Author: "Acquisition, representation and transformations for image synthesis (ARTIS)" / Topic: 0202 electrical engineering, electronic engineering, information engineering - Searchworks@Jio Institute Digital Library Search Results

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

1. Soft Shadow Volumes for Ray Tracing

Author: Samuli Laine, Timo Aila, Jaakko Lehtinen, Ulf Assarsson, Tomas Akenine-Möller, Helsinki University of Technology ( TKK ), Chalmers University of Technology [Göteborg], Acquisition, representation and transformations for image synthesis ( ARTIS ), Graphisme, Vision et Robotique ( 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 ), Lund University [Lund], TKK Helsinki University of Technology (TKK), 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: Computer science, Astrophysics::High Energy Astrophysical Phenomena, Shadow volume, 020207 software engineering, 02 engineering and technology, [ INFO.INFO-GR ] Computer Science [cs]/Graphics [cs.GR], Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Silhouette, Shadow algorithms, Computer graphics (images), Shadow, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Ray tracing (graphics), Shadow mapping, Distributed ray tracing, visibility determination
Abstract: International audience; We present a new, fast algorithm for rendering physically-based soft shadows in ray tracing-based renderers. Our method replaces the hundreds of shadow rays commonly used in stochastic ray tracers with a single shadow ray and a local reconstruction of the visibility function. Compared to tracing the shadow rays, our algorithm produces exactly the same image while executing one to two orders of magnitude faster in the test scenes used. Our first contribution is a two-stage method for quickly determining the silhouette edges that overlap an area light source, as seen from the point to be shaded. Secondly, we show that these partial silhouettes of occluders, along with a single shadow ray, are sufficient for reconstructing the visibility function between the point and the light source.
Published: 2005

2. MNPR: A Framework for Real-Time Expressive Non-Photorealistic Rendering of 3D Computer Graphics

Author: Amir Semmo, Davide Benvenuti, Joëlle Thollot, Santiago E. Montesdeoca, Romain Vergne, Hock Soon Seah, Pierre Bénard, Nanyang Technological University [Singapour], Hasso Plattner Institute [Potsdam, Germany], Melting the frontiers between Light, Shape and Matter ( MANAO ), Laboratoire Bordelais de Recherche en Informatique ( LaBRI ), Centre National de la Recherche Scientifique ( CNRS ) -École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Université Sciences et Technologies - Bordeaux 1-Université Bordeaux Segalen - Bordeaux 2-Centre National de la Recherche Scientifique ( CNRS ) -École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Université Sciences et Technologies - Bordeaux 1-Université Bordeaux Segalen - Bordeaux 2-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique ( Inria ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -Laboratoire Photonique, Numérique et Nanosciences ( LP2N ), Université de Bordeaux ( UB ) -Institut d'Optique Graduate School ( IOGS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Bordeaux ( UB ) -Institut d'Optique Graduate School ( IOGS ) -Centre National de la Recherche Scientifique ( CNRS ), Models and Algorithms for Visualization and Rendering ( MAVERICK ), 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-Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Université Pierre Mendès France - Grenoble 2 ( UPMF ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Institut National Polytechnique de Grenoble ( INPG ), Centre National de la Recherche Scientifique ( CNRS ) -Institut d'Optique Graduate School ( IOGS ) -Université de Bordeaux ( UB ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut d'Optique Graduate School ( IOGS ) -Université de Bordeaux ( UB ), Acquisition, representation and transformations for image synthesis ( ARTIS ), School of Computer Science and Engineering, School of Art, Design and Media, Interdisciplinary Graduate School (IGS), Expressive '18: Proceedings of the Joint Symposium on Computational Aesthetics and Sketch-Based Interfaces and Modeling and Non-Photorealistic Animation and Rendering, Melting the frontiers between Light, Shape and Matter (MANAO), Laboratoire Bordelais de Recherche en Informatique (LaBRI), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université de Bordeaux (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Models and Algorithms for Visualization and Rendering (MAVERICK ), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest
Subjects: Interaction, Computer science, Object-space stylization, Framework, 020207 software engineering, 02 engineering and technology, [ INFO.INFO-GR ] Computer Science [cs]/Graphics [cs.GR], Levels of control, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Non-photorealistic rendering, Object-space Stylization, Human–computer interaction, 0202 electrical engineering, electronic engineering, information engineering, Computer science and engineering [Engineering], 020201 artificial intelligence & image processing, Filtering, Expressive NPR, Real-time, 3D computer graphics, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; We propose a framework for expressive non-photorealistic rendering of 3D computer graphics: MNPR. Our work focuses on enabling stylization pipelines with a wide range of control, thereby covering the interaction spectrum with real-time feedback. In addition, we introduce control semantics that allow cross-stylistic art-direction, which is demonstrated through our implemented watercolor, oil and charcoal stylizations. Our generalized control semantics and their style-specific mappings are designed to be extrapolated to other styles, by adhering to the same control scheme. We then share our implementation details by breaking down our framework and elaborating on its inner workings. Finally, we evaluate the usefulness of each level of control through a user study involving 20 experienced artists and engineers in the industry, who have collectively spent over 245 hours using our system. MNPR is implemented in Autodesk ® Maya ® and open-sourced through this publication, to facilitate adoption by artists and further development by the expressive research and development community.
Published: 2018

3. A Compact Representation for Multiple Scattering in Participating Media using Neural Networks

Author: Nicolas Holzschuch, Beibei Wang, Liangsheng Ge, Lu Wang, Shandong University, Nanjing University of Science and Technology [Nanjing], Acquisition, representation and transformations for image synthesis ( ARTIS ), Graphisme, Vision et Robotique ( 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 ), Nanjing University of Science and Technology (NJUST), Models and Algorithms for Visualization and Rendering (MAVERICK ), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK ), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Multiple Scattering, Artificial neural network, Neural Networks, Computer science, Scattering, Computation, 020207 software engineering, 02 engineering and technology, [ INFO.INFO-GR ] Computer Science [cs]/Graphics [cs.GR], Discrete dipole approximation, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Computational science, Participating Media, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Representation (mathematics), ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; Many materials, such as milk or wax, exhibit scattering effects; incoming light enters the material and is scattered inside, giving a translucent aspect. These effects are computationally intensive as they require simulating a large number of events. Full computations are expensive, even with accelerating methods such as Virtual Ray Lights. We present a method to encode multiple scattering effects using a neural network. We replace the precomputed multiple scattering table with a trained neural network, with a cost of 6490 bytes (1623 floats). At runtime, the neural network is used to generate multiple scattering. We demonstrate the effects combined with Virtual Ray Lights (VRL), but our approach can be integrated with other rendering algorithms.
Published: 2018

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. Accurate detection of symmetries in 3D shapes

Author: François X. Sillion, Aurélien Martinet, Nicolas Holzschuch, Cyril Soler, 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), ANR Masses de Données 'SHOW', 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: Work (thermodynamics), Computation, Spherical harmonics, 020207 software engineering, 02 engineering and technology, Topology, 3d shapes, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Maxima and minima, Range (mathematics), Compression (functional analysis), Homogeneous space, 0202 electrical engineering, electronic engineering, information engineering, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.5: Computational Geometry and Object Modeling/I.3.5.2: Curve, surface, solid, and object representations, 020201 artificial intelligence & image processing, Algorithm, ComputingMethodologies_COMPUTERGRAPHICS, Mathematics
Abstract: We propose an automatic method for finding symmetries of 3D shapes, that is, isometric transforms which leave a shape globally unchanged. These symmetries are deterministically found through the use of an intermediate quantity: the generalized moments. By examining the extrema and spherical harmonic coefficients of these moments, we recover the parameters of the symmetries of the shape. The computation for large composite models is made efficient by using this information in an incremental algorithm capable of recovering the symmetries of a whole shape using the symmetries of its subparts. Applications of this work range from coherent remeshing of geometry with respect to the symmetries of a shape to geometric compression, intelligent mesh editing, and automatic instantiation.
Published: 2006

11. 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

12. Frequency based kernel estimation for progressive photon mapping

Author: Cyril Soler, Laurent Belcour, 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), ACM SIGGRAPH, Zhigeng Pan, 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: Frequency analysis, Photon, Photon mapping, frequency analysis, Kernel density estimation, 020207 software engineering, 02 engineering and technology, Radius, Density estimation, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Computational physics, law.invention, law, Statistics, Convergence (routing), 0202 electrical engineering, electronic engineering, information engineering, Radiance, progressive photon mapping, Mathematics
Abstract: Poster; International audience; We present an extension to Hachisuka et al.'s Progressive Photon Mapping (or PPM) algorithm [Hachisuka et al. 2008] in which we estimate the radius of the density estimation kernels using frequency analysis of light transport [Durand et al. 2005]. We predict the local radiance frequency at the surface of objects using a Gaussian approximation, and use it to drive the size of the density estimation kernels, in order to accelerate convergence. The key is to add frequency information to a small proportion of photons: frequency photons. In addition to contributing to the density estimation, they will provide frequency information.
Published: 2011

13. State-of-the-Art Report on Temporal Coherence for Stylized Animations

Author: Joëlle Thollot, Pierre Bénard, 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), 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), 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: Painting, Stylized fact, Multimedia, Computer science, media_common.quotation_subject, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, 02 engineering and technology, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.3: Picture/Image Generation, computer.software_genre, Computer Graphics and Computer-Aided Design, GeneralLiterature_MISCELLANEOUS, non-photorealistic rendering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Non-photorealistic rendering, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Perception, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, stylization, computer, temporal coherence, media_common, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; Non-photorealistic rendering (NPR) algorithms allow the creation of images in a variety of styles, ranging from line drawing and pen-and-ink to oil painting and watercolor. These algorithms provide greater flexibility, control and automation over traditional drawing and painting. Despite significant progress over the past 15 years, the application of NPR to the generation of stylized animations remains an active area of research. The main challenge of computer generated stylized animations is to reproduce the look of traditional drawings and paintings while minimizing distracting flickering and sliding artifacts present in hand-drawn animations. These goals are inherently conflicting and any attempt to address the temporal coherence of stylized animations is a trade-off. This state-of-the-art report is motivated by the growing number of methods proposed in recent years and the need for a comprehensive analysis of the trade-offs they propose. We formalize the problem of temporal coherence in terms of goals and compare existing methods accordingly. We propose an analysis for both line and region stylization methods and discuss initial steps toward their perceptual evaluation. The goal of our report is to help uninformed readers to choose the method that best suits their needs, as well as motivate further research to address the limitations of existing methods.
Published: 2011

14. 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

15. 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

16. 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

17. Link Conditions for Simplifying Meshes with Embedded Structures

Author: Dilip Mathew Thomas, Vijay Natarajan, Georges-Pierre Bonneau, Indian Institute of Science [Bangalore] (IISc Bangalore), 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), INRIA, Indian Institute of Science, and Grenoble University
Subjects: Quadric, Theoretical computer science, Computer science, 010102 general mathematics, 020207 software engineering, 02 engineering and technology, Topology, 01 natural sciences, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Domain (software engineering), Mesh generation, [MATH.MATH-AT]Mathematics [math]/Algebraic Topology [math.AT], Signal Processing, Metric (mathematics), 0202 electrical engineering, electronic engineering, information engineering, Edge contraction, Polygon mesh, Computer Vision and Pattern Recognition, Supercomputer Education & Research Centre, 0101 mathematics, Computer Science & Automation, Software, Topology (chemistry)
Abstract: International audience; Interactive visualization applications benefit from simplification techniques that generate good quality coarse meshes from high resolution meshes that represent the domain. These meshes often contain interesting substructures, called embedded structures, and it is desirable to preserve the topology of the embedded structures during simplification, in addition to preserving the topology of the domain. This paper describes a proof that link conditions, proposed earlier, are sufficient to ensure that edge contractions preserve topology of the embedded structures and the domain. Excluding two specific configurations, the link conditions are also shown to be necessary for topology preservation. Repeated application of edge contraction on an extended complex produces a coarser representation of the domain and the embedded structures. An extension of the quadric error metric is used to schedule edge contractions, resulting in a good quality coarse mesh that closely approximates the input domain and the embedded structures.
Published: 2011

18. Feature-Based Vector Simulation of Water Waves

Author: Qizhi Yu, Anthony Steed, Fabrice Neyret, 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), Department of Computer Science, and University College of London [London] (UCL)
Subjects: Surface (mathematics), real-time simulation, Computer science, water waves, 020207 software engineering, 02 engineering and technology, Animation, 01 natural sciences, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], 010305 fluids & plasmas, Controllability, Real-time simulation, Computer graphics (images), 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, procedural methods, Vector field, Polygon mesh, Graphics, Representation (mathematics), Software, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: We present a method for simulating local water waves caused by obstacles in water streams for real-time graphics applications. Given a low-resolution water surface and velocity field, our method is able to decorate the input water surface with high resolution detail for the animated waves around obstacles. We construct and animate a vector representation of the waves. It is then converted to feature-aligned meshes for capturing the surfaces of the waves. Results demonstrate that our method has the benefits of real-time performance and easy controllability. The method also fits well into a state-of-the-art river animation system. Copyright © 2011 John Wiley & Sons, Ltd.
Published: 2011

19. 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

20. 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

21. Stable Inverse Dynamic Curves

Author: Derouet-JourdanAlexandre, Bertails-DescoubesFlorence, ThollotJoëlle, 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), 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), Acquisition, representation and transformations for image synthesis (ARTIS), Grant from the Ecole Normale Superieure of Lyon (A. Derouet-Jourdan), 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, Stable equilibrium, Inverse, 020207 software engineering, Animation, 02 engineering and technology, 2d curve, elastica, Computer Graphics and Computer-Aided Design, Popularity, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Domain (software engineering), inverse statics, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, stable equilibrium, ComputingMethodologies_COMPUTERGRAPHICS, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism/I.3.7.0: Animation
Abstract: Proceedings of SIGGRAPH Asia 2010 - Technical Papers: Curves, Characters & Crowds (Article 137); International audience; 2d animation is a traditional but fascinating domain that has recently regained popularity both in animated movies and video games. This paper introduces a method for automatically converting a smooth sketched curve into a 2d dynamic curve at stable equilibrium under gravity. The curve can then be physically animated to produce secondary motions in 2d animations or simple video games. Our approach proceeds in two steps. We first present a new technique to fit a smooth piecewise circular arcs curve to a sketched curve. Then we show how to compute the physical parameters of a dynamic rod model (super-circle) so that its stable rest shape under gravity exactly matches the fitted circular arcs curve. We demonstrate the interactivity and controllability of our approach on various examples where a user can intuitively setup efficient and precise 2d animations by specifying the input geometry.
Published: 2010

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. Real-time Rendering of Heterogeneous Translucent Objects with Arbitrary Shapes

Author: Jun-Hai Yong, Jiaping Wang, Nicolas Holzschuch, Yajun Wang, Kartic Subr, Baining Guo, 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), Tsinghua University [Beijing] (THU), Microsoft Research Asia, School of Software (THSS), National Science Foundation of China (60625202, 60911130368), Chinese 863 Program (2007AA040401), and INRIA internship grant, and ANR-07-BLAN-0331,HFIBMR,High-Fidelity Image-Based Modeling and Rendering(2007)
Subjects: Diffusion equation, Computer science, OpenGL, 020207 software engineering, 02 engineering and technology, Computer Graphics and Computer-Aided Design, Light scattering, Real-time rendering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Computer Science::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, 020201 artificial intelligence & image processing, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: EUROGRAPHICS 2010 (full paper) - Session Rendering I; International audience; We present a real-time algorithm for rendering translucent objects of arbitrary shapes. We approximate the scattering of light inside the objects using the diffusion equation, which we solve on-the-fly using the GPU. Our algorithm is general enough to handle arbitrary geometry, heterogeneous materials, deformable objects and modifications of lighting, all in real-time. In a pre-processing step, we discretize the object into a regular 4-connected structure (quadgraph). Due to its regular connectivity, this structure is easily packed into a texture and stored on the GPU. At runtime, we use the quadgraph stored on the GPU to solve the diffusion equation, in real-time, taking into account the varying input conditions: incoming light, object material and geometry. We handle deformable objects, provided the deformation does not change the topological structure of the objects.
Published: 2010

29. 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

30. 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

31. 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

32. 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

33. 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

34. Single Scattering in Refractive Media with Triangle Mesh Boundaries

Author: Kavita Bala, Bruce Walter, Shuang Zhao, Nicolas Holzschuch, Program of Computer Graphics (PCG), Cornell University [New York], Department of Computer Science [Ithaca], 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), INRIA programme sabbatique INRIA Equipe Associée 'CIPRUS', and ANR-07-BLAN-0331,HFIBMR,High-Fidelity Image-Based Modeling and Rendering(2007)
Subjects: Snell's law, Scattering, Physics::Optics, 020207 software engineering, Geometry, 010103 numerical & computational mathematics, 02 engineering and technology, Solver, 01 natural sciences, Computer Graphics and Computer-Aided Design, Refraction, Light scattering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Computer graphics, symbols.namesake, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Triangle mesh, 0202 electrical engineering, electronic engineering, information engineering, symbols, 020201 artificial intelligence & image processing, Polygon mesh, 0101 mathematics, Algorithm, Mathematics, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: Light scattering in refractive media is an important optical phenomenon for computer graphics. While recent research has focused on multiple scattering, there has been less work on accurate solutions for single or low-order scattering. Refraction through a complex boundary allows a single external source to be visible in multiple directions internally with different strengths; these are hard to find with existing techniques. This paper presents techniques to quickly find paths that connect points inside and outside a medium while obeying the laws of refraction. We introduce: a half-vector based formulation to support the most common geometric representation, triangles with interpolated normals; hierarchical pruning to scale to triangular meshes; and, both a solver with strong accuracy guarantees, and a faster method that is empirically accurate. A GPU version achieves interactive frame rates in several examples.
Published: 2009

35. 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

36. Volumetric Billboards

Author: Decaudin, Philippe, Neyret, Fabrice, 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), and Acquisition, representation and transformations for image synthesis (ARTIS)
Subjects: 05 social sciences, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 050301 education, real-time rendering, 020207 software engineering, 02 engineering and technology, geometry shader, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], billboards, 0202 electrical engineering, electronic engineering, information engineering, image-based rendering, 0503 education, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; We introduce an image-based representation, called volumetric billboards, allowing for the real-time rendering of semi-transparent and visually complex objects arbitrarily distributed in a 3D scene. Our representation offers full parallax effect from any viewing direction and improved anti-aliasing of distant objects. It correctly handles transparency between multiple and possibly overlapping objects without requiring any primitive sorting. Furthermore, volumetric billboards can be easily integrated into common rasterization-based renderers, which allows for their concurrent use with polygonal models and standard rendering techniques such as shadow-mapping. The representation is based on volumetric images of the objects and on a dedicated real-time volume rendering algorithm that takes advantage of the GPU geometry shader. Our examples demonstrate the applicability of the method in many cases including levels-of-detail representation for multiple intersecting complex objects, volumetric textures, animated objects and construction of high-resolution objects by assembling instances of lowresolution volumetric billboards.
Published: 2009

37. 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

38. Scalable Real-Time Animation of Rivers

Author: Nicolas Holzschuch, Qizhi Yu, Eric Bruneton, Fabrice Neyret, 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), and Acquisition, representation and transformations for image synthesis (ARTIS)
Subjects: Scale (ratio), Advection, Computer science, 020207 software engineering, Terrain, 02 engineering and technology, Animation, Metaverse, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Physics::Fluid Dynamics, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.7: Three-Dimensional Graphics and Realism, Computer graphics (images), Scalability, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Realism, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; Many recent games and applications target the interactive exploration of realistic large scale worlds. These worlds consist mostly of static terrain models, as the simulation of animated fluids in these virtual worlds is computation- ally expensive. Adding flowing fluids, such as rivers, to these virtual worlds would greatly enhance their realism, but causes specific issues: as the user is usually observing the world at close range, small scale details such as waves and ripples are important. However, the large scale of the world makes classical methods impractical for simulating these effects. In this paper, we present an algorithm for the interactive simulation of realistic flowing fluids in large virtual worlds. Our method relies on two key contributions: the local computation of the velocity field of a steady flow given boundary conditions, and the advection of small scale details on a fluid, following the velocity field, and uniformly sampled in screen space.
Published: 2009

39. Wind projection basis for real-time animation of trees

Author: Mathieu Rodriguez, Julien Diener, Lionel Baboud, Lionel Reveret, 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-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut National Polytechnique de Grenoble (INPG), Laboratoire d'hydrodynamique (LadHyX), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire de Physique et Physiologie Intégratives de l'Arbre Fruitier et Forestier (PIAF), Institut National de la Recherche Agronomique (INRA)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP), Acquisition, representation and transformations for image synthesis (ARTIS), ANR-06-BLAN-0210,CHENE-ROSEAU,Mécanismes de l'interaction dynamique entre vent et plantes déformables(2006), 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 École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Computer science, Graphics hardware, Modal analysis, real-time, 020207 software engineering, 02 engineering and technology, Animation, Computer Graphics and Computer-Aided Design, modal analysis, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], tree, Tree (data structure), Modal, Computer graphics (images), physical simulation, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Projection (set theory), ACM: J.: Computer Applications/J.0: GENERAL, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; This paper presents a real-time method to animate complex scenes of thousands of trees under a user-controllable wind load. Firstly, modal analysis is applied to extract the main modes of deformation from the mechanical model of a 3D tree. The novelty of our contribution is to precompute a new basis of the modal stress of the tree under wind load. At runtime, this basis allows to replace the modal projection of the external forces by a direct mapping for any directional wind. We show that this approach can be efficiently implemented on graphics hardware. This modal animation can be simulated at low computation cost even for large scenes containing thousands of trees.
Published: 2009

40. 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

41. 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

42. Reactive Balance Control in Immersive Visual Flows: 2D vs. 3D Virtual Stimuli

Author: Jean-Dominique Gascuel, Olivier Martin, GIPSA - Systèmes biomécaniques (GIPSA-SBM), Département Automatique (GIPSA-DA), Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Stendhal - Grenoble 3-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 Stendhal - Grenoble 3-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)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Stendhal - Grenoble 3-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 Stendhal - Grenoble 3-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), 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), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-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 Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Grenoble Images Parole Signal Automatique (GIPSA-lab), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-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 Stendhal - Grenoble 3-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, [SCCO.NEUR]Cognitive science/Neuroscience, Biomedical Engineering, Biophysics, Neuroscience (miscellaneous), 020207 software engineering, 02 engineering and technology, computer.software_genre, Virtual machine, 0202 electrical engineering, electronic engineering, information engineering, Reactivity (psychology), Control (linguistics), computer, Simulation, Balance (ability), Motion flow
Abstract: Oral conference abstract - http://www.frontiersin.org/events/Annual_CyberTherapy_and_CyberPsychology_2009_conference/257/abstracts; International audience; The aim is to study the effects of 2D vs. 3D visual inputs on balance control. Ten subjects were fully immersed in virtual environment, using 10 different 2D/3D motion flow conditions. Analysis of visual and postural responses shows significant differences of reactivity in 3D versus 2D.
Published: 2009
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43. Diffusion Curves: A Vector Representation for Smooth-Shaded Images

Author: David Salesin, Pascal Barla, Adrien Bousseau, Joëlle Thollot, Alexandrina Orzan, Holger Winnemöller, 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., Visualization and manipulation of complex data on wireless mobile devices (IPARLA ), Université Sciences et Technologies - Bordeaux 1 (UB)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Bordelais de Recherche en Informatique (LaBRI), Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS), Belcurves Technologies France, Belcurves, 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), Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB), Melting the frontiers between Light, Shape and Matter (MANAO), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université de Bordeaux (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Models and Algorithms for Visualization and Rendering (MAVERICK), 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), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Sciences et Technologies - Bordeaux 1, Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), and Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest
Subjects: Vector graphics, General Computer Science, Computer science, Anisotropic diffusion, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Iterative reconstruction, 02 engineering and technology, Tracing, Rendering (computer graphics), color diffusion, gradient mesh, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, vectorization, 0501 psychology and cognitive sciences, 050107 human factors, Mathematics, ComputingMethodologies_COMPUTERGRAPHICS, 05 social sciences, 020207 software engineering, Animation, image reconstruction, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Geometric design, Vectorization (mathematics), Family of curves, 020201 artificial intelligence & image processing, Poisson's equation, Diffusion curve, image creation
Abstract: We describe a new vector-based primitive for creating smooth-shaded images, called the diffusion curve . A diffusion curve partitions the space through which it is drawn, defining different colors on either side. These colors may vary smoothly along the curve. In addition, the sharpness of the color transition from one side of the curve to the other can be controlled. Given a set of diffusion curves, the final image is constructed by solving a Poisson equation whose constraints are specified by the set of gradients across all diffusion curves. Like all vector-based primitives, diffusion curves conveniently support a variety of operations, including geometry-based editing, keyframe animation, and ready stylization. Moreover, their representation is compact and inherently resolution-independent. We describe a GPU-based implementation for rendering images defined by a set of diffusion curves in realtime. We then demonstrate an interactive drawing system for allowing artists to create artworks using diffusion curves, either by drawing the curves in a freehand style, or by tracing existing imagery. The system is simple and intuitive: we show results created by artists after just a few minutes of instruction. Furthermore, we describe a completely automatic conversion process for taking an image and turning it into a set of diffusion curves that closely approximate the original image content.
Published: 2008

44. 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

45. 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

46. 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

47. Precomputed Atmospheric Scattering

Author: Eric Bruneton, Fabrice Neyret, 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-05-MMSA-0004,NatSim,Nature virtuelle: représentations hybrides pour la modélisation, la simulation, la visualisation, et la transmission de scènes naturelles animées.(2005)
Subjects: Twilight, Scattering, Computer science, 020209 energy, media_common.quotation_subject, Diffuse sky radiation, 020207 software engineering, 02 engineering and technology, Computer Graphics and Computer-Aided Design, Light scattering, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Computational physics, symbols.namesake, Aerial perspective, Sky, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, symbols, Daylight, Rayleigh scattering, media_common
Abstract: International audience; We present a new and accurate method to render the atmosphere in real time from any viewpoint from ground level to outer space, while taking Rayleigh and Mie multiple scattering into account. Our method reproduces many effects of the scattering of light, such as the daylight and twilight sky color and aerial perspective for all view and light directions, or the Earth and mountain shadows (light shafts) inside the atmosphere. Our method is based on a formulation of the light transport equation that is precomputable for all view points, view directions and sun directions. We show how to store this data compactly and propose a GPU compliant algorithm to precompute it in a few seconds. This precomputed data allows us to evaluate at runtime the light transport equation in constant time, without any sampling, while taking into account the ground for shadows and light shafts.More informations : http://evasion.imag.fr/Membres/Eric.Bruneton/#atmo
Published: 2008

48. 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

49. 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

50. Fast Non-Linear Projections using Graphics Hardware

Author: Jean-Dominique Gascuel, Nicolas Holzschuch, Gabriel Paul Marcel Fournier, Bernard Péroche, 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), Rendu Réaliste pour la Réalité Augmentée Mobile (R3AM), Laboratoire d'InfoRmatique en Image et Systèmes d'information (LIRIS), Université Lumière - Lyon 2 (UL2)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Lumière - Lyon 2 (UL2)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École Centrale de Lyon (ECL), Université de Lyon-Université Lumière - Lyon 2 (UL2)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Université Lumière - Lyon 2 (UL2)
Subjects: 020203 distributed computing, Computer science, Computation, Graphics hardware, Graphic hardware, 020207 software engineering, 02 engineering and technology, Hemicube, Convexity, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Projection (mathematics), Computer graphics (images), [INFO.INFO-IR]Computer Science [cs]/Information Retrieval [cs.IR], 0202 electrical engineering, electronic engineering, information engineering, Overhead (computing), Graphics, Shadow mapping, indirect lighting, non-linear projections, video games and GPU
Abstract: http://artis.imag.fr/Publications/2008/GHFP08/; International audience; Linear perspective projections are used extensively in graphics. They provide a non-distorted view, with simple computations that map easily to hardware. Non-linear projections, such as the view given by a fish-eye lens are also used, either for artistic reasons or in order to provide a larger field of view, e.g. to approximate environment reflections or omnidirectional shadow maps. As the computations related to non-linear projections are more involved, they are harder to implement, especially in hardware, and have found little use so far in practical applications. In this paper, we apply existing methods for non-linear projections [Lloyd et al. 2006; Hou et al. 2006; Fournier 2005] to a specific class: non-linear projections with a single center of projection, radial symmetry and convexity. This class includes, but is not limited to, paraboloid projections, hemispherical projections and fish-eye lenses. We show that, for this class, the projection of a 3D triangle is a single curved triangle, and we give a mathematical analysis of the curved edges of the triangle; this analysis allows us to reduce the computations involved, and to provide a faster implementation. The overhead for non-linearity is bearable and can be balanced with the fact that a single nonlinear projection can replaces as many as five linear projections (in a hemicube), with less discontinuities and a smaller memory cost, thus making non-linear projections a practical alternative. More at http://artis.imag.fr/Publications/2008/GHFP08
Published: 2008

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