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Now showing 1 - 10 of 28
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    Example-based Interpolation and Synthesis of Bidirectional Texture Functions
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Ruiters, Roland; Schwartz, Christopher; Klein, Reinhard; I. Navazo, P. Poulin
    Bidirectional Texture Functions (BTF) have proven to be a well-suited representation for the reproduction of measured real-world surface appearance and provide a high degree of realism. We present an approach for designing novel materials by interpolating between several measured BTFs. For this purpose, we transfer concepts from existing texture interpolation methods to the much more complex case of material interpolation. We employ a separation of the BTF into a heightmap and a parallax compensated BTF to cope with problems induced by parallax, masking and shadowing within the material. By working only on the factorized representation of the parallax compensated BTF and the heightmap, it is possible to efficiently perform the material interpolation. By this novel method to mix existing BTFs, we are able to design plausible and realistic intermediate materials for a large range of different opaque material classes. Furthermore, it allows for the synthesis of tileable and seamless BTFs and finally even the generation of gradually changing materials following user specified material distribution maps.
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    Perceptually Motivated Real-Time Compression of Motion Data Enhanced by Incremental Encoding and Parameter Tuning
    (The Eurographics Association, 2013) Firouzmanesh, Amirhossein; Cheng, Irene; Basu, Anup; M.- A. Otaduy and O. Sorkine
    We address the problem of efficient real-time motion data compression considering human perception. Using incremental encoding plus a database of motion primitives for each key point, our method achieves a higher or competitive compression rate with less online overhead. Trade-off between visual quality and bandwidth usage can be tuned by varying a single threshold value. A user study was performed to measure the sensitivity of human subjects to reconstruction errors in key rotation angles. Based on these evaluations we are able to perform lossy compression on the motion data without noticeable degradation in rendered qualities. While achieving real-time performance, our technique outperforms other methods in our experiments by achieving a compression ratio exceeding 50 : 1 on regular sequences.
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    Automatic Convergence Adjustment for Stereoscopy using Eye Tracking
    (The Eurographics Association, 2013) Fisker, Martin; Gram, Kristoffer; Thomsen, Kasper Kronborg; Vasilarou, Dimitra; Kraus, Martin; Miguel Chover and A. Augusto de Sousa
    When using stereoscopic displays, decoupling between convergence and accommodation can cause eyestrain. This paper proposes an adjustment method to automatically fit convergence at user fixation depth to accommodation by using eye tracking. Two different adjustment methods are proposed: one binocular, adjusting the images for both eyes, and one monocular, which adjusts only the image for the non-dominant eye. Preliminary results suggest better user comfort and a preference for binocular adjustment in high adjustment scenarios, while the adjustment is less noticeable with the monocular system.
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    A Novel Projection Technique with Detail Capture and Shape Correction for Smoke Simulation
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Wu, Xiaoyue; Yang, Xubo; Yang, Yang; I. Navazo, P. Poulin
    Smoke simulation on a large grid is quite time consuming and most of the computation time is spent on the projection step.We present a novel projection method which produces quite similar visual results as those produced with the traditional projection method, but uses much less computation time. Our method includes two steps: detail-capture and shape-correction. The first step preserves most of the smoke details using an efficient DST (Discrete Sine Transformation) Poisson Solver with auxiliary boundary sweeping. The second step maintains the overall flow shape by solving a correcting Poisson equation on a coarse grid. Our algorithm is very fast and quite easy to implement. Experiments show that our projection is approximately 10-30 times faster than the traditional projection with PCG(Preconditioned Conjugate Gradient), while convincingly preserving both the flow details and the overall shape of the smoke.
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    Volume Ray Casting quality estimation in terms of Peak Signal-to-Noise Ratio
    (The Eurographics Association, 2013) Gavrilov, Nikolay; Turlapov, V.; Miguel Chover and A. Augusto de Sousa
    In spite of a large number of techniques aimed for improvement of Direct Volume Rendering (DVR) quality and performance proposed in the literature, there is a lack of approaches for numerical quality estimation of the images obtained by visualization of medical and scientific volumetric datasets. In this paper we propose a method to estimate sampling artefacts. Using the proposed estimation method we compare different RC algorithms to expose optimal ones in quality-performance criteria.
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    Skeleton-based Joints Position Detection
    (The Eurographics Association, 2014) Madaras, Martin; Piovarci, Michal; Kovacovský, Tomás; Mathias Paulin and Carsten Dachsbacher
    We present a system for detection of joint positions in scans of articulated models. Our method is based purely on skeletons extracted from scanned point clouds of input models. First, skeletons are extracted from scans and then an estimation of possible matches between skeletons is performed. The matches are evaluated and sorted out. The whole matching process is fully automatic, but some user-driven suggestions can be included. Finally, we pick the best matching of skeletons and create a union-skeleton containing all the nodes from all the skeletons. We find nodes in the union-skeleton with rotation changes higher than the predefined threshold. We take these nodes as joints and visualize them in original scans.
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    A Nonobscuring Eye Tracking Solution for Wide Field-of-View Head-mounted Displays
    (The Eurographics Association, 2014) Stengel, Michael; Grogorick, Steve; Rogge, Lorenz; Magnor, Marcus; Mathias Paulin and Carsten Dachsbacher
    We present a solution for integrating a binocular eye tracker into current state-of-the-art lens-based head-mounted displays (HMDs) without affecting the available field-of-view on the display. Estimating the relative eye gaze of the user opens the door for HMDs to a much wider spectrum of virtual reality applications and games. Further, we present a concept of a low-cost head-mounted display with eye tracking and discuss applications which strongly depend on or benefit from gaze estimation.
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    Look me in the Eyes: A Survey of Eye and Gaze Animation for Virtual Agents and Artificial Systems
    (The Eurographics Association, 2014) Ruhland, K.; Andrist, S.; Badler, J. B.; Peters, C. E.; Badler, N. I.; Gleicher, M.; Mutlu, B.; McDonnell, R.; Sylvain Lefebvre and Michela Spagnuolo
    A person's emotions and state of mind are apparent in their face and eyes. As a Latin proverb states: ''The face is the portrait of the mind; the eyes, its informers.''. This presents a huge challenge for computer graphics researchers in the generation of artificial entities that aim to replicate the movement and appearance of the human eye, which is so important in human-human interactions. This State of the Art Report provides an overview of the efforts made on tackling this challenging task. As with many topics in Computer Graphics, a cross-disciplinary approach is required to fully understand the workings of the eye in the transmission of information to the user. We discuss the movement of the eyeballs, eyelids, and the head from a physiological perspective and how these movements can be modelled, rendered and animated in computer graphics applications. Further, we present recent research from psychology and sociology that seeks to understand higher level behaviours, such as attention and eye-gaze, during the expression of emotion or during conversation, and how they are synthesised in Computer Graphics and Robotics.
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    Enhanced Lattice Boltzmann Shallow Waters for Real-time Fluid Simulations
    (The Eurographics Association, 2013) Ojeda, Jesus; Susín, Anton; M.- A. Otaduy and O. Sorkine
    We present a novel approach at simulating fluids in real-time by coupling the Lattice Boltzmann Method for Shallow Waters (LBMSW) with particle systems. The LBM can handle arbitrary underlying terrain and arbitrary fluid depth, which, in turn, allows us to extend it to track dry regions. The LBM is also two-way coupled with rigid bodies. The particle system adds more detail to the LBM; breaking waves are detected from the surface simulation and particles are generated to provide the effect, taking effectively certain amounts of fluid and reintegrating it back once they fall over again. Both the LBM and the particle simulation are implemented in CUDA, although rigid bodies are simulated in CPU. Finally, we show the effectiveness of the method on commodity hardware.
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    Analytic Visibility on the GPU
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Auzinger, Thomas; Wimmer, Michael; Jeschke, Stefan; I. Navazo, P. Poulin
    This paper presents a parallel, implementation-friendly analytic visibility method for triangular meshes. Together with an analytic filter convolution, it allows for a fully analytic solution to anti-aliased 3D mesh rendering on parallel hardware. Building on recent works in computational geometry, we present a new edge-triangle intersection algorithm and a novel method to complete the boundaries of all visible triangle regions after a hidden line elimination step. All stages of the method are embarrassingly parallel and easily implementable on parallel hardware. A GPU implementation is discussed and performance characteristics of the method are shown and compared to traditional sampling-based rendering methods.