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59 results on '"Acquisition, representation and transformations for image synthesis (ARTIS)"'

1. Edge-preserving multiscale image decomposition based on local extrema

Author: Kartic Subr, Frédo Durand, Cyril Soler, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Massachusetts Institute of Technology (MIT), ANR-07-BLAN-0331,HFIBMR,High-Fidelity Image-Based Modeling and Rendering(2007), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF), Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, and Durand, Fredo
Subjects: Computer science, Property (programming), ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, ACM: I.: Computing Methodologies/I.4: IMAGE PROCESSING AND COMPUTER VISION/I.4.3: Enhancement/I.4.3.0: Filtering, 02 engineering and technology, computer.software_genre, Image (mathematics), Computational photography, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Computer vision, Mathematics, image decomposition, Multimedia, business.industry, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.5: Computational Geometry and Object Modeling/I.3.5.7: Physically based modeling, 020207 software engineering, Contrast (music), Computer Graphics and Computer-Aided Design, Computational photography (artistic), Maxima and minima, [INFO.INFO-TI]Computer Science [cs]/Image Processing [eess.IV], Key (cryptography), computational photography, 020201 artificial intelligence & image processing, Artificial intelligence, Enhanced Data Rates for GSM Evolution, business, Maxima, computer, Algorithm
Abstract: We propose a new model for detail that inherently captures oscillations , a key property that distinguishes textures from individual edges. Inspired by techniques in empirical data analysis and morphological image analysis, we use the local extrema of the input image to extract information about oscillations: We define detail as oscillations between local minima and maxima. Building on the key observation that the spatial scale of oscillations are characterized by the density of local extrema, we develop an algorithm for decomposing images into multiple scales of superposed oscillations. Current edge-preserving image decompositions assume image detail to be low contrast variation. Consequently they apply filters that extract features with increasing contrast as successive layers of detail. As a result, they are unable to distinguish between high-contrast, fine-scale features and edges of similar contrast that are to be preserved. We compare our results with existing edge-preserving image decomposition algorithms and demonstrate exciting applications that are made possible by our new notion of detail.
Published: 2009

2. Frequency analysis and sheared reconstruction for rendering motion blur

Author: Frédo Durand, Kevin Egan, Yu-Ting Tseng, Nicolas Holzschuch, Ravi Ramamoorthi, Department of Computer Science [New York], Columbia University [New York], Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Massachusetts Institute of Technology (MIT), Computer Science and Artificial Intelligence Laboratory [Cambridge] (CSAIL), Department of Electrical Engineering and Computer Science [Berkeley] (EECS), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), ANR-07-BLAN-0331,HFIBMR,High-Fidelity Image-Based Modeling and Rendering(2007), University of California [Berkeley], University of California-University of California, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, and Durand, Fredo
Subjects: Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 02 engineering and technology, Reconstruction filter, Anti-aliasing, law.invention, Rendering (computer graphics), ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, law, 0202 electrical engineering, electronic engineering, information engineering, 0601 history and archaeology, Computer vision, 14. Life underwater, Specular reflection, ComputingMethodologies_COMPUTERGRAPHICS, Frequency analysis, 060102 archaeology, Pixel, business.industry, Motion blur, 020207 software engineering, 06 humanities and the arts, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Computer Science::Graphics, Frequency domain, 020201 artificial intelligence & image processing, Artificial intelligence, business
Abstract: Motion blur is crucial for high-quality rendering, but is also very expensive. Our first contribution is a frequency analysis of motion-blurred scenes, including moving objects, specular reflections, and shadows. We show that motion induces a shear in the frequency domain, and that the spectrum of moving scenes can be approximated by a wedge. This allows us to compute adaptive space-time sampling rates, to accelerate rendering. For uniform velocities and standard axis-aligned reconstruction, we show that the product of spatial and temporal bandlimits or sampling rates is constant, independent of velocity. Our second contribution is a novel sheared reconstruction filter that is aligned to the first-order direction of motion and enables even lower sampling rates. We present a rendering algorithm that computes a sheared reconstruction filter per pixel, without any intermediate Fourier representation. This often permits synthesis of motion-blurred images with far fewer rendering samples than standard techniques require., United States. Office of Naval Research. Young Investigator Program (N00014-07-1-0900), United States. Office of Naval Research. (Grant number N00014-09-1-0741), National Science Foundation (U.S.). Graduate Research Fellowship Program, National Science Foundation (U.S.). (Grant number 0446916), National Science Foundation (U.S.). (Grant number 044756), National Science Foundation (U.S.). (Grant number 0701775), Alfred P. Sloan Foundation Fellowship, Microsoft Corporation. New Faculty Fellowship
Published: 2009

3. Texture Design and Draping in 2D Images

Author: Holger Winnemöller, Laurence Boissieux, A. Orzan, Joëlle Thollot, Adobe Systems Inc. (Adobe Advanced Technology Labs), Adobe Systems Inc., Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF), SED [Grenoble], Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), and Service Expérimentation et Développement (SED [Grenoble])
Subjects: 2d images, Computer science, business.industry, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, 02 engineering and technology, 3D modeling, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, business, Texture design
Abstract: International audience; We present a complete system for designing and manipulating regular or near-regular textures in 2D images. We place emphasis on supporting creative workflows that produce artwork from scratch. As such, our system provides tools to create, arrange, and manipulate textures in images with intuitive controls, and without requiring 3D modeling. Additionally, we ensure continued, non-destructive editability by expressing textures via a fully parametric descriptor. We demonstrate the suitability of our approach with numerous example images, created by an artist using our system, and we compare our proposed workflow with alternative 2D and 3D methods.
Published: 2009

4. Apparent Greyscale: A Simple and Fast Conversion to Perceptually Accurate Images and Video

Author: Pierre-Edouard Landes, Kaleigh Smith, Karol Myszkowski, Joëlle Thollot, Max-Planck-Institut für Informatik (MPII), Max-Planck-Gesellschaft, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: Lightness, business.industry, Computer science, media_common.quotation_subject, 020207 software engineering, 02 engineering and technology, Computer Graphics and Computer-Aided Design, Grayscale, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], law.invention, Image (mathematics), Chromatic contrast, Range (mathematics), Achromatic lens, law, Simple (abstract algebra), 0202 electrical engineering, electronic engineering, information engineering, Contrast (vision), 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, business, media_common
Abstract: International audience; The basic problem of greyscale transformation is to reproduce the intent of the colour original, its contrasts and salient features, while preserving the perceived magnitude and direction of its gradients. The transformation consists of two interdependent tasks: a mapping that assigns a grey value to each pixel or colour, and a discriminability constraint so that the achromatic differences match their corresponding original colour differences. Recent approaches solve discriminability constraints to determine the grey values, producing images in which the original colour contrasts are highly discriminable. However, the greyscale images may exhibit exaggerated dynamic range, an arbitrary achromatic order that differs among colour palettes, and a smoothing or masking of details. These modifications all contribute to make the grey version appear dissimilar from its original and create inconsistency among like images and video frames. The goal of this work is to create a perceptually accurate version of the colour image that represents its psychophysical effect on a viewer. Such greyscale imagery is important for printed textbooks and catalogues, the stylization of videos and for display on monochromatic medical displays. A perceptually accurate image is one that emulates both global and local impressions: it matches the original values' range and average luminance, its local contrasts are neither exaggerated nor understated, its grey values are ordered according to colour appearance and differences in spatial details are imperceptible. Strong perceptual similarity is particularly important for consistency over varying palettes and temporal coherence for animations.
Published: 2008

5. Clip Art Rendering of Smooth Isosurfaces

Author: Elmar Eisemann, Matei Stroila, John Hart, University of Illinois at Urbana-Champaign [Urbana], University of Illinois System, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), University of Illinois at Urbana Champaign (UIUC), and University of Illinois System-University of Illinois System
Subjects: Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Clip art, 02 engineering and technology, non-photorealistic rendering, 050105 experimental psychology, Pattern Recognition, Automated, Silhouette, Rendering (computer graphics), Computer graphics, User-Computer Interface, Vector graphics, Imaging, Three-Dimensional, Computer graphics (images), Image Interpretation, Computer-Assisted, Shadow, Computer Graphics, 0202 electrical engineering, electronic engineering, information engineering, 0501 psychology and cognitive sciences, Computer vision, particle systems, ComputingMethodologies_COMPUTERGRAPHICS, Particle system, business.industry, line art drawing, 05 social sciences, 020207 software engineering, Image Enhancement, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Non-photorealistic rendering, Signal Processing, Polygon, Computer Vision and Pattern Recognition, Artificial intelligence, business, Algorithms, Software
Abstract: International audience; Clip art is a simplified illustration form consisting of layered filled polygons or closed curves used to convey 3-D shape information in a 2-D vector graphics format. This paper focuses on the problem of direct conversion of smooth surfaces, ranging from the free-form shapes of art and design to the mathematical structures of geometry and topology, into a clip art form suitable for illustration use in books, papers and presentations. We show how to represent silhouette, shadow, gleam and other surface feature curves as the intersection of implicit surfaces, and derive equations for their efficient interrogation via particle chains. We further describe how to sort, orient, identify and fill the closed regions that overlay to form clip art. We demonstrate the results with numerous renderings used to illustrate the paper itself. More at http://artis.imag.fr/Publications/2008/SEH08/
Published: 2008

6. Stroke Pattern Analysis and Synthesis

Author: Simon Breslav, Pascal Barla, François X. Sillion, Joëlle Thollot, Lee Markosian, Acquisition, representation and transformations for image synthesis (ARTIS), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), Department of Electrical Engineering and Computer Science (EECS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Eduard Gröller and László Szirmay-Kalos, and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Inria Grenoble - Rhône-Alpes
Subjects: ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism/I.3.7.1: Color, shading, shadowing, and texture, business.industry, Computer science, media_common.quotation_subject, Pattern analysis, 020207 software engineering, 02 engineering and technology, Extension (predicate logic), medicine.disease, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.4: Graphics Utilities/I.3.4.5: Paint systems, Perception, 0202 electrical engineering, electronic engineering, information engineering, medicine, 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, business, Stroke, media_common, Texture synthesis
Abstract: International audience; We present a synthesis technique that can automatically generate stroke patterns based on a user-speciﬁed reference pattern. Our method is an extension of texture synthesis techniques to vector-based patterns. Such an extension requires (a) an analysis of the pattern properties to extract meaningful pattern elements (deﬁned as clusters of strokes) and (b) a synthesis algorithm based on similarities in the detected stroke clusters. Our method is based on results from human vision research concerning perceptual organization. The resulting synthesized patterns effectively reproduce the properties of the input patterns, and can be used to ﬁll both 1D paths and 2D regions.
Published: 2006

7. Real-Time Rendering of Rough Refraction

Author: Adrien Bousseau, Ravi Ramamoorthi, Kartic Subr, Charles de Rousiers, Nicolas Holzschuch, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Rendering and virtual environments with sound (REVES), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Computer science department [University College London] (UCL-CS), University College of London [London] (UCL), Models and Algorithms for Visualization and Rendering (MAVERICK), Department of Electrical Engineering and Computer Science [Berkeley] (EECS), University of California [Berkeley], University of California-University of California, ANR-07-MDCO-0001,ATROCO,Acquisition, Traitement et Rendu d'Objets Complexes(2007), Department of Computer science [University College of London] (UCL-CS), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)
Subjects: Photon mapping, Scattering, business.industry, Computer science, 020207 software engineering, 02 engineering and technology, Computer Graphics and Computer-Aided Design, Real-time rendering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Optics, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Signal Processing, 0202 electrical engineering, electronic engineering, information engineering, Surface roughness, Transmittance, 020201 artificial intelligence & image processing, Computer vision, Computer Vision and Pattern Recognition, Artificial intelligence, Cone tracing, business, Software, Distributed ray tracing
Abstract: International audience; We present an algorithm to render objects made of transparent materials with rough surfaces in real-time, under all-frequency distant illumination. Rough surfaces cause wide scattering as light enters and exits objects, which significantly complicates the rendering of such materials. We present two contributions to approximate the successive scattering events at interfaces, due to rough refraction: First, an approximation of the Bidirectional Transmittance Distribution Function (BTDF), using spherical Gaussians, suitable for real-time estimation of environment lighting using pre-convolution; second, a combination of cone tracing and macro-geometry filtering to efficiently integrate the scattered rays at the exiting interface of the object. We demonstrate the quality of our approximation by comparison against stochastic ray-tracing. Furthermore we propose two extensions to our method for supporting spatially varying roughness on object surfaces and local lighting for thin objects.
Published: 2012

8. Interactive Indirect Illumination Using Voxel Cone Tracing

Author: Cyril Crassin, Miguel Sainz, Elmar Eisemann, Simon Green, Fabrice Neyret, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), NVIDIA (NVIDIA), and Télécom ParisTech
Subjects: Computer science, Global illumination, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, GPU, 02 engineering and technology, computer.software_genre, Octree, cone-tracing, Voxel, Computer graphics (images), final gather, 0202 electrical engineering, electronic engineering, information engineering, Computer vision, ComputingMethodologies_COMPUTERGRAPHICS, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism/I.3.7.1: Color, shading, shadowing, and texture, business.industry, Visibility (geometry), 020207 software engineering, real-time rendering, Computer Graphics and Computer-Aided Design, Real-time rendering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Image synthesis, voxels, global illumination, Ambient occlusion, 020201 artificial intelligence & image processing, Artificial intelligence, Cone tracing, Bidirectional reflectance distribution function, business, computer, indirect lighting
Abstract: Special issue: Proceedings of Pacific Graphics - Session: Lighting & Rendering; International audience; Indirect illumination is an important element for realistic image synthesis, but its computation is expensive and highly dependent on the complexity of the scene and of the BRDF of the involved surfaces. While off-line computation and pre-baking can be acceptable for some cases, many applications (games, simulators, etc.) require real-time or interactive approaches to evaluate indirect illumination. We present a novel algorithm to compute indirect lighting in real-time that avoids costly precomputation steps and is not restricted to low-frequency illumination. It is based on a hierarchical voxel octree representation generated and updated on the fly from a regular scene mesh coupled with an approximate voxel cone tracing that allows for a fast estimation of the visibility and incoming energy. Our approach can manage two light bounces for both Lambertian and glossy materials at interactive framerates (25-70FPS). It exhibits an almost scene-independent performance and can handle complex scenes with dynamic content thanks to an interactive octree-voxelization scheme. In addition, we demonstrate that our voxel cone tracing can be used to efficiently estimate Ambient Occlusion.
Published: 2011

9. Visualization of uncertain scalar data fields using color scales and perceptually adapted noise

Author: Jacques Droulez, Alexandre Coninx, Guillaume Thibault, Georges-Pierre Bonneau, Laboratoire de Physiologie de la Perception et de l'Action (LPPA), Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS), Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), EDF (EDF), EDF R&D and a CIFRE grant from Association Nationale de la Recherche et de la Technologie, SIGGRAPH, and Stephen N. Spencer
Subjects: Computer science, Data field, 02 engineering and technology, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.3: Picture/Image Generation/I.3.3.3: Display algorithms, 050105 experimental psychology, Computer graphics, psychophysics, 0202 electrical engineering, electronic engineering, information engineering, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.8: Applications, 0501 psychology and cognitive sciences, Computer vision, Sensitivity (control systems), scientific visualization, ComputingMethodologies_COMPUTERGRAPHICS, contrast sensitivity, business.industry, 05 social sciences, Scientific visualization, Scalar (physics), 020207 software engineering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Visualization, Noise, computer graphics, [SCCO.PSYC]Cognitive science/Psychology, uncertainty visualization, Artificial intelligence, Perlin noise, business
Abstract: Session: Visualization; International audience; We present a new method to visualize uncertain scalar data fields by combining color scale visualization techniques with animated, perceptually adapted Perlin noise. The parameters of the Perlin noise are controlled by the uncertainty information to produce animated patterns showing local data value and quality. In order to precisely control the perception of the noise patterns, we perform a psychophysical evaluation of contrast sensitivity thresholds for a set of Perlin noise stimuli. We validate and extend this evaluation using an existing computational model. This allows us to predict the perception of the uncertainty noise patterns for arbitrary choices of parameters. We demonstrate and discuss the efficiency and the benefits of our method with various settings, color maps and data sets.
Published: 2011

10. Multiscale Feature-Preserving Smoothing of Tomographic Data

Author: Nicolas Holzschuch, Kartic Subr, Nassim Jibai, Cyril Soler, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF), Computer science department [University College London] (UCL-CS), University College of London [London] (UCL), ACM, Dan Wexler, Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), and Department of Computer science [University College of London] (UCL-CS)
Subjects: Anisotropic diffusion, Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Feature-preserving smoothing, Edge-preserving smoothing, computer.software_genre, [INFO.INFO-CG]Computer Science [cs]/Computational Geometry [cs.CG], 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Voxel, Histogram, Medical imaging, Computer vision, 030304 developmental biology, ComputingMethodologies_COMPUTERGRAPHICS, 0303 health sciences, Contouring, business.industry, anisotropic diffusion, Feature (computer vision), Tomography, Artificial intelligence, business, computer, Smoothing, Diffusion MRI
Abstract: Poster; International audience; Computer tomography (CT) has wide application in medical imaging and reverse engineering. Due to the limited number of projections used in reconstructing the volume, the resulting 3D data is typically noisy. Contouring such data, for surface extraction, yields surfaces with localised artifacts of complex topology. To avoid such artifacts, we propose a method for feature-preserving smoothing of CT data. The smoothing is based on anisotropic diffusion, with a diffusion tensor designed to smooth noise up to a given scale, while preserving features. We compute these diffusion kernels from the directional histograms of gradients around each voxel, using a fast GPU implementation.
Published: 2011

11. 3D Inverse Dynamic Modeling of Strands

Author: Florence Bertails-Descoubes, Alexandre Derouet-Jourdan, Joëlle Thollot, Modelling, Simulation, Control and Optimization of Non-Smooth Dynamical Systems (BIPOP), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Acquisition, representation and transformations for image synthesis (ARTIS), ACM SIGGRAPH, Dan Wexler, and Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)
Subjects: Flexibility (engineering), ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.0: General, business.industry, Computation, Process (computing), Motion (geometry), 020207 software engineering, 02 engineering and technology, Animation, 01 natural sciences, Pipeline (software), [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, GeneralLiterature_MISCELLANEOUS, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], 010305 fluids & plasmas, Range (mathematics), Geometric design, ACM: A.: General Literature/A.2: REFERENCE (e.g., dictionaries, encyclopedias, glossaries), Computer graphics (images), 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Computer vision, Artificial intelligence, business, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: 1D deformable structures, often called strands, are ubiquitous in the real world. They range from plants (grass, lianas, stalks) to creatures organs (hair, tail, tentacles) and manufactured objects (cables, ropes). The realistic modeling and animation of such objects is essential for representing convincing virtual environments. Most often, the design pipeline is split in two distinct parts: the geometry creation process itself, namely geometric design, followed by the computation of motion, namely animation. For the sake of flexibility and control, the geometric design generally relies on a pure geometric process that allows the user to interactively edit curve primitives such as splines. In contrast, the animation of strands is often considered as a passive and complex phenomenon that can be realistically captured using physics-based simulation.
Published: 2011

12. Interactive indirect illumination using voxel cone tracing

Author: Fabrice Neyret, Miguel Sainz, Elmar Eisemann, Cyril Crassin, Simon Green, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), NVIDIA (NVIDIA), and Télécom ParisTech
Subjects: Global illumination, Computer science, Computation, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 02 engineering and technology, computer.software_genre, GeneralLiterature_MISCELLANEOUS, Voxel, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Computer vision, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), Shader, ComputingMilieux_MISCELLANEOUS, ComputingMethodologies_COMPUTERGRAPHICS, Pixel, business.industry, Visibility (geometry), 020207 software engineering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], 020201 artificial intelligence & image processing, ComputingMethodologies_GENERAL, Artificial intelligence, Cone tracing, Bidirectional reflectance distribution function, business, computer
Abstract: Indirect illumination is an important element for realistic image synthesis, but its computation is expensive and highly dependent on the complexity of the scene and of the BRDF of the surfaces involved. While off-line computation and pre-baking can be acceptable for some cases, many applications (games, simulators, etc.) require real-time or interactive approaches to evaluate indirect illumination. In this paper, we present a novel real-time solution that calculates two light bounces - either glossy or diffuse - using a hierarchical voxel representation generated from a regular scene mesh. Our algorithm consists of two steps. First, direct illumination information (energy and direction) is emitted from dynamic area light sources and splatted into the voxel hierarchy, accounting for possible occluders. Secondly, we draw the scene mesh and compute the illumination in the pixel shader by combining the direct illumination and the indirect illumination received from the rest of the scene. For the latter, our approach employs an approximate voxel cone tracing to efficiently collect visibility and light in the hierarchical voxel representation of the scene. Our solution offers real-time and almost geometry-independent performance with a high visual quality for complex scenes with diffuse, as well as glossy surfaces.
Published: 2011

13. Lagrangian Texture Advection: Preserving both Spectrum and Velocity Field

Author: Nicolas Holzschuch, Fabrice Neyret, Eric Bruneton, Qizhi Yu, Virtual environments for animation and image synthesis of natural objects (EVASION), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Acquisition, representation and transformations for image synthesis (ARTIS), Marie Curie PhD grant through the VISITOR project (first author)., and ANR-07-MDCO-0001,ATROCO,Acquisition, Traitement et Rendu d'Objets Complexes(2007)
Subjects: Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 02 engineering and technology, Computer graphics, Physics::Fluid Dynamics, Image texture, Texture filtering, 0202 electrical engineering, electronic engineering, information engineering, Computer Graphics, Computer vision, Texture advection, Statistical physics, Texture, ComputingMethodologies_COMPUTERGRAPHICS, Pixel, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism/I.3.7.1: Color, shading, shadowing, and texture, business.industry, Texture (cosmology), Lagrangian methods, 020207 software engineering, Animation, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Visualization, Noise, Computer Science::Graphics, Particles, Computer Science::Computer Vision and Pattern Recognition, Signal Processing, 020201 artificial intelligence & image processing, Vector field, Computer Vision and Pattern Recognition, Artificial intelligence, business, Software
Abstract: International audience; Texturing an animated fluid is a useful way to augment the visual complexity of pictures without increasing the simulation time. But texturing flowing fluids is a complex issue, as it creates conflicting requirements: we want to keep the key texture properties (features, spectrum) while advecting the texture with the underlying flow - which distorts it. In this paper, we present a new, Lagrangian, method for advecting textures: the advected texture is computed only locally and follows the velocity field at each pixel. The texture retains its local properties, including its Fourier spectrum, even though it is accurately advected. Due to its Lagrangian nature, our algorithm can perform on very large, potentially infinite scenes in real time. Our experiments show that it is well suited for a wide range of input textures, including, but not limited to, noise textures.
Published: 2010

14. Adaptive GPU Ray Casting Based on Spectral Analysis

Author: Rüdiger Dillmann, Stefan Suwelack, Roland Unterhinninghofen, Eric Heitz, Karlsruhe Institute of Technology (KIT), Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Klaus Tschira Foundation, Hongen Liao, P. J. 'Eddie' Edwards, Xiaochuan Pan, Yong Fan, and Guang-Zhong Yang
Subjects: Adaptive sampling, Speedup, business.industry, Computer science, 020207 software engineering, Volume rendering, 02 engineering and technology, Spectral analysis, Transfer function, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], 030218 nuclear medicine & medical imaging, Matrix decomposition, Visualization, Rendering (computer graphics), Gpu raycasting, 03 medical and health sciences, 0302 clinical medicine, Ray casting, 0202 electrical engineering, electronic engineering, information engineering, Computer vision, Artificial intelligence, business, Algorithm
Abstract: Oral session: Shape Modeling and Morphometry; International audience; GPU based ray casting has become a valuable tool for the visualization of medical image data. While the method produces high- quality images, its main drawback is the high computational load. We present a novel adaptive approach to speed up the rendering. In contrast to well established heuristic methods, we use the spectral decomposition of the transfer function and the dataset to derive a suitable sampling criterion. It is shown how this criterion can be e ciently incorporated into an adaptive ray casting algorithm. Two medical datasets, which each represent a typical, but di erent material distribution, are rendered using the proposed method. An analysis of the number of sample points per ray reveals that the new algorithm requires 50% to 80% less points compared to a non-adaptive method without any quality loss. We also show that the rendering speed of the GPU implementation is greatly increased with reference to the non-adaptive algorithm.
Published: 2010

15. A Deferred Shading Pipeline for Real-Time Indirect Illumination

Author: Olivier Hoel, Frank Rochet, Cyril Soler, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF), EDEN Games, GARDEN (FUI), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: Deferred shading, business.industry, Computer science, Global illumination, Pipeline (computing), ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, Context (language use), 02 engineering and technology, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Constant (computer programming), Image-based lighting, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, business, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: CD Rom - Talk session: Split Second Screen Space; International audience; We present a deferred shading algorithm for computing screen-space multi-bounce indirect illumination with visibility, in real time. For each frame, we compute mipmapped G-Buffers of depth, normals, illumination and voxelized geometry. To each mipmap level we apply a single shader that gathers screen-space illumination using local Monte-Carlo integration. We upsample the illumination for all levels and smoothly combine them together. Our calculation is approximate but does not show artifacts, because it relies on noise-free Monte-Carlo integration of incoming illumination and temporal filtering. Our method simulates arbitrary distant illumination including visibility at a very low cost, because we only perform local texture lookups during computation. Besides, its deferred shading nature makes it independent of geometric and lighting complexity.
Published: 2010

16. NPR Gabor Noise for Coherent Stylization

Author: Pierre Bénard, Ares Lagae, Sylvain Lefebvre, Joëlle Thollot, George Drettakis, Peter Vangorp, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Rendering and virtual environments with sound (REVES), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Department of Computer Science [Leuven] (CS), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Geometry and Lighting (ALICE), INRIA Lorraine, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université Henri Poincaré - Nancy 1 (UHP)-Université Nancy 2-Institut National Polytechnique de Lorraine (INPL)-Centre National de la Recherche Scientifique (CNRS)-Université Henri Poincaré - Nancy 1 (UHP)-Université Nancy 2-Institut National Polytechnique de Lorraine (INPL)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)
Subjects: noise, business.industry, Computer science, expressive rendering, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, 02 engineering and technology, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.3: Picture/Image Generation, 3D rendering, non-photorealistic rendering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Non-photorealistic rendering, Rendering (computer graphics), user study, Motion field, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, business, temporal coherence, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: Talk session: Fun In Flatland; International audience; We present a new solution for temporal coherence in non-photorealistic rendering (NPR) of animations. Given the conflicting goals of preserving the 2D aspect of the style and the 3D scene motion, any such solution is a trade-off. We observe that primitive-based methods in NPR can be seen as texture-based methods when using large numbers of primitives, leading to our key insight, namely that this process is similar to sparse convolution noise in procedural texturing. Consequently, we present a new primitive for NPR based on Gabor noise, that preserves the 2D aspect of noise, conveys the 3D motion of the scene, and is temporally continuous. We can thus use standard techniques from procedural texturing to create various styles, which we show for interactive NPR applications. We also present a user study to evaluate this and existing solutions, and to provide more insight in the trade-off implied by temporal coherence. The results of the study indicate that maintaining coherent motion is important, but also that our new solution provides a good compromise between the 2D aspect of the style and 3D motion.
Published: 2010

17. Diffusion Constraints for Vector Graphics

Author: Elmar Eisemann, Doug DeCarlo, Joëlle Thollot, Hedlena Bezerra, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF), Télécom ParisTech, Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers), CAPES Brazil (H. Bezerra) - The Alexander von Humboldt Foundation and the National Science Foundation under grant CCF-0541185 (D. DeCarlo)., and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: Diffusion (acoustics), Expressive rendering, business.industry, Anisotropic diffusion, Computer science, Linear system, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, 02 engineering and technology, Poisson equation, [INFO.INFO-CL]Computer Science [cs]/Computation and Language [cs.CL], Image (mathematics), Set (abstract data type), Vector graphics, Software, Diffusion process, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, business, Algorithm, Color diffusion
Abstract: Session: Research papers; International audience; The formulation of Diffusion Curves [Orzan et al. 2008] allows for the flexible creation of vector graphics images from a set of curves and colors: a diffusion process fills out the parts of the image that are away from curves. However, this model has limitations in certain situations and does not always seem to agree with how an artist wants to use the software. First, the diffusion itself cannot be controlled, only the colors. Further, the fact that color needs to be defined everywhere along the curve can lead to tedious and nonintuitive interactions. In this paper, we present a number of adaptations to diffusion curves that constrain how color is spread across the image. Specifically, we argue for the utility of controlling the speed and direction of the color diffusion, and the ability to have barriers that can be defined without the need to specify a particular color along these curves. We also describe how this can be implemented by solving a linear system, and demonstrate the effectiveness of our solution on a number of examples.
Published: 2010

18. Self-Similar Texture for Coherent Line Stylization

Author: Adam Finkelstein, Pierre Bénard, Aleksey Golovinskiy, Forrester Cole, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Computer Science and Artificial Intelligence Laboratory [Cambridge] (CSAIL), Massachusetts Institute of Technology (MIT), Department of Computer Science, Princeton University, and Work sponsored in part by Adobe, Google, and the ExploraDoc program of the region Rhone-Alpes
Subjects: Texture representation, business.industry, Computer science, Line drawings, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, 02 engineering and technology, Animation, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Non-photorealistic rendering, line drawing, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, artmap, 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, Zoom, business, temporal coherence, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: Oral Session: Lines and Strokes; International audience; Stylized line rendering for animation has traditionally traded-off between two undesirable artifacts: stroke texture sliding and stroke texture stretching. This paper proposes a new stroke texture representation, the self-similar line artmap (SLAM), which avoids both these artifacts. SLAM textures provide continuous, infinite zoom while maintaining approximately constant appearance in screen-space, and can be produced automatically from a single exemplar. SLAMs can be used as drop-in replacements for conventional stroke textures in 2D illustration and animation. Furthermore, SLAMs enable a new, simple approach to temporally coherent rendering of 3D paths that is suitable for interactive applications. We demonstrate results for 2D and 3D animations.
Published: 2010

19. A dynamic noise primitive for coherent stylization

Author: Ares Lagae, George Drettakis, Pierre Bénard, Joëlle Thollot, Sylvain Lefebvre, Peter Vangorp, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF), Rendering and virtual environments with sound (REVES), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Department of Computer Science [Leuven] (CS), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Geometry and Lighting (ALICE), INRIA Lorraine, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université Henri Poincaré - Nancy 1 (UHP)-Université Nancy 2-Institut National Polytechnique de Lorraine (INPL)-Centre National de la Recherche Scientifique (CNRS)-Université Henri Poincaré - Nancy 1 (UHP)-Université Nancy 2-Institut National Polytechnique de Lorraine (INPL)-Centre National de la Recherche Scientifique (CNRS), K.U.Leuven CREA funding (CREA/08/017), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: noise, Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 02 engineering and technology, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.3: Picture/Image Generation, non-photorealistic rendering, 050105 experimental psychology, Rendering (computer graphics), 0202 electrical engineering, electronic engineering, information engineering, 0501 psychology and cognitive sciences, Computer vision, Dynamic noise, temporal coherence, ComputingMethodologies_COMPUTERGRAPHICS, expressive rendering, business.industry, 05 social sciences, 020207 software engineering, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Non-photorealistic rendering, user study, Procedural texture, Artificial intelligence, business, Algorithm
Abstract: We present a new solution for temporal coherence in non-photorealistic rendering (NPR) of animations. Given the conflicting goals of preserving the 2D aspect of the style and the 3D scene motion, any such solution is a trade-off. We observe that primitive-based methods in NPR can be seen as texture-based methods when using large numbers of primitives, leading to our key insight, namely that this process is similar to sparse convolution noise in procedural texturing. Consequently, we present a new primitive for NPR based on Gabor noise, that preserves the 2D aspect of noise, conveys the 3D motion of the scene, and is temporally continuous. We can thus use standard techniques from procedural texturing to create various styles, which we show for interactive NPR applications. We also present a user study to evaluate this and existing solutions, and to provide more insight in the trade-off implied by temporal coherence. The results of the study indicate that maintaining coherent motion is important, but also that our new solution provides a good compromise between the 2D aspect of the style and 3D motion. ispartof: Computer Graphics Forum vol:29 issue:4 pages:1497-1506 ispartof: location:Saarbrücken, Germany status: published
Published: 2010

20. Real-time Realistic Ocean Lighting using Seamless Transitions from Geometry to BRDF

Author: Fabrice Neyret, Nicolas Holzschuch, Eric Bruneton, Virtual environments for animation and image synthesis of natural objects (EVASION), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Acquisition, representation and transformations for image synthesis (ARTIS), and ANR-07-MDCO-0001,ATROCO,Acquisition, Traitement et Rendu d'Objets Complexes(2007)
Subjects: 010504 meteorology & atmospheric sciences, Computer science, media_common.quotation_subject, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Geometry, 02 engineering and technology, 01 natural sciences, Rendering (computer graphics), Computer graphics, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Computer vision, 0105 earth and related environmental sciences, media_common, ComputingMethodologies_COMPUTERGRAPHICS, business.industry, 020207 software engineering, Animation, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Sky, Bidirectional reflectance distribution function, Artificial intelligence, business, Level of detail
Abstract: EUROGRAPHICS 2010 (full paper) - Session Rendering I; International audience; Realistic animation and rendering of the ocean is an important aspect for simulators, movies and video games. By nature, the ocean is a difficult problem for Computer Graphics: it is a dynamic system, it combines wave trains at all scales, ranging from kilometric to millimetric. Worse, the ocean is usually viewed at several distances, from very close to the viewpoint to the horizon, increasing the multi-scale issue, and resulting in aliasing problems. The illumination comes from natural light sources (the Sun and the sky dome), is also dynamic, and often underlines the aliasing issues. In this paper, we present a new algorithm for modelling, animation, illumination and rendering of the ocean, in real-time, at all scales and for all viewing distances. Our algorithm is based on a hierarchical representation, combining geometry, normals and BRDF. For each viewing distance, we compute a simplified version of the geometry, and encode the missing details into the normal and the BRDF, depending on the level of detail required. We then use this hierarchical representation for illumination and rendering. Our algorithm runs in real-time, and produces highly realistic pictures and animations.
Published: 2010

21. User-assisted intrinsic images

Author: Sylvain Paris, Frédo Durand, Adrien Bousseau, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Adobe Systems Inc. (Adobe Advanced Technology Labs), Adobe Systems Inc., Massachusetts Institute of Technology (MIT), Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, and Durand, Fredo
Subjects: ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 02 engineering and technology, intrinsic images, 01 natural sciences, Image (mathematics), Upsampling, 010309 optics, Computational photography, Simple (abstract algebra), Component (UML), 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Computer vision, Mathematics, business.industry, reflectance illumination separation, 020207 software engineering, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Product (mathematics), 020201 artificial intelligence & image processing, Artificial intelligence, Closed-form expression, business, Energy (signal processing)
Abstract: For many computational photography applications, the lighting and materials in the scene are critical pieces of information. We seek to obtain intrinsic images, which decompose a photo into the product of an illumination component that represents lighting effects and a reflectance component that is the color of the observed material. This is an under-constrained problem and automatic methods are challenged by complex natural images. We describe a new approach that enables users to guide an optimization with simple indications such as regions of constant reflectance or illumination. Based on a simple assumption on local reflectance distributions, we derive a new propagation energy that enables a closed form solution using linear least-squares. We achieve fast performance by introducing a novel downsampling that preserves local color distributions. We demonstrate intrinsic image decomposition on a variety of images and show applications., National Science Foundation (U.S.) (NSF CAREER award 0447561), Institut national de recherche en informatique et en automatique (France) (Associate Research Team “Flexible Rendering”), Microsoft Research (New Faculty Fellowship), Alfred P. Sloan Foundation (Research Fellowship), Quanta Computer, Inc. (MIT-Quanta T Party)
Published: 2009

22. Quality Assessment of Fractalized NPR Textures: a Perceptual Objective Metric

Author: François X. Sillion, Joëlle Thollot, Pierre Bénard, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF), Katerina Mania, Bernhard E. Riecke, Stephen N. Spencer, Bobby Bodenheimer, and Carol O'Sullivan, and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: Computer science, media_common.quotation_subject, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Context (language use), 02 engineering and technology, non-photorealistic rendering, Distortion, 0202 electrical engineering, electronic engineering, information engineering, Computer vision, Quality (business), media_common, ComputingMethodologies_COMPUTERGRAPHICS, business.industry, 020207 software engineering, Pattern recognition, Animation, Coherence (statistics), [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Non-photorealistic rendering, Ranking, Metric (mathematics), 020201 artificial intelligence & image processing, Artificial intelligence, perceptual evaluation, ACM: I.: Computing Methodologies/I.4: IMAGE PROCESSING AND COMPUTER VISION/I.4.7: Feature Measurement/I.4.7.5: Texture, business, texture
Abstract: International audience; Texture fractalization is used in many existing approaches to ensure the temporal coherence of a stylized animation. This paper presents the results of a psychophysical user-study evaluating the relative distortion induced by a fractalization process of typical medium textures. We perform a ranking experiment, assess the agreement among the participants and study the criteria they used. Finally we show that the average co-occurrence error is an efficient quality predictor in this context.
Published: 2009

23. Beyond Triangles : GigaVoxels Effects In Video Games

Author: Fabrice Neyret, Cyril Crassin, Miguel Sainz, Sylvain Lefebvre, Elmar Eisemann, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Rendering and virtual environments with sound (REVES), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), NVIDIA (NVIDIA), Télécom ParisTech, and Saarland University [Saarbrücken]
Subjects: Computer science, depth-of-field, sparse, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, GPU, 02 engineering and technology, computer.software_genre, GeneralLiterature_MISCELLANEOUS, Rendering (computer graphics), Data visualization, Voxel, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Polygon mesh, Computer vision, ray-tracing, Geometric data analysis, ComputingMethodologies_COMPUTERGRAPHICS, Pixel, business.industry, 020207 software engineering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], voxels, soft shadows, 020201 artificial intelligence & image processing, Ray tracing (graphics), Artificial intelligence, business, computer, out-of-core, ACM: K.: Computing Milieux/K.8: PERSONAL COMPUTING/K.8.0: General/K.8.0.0: Games
Abstract: Conference sessions - Talks: Rendering and Visualization; International audience; Voxel representations are commonly used for scientific data visualization, but also for many special effects involving complex or fuzzy data (e.g., clouds, smoke, foam). Since voxel rendering permits better and easier filtering than triangle-based representations it is also an efficient high-quality choice for complex meshes (with several triangles per pixel) and detailed geometric data (e.g., boats in Pirates of the Caribbean).
Published: 2009

24. Non-Linear Aperture for Stylized Depth of Field

Author: Adrien Bousseau, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: Computer science, Aperture, ACM: I.: Computing Methodologies/I.4: IMAGE PROCESSING AND COMPUTER VISION/I.4.8: Scene Analysis, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 02 engineering and technology, GeneralLiterature_MISCELLANEOUS, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS, Optics, 0202 electrical engineering, electronic engineering, information engineering, Computer vision, Depth of field, Abstraction (linguistics), ComputingMethodologies_COMPUTERGRAPHICS, Stylized fact, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, 020207 software engineering, Filter (signal processing), ACM: A.: General Literature, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Nonlinear system, Computer Science::Computer Vision and Pattern Recognition, Physics::Accelerator Physics, 020201 artificial intelligence & image processing, Artificial intelligence, business
Abstract: Talk session: Cameras and Imaging; no note; International audience; We introduce in this paper non-linear apertures that produce stylized depth of field from lightfield data. A non linear aperture is similar in spirit to the conventional aperture of a camera, except that it replaces the blur of shallow depth of field by a more complex detail removal filtering. The resulting non-realistic apertures produce stylized images where the amount of abstraction varies automatically with depth.
Published: 2009

25. Appearance-guided Synthesis of Element Arrangements by Example

Author: P.-E. Landes, Thomas Hurtut, Yann Gousseau, Jean-François Coeurjolly, R. Drouillhet, Joëlle Thollot, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Laboratoire Traitement et Communication de l'Information (LTCI), Télécom ParisTech-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Statistique Appliquée et de Géométrie Aléatoire de Grenoble (SAGAG), Laboratoire Jean Kuntzmann (LJK), and Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)
Subjects: Correctness, NPR, Process (engineering), Computer science, 02 engineering and technology, Machine learning, computer.software_genre, Point process, Human–computer interaction, 0202 electrical engineering, electronic engineering, information engineering, Set (psychology), Spatial analysis, Point (typography), ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism/I.3.7.1: Color, shading, shadowing, and texture, business.industry, by-example synthesis, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.5: Computational Geometry and Object Modeling, 020207 software engineering, ACM: F.: Theory of Computation/F.2: ANALYSIS OF ALGORITHMS AND PROBLEM COMPLEXITY/F.2.2: Nonnumerical Algorithms and Problems/F.2.2.2: Geometrical problems and computations, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Vector texture synthesis, 020201 artificial intelligence & image processing, Artificial intelligence, Element (category theory), business, Heuristics, computer
Abstract: Paper session: Emulating the masters; International audience; We present a technique for the analysis and re-synthesis of 2D arrangements of stroke-based vector elements. The capture of an artist's style by the sole posterior analysis of his/her achieved drawing poses a formidable challenge. Such by-example techniques could become one of the most intuitive tools for users to alleviate creation process efforts. Here, we propose to tackle this issue from a statistical point of view and take specific care of accounting for information usually overlooked in previous research, namely the elements' very appearance. Composed of curve-like strokes, we describe elements by a concise set of perceptually relevant features. After detecting appearance dominant traits, we can generate new arrangements that respect the captured appearance-related spatial statistics using multitype point processes. Our method faithfully reproduces visually similar arrangements and relies on neither heuristics nor post-processes to ensure statistical correctness.
Published: 2009

26. Fourier depth of field

Author: Frédo Durand, François X. Sillion, Nicolas Holzschuch, Kartic Subr, Cyril Soler, Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Durand, Fredo, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Massachusetts Institute of Technology (MIT), Computer Science and Artificial Intelligence Laboratory [Cambridge] (CSAIL), ANR-07-BLAN-0331,HFIBMR,High-Fidelity Image-Based Modeling and Rendering(2007), and Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)
Subjects: sampling, Pixel, Aperture, business.industry, Sampling (statistics), 020207 software engineering, 02 engineering and technology, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, 0202 electrical engineering, electronic engineering, information engineering, Radiance, Depth of Field, 020201 artificial intelligence & image processing, Monte Carlo integration, Computer vision, Depth of field, Artificial intelligence, business, Focus (optics), Light field, Mathematics, Fourier analysis of light transport
Abstract: International audience; Optical systems used in photography and cinema produce depth of ﬁeld effects, that is, variations of focus with depth. These effects are simulated in image synthesis by integrating incoming radiance at each pixel over the lense aperture. Unfortunately, aperture integration is extremely costly for defocused areas where the incoming radiance has high variance, since many samples are then required for a noise-free Monte Carlo integration. On the other hand, using many aperture samples is wasteful in focused areas where the integrand varies little. Similarly, image sampling in defocused areas should be adapted to the very smooth appearance variations due to blurring. This paper introduces an analysis of focusing and depth of ﬁeld in the frequency domain, allowing a practical characterization of a light ﬁeld's frequency content both for image and aperture sampling. Based on this analysis we propose an adaptive depth of ﬁeld rendering algorithm which optimizes sampling in two important ways. First, image sampling is based on conservative bandwidth prediction and a splatting reconstruction technique ensures correct image reconstruction. Second, at each pixel the variance in the radiance over the aperture is estimated, and used to govern sampling. This technique is easily integrated in any sampling-based renderer, and vastly improves performance.
Published: 2009

27. GigaVoxels

Author: Elmar Eisemann, Fabrice Neyret, Cyril Crassin, Sylvain Lefebvre, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Rendering and virtual environments with sound (REVES), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Max-Planck-Institut für Informatik (MPII), and Max-Planck-Gesellschaft
Subjects: Exploit, business.industry, Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, 02 engineering and technology, computer.software_genre, External Data Representation, Data structure, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], 3D rendering, Real-time rendering, Rendering (computer graphics), ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Voxel, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Polygon mesh, Computer vision, Artificial intelligence, business, computer, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; We propose a new approach to efficiently render large volumetric data sets. The system achieves interactive to real-time rendering performance for several billion voxels. Our solution is based on an adaptive data representation depending on the current view and occlusion information, coupled to an efficient ray-casting rendering algorithm. One key element of our method is to guide data production and streaming directly based on information extracted during rendering. Our data structure exploits the fact that in CG scenes, details are often concentrated on the interface between free space and clusters of density and shows that volumetric models might become a valuable alternative as a rendering primitive for real-time applications. In this spirit, we allow a quality/performance trade-off and exploit temporal coherence. We also introduce a mipmapping-like process that allows for an increased display rate and better quality through high quality filtering. To further enrich the data set, we create additional details through a variety of procedural methods. We demonstrate our approach in several scenarios, like the exploration of a 3D scan (81923 resolution), of hypertextured meshes (163843 virtual resolution), or of a fractal (theoretically infinite resolution). All examples are rendered on current generation hardware at 20-90 fps and respect the limited GPU memory budget.
Published: 2009

28. Dynamic Solid Textures for Real-Time Coherent Stylization

Author: Pierre Bénard, Joëlle Thollot, Adrien Bousseau, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)
Subjects: 3d surfaces, Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Stylized rendering, 02 engineering and technology, infinite zoom, non-photorealistic rendering, Rendering (computer graphics), ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Computer vision, Zoom, temporal coherence, ComputingMethodologies_COMPUTERGRAPHICS, Texture atlas, business.industry, 020207 software engineering, Screen space, real-time rendering, Real-time rendering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Non-photorealistic rendering, 020201 artificial intelligence & image processing, Artificial intelligence, business, stylization
Abstract: Paper session: Non-photorealistic rendering; International audience; Stylized rendering methods, which aim at depicting 3D scenes with 2D marks such as pigments or strokes, are often faced with temporal coherence issues when applied to dynamic scenes. These issues arise from the difficulty of having to satisfy two contrary goals: ensuring that the style marks follow 3D motions while preserving their 2D appearance. In this paper we describe a new texture based method for real-time temporally coherent stylization called dynamic textures. A dynamic texture is a standard texture mapped on the object and enriched with an infinite zoom mechanism. This simple and fast mechanism maintains quasi-constant size and density of texture elements in screen space for any distance from the camera. We show that these dynamic textures can be used in many stylization techniques, enforcing the 2D appearance of the style marks while preserving the accurate 3D motion of the depicted objects. Although our infinite zoom technique can be used with both 2D or 3D textures, we focus in this paper on the 3D case (dynamic solid textures) which avoids the need for complex parameterizations of 3D surfaces. This makes dynamic textures easy to integrate in existing rendering pipelines with almost no loss in performance, as demonstrated by our implementation in a game rendering engine.
Published: 2009

29. A meshless hierarchical representation for light transport

Author: François X. Sillion, Emmanuel Turquin, Matthias Zwicker, Frédo Durand, Timo Aila, Janne Kontkanen, Jaakko Lehtinen, Computer Science and Artificial Intelligence Laboratory [Cambridge] (CSAIL), Massachusetts Institute of Technology (MIT), Department of Computer Science and Engineering [San Diego] (CSE-UCSD), University of California [San Diego] (UC San Diego), University of California-University of California, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), PDI Dreamworks, Dreamworks, NVIDIA (NVIDIA), Department of Computer Science and Engineering [Univ California San Diego] (CSE - UC San Diego), and University of California (UC)-University of California (UC)
Subjects: Computer science, Global illumination, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Basis function, Image processing, 02 engineering and technology, Rendering (computer graphics), Wavelet, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, 0202 electrical engineering, electronic engineering, information engineering, Computer vision, scattered data, ComputingMethodologies_COMPUTERGRAPHICS, business.industry, 020207 software engineering, Data structure, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Finite element method, Precomputed Radiance Transfer, Precomputation, precomputed radiance transfer, 020201 artificial intelligence & image processing, meshless basis functions, Artificial intelligence, business, Algorithm
Abstract: International audience; We introduce a meshless hierarchical representation for solving light transport problems. Precomputed radiance transfer (PRT) and finite elements require a discrete representation of illumination over the scene. Non-hierarchical approaches such as per-vertex values are simple to implement, but lead to long precomputation. Hierarchical bases like wavelets lead to dramatic acceleration, but in their basic form they work well only on flat or smooth surfaces. We introduce a hierarchical function basis induced by scattered data approximation. It is decoupled from the geometric representation, allowing the hierarchical representation of illumination on complex objects. We present simple data structures and algorithms for constructing and evaluating the basis functions. Due to its hierarchical nature, our representation adapts to the complexity of the illumination, and can be queried at different scales. We demonstrate the power of the new basis in a novel precomputed direct-to-indirect light transport algorithm that greatly increases the complexity of scenes that can be handled by PRT approaches.
Published: 2008

30. Dynamic Label placement for Improved Interactive Exploration

Author: Thierry Stein, Xavier Décoret, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Phoenix Interactive, Anjyo, Ken and Sillion, and François
Subjects: Theoretical computer science, Automatic label placement, Optimization problem, business.industry, Computer science, Apollonius diagram, OpenGL, GPU, 020207 software engineering, 02 engineering and technology, Machine learning, computer.software_genre, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Visualization, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.6: Methodology and Techniques, Labelling, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, SAT, Artificial intelligence, business, computer, Image based, Drawback
Abstract: International audience; This work presents a novel approach for dynamically rendering annotations attached to a 3D scene. We formulate the problem as a general optimization under constraints, accounting for certain desirable properties. To approximately solve the NP-hard optimization problem in real-time, we present a particular heuristic that greedily places labels while maintaining constraints. Typical greedy label placement algorithms do not pay particular attention to the order of placement and, as a result, suffer from the fundamental limitation that successive labels get progressively more difficult to place. We use algorithmic and mathematical tools that compensate for the drawback of typical greedy approaches. In addition, they are well suited for GPU implementation, because they are completely image based. As a result, we can place tens of labels in real-time, as demonstrated in this paper.
Published: 2008

31. Stylized Vector Art from 3D Models with Region Support

Author: Holger Winnemöller, John Hart, David Salesin, Elmar Eisemann, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Adobe Systems Inc. (Adobe Advanced Technology Labs), Adobe Systems Inc., University of Illinois at Urbana Champaign (UIUC), University of Illinois at Urbana-Champaign [Urbana], University of Illinois System-University of Illinois System, Department of Computer Science & Engineering (CSE), University of Washington [Seattle], and University of Illinois System
Subjects: Stylized fact, Computer science, business.industry, Clip art, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, 02 engineering and technology, Geometry processing, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Vector graphics, clip art, Computer Science::Graphics, vector graphics, Shadow, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Polygon mesh, Computer vision, Artificial intelligence, Vertex normal, business, stylization, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: http://artis.imag.fr/Publications/2008/EWHS08/; International audience; We describe a rendering system that converts a 3D meshed model into the stylized 2D filled-region vector-art commonly found in clip-art libraries. To properly define filled regions, we analyze and combine accurate but jagged face-normal contours with smooth but inaccurate interpolated vertex normal contours, and construct a new smooth shadow contour that properly surrounds the actual jagged shadow contour. We decompose region definition into geometric and topological components, using machine precision for geometry processing and raster-precision to accelerate topological queries. We extend programmable stylization to simplify, smooth and stylize filled regions. The result renders 10K-face meshes into custom clip-art in seconds.
Published: 2008

32. Sample-based Visibility for Soft Shadows Using Alias-free Shadow Maps

Author: Ulf Assarsson, Elmar Eisemann, Erik Sintorn, Chalmers University of Technology [Göteborg], Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: Alias, Computer science, Shadow volume, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, GPU, 02 engineering and technology, Planar, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Shadow, 0202 electrical engineering, electronic engineering, information engineering, Computer vision, Shadow mapping, ComputingMethodologies_COMPUTERGRAPHICS, Pixel, business.industry, 020207 software engineering, Depth peeling, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], 020201 artificial intelligence & image processing, Shading, Artificial intelligence, business, Interpolation, Shadows, alias-free
Abstract: International audience; This paper introduces an accurate real-time soft shadow algorithm that uses sample based visibility. Initially, we present a GPU-based alias-free hard shadow map algorithm that typically requires only a single render pass from the light, in contrast to using depth peeling and one pass per layer. For closed objects, we also suppress the need for a bias. The method is extended to soft shadow sampling for an arbitrarily shaped area-/volumetric light source using 128-1024 light samples per screen pixel. The alias-free shadow map guarantees that the visibility is accurately sampled per screen-space pixel, even for arbitrarily shaped (e.g. non-planar) surfaces or solid objects. Another contribution is a smooth coherent shading model to avoid common light leakage near shadow borders due to normal interpolation. More at http://artis.imag.fr/Publications/2008/SEA08
Published: 2008

33. Occlusion Textures for Plausible Soft Shadows

Author: Xavier Décoret, Elmar Eisemann, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: plausible, Caster, Computer science, business.industry, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, GPU, 020207 software engineering, 02 engineering and technology, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], shadow, Occlusion, Shadow, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Point (geometry), Computer vision, Artificial intelligence, business, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; This paper presents a new approach to compute plausible soft shadows for complex dynamic scenes and rectangular light sources. We estimate the occlusion at each point of the scene using prefiltered occlusion textures, which dynamically approximate the scene geometry. The algorithm is fast and its performance independent of the light's size. Being image-based, it is mostly independent of the scene complexity and type. No a priori information is needed, and there is no caster/receiver separation. This makes the method appealing and easy to use.
Published: 2008

34. Structure-preserving manipulation of photographs

Author: Pascal Barla, Adrien Bousseau, Alexandrina Orzan, Joëlle Thollot, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: business.industry, Computer science, visual communication, Binary image, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, Image processing, 02 engineering and technology, multiscale analysis, image reconstruction, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], image processing, Gradient-domain image processing, Automatic image annotation, Image texture, Digital image processing, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, business, Image restoration, Feature detection (computer vision)
Abstract: International audience; Visual content is often better communicated by simpliﬁed or exaggerated images than by the "real world like" images. In this paper, we offer a tool for creating such enhanced representations of photographs in a way consistent with the original image content. To do so, we develop a method to identify the relevant image strucures and their importance. Our approach (a) uses edges as the basic structural unit in the image, (b) proposes tools to manipulate this structure in a ﬂexible way, and (c) employs gradient domain image processing techniques to reconstruct the ﬁnal image from a "cropped" gradient information. This edge-based approach to non-photorealistic image processing is made feasible by two new techniques we introduce: an addition to the Gaussian scale space theory to compute a perceptually meaningful hierarchy of structures, and a contrast estimation method necessary for faithful gradient-based reconstructions. We ﬁnally present various applications that manipulate image structure in different ways.
Published: 2007

35. Video Watercolorization using Bidirectional Texture Advection

Author: David Salesin, Fabrice Neyret, Joëlle Thollot, Adrien Bousseau, Adobe Systems Inc. (Adobe Advanced Technology Labs), Adobe Systems Inc., Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Department of Computer Science & Engineering (CSE), University of Washington [Seattle], and Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)
Subjects: business.industry, Computer science, abstract stylization, Optical flow, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, 02 engineering and technology, Animation, Mathematical morphology, animated textures, Computer Graphics and Computer-Aided Design, Non-photorealistic rendering, Distortion, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, [INFO.INFO-DL]Computer Science [cs]/Digital Libraries [cs.DL], Computer vision, 020201 artificial intelligence & image processing, Texture advection, Artificial intelligence, business, temporal coherence, Abstraction (linguistics), ComputingMethodologies_COMPUTERGRAPHICS
Abstract: Special Issue: SIGGRAPH 2007; International audience; In this paper, we present a method for creating watercolor-like animation, starting from video as input. The method involves two main steps: applying textures that simulate a watercolor appearance; and creating a simpliﬁed, abstracted version of the video to which the texturing operations are applied. Both of these steps are subject to highly visible temporal artifacts, so the primary technical contributions of the paper are extensions of previous methods for texturing and abstraction to provide temporal coherence when applied to video sequences. To maintain coherence for textures, we employ texture advection along lines of optical ﬂow. We furthermore extend previous approaches by incorporating advection in both forward and reverse directions through the video, which allows for minimal texture distortion, particularly in areas of disocclusion that are otherwise highly problematic. To maintain coherence for abstraction, we employ mathematical morphology extended to the temporal domain, using ﬁlters whose temporal extents are locally controlled by the degree of distortions in the optical ﬂow. Together, these techniques provide the ﬁrst practical and robust approach for producing watercolor animations from video, which we demonstrate with a number of examples.
Published: 2007

36. Dynamic 2D Patterns for Shading 3D Scenes

Author: SzerszenKarol, MarkosianLee, BreslavSimon, BarlaPascal, ThollotJoëlle, Department of Electrical Engineering and Computer Science (EECS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: Structure (mathematical logic), Similarity (geometry), Computer science, business.industry, 020207 software engineering, 02 engineering and technology, Variety (linguistics), Computer Graphics and Computer-Aided Design, Motion (physics), [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Variety (cybernetics), Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Quality (philosophy), Frame (artificial intelligence), 020201 artificial intelligence & image processing, Computer vision, Shading, Artificial intelligence, business, 3D computer graphics
Abstract: Special Issue: SIGGRAPH 2007; International audience; We describe a new way to render 3D scenes in a variety of non-photorealistic styles, based on patterns whose structure and motion are deﬁned in 2D. In doing so, we sacriﬁce the ability of patterns that wrap onto 3D surfaces to convey shape through their structure and motion. In return, we gain several advantages, chieﬂy that 2D patterns are more visually abstract - a quality often sought by artists, which explains their widespread use in hand-drawn images. Extending such styles to 3D graphics presents a challenge: how should a 2D pattern move? Our solution is to transform it each frame by a 2D similarity transform that closely follows the under-lying 3D shape. The resulting motion is often surprisingly effective, and has a striking cartoon quality that matches the visual style.
Published: 2007

37. Fast Precomputed Ambient Occlusion for Proximity Shadows

Author: Mattias Malmer, Ulf Assarsson, Nicolas Holzschuch, Fredrik Malmer, Syndicate, Chalmers University of Technology [Göteborg], Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: Computer science, business.industry, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, 02 engineering and technology, Grid, GeneralLiterature_MISCELLANEOUS, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.1: Hardware Architecture/I.3.1.0: Graphics processors, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Screen space ambient occlusion, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Ambient occlusion, 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, business, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; Ambient occlusion is used widely for improving the realism of real-time lighting simulations. We present a new method for precomputed ambient occlusion, where we store and retrieve unprocessed ambient occlusion values in a 3D grid. Our method is very easy to implement, has a reasonable memory cost, and the rendering time is independent from the complexity of the occluder or the receiving scene. This makes the algorithm highly suitable for games and other real-time applications.
Published: 2007

38. A sketch-based interface for clothing virtual characters

Author: Emmanuel Turquin, J. Wither, Marie-Paule Cani, Laurence Boissieux, John Hughes, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Virtual environments for animation and image synthesis of natural objects (EVASION), Service Expérimentation et Développement (SED [Grenoble]), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Department of Computer Science (Brown University), Brown University, and SED [Grenoble]
Subjects: 010407 polymers, Interface (Java), Computer science, 02 engineering and technology, 01 natural sciences, GeneralLiterature_MISCELLANEOUS, Silhouette, Clothing, Computer graphics, User-Computer Interface, Imaging, Three-Dimensional, ComputerApplications_MISCELLANEOUS, Computer graphics (images), Image Interpretation, Computer-Assisted, 0202 electrical engineering, electronic engineering, information engineering, Computer Graphics, Humans, Sketching clothes folds, ComputingMethodologies_COMPUTERGRAPHICS, Graphical user interface, business.industry, Sketch-based interface, 020207 software engineering, 3D modeling, Computer Graphics and Computer-Aided Design, 3D modelling, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Sketch, 0104 chemical sciences, Character (mathematics), Paintings, garment design, business, Software, Algorithms
Abstract: Special issue on sketch based modeling; International audience; We present a new method for interactively creating garments for dressing virtual characters. The user draws an outline of the front and back of the garment, and the system makes reasonable geometric inferences about the overall shape of the garment (ignoring constraints arising from physics). Both the garment's shape and the way the character is wearing it are determined at once. We use the distance from the 2D garment silhouette to the character model to infer the variations of the distance between the remainder of the garment and the character in 3D. The garment surface is generated from the silhouette and border lines and this varying distance information, using a distance field to the character's body. This method is integrated in an interactive system in which the user sketches the garment over the 3D model of the character. Our results show that the system can be used to create a broad range of clothes that may be worn in a variety of ways.
Published: 2007

39. Soft Shadow Maps: Efficient Sampling of Light Source Visibility

Author: Nicolas Holzschuch, Marc Lapierre, Jean-Marc Hasenfratz, François X. Sillion, Lionel Atty, Charles Hansen, Acquisition, representation and transformations for image synthesis (ARTIS), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), Modeling, localization, recognition and interpretation in computer vision (MOVI), School of computing [UTAH], University of Utah, and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes
Subjects: Computer science, Shadow volume, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 02 engineering and technology, Position (vector), ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Computer graphics (images), Shadow, 0202 electrical engineering, electronic engineering, information engineering, Computer vision, Shadow mapping, ComputingMethodologies_COMPUTERGRAPHICS, business.industry, Visibility (geometry), 020207 software engineering, Computer Graphics and Computer-Aided Design, Sample (graphics), Real-time rendering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Image synthesis, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.1: Hardware Architecture, Polygon, 020201 artificial intelligence & image processing, Artificial intelligence, business, Scale (map), Texel
Abstract: International audience; Shadows, particularly soft shadows, play an important role in the visual perception of a scene by providing visual cues about the shape and position of objects. Several recent algorithms produce soft shadows at interactive rates, but they do not scale well with the number of polygons in the scene or only compute the outer penumbra. In this paper, we present a new algorithm for computing interactive soft shadows on the GPU. Our new approach provides both inner- and outer-penumbra, and has a very small computational cost, giving interactive frame-rates for models with hundreds of thousands of polygons. Our technique is based on a sampled image of the occluders, as in shadow map techniques. These shadow samples are used in a novel manner, computing their effect on a second projective shadow texture using fragment programs. In essence, the fraction of the light source area hidden by each sample is accumulated at each texel position of this Soft Shadow Map. We include an extensive study of the approximations caused by our algorithm, as well as its computational costs.
Published: 2006

40. Accurate Specular Reflections in Real-Time

Author: Nicolas Holzschuch, David Roger, Acquisition, representation and transformations for image synthesis (ARTIS), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes
Subjects: Vertex (computer graphics), Computer science, business.industry, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, 02 engineering and technology, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, 020204 information systems, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Specular highlight, Computer vision, Specular reflection, Artificial intelligence, Parallax, business, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; Specular reflections provide many important visual cues in our daily environment. They inform us of the shape of objects, of the material they are made of, of their relative positions, etc. Specular reflections on curved objects are usually approximated using environment maps. In this paper, we present a new algorithm for real-time computation of specular reflections on curved objects, based on an exact computation for the reflection of each scene vertex. Our method exhibits all the required parallax effects and can handle arbitrary proximity between the reflector and the reflected objects.
Published: 2006

41. A dynamic drawing algorithm for interactive painterly rendering

Author: Pascal Barla, François X. Sillion, David Vanderhaeghe, Joëlle Thollot, Acquisition, representation and transformations for image synthesis (ARTIS), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes
Subjects: Painting, Painterly rendering, business.industry, Computer science, media_common.quotation_subject, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Fidelity, 020207 software engineering, 02 engineering and technology, Curvature, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Silhouette, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Depiction, 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, business, Algorithm, media_common, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; We present a new approach to create painterly renderings of an animated 3D scene, allowing a controllable trade-off between scene fidelity and stylistic design. Our approach extends and complements existing systems in order to ensure temporal coherence while maintaining consistent stroke density, and allowing a wide variety of stroke styles. It is based on a new dynamic painting algorithm which selects a suitable set of sample stroke locations based on an object-space hierarchy. Strokes are created at these locations, with attributes assigned using arbitrary stylistic choices: examples include scene-derived decisions such as having stroke orientation follow curvature or silhouette directions, or user-supplied constraints such as global orientation or thickness. Stroke rendering is then performed using appropriately filtered information from a set of G-buffers. We describe an improved stroke rendering technique which allows a faithful depiction of the scene while letting the user specify his prefered stroke style. All rendering is interactive and performed on the GPU.
Published: 2006

42. Visual Shapes of Silhouette Sets

Author: Marc Lapierre, Edmond Boyer, Jean-Sébastien Franco, Modeling, localization, recognition and interpretation in computer vision (MOVI), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), University of North Carolina [Chapel Hill] (UNC), University of North Carolina System (UNC), and Acquisition, representation and transformations for image synthesis (ARTIS)
Subjects: Smoothness, Class (computer programming), Approximations of π, business.industry, Binary number, [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], 020207 software engineering, Pattern recognition, 02 engineering and technology, Iterative reconstruction, Silhouette, Visual hull, Image texture, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, business, Mathematics
Abstract: International audience; Shape from silhouette methods are extensively used to model dynamic and non-rigid objects using binary foreground-background images. Since the problem of reconstructing shapes from silhouettes is ambiguous, a number of solutions exist and several approaches only consider the one with a maximal volume, called the visual hull. However, the visual hull is not always a good approximation of shapes, in particular when observing smooth surfaces with few cameras. In this paper, we consider instead a class of solutions to the silhouette reconstruction problem that we call visual shapes. Such a class includes the visual hull, but also better approximations of the observed shapes which can take into account local assumptions such as smoothness, among others. Our contributions with respect to existing works is rst to identify silhouette consistent shapes different from the visual hull, and second to give a practical way to estimate such shapes in real time. Experiments on various sets of data including human body silhouettes are shown to illustrate the principle and the interests of visual shapes.
Published: 2006

43. A Computer-Assisted Colorization Algorithm based on Topological Difference

Author: Bruno Feijó, Luiz Velho, H. Bezerra, Pontifical Catholic University of Rio de Janeiro (PUC), Acquisition, representation and transformations for image synthesis (ARTIS), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Matemática Pura e Aplicada (IMPA), and Instituto Nacional de matematica pura e aplicada
Subjects: Similarity (geometry), business.industry, Process (computing), ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, Graph theory, 02 engineering and technology, Animation, Topology, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Image (mathematics), 0202 electrical engineering, electronic engineering, information engineering, Graph (abstract data type), 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, business, Algorithm, Computer animation, Topology (chemistry), Mathematics, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: National audience; Region-based approaches to cel painting typically use shape similarity and topology relations between regions of consecutive animation frames. This paper presents a new colorization algorithm based on topological differences defined over a hierarchical graph of adjacent regions, which allows an almost full automatic colorization process. Also this paper discusses other attributes that improve the solution of the image association problem.
Published: 2006

44. Interactive watercolor rendering with temporal coherence and abstraction

Author: Adrien Bousseau, Joëlle Thollot, Matthew Kaplan, François X. Sillion, Acquisition, representation and transformations for image synthesis (ARTIS), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), Evasion, Team, and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes
Subjects: NPR, Computer science, business.industry, [INFO.INFO-GR] Computer Science [cs]/Graphics [cs.GR], 020207 software engineering, 3d model, 02 engineering and technology, abstraction, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Non-photorealistic rendering, Rendering (computer graphics), watercolor, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, business, temporal coherence, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; This paper presents an interactive watercolor rendering technique that recreates the specific visual effects of lavis watercolor. Our method allows the user to easily process images and 3d models and is organized in two steps: an abstraction step that recreates the uniform color regions of watercolor and an effect step that filters the resulting abstracted image to obtain watercolor-like images. In the case of 3d environments we also propose two methods to produce temporally coherent animations that keep a uniform pigment repartition while avoiding the shower door effect.
Published: 2006

45. Plausible Image Based Soft Shadows Using Occlusion Textures

Author: Elmar Eisemann, Xavier Décoret, Acquisition, representation and transformations for image synthesis (ARTIS), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), IEEE, Oliveira Neto, Manuel Menezes deCarceroni, and Rodrigo Lima
Subjects: Texture atlas, Computer science, business.industry, Visibility (geometry), ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, real-time, 020207 software engineering, 02 engineering and technology, Image-based modeling and rendering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Real-time computer graphics, Computer graphics, Image texture, Occlusion, 0202 electrical engineering, electronic engineering, information engineering, soft shadows, 020201 artificial intelligence & image processing, Point (geometry), Computer vision, Artificial intelligence, image-based, business, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; This paper presents a novel image-based approach to render plausible soft shadows for complex dynamic scenes with rectangular light sources. The algorithm's performance is mostly independent of the scene complexity and the source's size. Occluders and receivers do not need to be separated and no knowledge about the scene representation is required, making the method easy to use. The main idea is to approximate the occlusion in the scene with pre- filtered occlusion textures. The visibility of the light source at a point in space is estimated by accumulating the occlusion caused by each texture, using a novel formula based on probabilities.
Published: 2006

46. Fast Scene Voxelization and Applications

Author: Xavier Décoret, Elmar Eisemann, Acquisition, representation and transformations for image synthesis (ARTIS), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Inria Grenoble - Rhône-Alpes, and École normale supérieure - Paris (ENS Paris)
Subjects: Computer science, Graphics hardware, OpenGL, Shadow volume, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, GPU, 02 engineering and technology, computer.software_genre, 01 natural sciences, GeneralLiterature_MISCELLANEOUS, Rendering (computer graphics), voxelization, Voxel, Computer graphics (images), Shadow, shadows, 0202 electrical engineering, electronic engineering, information engineering, Computer vision, Graphics, 0101 mathematics, Representation (mathematics), ComputingMethodologies_COMPUTERGRAPHICS, refraction, business.industry, 020207 software engineering, Sketch, Clamping, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], 010101 applied mathematics, Polygon, 020201 artificial intelligence & image processing, Artificial intelligence, business, computer, Data transmission
Abstract: International audience; This paper presents a novel approach that uses graphics hardware to dynamically calculate a voxel-based representation of a scene. The voxelization is obtained on run-time in the order of milliseconds, even for complex and dynamic scenes containing more than 1,000,000 polygons. The voxelization is created and stored on the GPU avoiding unnecessary data transfer. The approach can handle both regular grids and locally optimized grids that better fit the scene geometry. The paper demonstrates applications to shadow calculation, refraction simultation and shadow volume culling/clamping. copyright ACM, 2006. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in Proceedings of I3D 2006
Published: 2006

47. A Frequency Analysis of Light Transport

Author: Nicolas Holzschuch, François X. Sillion, Cyril Soler, Frédo Durand, Eric Chan, Massachusetts Institute of Technology (MIT), Computer Science and Artificial Intelligence Laboratory [Cambridge] (CSAIL), Acquisition, representation and transformations for image synthesis (ARTIS), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), INRIA Équipe Associée ARTIS-MIT, and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Inria Grenoble - Rhône-Alpes
Subjects: Physics, Frequency analysis, Angular frequency, business.industry, Mathematical analysis, 020207 software engineering, 02 engineering and technology, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], law.invention, Rendering (computer graphics), Optics, Precomputed Radiance Transfer, law, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Inverse rendering, Frequency domain, 0202 electrical engineering, electronic engineering, information engineering, Radiance, 020201 artificial intelligence & image processing, business, Fourier domain
Abstract: International audience; We present a signal-processing framework for light transport. We study the frequency content of radiance and how it is altered by phenomena such as shading, occlusion, and transport. This extends previous work that considered either spatial or angular dimensions, and it offers a comprehensive treatment of both space and angle. We show that occlusion, a multiplication in the primal, amounts in the Fourier domain to a convolution by the spectrum of the blocker. Propagation corresponds to a shear in the space-angle frequency domain, while reflection on curved objects performs a different shear along the angular frequency axis. As shown by previous work, reflection is a convolution in the primal and therefore a multiplication in the Fourier domain. Our work shows how the spatial components of lighting are affected by this angular convolution. Our framework predicts the characteristics of interactions such as caustics and the disappearance of the shadows of small features. Predictions on the frequency content can then be used to control sampling rates for rendering. Other potential applications include precomputed radiance transfer and inverse rendering.
Published: 2005

48. Texture sprites

Author: Samuel Hornus, Sylvain Lefebvre, Fabrice Neyret, Virtual environments for animation and image synthesis of natural objects (EVASION), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), Acquisition, representation and transformations for image synthesis (ARTIS), ACM SIGGRAPH, and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes
Subjects: Texture atlas, Texture compression, Computer science, business.industry, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Data structure, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Real-time rendering, Rendering (computer graphics), Sprite (lightning), Texture filtering, Computer graphics (images), Computer vision, Artificial intelligence, business, Texture memory, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; We present a new interactive method to texture complex geometries at very high resolution, while using little memory and without the need for a global planar parameterization. We rely on small texture elements, the texture sprites, locally splatted onto the surface to define a composite texture. The sprites can be arbitrarily blended to create complex surface appearances. Their attributes (position, size, texture id) can be dynamically updated, thus providing a convenient framework for interactive editing and animated textures. We demonstrate the flexibility of our method by creating new surface aspects difficult to achieve with other methods. Each sprite is described by a small set of attributes which is stored in a hierarchical structure surrounding the object's surface. The patterns supported by the sprites are stored only once. The whole data structure is compactly encoded into GPU memory. At run time, it is accessed by a fragment program which computes the final appearance of a surface point from all the sprites covering it. The overall memory cost of the structure is very low compared to the resulting texturing resolutions. Rendering is done in real-time. The resulting texture is linearly interpolated and altered.
Published: 2005

49. Geometric clustering for line drawing simplification

Author: Pascal Barla, François X. Sillion, Joëlle Thollot, Acquisition, representation and transformations for image synthesis (ARTIS), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS), Juan Buhler, Oliver Deussen and Alexander Keller and Kavita Bala and Philip Dutré and Dieter W. Fellner and Stephen N. Spencer, and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes
Subjects: ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.3: Picture/Image Generation/I.3.3.4: Line and curve generation, business.industry, Computer science, Error threshold, Line drawings, 020207 software engineering, 3d model, Pattern recognition, 02 engineering and technology, non-photorealistic rendering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Non-photorealistic rendering, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Artificial intelligence, Cluster analysis, business
Abstract: International audience; We present a new approach to the simplification of line drawings, that maintains the morphological structure of the original drawing while decreasing the number of lines. The technique works by analyzing the structure of the drawing at a certain scale and identifying clusters of lines. These clusters are then processed to create new lines in a separate stage where different scenarios can be favored based on the target application. This two-stages decomposition naturally adapts to various applications: density reduction of a drawing, where too many lines project in a given region of the image; Level-of-detail (LOD) representations for line-based rendering (contours and hatching), where the number of lines must vary with scale; and progressive editing, where the user refines a curve by successive sketches, viewed as an iterative simplification of the set of line sketches drawn by the user. Our goal is to provide a low-level tool common to these applications.
Published: 2005

50. Progressive surface reconstruction from images using a local prior

Author: Sylvain Paris, Gang Zeng, Long Quan, François X. Sillion, Computer Science and Artificial Intelligence Laboratory [Cambridge] (CSAIL), Massachusetts Institute of Technology (MIT), Acquisition, representation and transformations for image synthesis (ARTIS), Laboratoire d'informatique GRAphique, VIsion et Robotique de Grenoble (GRAVIR - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, and Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)
Subjects: multiple views, business.industry, Visibility (geometry), 3D reconstruction, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, 02 engineering and technology, Iterative reconstruction, Real image, patches, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Progressive refinement, Aliasing, distance field, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Computer vision, Artificial intelligence, business, Distance transform, Surface reconstruction, ComputingMethodologies_COMPUTERGRAPHICS, Mathematics
Abstract: International audience; This paper introduces a new method for surface reconstruction from multiple calibrated images. The primary contribution of this work is the notion of local prior to combine the flexibility of the carving approach with the accuracy of graph-cut optimization. A progressive refinement scheme is used to recover the topology and reason the visibility of the object. Within each voxel, a detailed surface patch is optimally reconstructed using a graph-cut method. The advantage of this technique is its ability to handle complex shape similarly to level sets while enjoying a higher precision. Compared to carving techniques, the addressed problem is well-posed, and the produced surface does not suffer from aliasing. In addition, our approach seamlessly handles complete and partial reconstructions: If the scene is only partially visible, the process naturally produces an open surface; otherwise, if the scene is fully visible, it creates a complete shape. These properties are demonstrated on real image sequences.
Published: 2005

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