Italian Chapter Conference 2007

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

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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].
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.
Rendering Order Optimization for SVGStat Improvement
(The Eurographics Association, 2007) Battiato, Sebastiano; Puglisi, Giovanni; Raffaele De Amicis and Giuseppe Conti
Vector representation of digital images offers a number of advantages over the more common raster representation, such as scalability and resolution independence. Many efforts have been made to deploy scalable raster standards for photographic imagery addressed to portable applications. However, they lack the flessibility and simplicity of vector representation. Vector graphics is a new and little explored alternative to the more common representation. In this paper we present our raster to vector technique, called SVGStat, improved with a new boundaries simplification algorithm.
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.
Techniques for Computer Assisted Surgery
(The Eurographics Association, 2007) Turini, G.; Pietroni, N.; Ganovelli, F.; Scopigno, R.; Raffaele De Amicis and Giuseppe Conti
In the recent decades robotic and computer science have been gaining more and more relevance in all aspects of our lives. In surgery, for example, they gave birth to procedures that would be impossible to perform otherwise (e.g. tele-surgery, nano-surgery). On this regard, these applied sciences already play an important role in assisting the surgeon both in the operative room and as a support in the education of young surgeons, but much work has still to be done. This paper presents some research and applicative results on Computer Assisted Surgery achieved in the framework of Endocas, a newly founded Center of Excellence in Pisa: a method for segmentation of anatomic parts from 3D dataset able to recover shapes from noisy 3D dataset; a technique for simulating bone drilling using a adaptive decomposition of tetrahedral meshes; a new open source library to support the implementation of techniques for simulating deformable objects.
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.
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.
A Mixed Environment for Ergonomics Tests: Tuning of Stereo Viewing Parameters
(The Eurographics Association, 2007) Bordegoni, Monica; Caruso, Giandomenico; Ferrise, Francesco; Giraudo, Umberto; Raffaele De Amicis and Giuseppe Conti
Virtual Reality and related technologies are becoming a common practice in the design industry in general and more specifically in the automotive field. By the joined use of virtual prototyping methodologies it is possible to achieve the reduction of the time-to-market, as well as the costs deriving from the creation of physical prototypes. Ergonomics tests conducted in Virtual Reality environments can be successfully used to influence the design of products. We have set up a mixed reality environment that allows us to simulate and test postural aspects as well as various levels and modalities of users' interaction. In order to achieve a performing interaction, correct registration and visualization parameters must be carefully set for preventing possible interaction errors, such as pointing with precision to the assigned target. The paper presents a methodology for tuning stereoscopic properties of the mixed reality environments used for ergonomic tests of a car interior in order to achieve correct visualization and positioning parameters. The environment includes a virtual human controlled by an optical motion tracking system, physical objects onto which the graphic virtual environment is superimposed, and a rotatory haptic device for controlling the car on-board infotainment. interface.
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.
Use of a 3D Graphical User Interface in Microelectronics Learning and Simulation of an Industrial Application
(The Eurographics Association, 2007) Bilotta, E.; Pantano, P.; Rinaudo, S.; Servidio, R.; Talarico, V.; Raffaele De Amicis and Giuseppe Conti
The COMSON project (COupled Multiscale Simulation and Optimization in Nanoelectronics) is a Marie Curie Research Training Network (RTN) supported by the European Commission within the 6th Framework Research Programme of the EU. One of the outcomes of the COMSON project is the e-learning system linked to the Demonstrator Platform (DP). This framework is intended for researches in the Microelectronics, Physics and Applied Mathematics fields. It is also intended for industries and expert technical personnel. The main aim of the project is to provide an effective training to students and young researchers with a hands-on experience with the DP, which comprises coupled simulation of devices, interconnects, circuits, electromagnetic (EM) fields and thermal effects in one single framework. Furthermore, the project has a Virtual Working Place system in which it is possible to share experiments and results among the partners. As this domain of knowledge is very complex - there are strong requirements in Industry in order to train young researchers and improve the know-how in a process of continuous education in these topics - the approach we propose overcomes the traditional difficulties of delivering contents, providing the user with a transparent interface, which hides the mathematical technalities. The user has only to follow a procedure by using a visual, tactile and explorative interface. It allows a graphical access to a preset library of models in the form of equations and algorithms for model manipulation. Furthermore, in this approach the researcher can define new models and algorithms by means of a constructivist metaphor. Finally, this method permits an easy control of the DP simulation function, together with a complete monitoring and data analysis facility.
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.
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.
Preserving Information from Real Objects to Digital Shapes
(The Eurographics Association, 2007) Albertoni, Riccardo; Papaleo, Laura; Robbiano, Francesco; Raffaele De Amicis and Giuseppe Conti
Nowadays, the success of the scientific enterprise largely depends on the ability of sharing resources among the scientific community. This problem is particularly relevant in the field of Computer Graphics and Vision. During the last years specific domains ontologies are emerging in support of different contexts, aiming at facilitating automated resource-sharing among information systems in specific fields. A fast evolution of Computer Graphics and Vision is now conditioned by how research teams will be able to intercommunicate. The shared resources should preserve as much meaningful information as possible, in order to allow and improve collaborative research and complete understanding of complex tasks. A critical phase in Computer Graphics and Vision is the Acquisition Phase, which includes different conditions and properties related to the object to be scanned, to the surrounding environment or even to the knowledge of the scanning experts. The novelty of our work is the tentative to integrate Knowledge Management approaches to Computer Graphics and Vision and, in particular, we aim at preserving information when passing from the real world (Real Objects) to the digital one (Digital Shapes). This is a fundamental step for moving knowledge from humans to machines.
Spline-based Shape Modeling by 3D Sketching
(The Eurographics Association, 2007) Han, Li; Amicis, Raffaele De; Conti, Giuseppe; Raffaele De Amicis and Giuseppe Conti
The increasing domination of spline-based graphic objects in CAD/CAS has driven a great attention to methods focusing on natural and intelligent free-form shape manipulation. We present a novel sketch-based system for the interactive modeling of a variety of free-form 3D objects using just simple spline sketches. Our technique addresses the issue of the traditional illustrations for depicting 3D subjects, ranging from geometric modeling to progressive refinement. The robust surface interpreters we proposed support NURBS surface construction respecting the designers' different drawing styles, and a so called spline-driven deformation technique provides designer predictable surface edition. In our system the spline strokes are freely sketched in 3D space and they are controlled by 3D dragger, which will produce a sequence of dynamic deformations to facilitate the user to achieve the desired models. The method has been tested with various types of sketches, which are rendered in a 3D environment.
An Efficient Algorithm for Adaptive Segmentation and Tessellation with Pixel Precision
(The Eurographics Association, 2007) Martinelli, Alessandro; Raffaele De Amicis and Giuseppe Conti
We propose a new algorithm to get a representation of a curved surface with the precision of the image pixel. This technique uses some results from Scan-line algorithms, but it considers also the new functionalities from graphics hardware and takes advantages from it. We explain the general method, with principles common to every kind of surface: then we illustrate how these principles can be applied to quadratic and cubic bezier triangles, showing formulas and some algorithm details.
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
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.
Medical Visualization with New Generation Spatial 3D Displays
(The Eurographics Association, 2007) Agus, Marco; Bettio, Fabio; Gobbetti, Enrico; Pintore, Giovanni; Raffaele De Amicis and Giuseppe Conti
In this paper the capabilities of a modern spatial 3D display are exploited for medical visualization tasks. The systemgives multiple viewers the illusion of seeing virtual objects floating at fixed physical locations. The usage of this kind of display in conjunction with 3D visualization techniques helps disambiguating complex images, so it is proven to be a real advantage for immediate understanding and visualization of medical data.We demonstrate this by reporting on some preliminary test cases of direct volume rendering techniques (Maximum Intensity Projection and X Ray simulation), as well as an example of a collaborative medical diagnostic application for analysis of Abdominal Aortic Aneurysms.
Modelling and Animation of Theatrical Greek Masks in an Authoring System
(The Eurographics Association, 2007) Bertacchini, P. A.; Bilotta, E.; Pantano, P.; Battiato, S.; Cronin, M.; Blasi, G. Di; Talarico, A.; Tavernise, A.; Raffaele De Amicis and Giuseppe Conti
This paper describes an authoring system for modelling Greek virtual masks that express emotions for synchronising their facial movements with pre-recorded speech files, and for creating theatrical performances. The system is related to parametric modelling and includes three interfaces: Editor, Recorder and Virtual Theatre. In the Editor interface it is possible to create several different 3D masks from a unique mask basic model. In the Recorder it is possible to import the models created in the Editor and select eight expressions (neutral, anger, surprise, sadness, fear, joy, disgust, attention), as well as to create and save little alterations in these expressions, and to synchronise the facial movements with speech on the time-line of the system. In the Virtual Theatre the animated Greek masks can be imported and can perform.

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