Search Results

Now showing 1 - 10 of 28
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    State of the Art in Global Illumination for Interactive Applications and High-quality Animations
    (Blackwell Publishers, Inc and the Eurographics Association, 2003) Damez, Cyrille; Dmitriev, Kirill; Myszkowski, Karol
    Global illumination algorithms are regarded as computationally intensive. This cost is a practical problem when producing animations or when interactions with complex models are required. Several algorithms have been proposed to address this issue. Roughly, two families of methods can be distinguished. The first one aims at providing interactive feedback for lighting design applications. The second one gives higher priority to the quality of results, and therefore relies on offline computations. Recently, impressive advances have been made in both categories. In this report, we present a survey and classification of the most up-to-date of these methods.ACM CSS: I.3.7 Computer Graphics-Three-Dimensional Graphics and Realism
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    Optimizing Disparity for Motion in Depth
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Kellnhofer, Petr; Ritschel, Tobias; Myszkowski, Karol; Seidel, Hans-Peter; Nicolas Holzschuch and Szymon Rusinkiewicz
    Beyond the careful design of stereo acquisition equipment and rendering algorithms, disparity post-processing has recently received much attention, where one of the key tasks is to compress the originally large disparity range to avoid viewing discomfort. The perception of dynamic stereo content however, relies on reproducing the full disparity-time volume that a scene point undergoes in motion. This volume can be strongly distorted in manipulation, which is only concerned with changing disparity at one instant in time, even if the temporal coherence of that change is maintained. We propose an optimization to preserve stereo motion of content that was subject to an arbitrary disparity manipulation, based on a perceptual model of temporal disparity changes. Furthermore, we introduce a novel 3D warping technique to create stereo image pairs that conform to this optimized disparity map. The paper concludes with perceptual studies of motion reproduction quality and task performance in a simple game, showing how our optimization can achieve both viewing comfort and faithful stereo motion.
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    Lightness Perception in Tone Reproduction for High Dynamic Range Images
    (The Eurographics Association and Blackwell Publishing, Inc, 2005) Krawczyk, Grzegorz; Myszkowski, Karol; Seidel, Hans-Peter
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    Temporally Coherent Irradiance Caching for High Quality Animation Rendering
    (The Eurographics Association and Blackwell Publishing, Inc, 2005) Smyk,, Miloslaw; Kinuwaki, Shin-ichi; Durikovic Roman; Myszkowski, Karol
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    Efficient Multi-image Correspondences for On-line Light Field Video Processing
    (The Eurographics Association and John Wiley & Sons Ltd., 2016) Dąbała, Łukasz; Ziegler, Matthias; Didyk, Piotr; Zilly, Frederik; Keinert, Joachim; Myszkowski, Karol; Seidel, Hans-Peter; Rokita, Przemysław; Ritschel, Tobias; Eitan Grinspun and Bernd Bickel and Yoshinori Dobashi
    Light field videos express the entire visual information of an animated scene, but their shear size typically makes capture, processing and display an off-line process, i. e., time between initial capture and final display is far from real-time. In this paper we propose a solution for one of the key bottlenecks in such a processing pipeline, which is a reliable depth reconstruction possibly for many views. This is enabled by a novel correspondence algorithm converting the video streams from a sparse array of off-the-shelf cameras into an array of animated depth maps. The algorithm is based on a generalization of the classic multi-resolution Lucas-Kanade correspondence algorithm from a pair of images to an entire array. Special inter-image confidence consolidation allows recovery from unreliable matching in some locations and some views. It can be implemented efficiently in massively parallel hardware, allowing for interactive computations. The resulting depth quality as well as the computation performance compares favorably to other state-of-the art light field-to-depth approaches, as well as stereo matching techniques. Another outcome of this work is a data set of light field videos that are captured with multiple variants of sparse camera arrays.
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    Perceptually-motivated Stereoscopic Film Grain
    (The Eurographics Association and John Wiley and Sons Ltd., 2014) Templin, Krzysztof; Didyk, Piotr; Myszkowski, Karol; Seidel, Hans-Peter; J. Keyser, Y. J. Kim, and P. Wonka
    Independent management of film grain in each view of a stereoscopic video can lead to visual discomfort. The existing alternative is to project the grain onto the scene geometry. Such grain, however, looks unnatural, changes object perception, and emphasizes inaccuracies in depth arising during 2D-to-3D conversion. We propose an advanced method of grain positioning that scatters the grain in the scene space. In a series of perceptual experiments, we estimate the optimal parameter values for the proposed method, analyze the user preference distribution among the proposed and the two existing methods, and show influence of the method on the object perception.
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    Rendering Pearlescent Appearance Based On Paint-Composition Modelling
    (Blackwell Publishers Ltd and the Eurographics Association, 2001) Ershov, Sergey; Kolchin, Konstantin; Myszkowski, Karol
    We describe a new approach to modelling pearlescent paints based on decomposing paint layers into stacks of imaginary thin sublayers. The sublayers are chosen so thin that multiple scattering can be considered across different sublayers, while it can be neglected within each of the sublayers. Based on this assumption, an efficient recursive procedure of assembling the layers is developed, which enables to compute the paint BRDF at interactive speeds. Since the proposed paint model connects fundamental optical properties of multi-layer pearlescent and metallic paints with their microscopic structure, interactive prediction of the paint appearance based on its composition becomes possible.
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    Manipulating Refractive and Reflective Binocular Disparity
    (The Eurographics Association and John Wiley and Sons Ltd., 2014) Dabala, Lukasz; Kellnhofer, Petr; Ritschel, Tobias; Didyk, Piotr; Templin, Krzysztof; Myszkowski, Karol; Rokita, P.; Seidel, Hans-Peter; B. Levy and J. Kautz
    Presenting stereoscopic content on 3D displays is a challenging task, usually requiring manual adjustments. A number of techniques have been developed to aid this process, but they account for binocular disparity of surfaces that are diffuse and opaque only. However, combinations of transparent as well as specular materials are common in the real and virtual worlds, and pose a significant problem. For example, excessive disparities can be created which cannot be fused by the observer. Also, multiple stereo interpretations become possible, e. g., for glass, that both reflects and refracts, which may confuse the observer and result in poor 3D experience. In this work, we propose an efficient method for analyzing and controlling disparities in computer-generated images of such scenes where surface positions and a layer decomposition are available. Instead of assuming a single per-pixel disparity value, we estimate all possibly perceived disparities at each image location. Based on this representation, we define an optimization to find the best per-pixel camera parameters, assuring that all disparities can be easily fused by a human. A preliminary perceptual study indicates, that our approach combines comfortable viewing with realistic depiction of typical specular scenes.
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    Contrast Restoration by Adaptive Countershading
    (The Eurographics Association and Blackwell Publishing Ltd, 2007) Krawczyk, Grzegorz; Myszkowski, Karol; Seidel, Hans-Peter
    The ABSTRACT is to be in fully-justified italicized text, between two horizontal lines, in one-column format, below the author and affiliation information. Use the word Abstract as the title, in 9-point Times, boldface type, left-aligned to the text, initially capitalized. The abstract is to be in 9-point, single-spaced type. The abstract may be up to 3 inches (7.62 cm) long. Leave one blank line after the abstract, then add the subject categories according to the ACM Classification Index (see http://www.acm.org/class/1998/).
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    NoRM: No-Reference Image Quality Metric for Realistic Image Synthesis
    (The Eurographics Association and John Wiley and Sons Ltd., 2012) Herzog, Robert; Cadík, Martin; Aydin, Tunç O.; Kim, Kwang In; Myszkowski, Karol; Seidel, Hans-Peter; P. Cignoni and T. Ertl
    Synthetically generating images and video frames of complex 3D scenes using some photo-realistic rendering software is often prone to artifacts and requires expert knowledge to tune the parameters. The manual work required for detecting and preventing artifacts can be automated through objective quality evaluation of synthetic images. Most practical objective quality assessment methods of natural images rely on a ground-truth reference, which is often not available in rendering applications. While general purpose no-reference image quality assessment is a difficult problem, we show in a subjective study that the performance of a dedicated no-reference metric as presented in this paper can match the state-of-the-art metrics that do require a reference. This level of predictive power is achieved exploiting information about the underlying synthetic scene (e.g., 3D surfaces, textures) instead of merely considering color, and training our learning framework with typical rendering artifacts. We show that our method successfully detects various non-trivial types of artifacts such as noise and clamping bias due to insufficient virtual point light sources, and shadow map discretization artifacts. We also briefly discuss an inpainting method for automatic correction of detected artifacts.