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Now showing 1 - 10 of 59
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    High Dynamic Range Techniques in Graphics: from Acquisition to Display
    (The Eurographics Association, 2005) Goesele, Michael; Heidrich, Wolfgang; Höfflinger, Bernd; Krawczyk, Grzegorz; Myszkowski, Karol; Trentacoste, Matthew; Ming Lin and Celine Loscos
    This course is motivated by tremendous progress in the development and accessibility of high dynamic range technology (HDR) that happened just recently, which creates many interesting opportunities and challenges in graphics. The course presents a complete pipeline for HDR image and video processing from acquisition, through compression and quality evaluation, to display. Also, successful examples of the use of HDR technology in research setups and industrial applications are provided. Whenever needed relevant background information on human perception is given which enables better understanding of the design choices behind the discussed algorithms and HDR equipment.
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    Multimodal Interfaces: an Introduction to ENACTIVE systems
    (The Eurographics Association, 2005) Bergamasco, Massimo; Ming Lin and Celine Loscos
    Enactive Interfaces are related to a fundamental "interaction" concept which is not exploited by most of the existing human-computer interface technologies. The traditional interaction with the information mediated by a computer is mostly based on symbolic or iconic knowledge, and not on enactive knowledge. While in the symbolic way of learning knowledge is stored as words, mathematical symbols or other symbol systems, in the iconic stage knowledge is stored in the form of visual images, such as diagrams and illustrations that can accompany verbal information. On the other hand, enactive knowledge is a form of knowledge based on the active use of the hand for apprehension tasks. Enactive knowledge is not simply multisensory mediated knowledge, but knowledge stored in the form of motor responses and acquired by the act of "doing". A typical example of enactive knowledge is constituted by the competence required by tasks such as typing, driving a car, dancing, playing a musical instrument, modelling objects from clay, which would be difficult to describe in an iconic or symbolic form. This type of knowledge transmission can be considered the most direct, in the sense that it is natural and intuitive, since it is based on the experience and on the perceptual responses to motor acts.
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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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    Function-based Shape Modeling Framework in Multilevel Education
    (The Eurographics Association, 2005) Pasko, A.; Adzhiev, V.; Goto, Y.; Vilbrandt, C.; Jean-Jacques Bourdin and Hugh McCabe
    We describe how an approach to the development of a shape modeling and visualization framework based on the rapidly progressing function representation can be used in education. The modeling language and software tools are being developed within an international HyperFun Project. We applied the theoretical framework and software tools on different levels of education starting from elementary schools to doctoral thesis research in various areas related to mathematics, computer graphics, programming languages, artistic design and animation. We illustrate the presented approach by the practical experience examples from different educational institutions and countries
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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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    A Survey of General-Purpose Computation on Graphics Hardware
    (The Eurographics Association, 2005) Owens, John D.; Luebke, David; Govindaraju, Naga; Harris, Mark; Krüger, Jens; Lefohn, Aaron E.; Purcell, Timothy J.; Yiorgos Chrysanthou and Marcus Magnor
    The rapid increase in the performance of graphics hardware, coupled with recent improvements in its programmability, have made graphics hardware a compelling platform for computationally demanding tasks in a wide variety of application domains. In this report, we describe, summarize, and analyze the latest research in mapping general-purpose computation to graphics hardware. We begin with the technical motivations that underlie general-purpose computation on graphics processors (GPGPU) and describe the hardware and software developments that have led to the recent interest in this field. We then aim the main body of this report at two separate audiences. First, we describe the techniques used in mapping general-purpose computation to graphics hardware. We believe these techniques will be generally useful for researchers who plan to develop the next generation of GPGPU algorithms and techniques. Second, we survey and categorize the latest developments in general-purpose application development on graphics hardware. This survey should be of particular interest to researchers who are interested in using the latest GPGPU applications in their systems of interest.
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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.