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Now showing 1 - 10 of 61
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    Supporting Urban Search & Rescue Mission Planning through Visualization-Based Analysis
    (The Eurographics Association, 2014) Bock, Alexander; Kleiner, Alexander; Lundberg, Jonas; Ropinski, Timo; Jan Bender and Arjan Kuijper and Tatiana von Landesberger and Holger Theisel and Philipp Urban
    We propose a visualization system for incident commanders in urban search & rescue scenarios that supports access path planning for post-disaster structures. Utilizing point cloud data acquired from unmanned robots, we provide methods for assessment of automatically generated paths. As data uncertainty and a priori unknown information make fully automated systems impractical, we present a set of viable access paths, based on varying risk factors, in a 3D environment combined with the visual analysis tools enabling informed decisions and trade-offs. Based on these decisions, a responder is guided along the path by the incident commander, who can interactively annotate and reevaluate the acquired point cloud to react to the dynamics of the situation. We describe design considerations for our system, technical realizations, and discuss the results of an expert evaluation.
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    Efficient Unsupervised Temporal Segmentation of Human Motion
    (The Eurographics Association, 2014) Vögele, Anna; Krüger, Björn; Klein, Reinhard; Vladlen Koltun and Eftychios Sifakis
    This work introduces an efficient method for fully automatic temporal segmentation of human motion sequences and similar time series. The method relies on a neighborhood graph to partition a given data sequence into distinct activities and motion primitives according to self-similar structures given in that input sequence. In particular, the fast detection of repetitions within the discovered activity segments is a crucial problem of any motion processing pipeline directed at motion analysis and synthesis. The same similarity information in the neighborhood graph is further exploited to cluster these primitives into larger entities of semantic significance. The elements subject to this classification are then used as prior for estimating the same target values for entirely unknown streams of data. The technique makes no assumptions about the motion sequences at hand and no user interaction is required for the segmentation or clustering. Tests of our techniques are conducted on the CMU and HDM05 motion capture databases demonstrating the capability of our system handling motion segmentation, clustering, motion synthesis and transfer-of-label problems in practice - the latter being an optional step which relies on the preexistence of a small set of labeled data.
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    Efficient Self-Shadowing Using Image-Based Lighting on Glossy Surfaces
    (The Eurographics Association, 2014) Knuth, Martin; Altenhofen, Christian; Kuijper, Arjan; Bender, Jan; Jan Bender and Arjan Kuijper and Tatiana von Landesberger and Holger Theisel and Philipp Urban
    In this paper we present a novel natural illumination approach for real-time rasterization-based rendering with environment map-based high dynamic range lighting. Our approach allows to use all kinds of glossiness values for surfaces, ranging continuously from completely diffuse up to mirror-like glossiness. This is achieved by combining cosine-based diffuse, glossy and mirror reflection models in one single lighting model. We approximate this model by filter functions, which are applied to the environment map. This results in a fast, image-based lookup for the different glossiness values which gives our technique the high performance that is necessary for real-time rendering. In contrast to existing real-time rasterization-based natural illumination techniques, our method has the capability of handling high gloss surfaces with directional self-occlusion. While previous works exchange the environment map by virtual point light sources in the whole lighting and shadow computation, we keep the full image information of the environment map in the lighting process and only use virtual point light sources for the shadow computation. Our technique was developed for the usage in real-time virtual prototyping systems for garments since here typically a small scene is lit by a large environment which fulfills the requirements for imagebased lighting. In this application area high performance rendering techniques for dynamic scenes are essential since a physical simulation is usually running in parallel on the same machine. However, also other applications can benefit from our approach.
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    Interactive Rendering of Giga-Particle Fluid Simulations
    (The Eurographics Association, 2014) Reichl, Florian; Chajdas, Matthäus G.; Schneider, Jens; Westermann, Rüdiger; Ingo Wald and Jonathan Ragan-Kelley
    We describe the design of an interactive rendering system for particle-based fluid simulations comprising hundreds of millions of particles per time step. We present a novel binary voxel representation for particle positions in combination with random jitter to drastically reduce memory and bandwidth requirements. To avoid a time-consuming preprocess and restrict the workload to what is seen, the construction of this representation is embedded into frontto- back GPU ray-casting. For high speed rendering, we ray-cast spheres and extend on total-variation-based image de-noising models to smooth the fluid surface according to data specific boundary conditions. The regular voxel structure permits highly efficient ray-sphere intersection testing as well as classification of foam particles at runtime on the GPU. Foam particles are rendered volumetrically by reconstructing densities from the binary representation on-the-fly. The particular design of our system allows scrubbing through high-resolution animated fluids at interactive rates.
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    Automatic Garment Modeling From Front And Back Images
    (The Eurographics Association, 2014) Huang, Lifeng; Gao, Chengying; John Keyser and Young J. Kim and Peter Wonka
    We present a system which can automatically generate a realistic garment model from two images of an existing garment. Without the requirement of tailoring expertise and tedious operation, our method takes the front and back images of a real garment as input, and the system will make reasonable geometric modeling as well as physical simulation of the garment. Combining with mannequin's skeleton information, we propose a panel positioning method to place garment panels in appropriate positions. A key feature of our system is to automatically interpret sewn information, which effectively simplifies user interaction. In addition, panel deformation method based on mannequin's pose allows easy data capture. It extends the flexibility and utility of our method. The experiments demonstrate the effectiveness on generating models of various garment styles.
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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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    Reduced Precision for Hardware Ray Tracing in GPUs
    (The Eurographics Association, 2014) Keely, Sean; Ingo Wald and Jonathan Ragan-Kelley
    We propose a high performance, GPU integrated, hardware ray tracing system. We present and make use of a new analysis of ray traversal in axis aligned bounding volume hierarchies. This analysis enables compact traversal hardware through the use of reduced precision arithmetic. We also propose a new cache based technique for scheduling ray traversal. With the addition of our compact fixed function traversal unit and cache mechanism, we show that current GPU architectures are well suited for hardware accelerated ray tracing, requiring only small modifications to provide high performance. By making use of existing GPU resources we are able to keep all rays and scheduling traffic on chip and out of caches. We used simulations to estimate the performance of our architecture. Our system achieves an average ray rate of 3.4 billion rays per second while path tracing our test scenes.
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    Reducing Anisotropic BSDF Measurement to Common Practice
    (The Eurographics Association, 2014) Ward, Greg; Kurt, Murat; Bonneel, Nicolas; Reinhard Klein and Holly Rushmeier
    We address the problem of measuring and representing reflection and transmission for anisotropic materials without relying on mathematical models or a large sample database. By eliminating assumptions of material behavior, we arrive at a general method that works for any surface class, from metals to fabrics, fritted glazing, and prismatic films. To make data gathering practical, we introduce a robust analysis method that interpolates a sparse set of incident angle measurements to obtain a continuous function over the full 4-D domain. We then convert this interpolant to a standard representation tailored for efficient rendering and supported by a common library that facilitates data sharing. We conclude with some remaining challenges to making anisotropic BSDF measurements truly practical for rendering
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    Interactive Appearance Editing in RGB-D Images
    (The Eurographics Association, 2014) Bergmann, Stephan; Ritschel, Tobias; Dachsbacher, Carsten; Jan Bender and Arjan Kuijper and Tatiana von Landesberger and Holger Theisel and Philipp Urban
    The availability of increasingly powerful and affordable image and depth sensors in conjunction with the necessary processing power creates novel possibilities for more sophisticated and powerful image editing tools. Along these lines we present a method to alter the appearance of objects in RGB-D images by re-shading their surfaces with arbitrary BRDF models and subsurface scattering using the dipole diffusion approximation. To evaluate the incident light for re-shading we combine ray marching using the depth buffer as approximate geometry and environment lighting. The environment map is built from information solely contained in the RGB-D input image exploiting both the reflections on glossy surfaces as well as geometric information. Our CPU/GPU implementation provides interactive feedback to facilitate intuitive editing.We compare and demonstrate our method with rendered images and digital photographs.
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    Perceptually Optimised Illumination for Seamless Composites
    (The Eurographics Association, 2014) Chalmers, Andrew; Choi, Jong Jin; Rhee, Taehyun; John Keyser and Young J. Kim and Peter Wonka
    Realistic illumination in composition is important for a seamless mixture between the virtual and real world objects in visual effects and mixed reality. The seamlessness is the measure of how perceivably apparent the synthetic object in the final composition is, and how indistinguishable it is from the photographed scene. Given that the ultimate receiver of image information is the human eye, the metric is determined by the Human Visual System (HVS). We conducted a series of psychophysical studies to observe and capture the thresholds of the HVS's ability to perceive illumination inconsistencies between the rendered subject and the photographed scene. Based on our observations, we find perceptually optimised thresholds for reducing resources across resolution and dynamic range of the radiance map (RM) for image based lighting (IBL). We evaluated our thresholds to illuminate virtual objects for seamless composition with photographed scenes.