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Now showing 1 - 10 of 89
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    Use of Shader Technology for Realistic Presentation of Train Prototypes in Virtual Reality
    (The Eurographics Association, 2006) Gironimo, G. Di; Papa, S.; S. Battiato and G. Gallo and F. Stanco
    The aim of the paper is to make up a virtual showroom and work-through of a train model in order to allow railway companies showing new trains prototypes, in phase of concept, and present their new design in more exhaustive way than simply technical documentation. The possibility of applying Virtual Reality (VR) methodologies to make a scene more realistic as possible is a great advantage for the effectiveness of the presentation, in order to increase their competitivity. Shader technology allows the programmers to have control over shape, appearance (such as colour, lighting, reflection) and animation of objects, in order to make very realistic real-time rendering. In the paper the authors describe the use of shader technology in Virtual Design 2 (VD2) for realistic presentation of train prototypes in VR. The software VD2 is an extensive tool that allows following many phases of product development, from the creation of showroom for realistic presentations supporting shader technology to the assembly simulation or ergonomics analysis. Moreover, the possibility of interfacing with a wide range of input/output devices and the possibility to access to the API made this software to be chosen for Virtual Reality applications in the VR laboratory of the Competence Center for the Qualification of Transportation Systems founded by Campania Region (www.centrodicompetenzatrasporti.unina.it).
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    A Natural and Effective Calibration of the CyberGlove
    (The Eurographics Association, 2006) Partipilo, S.; Felice, F. De; Renna, F.; Attolico, G.; Distante, A.; S. Battiato and G. Gallo and F. Stanco
    This work addresses the calibration of the CyberGlove, a device which provides information about the position and attitude in space of all the components of the user hand in a haptic system for the fruition of digital 3D contents by blind people. A realistic haptic interaction requires a reliable detection of user movements and a good calibration of the device to account for size and articulation capability of the specific hand. At the same time the application of interest calls for a calibration procedure that should be executable in a natural and straightforward way by every user. The two methods provided by the CyberGlove software are not suitable for these purposes: one is very simple and fast but produces quite imprecise results while the other is effective and accurate but involves a complex and cumbersome trial-and-error process not suited for general users. The proposed method aims to reach satisfactory results using a intuitive and simple approach. The user is asked to assume with his hand several pre-defined poses, each supplying the sensors output associated to known joints angles. Combining these data with the constraints derived by the anatomical structure of the hand it is possible to evaluate the values of the two parameters, gain and offset, that drive the digitalization of the sensor output. This process, in spite of its simplicity, has provided satisfactory results in several experimental sessions, enabling a realistic and reliable mirroring of user movements in the virtual space.
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    Unambiguous Analysis of Woman Breast Shape for Plastic Surgery Outcome Evaluation
    (The Eurographics Association, 2006) Farinella, G. M.; Impoco, G.; Gallo, G.; Spoto, S.; Catanuto, G.; S. Battiato and G. Gallo and F. Stanco
    This paper reports a multidisciplinary research between computer science and plastic and reconstructive surgery. In particular, a new method is proposed to unambiguously define a geometric partitioning of a large thoracic area including the breast mound. The new technique uses only well-defined anatomical points, defined and selected by surgeons. A simple sequence of geometric operations is performed to partition the breast surface into four anatomic subunits, according to clinically derived breast meridian and equator lines. Using this breast shape partition, useful measurement can be extrapolated on 3D model data set. Our method has been validated on a number of breast 3D models acquired by means of a commercial scanner on real clinical cases collected by Istituto Nazionale dei Tumori in Milan (INT).
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    Augmented Reality with Multilayer Occlusion
    (The Eurographics Association, 2006) Feng, Yan; Chen, Yimin; Louise M. Lever and Mary McDerby
    An algorithm for realizing multilayer occlusion in augmented reality (AR) is presented in this paper. We have designed a special scene graph tree comprised of some special nodes, namely EMO nodes. According to the location of real moving object, different EMO node will be activated in real-time, consequently realizing the multilayer occlusion. Differing qualitatively from previous work in AR occlusion, our algorithm realizes multilayer occlusion, and its application domain involves indoor-field occluded objects, which are several meters distant from the viewer. Previous related work has focused on monolayer occlusion, and near-field occluded objects, which are within or just beyond arm s reach. In addition, BP neural network is improved to correct the nonlinear error of magnetic sensor, consequently to detect occlusion more effectively. Experimental results are provided to demonstrate the multilayer indoor-field occlusion.
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    Sub-part correspondence using structure and geometry
    (The Eurographics Association, 2006) Biasotti, S.; Marini, S.; S. Battiato and G. Gallo and F. Stanco
    The paper describes a method for recognizing similar sub-parts of objects described by 3D polygonal meshes. The innovation of our method is the coupling of structure and geometry in the matching process. First of all, the structure of the shape is coded in a graph where each node is associated to a sub-part of the shape. Then, the matching between two shapes is approached using a graph-matching technique relying upon a geometric description of each sub-part.
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    Recognizing Hand Gestures with CALI
    (The Eurographics Association, 2006) Jota, Ricardo; Ferreira, Alfredo; Cerejo, Mariana; Santos, José; Fonseca, Manuel J.; Jorge, Joaquim A.; Pere Brunet and Nuno Correia and Gladimir Baranoski
    Human computer interaction techniques that do not rely on devices are often perceived as more natural by users. Many of these, include hand pose recognition as an interaction technique appealing to users. In this paper we describe and evaluate two techniques for hand pose recognition, based on CALI, a general library for gesture recognition. This library was initially designed for calligraphic recognition, however recent usage shows that CALI is able to support other applications. One unexplored research area includes its application to hand pose recognition, even though there are already different approaches to the subject using techniques such as Hidden Markov Models or Model-based tracking. We developed and tested a new approach to recognize hand poses taking advantage of the features obtained from CALI. To explore this approach we implemented two techniques. The first recognizes bare-hands by their outer contours, the second uses color marks on each fingertip to track the hand and recognize its pose. Experimental results show that both approaches present recognitions rates around 93%.
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    Real-time Cataract Surgery Simulation for Training
    (The Eurographics Association, 2006) Agus, M.; Gobbetti, E.; Pintore, G.; Zanetti, G.; Zorcolo, A.; S. Battiato and G. Gallo and F. Stanco
    Cataract is a clouding of the eye's natural lens, normally due to natural aging changes, and involving at least half of the population over 65 years. Cataract extraction is the only solution for restoring a clear vision, and nowadays is probably the most frequently practiced surgical procedure. This paper describes a novel virtual reality simulation system for cataract surgery training, involving the capsulorhexis and phacoemulsification tasks. The simulator runs on a multiprocessing PC platform and provides realistic physically-based visual simulations of tools interactions. The current setup employs SensAble PHANToM for simulating the interaction devices, and a binocular display for presenting images to the user.
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    ATIP: A Tool for 3D Navigation inside a Single Image with Automatic Camera Calibration
    (The Eurographics Association, 2006) Boulanger, Kevin; Bouatouch, Kadi; Pattanaik, Sumanta; Louise M. Lever and Mary McDerby
    Automatic Tour Into the Picture (ATIP) is an extension of the Tour Into the Picture method [HAA97] that allows an approximative but visually convincing 3D walk-through inside a single image by rendering a box textured using the input image data. The original algorithm requires a long and tedious user interaction to determine the box dimensions and the perspective parameters, and imposes several constraints on the input image orientation. The goal of this paper is to present a framework providing fully automatic and fast camera calibration for any view orientation without using a calibration target. Our method reduces the user interaction, hence only a couple of seconds are required between the input image loading and the final walk-through.
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    Polynomial Approximation of Blinn-Phong Model
    (The Eurographics Association, 2006) Öztürk, Aydin; Bilgili, Ahmet; Kurt, Murat; Louise M. Lever and Mary McDerby
    The Phong model has been one of the oldest and the most popular reflection models in Computer Graphics. It can be used to model specular highlights of various materials. In this paper, we consider a polynomial model and obtain a linear approximation of the Blinn-Phong model. Approximation errors were obtained for the proposed model and empirical comparisons were made using a measured BRDF data set. Based on the empirical results, it is shown that proposed model provides visually convincing representation of BRDF and performs well for modeling the surface reflectance.
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    A Mixed Reality Anatomy Teaching Tool
    (The Eurographics Association, 2006) Thomas, Rhys G.; John, Nigel W.; Lim, Ik Soo; Louise M. Lever and Mary McDerby
    In this paper we present an inexpensive Mixed Reality software tool for training medical students in anatomy. The software integrates the ARToolkit and Visualization Toolkit (VTK) to create a novel interactive environment in which the user can manipulate the position and orientation of the volume rendering using a plastic model of the organ to be observed. The volume rendering can then be clipped relative to an arbitrary plane to reveal data from its interior, using a second prop.