Browsing by Author "Weiss, Sebastian"

Now showing 1 - 3 of 3
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    Analytic Ray Splitting for Controlled Precision DVR
    (The Eurographics Association, 2021) Weiss, Sebastian; Westermann, Rüdiger; Agus, Marco and Garth, Christoph and Kerren, Andreas
    For direct volume rendering of post-classified data, we propose an algorithm that analytically splits a ray through a cubical cell at the control points of a piecewise-polynomial transfer function. This splitting generates segments over which the variation of the optical properties is described by piecewise cubic functions. This allows using numerical quadrature rules with controlled precision to obtain an approximation with prescribed error bounds. The proposed splitting scheme can be used to find all piecewise linear or monotonic segments along a ray, and it can thus be used to improve the accuracy of direct volume rendering, scale-invariant volume rendering, and multi-isosurface rendering.
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    Evaluation of Volume Representation Networks for Meteorological Ensemble Compression
    (The Eurographics Association, 2022) Höhlein, Kevin; Weiss, Sebastian; Necker, Tobias; Weissmann, Martin; Miyoshi, Takemasa; Westermann, Rüdiger; Bender, Jan; Botsch, Mario; Keim, Daniel A.
    Recent studies have shown that volume scene representation networks constitute powerful means to transform 3D scalar fields into extremely compact representations, from which the initial field samples can be randomly accessed. In this work, we evaluate the capabilities of such networks to compress meteorological ensemble data, which are comprised of many separate weather forecast simulations. We analyze whether these networks can effectively exploit similarities between the ensemble members, and how alternative classical compression approaches perform in comparison. Since meteorological ensembles contain different physical parameters with various statistical characteristics and variations on multiple scales of magnitude, we analyze the impact of data normalization schemes on learning quality. Along with an evaluation of the trade-offs between reconstruction quality and network model parameterization, we compare compression ratios and reconstruction quality for different model architectures and alternative compression schemes.
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    Graph-Based Synthesis for Skin Micro Wrinkles
    (The Eurographics Association and John Wiley & Sons Ltd., 2023) Weiss, Sebastian; Moulin, Jonathan; Chandran, Prashanth; Zoss, Gaspard; Gotardo, Paulo; Bradley, Derek; Memari, Pooran; Solomon, Justin
    We present a novel graph-based simulation approach for generating micro wrinkle geometry on human skin, which can easily scale up to the micro-meter range and millions of wrinkles. The simulation first samples pores on the skin and treats them as nodes in a graph. These nodes are then connected and the resulting edges become candidate wrinkles. An iterative optimization inspired by pedestrian trail formation is then used to assign weights to those edges, i.e., to carve out the wrinkles. Finally, we convert the graph to a detailed skin displacement map using novel shape functions implemented in graphics shaders. Our simulation and displacement map creation steps expose fine controls over the appearance at real-time framerates suitable for interactive exploration and design. We demonstrate the effectiveness of the generated wrinkles by enhancing state-of-art 3D reconstructions of real human subjects with simulated micro wrinkles, and furthermore propose an artist-driven design flow for adding micro wrinkles to fictional characters.