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Now showing 1 - 10 of 241
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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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    Energy Aware Color Sets
    (The Eurographics Association and Blackwell Publishing Ltd, 2009) Chuang, Johnson; Weiskopf, Daniel; Moeller, Torsten
    We present a design technique for colors with the purpose of lowering the energy consumption of the display device. Our approach is based on a screen space variant energy model. The result of our design is a set of distinguishable iso-lightness colors guided by perceptual principles. We present two variations of our approach. One is based on a set of discrete user-named (categorical) colors, which are analyzed according to their energy consumption. The second is based on the constrained continuous optimization of color energy in the perceptually uniform CIELAB color space. We quantitatively compare our two approaches with a traditional choice of colors, demonstrating that we typically save approximately 40 percent of the energy. The color sets are applied to examples from the 2D visualization of nominal data and volume rendering of 3D scalar fields.
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    Scalable, Versatile and Simple Constrained Graph Layout
    (The Eurographics Association and Blackwell Publishing Ltd., 2009) Dwyer, Tim; H.-C. Hege, I. Hotz, and T. Munzner
    We describe a new technique for graph layout subject to constraints. Compared to previous techniques the proposed method is much faster and scalable to much larger graphs. For a graph with n nodes, m edges and c constraints it computes incremental layout in time O(nlogn+m+c) per iteration. Also, it supports a much more powerful class of constraint: inequalities or equalities over the Euclidean distance between nodes.We demonstrate the power of this technique by application to a number of diagramming conventions which previous constrained graph layout methods could not support. Further, the constraint-satisfaction method inspired by recent work in position-based dynamics is far simpler to implement than previous methods.
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    Interactive Visualization of Function Fields by Range-Space Segmentation
    (The Eurographics Association and Blackwell Publishing Ltd., 2009) Anderson, John C.; Gosink, Luke J.; Duchaineau, Mark A.; Joy, Ken I.; H.-C. Hege, I. Hotz, and T. Munzner
    We present a dimension reduction and feature extraction method for the visualization and analysis of function field data. Function fields are a class of high-dimensional, multi-variate data in which data samples are onedimensional scalar functions. Our approach focuses upon the creation of high-dimensional range-space segmentations, from which we can generate meaningful visualizations and extract separating surfaces between features. We demonstrate our approach on high-dimensional spectral imagery, and particulate pollution data from air quality simulations.
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    Frontmatter
    (The Eurographics Association and Blackwell Publishing Ltd, 2009)
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    Motion Compression using Principal Geodesics Analysis
    (The Eurographics Association and Blackwell Publishing Ltd, 2009) Tournier, M.; Wu, X.; Courty, N.; Arnaud, E.; Reveret, L.
    Due to the growing need for large quantities of human animation data in the entertainment industry, it has become a necessity to compress motion capture sequences in order to ease their storage and transmission. We present a novel, lossy compression method for human motion data that exploits both temporal and spatial coherence. Given one motion, we first approximate the poses manifold using Principal Geodesics Analysis (PGA) in the configuration space of the skeleton. We then search this approximate manifold for poses matching end-effectors constraints using an iterative minimization algorithm that allows for real-time, data-driven inverse kinematics. The compression is achieved by only storing the approximate manifold parametrization along with the end-effectors and root joint trajectories, also compressed, in the output data. We recover poses using the IK algorithm given the end-effectors trajectories. Our experimental results show that considerable compression rates can be obtained using our method, with few reconstruction and perceptual errors.
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    Texture Splicing
    (The Eurographics Association and Blackwell Publishing Ltd, 2009) Liu, Yiming; Wang, Jiaping; Xue, Su; Tong, Xin; Kang, Sing Bing; Guo, Baining
    We propose a new texture editing operation called texture splicing. For this operation, we regard a texture as having repetitive elements (textons) seamlessly distributed in a particular pattern. Taking two textures as input, texture splicing generates a new texture by selecting the texton appearance from one texture and distribution from the other. Texture splicing involves self-similarity search to extract the distribution, distribution warping, context-dependent warping, and finally, texture refinement to preserve overall appearance. We show a variety of results to illustrate this operation.
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    Example-Based Rendering of Eye Movements
    (The Eurographics Association and Blackwell Publishing Ltd, 2009) Banf, Michael and Blanz, Volker
    This paper describes a model for example-based, photo-realistic rendering of eye movements in 3D facial animation. Based on 3D scans of a face with different gaze directions, the model captures the motion of the eyeball along with the deformation of the eyelids and the surrounding skin. These deformations are represented in a 3D morphable model.Unlike the standard procedure in facial animation, the eyeball is not modeled as a rotating 3D sphere located behind the skin surface. Instead, the visible region of the eyeball is part of a continuous face mesh, and displacements of the iris as well as occlusions by the lids are modeled in a texture mapping approach. The algorithm avoids artifacts that are widely encountered in 3D facial animation, and it presents a new concept of handling occlusions and discontinuities in morphing algorithms.
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    Interactive Graphics for Computer Adaptive Testing
    (The Eurographics Association and Blackwell Publishing Ltd, 2009) Cheng, I.; Basu, A.
    Interactive graphics are commonly used in games and have been shown to be successful in attracting the general audience. Instead of computer games, animations, cartoons, and videos being used only for entertainment, there is now an interest in using interactive graphics for innovative testing . Rather than traditional pen-and-paper tests, audio, video and graphics are being conceived as alternative means for more effective testing in the future. In this paper, we review some examples of graphics item types for testing. As well, we outline how games can be used to interactively test concepts; discuss designing chemistry item types with interactive 3D graphics; suggest approaches for automatically adjusting difficulty level in interactive graphics based questions; and propose strategies for giving partial marks for incorrect answers. We study how to test different cognitive skills, such as music, using multimedia interfaces; and also evaluate the effectiveness of our model. Methods for estimating difficulty level of a mathematical item type using Item Response Theory (IRT) and a molecule construction item type using Graph Edit Distance are discussed. Evaluation of the graphics item types through extensive testing on some students is described. We also outline the application of using interactive graphics over cell phones. All of the graphics item types used in this paper are developed by members of our research group.
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    Frontmatter
    (The Eurographics Association and Blackwell Publishing Ltd, 2009)