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Now showing 1 - 10 of 564
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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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    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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    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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    Inverse Kinematics and Kinetics for Virtual Humanoids
    (The Eurographics Association, 2007) Boulic, Ronan; Kulpa, Richard; Karol Myszkowski and Vlastimil Havran
    The present tutorial deals with the use of inverse kinematics and kinetics for postural adaptations of virtual hu- manoids to different kind of constraints. It first proposes an overview of the problematic of this thematic and then of the existing techniques. Then it technically describes two key approaches: the prioritized inverse kinematics for accurate and realistic adaptation and a CCD-like algorithm based on groups for fast and realistic adaptation of hundreds of characters in real-time.
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    A Survey of Haptic Rendering Techniques
    (The Eurographics Association and Blackwell Publishing Ltd, 2007) Laycock, S.D.; Day, A.M.
    Computer Graphics technologies have developed considerably over the past decades. Realistic virtual environments can be produced incorporating complex geometry for graphical objects and utilising hardware acceleration for per pixel effects. To enhance these environments, in terms of the immersive experience perceived by users, the human s sense of touch, or haptic system, can be exploited. To this end haptic feedback devices capable of exerting forces on the user are incorporated. The process of determining a reaction force for a given position of the haptic device is known as haptic rendering. For over a decade users have been able to interact with a virtual environment with a haptic device. This paper focuses on the haptic rendering algorithms which have been developed to compute forces as users manipulate the haptic device in the virtual environment.
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    Capturing Reflectance - From Theory to Practice
    (The Eurographics Association, 2007) Lensch, Hendrik P. A.; Goesele, Michael; M¨uller, Gero; Karol Myszkowski and Vlastimil Havran
    One important problem in photorealistic or predictive rendering nowadays is to realistically model the light interaction with objects. Measurements can capture the reflection properties of real world surface, i.e., they are one way of obtaining realistic reflection properties. For arbitrary (non-fluorescent, non-phosphorescent) materials, the reflection properties can be described by the 8D reflectance field of the surface, also called BSSRDF. Since densely sampling an 8D function is currently not practical various acquisition methods have been proposed which reduce the number of dimensions by restricting the viewing or relighting capabilities of the captured data sets. In this tutorial we will mainly focus on three different approaches, the first allowing to reconstruct opaque surfaces from a very small set of input images, the second allows for arbitrary surfaces but under the assumption of distant light sources and the last which allows for relighting an arbitrary scene with arbitrary spatially varying light patterns. After a short introduction explaining some fundamental concepts regarding measuring and representing reflection properties, the basics of data acquisition with photographs will be addressed. The tutorial present the set of current state-of-the art algorithms for acquiring and modeling 3D objects. The tutorial investigates the strengths and limitations of each technique and sorts them by their complexity with regard to acquisition costs. Besides describing the theoretical contributions we will furthermore point out the practical issues when acquiring reflectance fields in order to help interested users to build and implement their own acquisition setup.
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    A Knowledge Base for the Emerging Discipline of Computer Graphics
    (The Eurographics Association, 9-7-2007) Orr, Genevieve; Alley, Tony; Laxer, Cary; Geigel, Joe; Gold, Susan; -
    Computer Graphics is evolving as a discipline characterized by the fusion of artistic and technical theories and skills. The goal of the SIGGRAPH Curriculum Working Group has been to create a knowledge base that defines this discipline. This knowledge base is presented as a palette of subject areas and skills that forms the necessary educational framework for creation of undergraduate curricula that specialize in computer graphics. It facilitates the development of attributes that will create paths toward professional work, graduate studies, and lifelong skills-development and learning focused on computer graphics. The details provided here are principally oriented toward faculty members designing new computer graphics programs or those evolving existing ones. They also benefit students who wish to craft their own programs in computer graphics, as well as administrators and accreditors seeking guidance for framing and assessing these programs.
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    Photorealistic Image Rendering with Population Monte Carlo Energy Redistribution
    (The Eurographics Association, 2007) Lai, Yu-Chi; Fan, Shao Hua; Chenney, Stephen; Dyer, Charcle; Jan Kautz and Sumanta Pattanaik
    This work presents a novel global illumination algorithm which concentrates computation on important light transport paths and automatically adjusts energy distributed area for each light transport path. We adapt statistical framework of Population Monte Carlo into global illumination to improve rendering efficiency. Information collected in previous iterations is used to guide subsequent iterations by adapting the kernel function to approximate the target distribution without introducing bias into the final result. Based on this framework, our algorithm automatically adapts the amount of energy redistribution at different pixels and the area over which energy is redistributed. Our results show that the efficiency can be improved by exploring the correlated information among light transport paths.