD) analysis was carried out using the software ANSYS Fluent to determine the optimal flow path that results in least pressure drop, highest average velocity and least energy losses. Fluid–structure interaction (FSI) simulations, processed with imported pressure distribution from the CFD, were conducted to determine the resulting loading and deformations of the manifold assembly. Findings: The new design offers a 23 per cent reduction of oil volume in the circuit, while weighing 84 per cent less. When using the new design, a decrease of pressure drop by nearly 25 per cent and an increase in the average velocity by 2.5 per cent is achieved. A good agreement, within 16 per cent, is found in terms of the pressure drop between the experiment and computational model. Originality/value: It is possible to build an efficient hydraulic manifold design by iterative refinement for adequate production via selective laser melting (SLM) and minimize used material to circumventing building support structures in non-machinable features of the manifold.

Keywords: 3D | Actuators | Computational model | Design | Efficiency | Layered manufacturing

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: Aboveground biomass (AGB) is a parameter commonly used for assessing and monitoring primary productivity of grassland communities. Destructive AGB measurements, although accurate, are time-consuming and do not allow for repeated measurements as required by monitoring protocols. Structure-from-motion (SfM) photogrammetry has been proved to be a reliable tool for rapid and not destructive AGB estimations in grass systems. Three-dimensional (3D) models of fourteen 1 × 1 m2 pasture plots were reconstructed and AGB volume measured under several measurement settings. Volume-based AGB measures were regressed to AGB values resulting from destructive methods to identify the measurement settings that show the best fit. Furthermore, 3D models of four mountain pasture plots were reconstructed in May, July, and August. Models relative to the same plot were aligned and their relative difference measured to produce a diachronic canopy variation model (DCVM). On the measured volume (Vd), the coefficient of density (cρ) was applied to adjust the volume values (Vadj) in relation to variation due to different DCVM point densities. The measurement setting for AGB volume estimations strongly influenced their correlation with traditional AGB scores. The best fit was obtained selecting 1 mm grid cell size and minimum point height distance. Such options were then selected to measure the DCVM. Adjusted volumes were fully correlated with the average point distance. Three plots revealed higher rates of AGB in the spring compared to summer season, as justified by the summer aridity constraints affecting vegetation productivity in Mediterranean areas. In one plot, we found an anomalous seasonal pattern, showing an AGB reduction in spring, which can be correlated with grazing, that promoted a subsequent increment in summer. Our study indicates that image-based photogrammetric techniques allow for reliable non-destructive measurements of surface biomass in diachronic analyses, offering a valuable tool for evaluating occurrence, magnitude, and spatial patterns of variations of community primary productivity over time. Diachronic canopy variation model produced congruent patterns of inter-seasonal canopy variations proving to be a useful tool for analyzing local disturbance to vegetation canopy caused by grazing.

Keywords: biomass | coefficient of density | diachronic variation | local disturbance | non-destructive measurements | pasture community | photogrammetry | structure-from-motion

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 these last years, with the advent of Additive Manufacturing, a deep review of the design methodologies has occurred. This is mainly due to two reasons: The technological progress and the new manufacturing capabilities that offer designers much greater freedom for the creation of complex geometries; the modern engineering optimization tools that are spreading widely in the industrial design field, and offer new opportunities for searching a compromise between form and function. On the basis of these two reasons, the paper presents some reflections and exemplifications on the changes that new AM technologies, together with the optimization tools, are bringing in the design process.

Keywords: Additive manufacturing | Design theory and methodology | Topology optimization

Abstract: Hybrid manufacturing is a new production strategy based on the combination of various processes to manufacture components more efficiently in terms of quality, productivity, and/or sustainability. Combinations of subtractive, forming, and additive manufacturing processes can follow one another to produce the desired parts. Hence, both part complexity and performance can increase significantly. The highlighted strategy has been tested by considering two different processes that are typically utilised for small batches of customised parts. Specifically, selective laser sintering has been used to thicken sheets locally, which are subsequently formed by single point incremental forming. This process combination can result in the development of a rapid prototyping technique that exploits the peculiarities of both the utilised processes, and thus allows for the manufacturing of more complex and/or higher quality parts, in a more flexible manner. In the research herein reported, various solutions have been tested to analyse the impact of the proposed hybrid manufacturing strategy on the a) dimensional accuracy, in terms of deviation from the nominal shape, b) quality, in terms of thickness distribution, and c) part complexity, in terms of the obtainable three-dimensional shape, of stainless-steel-formed sheets.

Keywords: Additive manufacturing | Hybrid manufacturing | SPIF

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: 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: The present work is focused on the analysis of fracture in adhesive bonded Double Cantilever Beam (DCB) specimens with 3D printed nylon substrates. The substrates were obtained using selective laser sintering of polyamide powder and embed sub-surface channels with circular and square cross-section. The proposed strategy allows to mimic the crack trapping effect already observed in a multitude of biological materials, that is originated by the spatial modulation of the driving force available for crack growth. Mechanical tests have shown that the channels induce load fluctuations in the global load-displacement response. A significant increase in the total dissipated energy was observed with respect to bulk samples, i.e. no channels. The observed fluctuations in the global response were associated to the sequential storage and sudden release of elastic energy. Indeed, the spatial modulation of the stiffness around the interfacial region ultimately affects the crack driving force.

Keywords: bio-inspired interfaces | crack trapping | double cantilever beam | selective laser sintering

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: Today, autonomous underwater vehicles (AUVs) are mostly used for survey missions, but many existing applications require manipulation capabilities, such as the maintenance of permanent observatories, submerged oil wells, cabled sensor networks, and pipes; the deployment and recovery of benthic stations; or the search and recovery of black boxes. Currently, these tasks require the use of work-class remotely operated vehicles (ROVs) deployed from vessels equipped with dynamic positioning, leaving such solutions expensive to adopt. To face these challenges during the last 25 years, scientists have researched the idea of increasing the autonomy of underwater intervention systems.

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: Many systems have been developed to facilitate upper limb rehabilitation procedures in human subjects affected by trauma or pathologies and to retrieve information about patient performance. The Microsoft Kinect sensor can be used in this context to track body motion and detect objects. In order to evaluate the usability of this device in the upper limb rehabilitation field, a comparison with a marker-based system is presented in this paper. The upper limb motion is specifically considered and the performance on its detection and tracking is evaluated. The effect of the relative location between the Kinect and the observed subject is also investigated through experimental tests performed in different configurations.

Keywords: Kinect V2 | Upper limb joints tracking | Upper limb rehabilitation

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: 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 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: 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 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: 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 paper presents a methodology aimed at the improvement of the product development cycle through the integration of Computer-Aided Innovation (CAI) with Optimization and PLM systems. The interoperability of these tools is obtained through the adoption of Optimization systems as a bridging element between CAI and PLM systems. This methodology was developed within the PROSIT project (http://www.kaemart.it/prosit). The paper describes the main issues related to the integration of these complementary instruments and the solutions proposed by the authors. More specifically, the main idea of the PROSIT project to link CAI and Optimization systems is the adoption of the latter tools not just to generate optimized solutions, but also as a design analysis tool, capable to outline critical aspects of a mechanical component in terms of conflicting design requirements or parameters. CAI systems are then applied to overcome the contradictory requirements. The second step, i.e. the integration between Optimization and PLM systems, has been obtained through the development of Knowledge-Based (KB) tools to support designer's activities. More in details, they provide means to analyze and extrapolate useful geometrical information from the results provided by the optimizer, as well as semi-automatic modelling features for some specific geometries. A detailed example related to the design of a plastic wheel for light moto-scooters clarifies the whole procedure. The paper integrates, extends and updates topics presented in Cugini et al., Barbieri et al. and Cascini et al. [U. Cugini, G. Cascini, M. Ugolotti, Enhancing interoperability in the design process-the PROSIT approach, in: Proceedings of the 2nd IFIP Working Conference on Computer-Aided Innovation, Brighton (MI), USA, October 8-9, 2007, published on Trends in Computer-Aided Innovation, Springer, ISBN 978-0-387-75455-0, pp. 189-200; L. Barbieri, F. Bruno, M. Muzzupappa, U. Cugini, Design automation tools as a support for knowledge management in topology optimization, in: Proceedings of the ASME 2008 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference (IDETC/CIE 2008), Brooklyn, New York, USA, August 3-6, 2008; L. Barbieri, F. Bruno, M. Muzzupappa, U. Cugini, Guidelines for an efficient integration of topological optimization tools in the product development process, in: Third International Conference on Design Computing and Cognition, Atlanta, USA, June 23-25, 2008; G. Cascini, P. Rissone, F. Rotini, From design optimization systems to geometrical contradictions, in: Proceedings of the 7th ETRIA TRIZ Future Conference, Frankfurt, Germany, November 6-8, 2007]. © 2009 Elsevier B.V. All rights reserved.

Keywords: Computer-Aided Innovation | Knowledge-Based Engineering | Optimization systems | Product Lifecycle Management

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: This paper describes a web application for supporting the user in the assessment of the optimal loading configuration for several carriers (i.e. trucks, containers, ship, etc.). The application has a standard form-based user-interface to insert data of the available carriers and items have to be loaded. The solution of this problem (known as Bin-Packing Problem (BPP)) is found by a specific algorithm and visualized by a 3D graphics representation inside the web page. Although some commercial applications already exist, ours runs directly on the web and offers, at the same time, an efficient and robust solver and a 3D visualization allowing the user to better understand the localization of the items inside the carrier and to interactively change some of the problem constraints directly on the 3D representation.

Keywords: Bin-packing | Logistics | Web3D

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: The key focus of this paper is to introduce an approach to collaborative concept design which makes use of critical thinking styles and methods. It consists of four stages aimed to generate concept ideas, in response to identified needs, to explore them, to develop a set of solutions, and to finally choose a solution through critical examination of the solution set. Experimental findings and results obtained from an implementation of this approach in a blended learning classroom are also presented and discussed. © 2008 International Federation for Information Processing.

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: It is well known that the geometrical accuracy is a very relevant problem in Incremental Forming operations, since the material is not well sustained and, then, the elastic springback plays a significant role during the process. A number of researches are involved in the study of geometrical precision after the forming stage but considering the sheet clamped to the equipment. However, it is well known that material coupling is carried out after trimming, when it could change its shape after the new equilibrium. In the paper here addressed the above concept is kept in touch and a wide experimental campaign has been set-up in order to acquire experimental information on the effect of unclamping and trimming after incremental forming processes. The obtained results are able to suggest to the process designer some best practices which are accurately discussed in the paper.

Keywords: Incremental forming | Precision | Sheet metal forming

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: 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: Recently much interest has been devoted to novel distributed approaches which lead to the formation of collaborative networked organizations, e.g. virtual organizations, specifically oriented to generate an innovative product concept. Making use of logical-formal structures based on concepts related to directed hypergraphs, we formally represent competitive inter-organization and collaborative intra-organization relationships. Thanks to these structures, models for distributed processes which lead to the emergence of both design chains and functional architectures of an innovative product are formally described and then illustrated through examples from an applicative scenario.

Abstract: Incremental forming applications are currently increasing in industry, especially for the production of small batches or single components. In fact, sufficient know-how is now available for the manufacture of simple products. However, further efforts are required to reduce the drawbacks of typical incremental forming processes, which compromise important advantages in terms of costs and flexibility. First of all the duration of the process, usually a few minutes, influences this kind of process, even if the operations are carried out on high-speed digitally controlled units. A tendency to produce inaccurate parts can reduce industrial interest with respect to incremental forming. Different approaches could be proposed to reduce this drawback, and a feasible and easily implemented strategy is the design of modified trajectories able to take into account both springback effects and stiffness reduction owing to specific clamping equipment. In this paper, such a strategy is pursued by integrating an on-line measuring system, composed of a digital inspector and a computer numerically controlled (CNC) open program. The geometry obtained is sampled in particular steps and an appropriate routine modifies the coordinates of the future punch path. This procedure of automatic control has been developed using an effective finite element (FE) code. An experimental design illustrates the potential use of the suggested methodology. © IMechE 2005.

Keywords: Incremental forming | Net shape | Sheet metal forming

Abstract: Incremental Forming processes have been introduced in the recent past as an alternative to the money consuming stamping technology, when small batches have to be manufactured. Anyway, they introduce some advantages in terms of flexibility and material formability but, also, some problems such as the dimensional accuracy decreasing. In this paper, a particular application is carried out taking into account the development of an innovative technique to produce a customised ankle support. In this way Incremental Forming process has been selected for the sheet profiling, exalting the role that this technology may play when single complex product has to be manufactured. The producing procedure finishes with a measure of the dimensional accuracy that shown a good result for the desired application. © 2005 Elsevier B.V. All rights reserved.

Keywords: Ankle support | Incremental Forming | Reverse engineering

Abstract: In this paper, we propose a collaborative and joint approach for the identification of partners and the formation of virtual enterprise for concept designing, without compromising design rights or proprietary knowledge. Besides, we introduce a framework for a Multi-Agent System model which is capable of supporting such an approach. The approach described in this paper enables the formalization of distributed processes which lead to the emergence of both conceptual design chains and functional architectures of an innovative product. © 2005 by International Federation for Information Processing.

Abstract: As known, incremental forming is a flexible and innovative sheet metal forming process which allows complex shape shells forming without the need for any die. For these reasons, incremental forming is nowadays suggested for rapid prototyping and customised products. The present paper is focused on material formability in incremental forming and, in particular, on the evaluation and compensation of elastic springback. The latter significantly modifies the imposed shape. For this purpose, a deeper assessment of the process was developed following three different approaches. First of all, a wide experimental investigation on the influence of some relevant process parameters was developed. At the same time, an explicit FEM analysis of incremental forming process was carried out in order to verify its effectiveness and, as a consequence, its ability to be used as a design tool. Furthermore, the obtained parts were analysed by a reverse engineering technique and the measured geometry was numerically compared with the desired one, with the aim to quantify the geometrical discrepancies. In this way, an integrated numerical/experimental procedure is proposed in order to limit the shape defects between the obtained geometry and the desired one. © 2004 Elsevier B.V. All rights reserved.

Keywords: FEM | Geometrical accuracy | Incremental forming

Abstract: Recently, some web-based tools have been proposed to support both individual designer and design teams in the management of information and in assisting concurrent distributed design activities. The rationale which is often underlying such proposal is to enhance design-manufacturing engineering or product data management (PDM) systems for managing product development as a single integrated business process. The focus of this paper is on presenting a logical model which can drive the conception of tools for supporting the distributed management of design data of mechanical products (DDDM: Design Data Distributed Management). How the model can be fruitfully used to support individual/group technical activities and group organisational activities, especially in the product design review phases during the product development process, is discussed. The main functionality and the client/server architecture of one of these tools is also described, and, lastly, a case of study is reported in order to explain how the model can be applied.

Abstract: Incremental forming is nowadays increasing its presence in industry as a new but interesting process, especially for production of small batches or unique components. Anyway, relevant efforts have to be spent in order to reduce the typical incremental forming processes drawbacks that risk to belittle the high advantages in terms of costs and simplicity. In fact, the process duration, usually equal to several minutes even if the operations are carried out on high speed numerical controlled units, and a certain tendency to produce no precise parts, can reduce industrial interest about incremental forming. A possible strategy to reduce the latter item is the design of modified trajectories able to take into account both the springback effects and the stiffness reduction due to the particular clamping equipment. In this paper the above introduced strategy is pursued integrating an on-line measuring system, based on a digital inspector, and a CNC open program. The actual geometry is acquired in some remarkable points and a compensation routine modifies the coordinates of the future punch path. The modification policy has been developed by using an effective FE code. An experimental verification shows the good potentiality of the suggested methodology.

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

Abstract: This paper deals with a semester-long educational experience the authors led at the University of Calabria for reproducing current developments and uncertainties in real-world concurrent engineering, knowledge management practice and virtual enterprise organization. Students with different backgrounds (mechanical engineering, computer science engineering and management engineering) were selected in order to form a laboratory class and then were divided into many multidisciplinary teams. Such teams played different roles and were required to collaborate on the Web to simulate a virtual enterprise, which was aimed at designing virtual prototypes of average complexity articles. In addition to that, any team was involved in the construction of a knowledge base for codifying the explicit knowledge arising from the execution of technical and managerial tasks. The paper deals with models, methodologies and technologies that have been used in this laboratory experience and, moreover, it describes an approach for simulating, in an educational environment, some aspects of the behaviour of virtual enterprises generated by a virtual organization.

Abstract: This paper deals with a semester-long educational experience the authors led at the University of Calabria for reproducing current developments and uncertainties in real-world concurrent engineering, knowledge management practice and virtual enterprise organization. Students with different backgrounds (mechanical engineering, computer science engineering and management engineering) were selected in order to form a laboratory class and then were divided into many multidisciplinary teams. Such teams played different roles and were required to collaborate on the Web to simulate a virtual enterprise, which was aimed at designing virtual prototypes of average complexity articles. In addition to that, any team was involved in the construction of a knowledge base for codifying the explicit knowledge arising from the execution of technical and managerial tasks. The paper deals with models, methodologies and technologies that have been used in this laboratory experience and, moreover, it describes an approach for simulating, in an educational environment, some aspects of the behaviour of virtual enterprises generated by a virtual organization. © 2001 Taylor & Francis Ltd.

Abstract: In the present paper, a procedure is described whereby the elastic properties of a ceramic material are evaluated during a biaxial flexure test. The disk specimen is supported on three points and loaded by a uniform pressure on the opposite face. The whole displacement field undergone by the upper face, measured by a digital speckle interferometer, is approximated by a set of polynomials whose weights depend on the elastic properties. This dependence, previously determined by finite element analysis, is exploited to derive the values of the elastic properties from the displacement field experimentally detected. The procedure proposed was applied to a silicon carbide specimen.

Keywords: Biaxial flexural test | Ceramic material | Elastic properties | Speckle interferometry | Zernike polynomials