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Item Lightness Perception in Tone Reproduction for High Dynamic Range Images(The Eurographics Association and Blackwell Publishing, Inc, 2005) Krawczyk, Grzegorz; Myszkowski, Karol; Seidel, Hans-PeterItem Harmonic Guidance for Surface Deformation(The Eurographics Association and Blackwell Publishing, Inc, 2005) Zayer, Rhaleb; Roessl, Christian; Karni, Zachi; Seidel, Hans-PeterItem Efficient Rendering of Local Subsurface Scattering(The Eurographics Association and Blackwell Publishing Ltd., 2005) Mertens, Tom; Kautz, Jan; Bekaert, Philippe; Van Reeth, Frank; Seidel, Hans-PeterA novel approach is presented to efficiently render local subsurface scattering effects. We introduce an importance sampling scheme for a practical subsurface scattering model. It leads to a simple and efficient rendering algorithm, which operates in image space, and which is even amenable for implementation on graphics hardware. We demonstrate the applicability of our technique to the problem of skin rendering, for which the subsurface transport of light typically remains local. Our implementation shows that plausible images can be rendered interactively using hardware acceleration.Item Fast Final Gathering via Reverse Photon Mapping(The Eurographics Association and Blackwell Publishing, Inc, 2005) Havran, Vlastimil; Herzog, Robert; Seidel, Hans-PeterItem Using Procedural RenderMan Shaders for Global Illurnination(Blackwell Science Ltd and the Eurographics Association, 1995) Slusallek, Philipp; Pflaum, Thomas; Seidel, Hans-PeterGlobal illumination techniques like radiosity or Monte-Carlo ray-tracing are becoming standard features of rendering systems. However, there is currently no accepted interface format which supports an appropriate physically-based scene description. In this paper we present extensions to the well-known RenderMan interface, which allow for a physically based scene description and support advanced global illumination techniques. Special emphasis has been laid on the support for procedural descriptions of reflection and emission by RenderMan surface shaders. So far, they could not be used with most global illumination algorithms. The extensions have been implemented in a physically-based rendering system and are illustrated with examples.Item Measurement-Based Interactive Simulation of Viscoelastic Solids(The Eurographics Association and Blackwell Publishing, Inc, 2004) Schoner, Jeffrey L.; Lang, Jochen; Seidel, Hans-PeterAnimation of viscoelastic solids in entertainment and medical applications as well as scientific simulation can be improved through observations of real world objects. This paper presents a method for simulating viscoelastic solids in real-time for visual and haptic display along with a method for determining the parameters of the the underlying model from automated physical measurements of real world objects. The viscoelastic model is a novel extension of the discrete Green's function matrix for linear elasticity, which combines static behavior represented by Green's functions with dynamic behavior expressed by differential equations inspired by particle systems. We describe a novel estimation method of dynamic contact behavior for heterogeneous complex objects based on these measurements. For this estimation, our method relies only on measurement data previously used in the acquisition less realistic elastostatic models. In this way our method allows more physically accurate realism in animation of viscoelastic solids without large additional computational costs or any measurements besides those associated with related methods for elastostatic solids.Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Physically based modeling I.3.7 [Computer Graphics]: Virtual reality, animationItem Editorial(Blackwell Publishers Ltd and the Eurographics Association, 1998) Coquillart, Sabine; Seidel, Hans-PeterItem Editorial(Blackwell Publishers Ltd and the Eurographics Association, 1999) Coquillart, Sabine; Seidel, Hans-PeterItem Exchanging Faces in Images(The Eurographics Association and Blackwell Publishing, Inc, 2004) Blanz, Volker; Scherbaum, Kristina; Vetter, Thomas; Seidel, Hans-PeterPasting somebody's face into an existing image with traditional photo retouching and digital image processing tools has only been possible if both images show the face from the same viewpoint and with the same illumination. However, this is rarely the case for given pairs of images. We present a system that exchanges faces across large differences in viewpoint and illumination. It is based on an algorithm that estimates 3D shape and texture along with all relevant scene parameters, such as pose and lighting, from single images. Manual interaction is reduced to clicking on a set of about 7 feature points, and marking the hairline in the target image. The system can be used for image processing, virtual try-on of hairstyles, and face recognition. By separating face identity from imaging conditions, our approach provides an abstract representation of images and a novel, high-level tool for image manipulation.Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: AnimationItem Efficient Fitting and Rendering of Large Scattered Data Sets Using Subdivision Surfaces(Blackwell Publishers, Inc and the Eurographics Association, 2002) Scheib, Vincent; Haber, Jorg; Lin, Ming C.; Seidel, Hans-PeterWe present a method to efficiently construct and render a smooth surface for approximation of large functional scattered data. Using a subdivision surface framework and techniques from terrain rendering, the resulting surface can be explored from any viewpoint while maintaining high surface fairness and interactive frame rates. We show the approximation error to be sufficiently small for several large data sets. Our system allows for adaptive simplification and provides continuous levels of detail, taking into account the local variation and distribution of the data.Categories and Subject Descriptors (according to ACM CCS): G.1.2 [Approximation]: Approximation of surfaces, Least squares approximation, Piecewise polynomial approximation; I.3.3 [Picture/Image Generation]: Display algorithms, Viewing algorithms; I.3.5 [Computational Geometry and Object Modeling]: Surface representation.