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Now showing 1 - 10 of 33
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    Fast Body-Cloth simulation with moving humanoids
    (The Eurographics Association, 2005) Rodriguez-Navarro, Javier; Sainz, Miguel; Susin, Antonio; John Dingliana and Fabio Ganovelli
    In this paper we present a very fast method for body-cloth animation. The usual bottle-neck in cloth simulation performance is collision detection, which becomes more difficult to solve when a complex geometry, like a human body, is involved. Recent image based methods, that use depth images to detect collisions, usually relays on CPU for collision correction. In our work we implement a GPU based simulation that takes care both of cloth simulation and body-cloth collisions when the humanoid is moving. Our solution is based on a hierarchic depth map structure. A high frame rate is obtained with both structured and unstructured cloth meshes with thousands of particles.
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    A Scalable Hardware and Software System for the Holographic Display of Interactive Graphics Applications
    (The Eurographics Association, 2005) Balogh, Tibor; Forgács, Tamás; Agács, Tibor; Balet, Olivier; Bouvier, Eric; Bettio, Fabio; Gobbetti, Enrico; Zanetti, Gianluigi; John Dingliana and Fabio Ganovelli
    We present a scalable holographic system design targeting multi-user interactive computer graphics applications. The display uses a specially arranged array of micro-displays and a holographic screen. Each point of the holographic screen emits light beams of different color and intensity to the various directions, in a controlled manner. The light beams are generated through a light modulation system arranged in a specific geometry and the holographic screen makes the necessary optical transformation to compose these beams into a perfectly continuous 3D view. With proper software control, the light beams leaving the various pixels can be made to propagate in multiple directions, as if they were emitted from physical objects at fixed spatial locations. The display is driven by DVI streams generated by multiple consumer level graphics boards and decoded in real-time by image processing units that feed the optical modules at high refresh rates. An OpenGL compliant library running on a client PC redefines the OpenGL behavior to multicast graphics commands to server PCs, where they are re-interpreted for implementing holographic rendering. The feasibility of the approach has been successfully evaluated with a working hardware and software 7.4M pixel prototype driven at 10-15Hz by three DVI streams.
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    Rendering Realistic Trees and Forests in Real Time
    (The Eurographics Association, 2005) Candussi, Alberto; Canduss, Nicola; Höllerer, Tobias; John Dingliana and Fabio Ganovelli
    Real-Time rendering of realistic trees on common graphics hardware represents a big challenge due to their inherent geometric complexity. In most cases, trees are composed of hundreds of thousands of leaves and branches with complex lighting interrelations. We present novel techniques to render and animate photorealistic trees in real-time. The described techniques are easily implemented with commonly available graphics cards, making them suitable to applications such as visual simulations and video games. Polygon counts are significantly reduced by the use of simplified textured geometry for minor branches and billboarded leaf textures. Fast and realistic lighting and shadowing of the leaves and surroundings enhances realism. We animate the tree branches and leaf textures using simple vertex shaders, creating a realistic effect of the tree swaying in the wind. Discrete levels of detail allow rendering of a large number of trees, making it possible to represent realistic forest scenes made of 1000-1500 trees.
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    A 3D Perceptual Metric using Just-Noticeable-Difference
    (The Eurographics Association, 2005) Cheng, Irene; Boulanger, Pierre; John Dingliana and Fabio Ganovelli
    In multimedia applications, it is essential to distribute resources efficiently among different types of data in order to optimize overall quality. We propose a perceptual metric using Just-Noticeable-Difference (JND) to identify redundant mesh data so that available bandwidth can be allocated to improve texture resolution. Evaluation of perceptual impact during runtime is based on statistics in a lookup table generated during preprocessing. If the impact is less than the JND, no mesh refinement is performed. We apply Weber s fraction to compute the JND threshold, which is verified by perceptual evaluations. Experimental result shows that our JND model can accurately predict perceptual impact based on the human visual system.
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    Video Textures Exploiting Symmetric Movements
    (The Eurographics Association, 2005) Haevre, William Van; Reeth, Frank Van; John Dingliana and Fabio Ganovelli
    In this paper, an extension to the traditional method for creating video textures is presented. By exploiting the symmetric properties of the frames in a given video sequence, a new endless video stream or video loop is generated by reversing video playback when appropriate. We aim at a larger set of possible input video's for video texture creation, including captured motions containing no smooth transitions (eg. turbulent plant movements). To achieve this, good turn points, instead of transitions are extracted from the video data, after which a simple algorithm synthesizes a new video sequence while optimally exploiting the original frame data. Visual artifacts caused by changed lighting conditions are reduced significantly.
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    Fast and Controllable 3D Modelling From Silhouettes
    (The Eurographics Association, 2005) Prasad, Mukta; Fitzgibbon, Andrew; Zisserman, Andrew; John Dingliana and Fabio Ganovelli
    We show how a 3D model of a complex curved object can be easily extracted from a single 2D image. A userdefined silhouette is the key input; and we show that finding the smoothest 3D surface which projects exactly to this silhouette can be expressed as a quadratic optimization, a result which has not previously appeared in the large literature on the shape-from-silhouette problem. For simple models, this process can immediately yield a usable 3D model; but for more complex geometries the user will wish to further shape the surface. We show that a variety of editing operations which can be defined either in the image or in 3D can also be expressed as linear constraints on the 3D shape parameters. We extend the system to fit higher genus surfaces. Our method has several advantages over the system of Zhang et al. [ZDPSS01] and over systems such as SKETCH and Teddy.
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    Facial Motion Cloning Using Global Shape Deformation
    (The Eurographics Association, 2005) Fratarcangeli, Marco; Schaerf, Marco; John Dingliana and Fabio Ganovelli
    We present a novel Facial Motion Cloning method relying on the combination of the radial basis functions (RBF) based scattered data interpolation with the encoding capabilities of the MPEG-4 Facial and Body Animation (FBA) international standard. Beside from an initial manual selection of feature points, our method works fully automatically without user interaction. The produced talking head is able to perform generic face animation which is stored in a MPEG-4 FBA data stream.
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    A Sharpness Dependent Approach to 3D Polygon Mesh Hole Filling
    (The Eurographics Association, 2005) Chen, Chun-Yen; Cheng, Kuo-Young; Liao, H.Y. Mark; John Dingliana and Fabio Ganovelli
    A sharpness dependent hole filling approach is proposed in this paper. The proposed method can fill the hole of a mesh-based model and recover its sharp feature located at the hole area. Interpolation based on radial basis function is applied to create a smooth implicit surface and this surface can approximate the shape of the missed data. Then, a regularized marching tetrahedral algorithm is adopted to triangulate the above implicit surface and to produce a polygonal hole patch. A repaired mesh model is obtained by stitching the hole patch and the hole boundary of the original model. Finally, a feature enhancement process is applied if there exists a sharp feature on the hole boundary of the original model. The introduction of a sharpness dependent filter enhances the sharp feature of a hole-filled model. Experiment results show that our approach can produce excellent reparation results especially for recovering sharp feature.
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    Leaf Cluster Impostors for Tree Rendering with Parallax
    (The Eurographics Association, 2005) Garcia, Ismael; Sbert, Mateu; Szirmay-Kalos, László; John Dingliana and Fabio Ganovelli
    This paper presents a simple method to render complex trees on high frame rates while maintaining parallax effects. Based on the recognition that a planar impostor is accurate if the represented polygon is in its plane, we find an impostor for each of those groups of tree leaves that lie approximately in the same plane. The groups are built automatically by a clustering algorithm. Unlike billboards, these impostors are not rotated when the camera moves, thus the expected parallax effects are provided. On the other hand, clustering allows the replacement of a large number of leaves by a single semi-transparent quadrilateral, which improves rendering time considerably. Our impostors well represent the tree from any direction and provide accurate depth values, thus the method is also good for shadow computation.
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    Estimating Mobile Memory Requirements and Rendering Time for Remote Execution of the Graphics Pipeline
    (The Eurographics Association, 2005) Banerjee, Kutty; Wu, Fan; Agu, Emmanuel; John Dingliana and Fabio Ganovelli
    Mobile devices have limited processing power, memory and battery power. Remote execution, wherein part or entire graphics pipeline is offloaded to a powerful surrogate server, is an attractive solution for low end mobile devices such as PDAs and cell phones that lack floating point units or GPUs. We have found that remote execution of floating-point-intensive pipeline stages such as transform and geometry operations can produce speedups of up to 10 times for a low-end mobile device. We introduce generalized pipeline-splitting, a paradigm whereby 15 sub-stages of the graphics pipeline are instrumented with networking code such that they can run either on a mobile client or a surrogate server. To validate our concepts, we create Remote Mesa (RMesa). As a foundation for deciding which stages of the pipeline would benefit from remote execution, this paper presents analytical models for the overall rendering time, memory requirements and roundtrip network delay incurred by RMesa.