Start date: 2007 × End date: 2009 ×

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Now showing 1 - 10 of 1765
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    Sense-Enabled Mixed Reality Museum Exhibitions
    (The Eurographics Association, 2007) Liarokapis, Fotis; Newman, Robert M.; Mount, Sarah; Goldsmith, Dan; Macan, Luis; Malone, Garry; Shuttleworth, James; D. Arnold and F. Niccolucci and A. Chalmers
    During the past few years museums and other cultural heritage institutions have started making use of handheld technologies to provide tourist guides to their visitors. For open-air sites, a number of experimental and commercial applications have been developed based on location-based guides. However, in museum environments static audiovisual guides are the dominant technologies used. In this paper, we present a novel pervasive mixed reality framework to a sensor network capturing ambient noise that can be used to create tangible cultural heritage exhibitions. Localisation of the visitors can be established in a hybrid manner based on machine vision and a wireless sensor network allowing visitors to interact naturally or with the help of sensors. In terms of interface design, a multimodal mixed reality visualisation domain allows for an audio-visual presentation of cultural heritage artefacts.
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    Consistent Scene Illumination using a Chromatic Flash
    (The Eurographics Association, 2009) Kim, Min H.; Kautz, Jan; Oliver Deussen and Peter Hall
    Flash photography is commonly used in low-light conditions to prevent noise and blurring artifacts. However, flash photography commonly leads to a mismatch between scene illumination and flash illumination, due to the bluish light that flashes emit. Not only does this change the atmosphere of the original scene illumination, it also makes it difficult to perform white balancing because of the illumination differences. Professional photographers sometimes apply colored gel filters to the flashes in order to match the color temperature. While effective, this is impractical for the casual photographer. We propose a simple but powerful method to automatically match the correlated color temperature of the auxiliary flash light with that of scene illuminations allowing for well-lit photographs while maintaining the atmosphere of the scene. Our technique consists of two main components. We first estimate the correlated color temperature of the scene, e.g., during image preview. We then adjust the color temperature of the flash to the scene's correlated color temperature, which we achieve by placing a small trichromatic LCD in front of the flash. We demonstrate the effectiveness of this approach with a variety of examples.
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    Haptic Simulation, Perception and Manipulation of Deformable Objects
    (The Eurographics Association, 2007) Magnenat-Thalmann, Nadia; Volino, Pascal; Bonanni, Ugo; Summers, Ian R.; Brady, A. C.; Qu, J.; Allerkamp, D.; Fontana, M.; Tarri, F.; Salsedo, F.; Bergamasco, Massimo; Karol Myszkowski and Vlastimil Havran
    This tutorial addresses haptic simulation, perception and manipulation of complex deformable objects in virtual environments (VE). We first introduce HAPTEX, a research project dealing with haptic simulation and perception of textiles in VEs. Then, we present state-of-the-art techniques concerning haptic simulation and rendering, ranging from physically based modelling to control issues of tactile arrays and force-feedback devices. In the section on cloth simulation for haptic systems we describe techniques for simulating textiles adapted to the specific context of haptic applications. The section concerning tactile aspects of virtual objects shows how arrays of contactors on the skin can be used to provide appropriate spatiotemporal patterns of mechanical excitation to the underlying mechanoreceptors. Finally, the last section addresses the problem of developing suitable force feedback technologies for the realistic haptic rendering of the physical interaction with deformable objects, addressing the design of novel force feedback systems, innovative concepts for curvature simulation and control algorithms for accuracy improvement.
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    Wind projection basis for real-time animation of trees
    (The Eurographics Association and Blackwell Publishing Ltd, 2009) Diener, Julien; Rodriguez, Mathieu; Baboud, Lionel; Reveret, Lionel
    This paper presents a real-time method to animate complex scenes of thousands of trees under a user-controllable wind load. Firstly, modal analysis is applied to extract the main modes of deformation from the mechanical model of a 3D tree. The novelty of our contribution is to precompute a new basis of the modal stress of the tree under wind load. At runtime, this basis allows to replace the modal projection of the external forces by a direct mapping for any directional wind. We show that this approach can be efficiently implemented on graphics hardware. This modal animation can be simulated at low computation cost even for large scenes containing thousands of trees.
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    Total Recall: A Debugging Framework for GPUs
    (The Eurographics Association, 2008) Sharif, Ahmad; Lee, Hsien-Hsin S.; David Luebke and John Owens
    GPUs have transformed from simple fixed-function processors to powerful, programmable stream processors and are continuing to evolve. Programming these massively parallel GPUs, however, is very different from programming a sequential CPU. Lack of native support for debugging coupled with the parallelism in the GPU makes program development for the GPU a non-trivial task. As GPU programs grow in complexity because of scaling in maximum allowed program size and increased demand in terms of realism, debugging GPU code is becoming a major timesink for content developers. In addition to more complex shaders, applications are using multi-pass effects in order to create more convincing reality. In this paper, we present a debugging framework that can be employed to debug complex code running on the GPU in an efficient manner. By observing the API calls of the application that are made to the 3D runtime, the framework can keep track of the program's state in memory. Upon the programmer's request, it is able to capture and deterministically replay the stream of instructions that caused the final write to a pixel of interest. This execution stream includes writes to intermediate render targets and spans across shader boundaries. The stream of instructions can then be replayed on the CPU via emulation and the programmer can debug the straight-line code with ease. We also present a hardware-friendly scheme that can be used to accelerate the debugging process for long-chain multi-pass effects.
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    Achieving Good Connectivity in Motion Graphs
    (The Eurographics Association, 2008) Zhao, Liming; Safonova, Alla; Markus Gross and Doug James
    Motion graphs provide users with a simple yet powerful way to synthesize human motions. While motion graphbased synthesis has been widely successful, the quality of the generatedmotion depends largely on the connectivity of the graph and the quality of transitions in it. However, achieving both of these criteria simultaneously in motion graphs is difficult. Good connectivity requires transitions between less similar poses, while good motion quality results only when transitions happen between very similar poses. This paper introduces a new method for building motion graphs. The method first builds a set of interpolated motion clips, which contain many more similar poses than the original dataset. Using this set, the method then constructs a motion graph and reduces its size by minimizing the number of interpolated poses present in the graph. The outcome of the algorithm is a motion graph called a well-connected motion graph with very good connectivity and only smooth transitions. Our experimental results show that well-connected motion graphs outperform standardmotion graphs across a number of measures, result in very good motion quality, allow for high responsiveness when used for interactive control, and even do not require post-processing of the synthesizedmotions
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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].
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    The Dynamic Animation of Ambulatory Arthropods
    (The Eurographics Association, 2007) Cenydd, Llyr ap; Teahan, William; Ik Soo Lim and David Duce
    Whilst advances in real-time computer graphics continue to permit the development of increasingly vivid virtual worlds, the degree of interaction between the environment and the animated characters within remains relatively limited. There has been little research into the realistic real-time simulation of creatures with the ability to scale arbitrary surfaces and fully explore their environment. Natural looking animations of such feats would greatly enhance immersion in computer games, as well as being of benefit to fields such as phobia therapy and Artificial Life research. We present a system for dynamically animating ground based arthropods in real-time, capable of traversing realistically across a complex, arbitrary environment. The physical simulation of the virtual world further grounds the creatures, enabling complex emergent animations to form.
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    A Low-Power Handheld GPU using Logarithmic Arithmetic and Triple DVFS Power Domains
    (The Eurographics Association, 2007) Nam, Byeong-Gyu; Lee, Jeabin; Kim, Kwanho; Lee, Seung Jin; Yoo, Hoi-Jun; Mark Segal and Timo Aila
    In this paper, a low-power GPU architecture is described for the handheld systems with limited power and area budgets. The GPU is designed using logarithmic arithmetic for power- and area-efficient design. For this GPU, a multifunction unit is proposed based on the hybrid number system of floating-point and logarithmic numbers and the matrix, vector, and elementary functions are unified into a single arithmetic unit. It achieves the single-cycle throughput for all these functions, except for the matrix-vector multiplication with 2-cycle throughput. The vertex shader using this function unit as its main datapath shows 49.3% cycle count reduction compared with the latest work for OpenGL transformation and lighting (TnL) kernel. The rendering engine uses also the logarithmic arithmetic for implementing the divisions in pipeline stages. The GPU is divided into triple dynamic voltage and frequency scaling power domains to minimize the power consumption at a given performance level. It shows a performance of 5.26Mvertices/s at 200MHz for the OpenGL TnL and 52.4mW power consumption at 60fps. It achieves 2.47 times performance improvement while reducing 50.5% power and 38.4% area consumption compared with the latest work.
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    Interactive Modeling of Virtual Ecosystems
    (The Eurographics Association, 2009) Benes, Bedrich; Andrysco, Nathan; Stava, Ondrej; Eric Galin and Jens Schneider
    We present a novel technique for interactive, intuitive, and efficient modeling of virtual plants and plant ecosystems. Our approach is biologically-based, but shades the user from overwhelming input parameters by simplifying them to intuitive controls. Users are able to create scenes that are populated by virtual plants. Plants communicate actively with the environment and attempt to generate an optimal spatial distribution that dynamically adapts to neighboring plants, to user defined obstacles, light, and gravity. We demonstrate simulations of ecosystems composed of up to 140 trees that are computed in less than two minutes. Various phenomena previously available for non-realtime procedural approaches are created interactively, such as plants competing for space, topiary, plant lighting, virtual forests, etc. Results are aimed at architectural modeling, the entertainment industry, and everywhere that quick and fast creation of believable biological plant models is necessary.