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Now showing 1 - 10 of 14
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    Geometry and Attribute Compression for Voxel Scenes
    (The Eurographics Association and John Wiley & Sons Ltd., 2016) Dado, Bas; Kol, Timothy R.; Bauszat, Pablo; Thiery, Jean-Marc; Eisemann, Elmar; Joaquim Jorge and Ming Lin
    Voxel-based approaches are today's standard to encode volume data. Recently, directed acyclic graphs (DAGs) were successfully used for compressing sparse voxel scenes as well, but they are restricted to a single bit of (geometry) information per voxel. We present a method to compress arbitrary data, such as colors, normals, or reflectance information. By decoupling geometry and voxel data via a novel mapping scheme, we are able to apply the DAG principle to encode the topology, while using a palette-based compression for the voxel attributes, leading to a drastic memory reduction. Our method outperforms existing state-of-the-art techniques and is well-suited for GPU architectures. We achieve real-time performance on commodity hardware for colored scenes with up to 17 hierarchical levels (a 128K3 voxel resolution), which are stored fully in core.
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    Inertial Steady 2D Vector Field Topology
    (The Eurographics Association and John Wiley & Sons Ltd., 2016) Günther, Tobias; Theisel, Holger; Joaquim Jorge and Ming Lin
    Vector field topology is a powerful and matured tool for the study of the asymptotic behavior of tracer particles in steady flows. Yet, it does not capture the behavior of finite-sized particles, because they develop inertia and do not move tangential to the flow. In this paper, we use the fact that the trajectories of inertial particles can be described as tangent curves of a higher dimensional vector field. Using this, we conduct a full classification of the first-order critical points of this higher dimensional flow, and devise a method to their efficient extraction. Further, we interactively visualize the asymptotic behavior of finite-sized particles by a glyph visualization that encodes the outcome of any initial condition of the governing ODE, i.e., for a varying initial position and/or initial velocity. With this, we present a first approach to extend traditional vector field topology to the inertial case.
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    Generalized Diffusion Curves: An Improved Vector Representation for Smooth-Shaded Images
    (The Eurographics Association and John Wiley & Sons Ltd., 2016) Jeschke, Stefan; Joaquim Jorge and Ming Lin
    This paper generalizes the well-known Diffusion Curves Images (DCI), which are composed of a set of Bezier curves with colors specified on either side. These colors are diffused as Laplace functions over the image domain, which results in smooth color gradients interrupted by the Bezier curves. Our new formulation allows for more color control away from the boundary, providing a similar expressive power as recent Bilaplace image models without introducing associated issues and computational costs. The new model is based on a special Laplace function blending and a new edge blur formulation. We demonstrate that given some user-defined boundary curves over an input raster image, fitting colors and edge blur from the image to the new model and subsequent editing and animation is equally convenient as with DCIs. Numerous examples and comparisons to DCIs are presented.
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    Regularizing Image Reconstruction for Gradient-Domain Rendering with Feature Patches
    (The Eurographics Association and John Wiley & Sons Ltd., 2016) Manzi, Marco; Vicini, Delio; Zwicker, Matthias; Joaquim Jorge and Ming Lin
    We present a novel algorithm to reconstruct high-quality images from sampled pixels and gradients in gradient-domain rendering. Our approach extends screened Poisson reconstruction by adding additional regularization constraints. Our key idea is to exploit local patches in feature images, which contain per-pixels normals, textures, position, etc., to formulate these constraints. We describe a GPU implementation of our approach that runs on the order of seconds on megapixel images. We demonstrate a significant improvement in image quality over screened Poisson reconstruction under the L1 norm. Because we adapt the regularization constraints to the noise level in the input, our algorithm is consistent and converges to the ground truth.
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    Single Image Weathering via Exemplar Propagation
    (The Eurographics Association and John Wiley & Sons Ltd., 2016) Iizuka, Satoshi; Endo, Yuki; Kanamori, Yoshihiro; Mitani, Jun; Joaquim Jorge and Ming Lin
    This paper presents an efficient approach for generating weathering effects with detailed appearance variations in a single image. Previous approaches merely change chroma or reflectance of weathered objects, which is not sufficient for materials with detailed shading and texture variations, such as growing moss and peeling plaster. Our method propagates such detailed features via seamless patch-based synthesis driven by weathering degree distribution. Unlike previous methods, the weathering degrees are calculated efficiently using Radial Basis Functions even for materials with wide color variations. We use graph cut-based optimization to identify the most weathered region as a ''weathering exemplar'', from which we sample weathering patches. We demonstrate our method enables us to generate various types of detailed weathering effects interactively.
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    Near-Instant Capture of High-Resolution Facial Geometry and Reflectance
    (The Eurographics Association and John Wiley & Sons Ltd., 2016) Fyffe, Graham; Graham, Paul; Tunwattanapong, Borom; Ghosh, Abhijeet; Debevec, Paul; Joaquim Jorge and Ming Lin
    We present a near-instant method for acquiring facial geometry and reflectance using a set of commodity DSLR cameras and flashes. Our setup consists of twenty-four cameras and six flashes which are fired in rapid succession with subsets of the cameras. Each camera records only a single photograph and the total capture time is less than the 67ms blink reflex. The cameras and flashes are specially arranged to produce an even distribution of specular highlights on the face. We employ this set of acquired images to estimate diffuse color, specular intensity, specular exponent, and surface orientation at each point on the face. We further refine the facial base geometry obtained from multi-view stereo using estimated diffuse and specular photometric information. This allows final submillimeter surface mesostructure detail to be obtained via shape-from-specularity. The final system uses commodity components and produces models suitable for authoring high-quality digital human characters.
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    Physically-based Rendering of Highly Scattering Fluorescent Solutions using Path Tracing
    (The Eurographics Association, 2016) Abdellah, Marwan; Bilgili, Ahmet; Eilemann, Stefan; Markram, Henry; Schürmann, Felix; Luis Gonzaga Magalhaes and Rafal Mantiuk
    We introduce a physically-plausible Monte Carlo rendering technique that is capable of treating highly scattering participating media in the presence of fluorescent mixtures. Our model accounts for the actual intrinsic spectroscopic characteristics of fluorescent dyes. The model leads to an estimator for simulating the light interaction with highly scattering fluorescent-tagged participating media. Our system is applied to render images of two fluorescent solutions under different conditions. The model is qualitatively analyzed and validated against experimental emission spectra of fluorescent dyes.
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    Real-Time Video Texture Synthesis for Multi-Frame Capsule Endoscopy Visualization
    (The Eurographics Association, 2016) Ecker, Ady; Luis Gonzaga Magalhaes and Rafal Mantiuk
    We present a real-world application of real-time video texture synthesis for capsule endoscopy
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    Augmenting Physical Maps: an AR Platform for Geographical Information Visualization
    (The Eurographics Association, 2016) Nóbrega, Rui; Jacob, João; Rodrigues, Rui; Coelho, António; Sousa, A. Augusto de; Luis Gonzaga Magalhaes and Rafal Mantiuk
    Physical maps of a city or region are important pieces of geographical information for tourists and local citizens. Unfortunately the amount of information that can be presented on a piece of paper is limited. In order to extend the map information we propose an augmented reality (AR) system, ARTourMap, for additional information visualization and interaction. This system provides an abstraction layer to develop applications based on the concept of separated logic map tiles taking advantage of a multi-target system where several regions of the map trigger different superimposed graphics. This allows the map to be folded, to be partially occluded, and to have dematerialized information. To demonstrate the proposed system ARTourMap, three layers were developed: a location-based game with points of interest (POIs), a 3D building visualization and an historical map layer.
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    General Projective Maps for Multidimensional Data Projection
    (The Eurographics Association and John Wiley & Sons Ltd., 2016) Lehmann, Dirk J.; Theisel, Holger; Joaquim Jorge and Ming Lin
    To project high-dimensional data to a 2D domain, there are two well-established classes of approaches: RadViz and Star Coordinates. Both are well-explored in terms of accuracy, completeness, distortions, and interaction issues. We present a generalization of both RadViz and Star Coordinates such that it unifies both approaches. We do so by considering the space of all projective projections. This gives additional degrees of freedom, which we use for three things: Firstly, we define a smooth transition between RadViz and Star Coordinates allowing the user to exploit the advantages of both approaches. Secondly, we define a data-dependent magic lens to explore the data. Thirdly, we optimize the new degrees of freedom to minimize distortion. We apply our approach to a number of high-dimensional benchmark datasets.