EG 2016 - Short Papers
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Browsing EG 2016 - Short Papers by Subject "I.3.7 [Computer Graphics]"
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Item Example-based Body Model Optimization and Skinning(The Eurographics Association, 2016) Fechteler, Philipp; Hilsmann, Anna; Eisert, Peter; T. Bashford-Rogers and L. P. SantosIn this paper, we present an example-based framework for the generation of a realistic kinematic 3D human body model that optimizes shape, pose and skinning parameters. For enhanced realism, the skinning is realized as a combination of Linear Blend Skinning (LBS) and Dual quaternion Linear Blending (DLB) which nicely compensates the deficiencies of using only one of these approaches (e.g. candy wrapper, bulging artifacts) and supports interpolation of more than two joint transformations. The optimization framework enforces two objectives: resembling both shape and pose as closely as possible by iteratively minimizing the objective function with respect to (a) the vertices, (b) the skinning weights and (c) the joint parameters. Smoothness is ensured by using a weighted Laplacian besides a typical data term in the objective function, which introduces the only parameter to be specified. With experimental results on publicly available datasets we demonstrate the effectiveness of the resulting shape model, exposing convincing naturalism. By using examples for the optimization of all parameters, our framework is easy to use and does not require sophisticated parameter tuning or user intervention.Item Garment Transfer for Quadruped Characters(The Eurographics Association, 2016) Narita, Fumiya; Saito, Shunsuke; Kato, Takuya; Fukusato, Tsukasa; Morishima, Shigeo; T. Bashford-Rogers and L. P. SantosModeling clothing to characters is one of the most time-consuming tasks for artists in 3DCG animation production. Transferring existing clothing models is a simple and powerful solution to reduce labor. In this paper, we propose a method to generate a clothing model for various characters from a single template model. Our framework consists of three steps: scale measurement, clothing transformation, and texture preservation. By introducing a novel measurement of the scale deviation between two characters with different shapes and poses, our framework achieves pose-independent transfer of clothing even for quadrupeds (e.g., from human to horse). In addition to a plausible clothing transformation method based on the scale measurement, our method minimizes texture distortion resulting from large deformation. We demonstrate that our system is robust for a wide range of body shapes and poses, which is challenging for current state-of-the-art methods.Item A Generic Physically-based Approach to the Opening Design Problem(The Eurographics Association, 2016) Κalampokis, Konstantinos; Papaioannou, Georgios; Gkaravelis, Anastasios; T. Bashford-Rogers and L. P. SantosToday architectural design harnesses photorealistic rendering to accurately assess energy transport for the design of energyefficient buildings. In this context, we present an automatic physically-based solution to the opening design problem, i.e. the goal-driven process of defining openings on the input geometry given a set of lighting constraints, to better exploit natural daylight. Based on a hierarchical approach that combines a linear optimization strategy and a genetic algorithm, our method computes the optimal number, position, size and shape of openings, using a path tracing-based estimator to precisely model the light transport for arbitrary materials and geometry. The method quickly converges to an opening configuration that optimally approximates the desired illumination, with no special geometry editing requirements and the ability to trade quality for performance for interactive applications. We validate our results against ground truth experiments for various scenes and time-of-day intervals.Item Peripheral Retinal Image Simulation Based on Retina Shapes(The Eurographics Association, 2016) Dias, Catarina; Wick, Michael; Rifai, Katharina; Wahl, Siegfried; T. Bashford-Rogers and L. P. SantosWe present a method to render the image of a scene reaching the retina, the retinal image, taking into account human offaxis optical aberrations. To this end, we consider realistic wide-angle eye models that offer an anatomical description of the refractive structures of the eye as a set of lenses and accurately reproduce the optical aberrations in the periphery. We then combine these with representative retinal shapes and with distributed ray tracing. Due to the interplay between the eye model and the curved retina, we obtain a realistic simulation of the retinal image, not only foveally but also in the periphery.Item Robust Transmission of Motion Capture Data using Interleaved LDPC and Inverse Kinematics(The Eurographics Association, 2016) Furtado, Antonio Carlos; Cheng, Irene; Dufaux, Frederic; Basu, Anup; T. Bashford-Rogers and L. P. SantosRecent advances in smart-sensor technology have improved precision in Motion Capture (MoCap) data for realistic animation. However, precision also imposes challenges on bandwidth. While research efforts have focussed on MoCap compression in recent years, little attention has been given to lossy transmission taking advantage of the human perceptual threshold, which allows many online applications, e.g., interactive games, on-demand broadcast, movies and tutoring using dynamic motion sequences. Given the growing applications on mobile devices and wireless networks, associated with insufficient bandwidth, unreliable connection and potential interference or shadowing, data loss is inevitable. We introduce a new Representation for MoCap data, integrating Interleaved Low-Density Parity-Check (I-LDPC), with Keyframe-based Interpolation and Inverse Kinematics, to better address the problem of MoCap data loss during transmission. We believe this is the first study to address robust transmission of MoCap data considering loss. Experimental results assessed using mean opinion scores demonstrate that our approach achieves substantial improvement over alternative transmission methods.Item Texel Shading(The Eurographics Association, 2016) Hillesland, Karl E.; Yang, J. C.; T. Bashford-Rogers and L. P. SantosWe have developed a texture space shading system built on modern graphics hardware. It begins with a conventional rasterization stage, but records texel accesses as shading work rather than running a shade per pixel. Shading is performed by a separate compute stage, storing the results in a texture. As a baseline, the texels correspond to those required for mipmapped texturing. A final stage collects data from the texture. Storing results in a texture allows for reuse across frames. We also show how adapting shade rate to less than once per pixel further increases performance. We vary shading load to show when these techniques provide a performance win, with up to 4.1x speedup in our experiments at shading times less than 4 ms.Item Two-Level Adaptive Sampling for Illumination Integrals using Bayesian Monte Carlo(The Eurographics Association, 2016) Marques, Ricardo; Bouville, Christian; Santos, Luis P.; Bouatouch, Kadi; T. Bashford-Rogers and L. P. SantosBayesian Monte Carlo (BMC) is a promising integration technique which considerably broadens the theoretical tools that can be used to maximize and exploit the information produced by sampling, while keeping the fundamental property of data dimension independence of classical Monte Carlo (CMC). Moreover, BMC uses information that is ignored in the CMC method, such as the position of the samples and prior stochastic information about the integrand, which often leads to better integral estimates. Nevertheless, the use of BMC in computer graphics is still in an incipient phase and its application to more evolved and widely used rendering algorithms remains cumbersome. In this article we propose to apply BMC to a two-level adaptive sampling scheme for illumination integrals. We propose an efficient solution for the second level quadrature computation and show that the proposed method outperforms adaptive quasi-Monte Carlo in terms of image error and high frequency noise.