Italian Chapter Conference 2007

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https://diglib.eg.org/handle/10.2312/911

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VR Studio: Solid Modelling in a Virtual Reality Environment
(The Eurographics Association, 2007) Cappello, F.; Ingrassia, T.; Romano, M.; Raffaele De Amicis and Giuseppe Conti
Today one of the most important industrial needs is to improve the design process, making it faster and more robust; of course such a requirement can be obtained by using virtual reality. In the field of mechanical design, in fact, there is a great demand for more intuitive and natural modelling systems to speed up the modelling process. All that can be reached by stereocopic visualization tecnology and 3D input systems. In this paper we present a software for 3D solid modelling in a virtual reality system. The CAD models, carried out by this software, can be studied in their natural scale thanks to a large screen display. Moreover the user is free to move his hands to sketch the models thanks to a 3D wireless input device.
Real Positioning in Virtual Environments Using Game Engines
(The Eurographics Association, 2007) Chiara, Rosario De; Santo, Valentina Di; Erra, Ugo; Scarano, Vittorio; Raffaele De Amicis and Giuseppe Conti
Immersive virtual environments offer a natural setting for educational and instructive experiences for users, and game engine technology offers an interesting, cost-effective and efficient solution for building them. In this paper we describe an ongoing project whose goal is to provide a virtual environment where the real location of the user is used to position the user's avatar into the virtual environment.
A Practical Vision Based Approach to Unencumbered Direct Spatial Manipulation in Virtual Worlds
(The Eurographics Association, 2007) Bettio, Fabio; Giachetti, Andrea; Gobbetti, Enrico; Marton, Fabio; Pintore, Giovanni; Raffaele De Amicis and Giuseppe Conti
We present a practical approach for developing interactive environments that allows humans to interact with large complex 3D models without them having to manually operate input devices. The system provides support for scene manipulation based on hand tracking and gesture recognition and for direct 3D interaction with the 3D models in the display space if a suitably registered 3D display is used. Being based on markerless tracking of a user's two hands, the system does not require users to wear any input or output devices. 6DOF input is provided by using both hands simultaneously,making the tracker more robust since only tracking of position information is required. The effectiveness of the method is demonstrated with a simple application for model manipulation on a large stereo display, in which rendering constraints are met by employing state-of-the-art multiresolution techniques.
The Dance of the Air: a Case Study in Interactive Digital Art
(The Eurographics Association, 2007) Cuoghi, E.; Gherardi, R.; Toldo, R.; Raffaele De Amicis and Giuseppe Conti
This paper describes the conception and realization of an interactive art installation called The Dance of the Air . The whole process is taken as a case study for the different challenges encounteredduring the implementation of the system. The project is followed from the seminal idea to the artistic specifications, the translation into technical requirements and the final deployment step.
Form Features in Non-manifold Shapes: A First Classification and Analysis
(The Eurographics Association, 2007) Crovetto, Chiara; Floriani, Leila De; Giannini, Franca; Raffaele De Amicis and Giuseppe Conti
During the industrial design process, a product model undergoes several analyses. One of the most common ones is the finite element analysis. This kind of analysis needs a simplified model, which can include idealised parts, and thus it is usually non-manifold and non-regular. During the idealisation process, the semantic information attached to the CAD model, such as features or surface types, or information used for model simplification, e.g. assumptions on the behavior type, is usually lost, thus making more difficult re-using, or, at least taking advantage, of performed simulations and models. This would be made easier if a meaningful interpretation of the object subparts is available. To this aim, in this paper, we provide a taxonomy of form features in non-manifold shapes and we describe an approach for their identification based on a decomposition of a non-manifold shapes into uniformly dimensional components proposed in [DHH06]. The process presented is the first step towards the identification of form features, since it analyzes those features containing non-manifold singularities.
Flexible Multimodal Architecture for CAD Application
(The Eurographics Association, 2007) Dellisanti, M.; Fiorentino, M.; Monno, G.; Uva, A. E.; Raffaele De Amicis and Giuseppe Conti
Multimodal interfaces are proved to increase the input\output bandwidth for a more efficient interaction in 3D activities. This work presents a novel framework designed to simplify the configuration procedures and to provide a high level of flexibility in multimodal interfaces. We propose an innovative system architecture to decouple input and output configuration from the application level and a multimodal engine designed to manage and synchronize the different inputs. The flexibility of the system is ensured by the use of a hierarchical XML-based configuration structure. This framework can be applied to test the advantage of multimodal interfaces in VRAD applications and provides tools to explore the synergy of different input\output techniques
Product Design, Reverse Engineering, Rapid Prototyping - a Case Study in Cutlery Production
(The Eurographics Association, 2007) Magrassi, Grazia; Bordegoni, Monica; Raffaele De Amicis and Giuseppe Conti
Reverse Engineering and Rapid Prototyping are consolidated practices in the industrial product design process. In any case, best practices should be set up according to the type of product and of objectives. This paper presents the results of a product re-engineering application in the field of high quality stainless steel cutlery. This activity included a re-modeling of a basis-shape that reproduces at best the original shape of a cutlery set designed in the Thirties for Alessi, which is still considered to be very fashionable. The shape of the manufactured physical pieces of cutlery has changed in time in respect to the original design, mainly because of some problems related to their manufacturing, which has been transferred from the central plant to other branches. We have obtained the digital model of the pieces of cutlery on the basis of the analysis of the available original 2D drawings, and of the laser scanning and subsequent re-engineering design of the available manufactured objects. Particularly complex activity was the removal of the shapes deviations due to the different forming techniques used in the various production factories. At the end of the reconstruction activity, physical prototypes of the new models were produced by means of a sintering process in order to evaluate and compare them to the original ones.
Explicit Adaptive Tessellation based on re-parametrization on Graphics Hardware
(The Eurographics Association, 2007) Martinelli, Alessandro; Raffaele De Amicis and Giuseppe Conti
We propose to use an explicit function for adaptive tessellation of parametric curves and surfaces. This function behaves as a new parametrization from the surface domain (or curve domain) to the domain itself; it is build using information about derivatives and curvature: a fixed tessellation may be re-arranged in an adaptive tessellation, which takes care of those parts of the curve or surface which need to be tessellated more and those which may use a poorer tessellation. We show how to produce and how to use the kernel function with four example: a simple cubic curve, a spline curve, a cubic bezièr triangle and a cubic quadrilateral patch. For every example, we compare the fixed tessellation with the adaptive one: the number of vertexes used is always the same, but the points are re-arranged in a better way. At the end we show how to use commonly known forward differencing methods to evaluate both the explicit parametrization and the curve or surface; we also show how simply this method may be implemented on common graphics cards.
Realtime Wavelet Video Encoding with Generic Graphics Processing Unit
(The Eurographics Association, 2007) Stocklöw, Carsten; Noll, Stefan; Raffaele De Amicis and Giuseppe Conti
Wavelet video encoding with multi-resolution analysis is the base for a layered coding scheme. From one video source streams of different resolutions can be generated in one coding process. To reduce computing time the graphics processing unit (GPU) of a PC system is used for tasks of video compression. Color space conversion and wavelet transformation with just one single rendering pass for horizontal and for vertical decomposition were done be the GPU. Together with the CPU the GPU increases the computed frames per second and possible resolutions for live videos. Live broadcasting and interactive systems with streaming video like video conferencing are applications which take advantage from the proposed concept. This is especially interesting for live video encoding up to the high definition TV (HDTV) formats 720p and better.
Benefits of Innovative Technologies for "Territorial Communication": the Case of Study "Virtual Museum Net of Magna Graecia"
(The Eurographics Association, 2007) Bertacchini, P. A.; Dell'Accio, A.; Mallamaci, L.; Pantano, E.; Raffaele De Amicis and Giuseppe Conti
Territorial communication aims at giving visibility and recognizability to a particular territory by emphasizing its distinctive aspects. It does not only supply information, but it has also a persuasive function, exciting interest and curiosity in the message receivers. In this vision, the use of innovative communication channels, such as Webbased Geographical Information Systems, as well as multimedia technologies and three-dimensional graphics, could be very effective. In this paper we introduce a case of study, the "Virtual Museum Net of Magna Graecia", a system in which technologies offer original procedures for the fruition of Calabrian Cultural Heritage.
Challenges for modern Scene-Graph Systems
(The Eurographics Association, 2007) Mueller-Wittig, Wolfgang; Voss, Gerrit; Raffaele De Amicis and Giuseppe Conti
Current scenegraph systems, especially systems used to build general purpose virtual reality systems, are trailing game engines and similar specialized systems in terms of the adaption of new renderingmethods like the different real-time shadow algorithms. This paper analysis the fundamental OpenGL state abstraction layers present in current scenegraph systems with respect to their influence on the adaption of new and complex rendering algorithms.
Rewriting Rules for the Dual Graph of a Stripified CLOD Mesh
(The Eurographics Association, 2007) Porcu, Massimiliano B.; Scateni, Riccardo; Raffaele De Amicis and Giuseppe Conti
A triangular mesh is the piecewise linear approximation of a sampled or analytical surface, when each patch is a triangle. The connectivity of the mesh can be easily represented using its dual graph. Each node of such a graph has at most three incident edges; if the surface is homeomorphic to a sphere, each node has exactly three incident edges. Several triangular meshes, representing the same surface, with an increasing number of triangles are a representation of the surface at different levels of detail (LOD). When the number of triangles from one LOD to another varies continuously we call such a structure a continuous level of detail (CLOD) approximation of the surface. Given a CLOD data structure we can extract, at each level, the mesh representing the surface and derive its dual graph. If we group the triangles forming each mesh in strips, to accelerate their rendering, we should use two colors for the dual graph's edges to distinguish between the edges linking nodes belonging to the same strip or not. The main goal of this paper is to present a set of rules to recolor the dual graph of the mesh when passing from one LOD to the next and back. The operations used to change the mesh are a Vertex Split (VS) when the resolution increases, and an Edge Collapse (EC) when the resolution decreases. We can, then, use a local topological analysis to derive the rules allowing to recolor the graph, and to show that, under certain conditions, the recoloring is optimal. This allows to keep effectively an optimal triangle strip structure over the mesh, while changing its resolution.
Bringing the Semantics into Digital Shapes: the AIM@SHAPE Approach
(The Eurographics Association, 2007) Falcidieno, Bianca; Raffaele De Amicis and Giuseppe Conti
This presentation describes the main objectives and achievements of the European Network of Excellence AIM@SHAPE. This NoE is aimed to advance research in the direction of semantic-based shape representations and tools able to acquire, build, transmit and process shapes with their associated knowledge. Acting on a multi-disciplinary research field, AIM@SHAPE deeply integrates geometry processing, computer graphics and vision with knowledge technologies. The core of the integration resides in the homogenisation of the approach to modelling shapes and their associated semantics using knowledge formalisation mechanisms: metadata and ontology. A main objective is also to develop an innovative e-science platform for modelling, processing and sharing digital shapes, called the Digital Shape Workbench (DSW). Through the definition of general and specific shape ontologies, the DSW is a framework able to store shapes, tools, and publications along with the knowledge related to them.
Ramses: a Visual Steganographic System
(The Eurographics Association, 2007) Battiato, S.; Blasi, G. Di; Gallo, G.; Patti, S.; Raffaele De Amicis and Giuseppe Conti
Steganography is the art of "secret communication". Its goal is to transmit a message (information) hidden inside another visible message. The typical visible message used in many steganographic systems is a digital image and the embedded message is usually hidden by working in the Fourier domain. In this paper we present Ramses, a novel approach to the steganography based on the Puzzle Image Mosaic (PIM) technique ( [DGP05]) which uses the metaphor of the hieroglyphicwriting to hide the message in the image. Themessage is first coded by a sequence of small irregular images and then merged inside another image together with many other small images.We prove that the Kerckhoff's principle required by a steganographic technique is satisfied and experimental results show how it is very difficult to detect the hidden message.
Marker-less Real-time Camera Registration for Mixed Reality
(The Eurographics Association, 2007) Liverani, Alfredo; Grandi, Stefania; Raffaele De Amicis and Giuseppe Conti
A real-time and robust algorithm for 3D camera registration in a Mixed Reality (MR) environment is described in this paper. The most used technique for camera pose (position and orientation with respect to a fixed or moving object) is based on fiducial marker tracking. This method guarantees good results in real-time with a single camera, but needs several high contrast printed markers on external world in order to make possible the calculation of camera parameters and positioning. Thus real 3D geometric data are grabbed only through already known markers. The aim of this research is a real-time monocular camera tracking and registration through automatic image features extraction from video streaming. The first implementation of the method, several examples and confrontation with non interactive algorithm for SFM (Structure From Motion) have demonstrated that this meets the real-time response and sufficient precision needed by a Mixed Reality environment.
Dynamic Rail Inspection by Vision System
(The Eurographics Association, 2007) Cerniglia, D.; Nigrelli, V.; Prior, F.; Raffaele De Amicis and Giuseppe Conti
Current in-field rail track ultrasonic inspection technologies, requiring contact between the probes and the rail surface, show limitations as defect detection is affected by rail surface condition, rail head geometry and defect geometry and orientation. Moreover, inspection speeds are moderate. To improve rail flaw detection, the partnership of the U-Rail project - within the sixth EU framework programme - proposes a new non-contact ultrasonic inspection system, consisting of a pulsed laser and air-coupled transducers. For a proper positioning, the inspection unit includes a laser optic triangulation unit and an automatic positioning system. The first determines the position of the rail, processes the data and drives the positioning system. The U-Rail system allows high speed inspection of the complete rail section. The paper describes the system and results of research activities of two U-Rail partners.
Multiple Techniques Approach to the 3D Virtual Reconstruction of Cultural Heritage
(The Eurographics Association, 2007) Gonzo, L.; Voltolini, F.; Girardi, S.; Rizzi, A.; Remondino, F.; El-Hakim, S. F.; Raffaele De Amicis and Giuseppe Conti
According to an UNESCO survey, Italy accounts for more than half of the Cultural Heritage of the entire world. Italy's Cultural Heritage therefore represents an enormous wealth not only for the country itself but also for the entire world and this asset should be preserved and documented for future generations and possibly used as source of revenues. Within the relevant methods of the Information Technology which can be applied to Cultural Heritage, that of accurate and realistic 3D "shape capture" of art works has been challenging the scientific community since a long time because an extremely high degree of realism is required. Thereby the virtual reconstruction of cultural heritage sites is becoming a significant field of application in the 3D modeling area. This paper proposes an integrated approach based upon a seamless combination of different 3D measurement techniques for the virtual reconstruction of complex architectures. Depending on the required spatial resolutions, different techniques can be used and at the end all the acquired data have to be integrated into a single 3D model. As example the model of a castle located in Trentino (Italy) was done using surveying, 3D laser scanner, close-range and aerial photogrammetry.
ImaginationTOOLS (TM)- A 3D Environment for Learning and Playing Music
(The Eurographics Association, 2007) Bilotta, E.; Pantano, P.; Bertacchini, F.; Gabriele, L.; Longo, G.; Mazzeo, V.; Rizzuti, C.; Talarico, A.; Tocci, G.; Vena, S.; Raffaele De Amicis and Giuseppe Conti
In this paper, we present ImaginationTOOLS, a software which uses mathematical models to generate, analyse and synthesize sound and music. User learns in an imaginary 3D-city basic concepts on mathematical models and music by interacting with pedagogical agents; composes in a laboratory room using a manipulatory agent-like interface; listens to music in an immersive room and creates interactive music with ad-hoc designed instruments and performs and shares music on the net. It represents a real advancement on the existing similar scientificallyoriented products available on the market and it is considered a fusion of different music and multimedia technologies, with a strong developmental trend into physical interaction design. It is the first software using 3D interaction in a 3D environment to produce sound and music, extending the potential of musicians by experimenting in the psycho-acoustical domain of sound and overcoming the problems of musical education, with simple interface.
3D Scene Comparison using Topological Graphs
(The Eurographics Association, 2007) Paraboschi, L.; Biasotti, S.; Falcidieno, B.; Raffaele De Amicis and Giuseppe Conti
New technologies for shape acquisition and rendering of digital shapes have simplified the process of creating virtual scenes; nonetheless, shape annotation, recognition and manipulation of both the complete virtual scenes and even of subparts of them are still open problems. In this paper we deal with the problem of comparing two (or more) object sets, where each model is represented by an attributed graph. We will define a new distance to estimate the possible similarities among the sets of graphs and will validate our work using the shape graph [BGSF06].
Mobile Presence - a Computer Graphics Utopia?
(The Eurographics Association, 2007) Stork, Andre; Danch, Daniel; Raffaele De Amicis and Giuseppe Conti
In this paper we set out a future scenario of mobile presence. We will define our understanding of the term mobile presence. We will derive the requirements imposed by mobile presence with respect to computer graphics and computer graphics research. Discussing the state of the art in various fields, we like to identify and stimulate approaches and areas of research relevant to mobile presence now and in the future.

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