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Now showing 1 - 7 of 7
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    Stereo from Shading
    (The Eurographics Association, 2015) Chapiro, Alexandre; O'Sullivan, Carol; Jarosz, Wojciech; Gross, Markus; Smolic, Aljoscha; Jaakko Lehtinen and Derek Nowrouzezahrai
    We present a new method for creating and enhancing the stereoscopic 3D (S3D) sensation without using the parallax disparity between an image pair. S3D relies on a combination of cues to generate a feeling of depth, but only a few of these cues can easily be modified within a rendering pipeline without significantly changing the content. We explore one such cue-shading stereopsis-which to date has not been exploited for 3D rendering. By changing only the shading of objects between the left and right eye renders, we generate a noticeable increase in perceived depth. This effect can be used to create depth when applied to flat images, and to enhance depth when applied to shallow depth S3D images. Our method modifies the shading normals of objects or materials, such that it can be flexibly and selectively applied in complex scenes with arbitrary numbers and types of lights and indirect illumination. Our results show examples of rendered stills and video, as well as live action footage.
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    Example Based Repetitive Structure Synthesis
    (The Eurographics Association and John Wiley & Sons Ltd., 2015) Roveri, Riccardo; Ă–ztireli, A. Cengiz; Martin, Sebastian; Solenthaler, Barbara; Gross, Markus; Mirela Ben-Chen and Ligang Liu
    We present an example based geometry synthesis approach for generating general repetitive structures. Our model is based on a meshless representation, unifying and extending previous synthesis methods. Structures in the example and output are converted into a functional representation, where the functions are defined by point locations and attributes. We then formulate synthesis as a minimization problem where patches from the output function are matched to those of the example. As compared to existing repetitive structure synthesis methods, the new algorithm offers several advantages. It handles general discrete and continuous structures, and their mixtures in the same framework. The smooth formulation leads to employing robust optimization procedures in the algorithm. Equipped with an accurate patch similarity measure and dedicated sampling control, the algorithm preserves local structures accurately, regardless of the initial distribution of output points. It can also progressively synthesize output structures in given subspaces, allowing users to interactively control and guide the synthesis in real-time. We present various results for continuous/discrete structures and their mixtures, residing on curves, submanifolds, volumes, and general subspaces, some of which are generated interactively.
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    Dispersion-based Color Projection using Masked Prisms
    (The Eurographics Association and John Wiley & Sons Ltd., 2015) Hostettler, Rafael; Habel, Ralf; Gross, Markus; Jarosz, Wojciech; Stam, Jos and Mitra, Niloy J. and Xu, Kun
    We present a method for projecting arbitrary color images using a white light source and an optical device with no colored components - consisting solely of one or two prisms and two transparent masks. When illuminated, the first mask creates structured white light that is then dispersed in the prism and attenuated by the second mask to create the color projection. We derive analytical expressions for the mask parameters from the physical components and validate our approach both in simulation and also demonstrate it on a wide variety of images using two different physical setups (one consisting of two inexpensive triangular prisms, and the other using a single rhombic prism). Furthermore, we show that optimizing the masks simultaneously enables obfuscating the image content, and provides a tradeoff between increased light throughput (by up to a factor of three) and maximum color saturation.
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    Hierarchical Planning and Control for Complex Motor Tasks
    (ACM Siggraph, 2015) Zimmermann, Daniel; Coros, Stelian; Ye, Yuting; Sumner, Robert W.; Gross, Markus; Florence Bertails-Descoubes and Stelian Coros and Shinjiro Sueda
    We present a planning and control framework that enables physically simulated characters to perform various types of motor tasks. To create physically-valid motion plans, our method uses a hierarchical set of simplified models. Computational resources are therefore focused where they matter most: motion plans for the immediate future are generated using higher-fidelity models, while coarser models are used to create motion plans with longer time horizons. Our framework can be used for different types of motor skills, including ones where the actions of the arms and legs must be precisely coordinated. We demonstrate controllers for tasks such as getting up from a chair, crawling onto a raised platform, or using a handrail while climbing stairs. All of the motions are simulated using a black-box physics engine from high level user commands, without requiring any motion capture data.
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    Sketch Abstractions for Character Posing
    (ACM Siggraph, 2015) Hahn, Fabian; Mutzel, Frederik; Coros, Stelian; Thomaszewski, Bernhard; Nitti, Maurizio; Gross, Markus; Sumner, Robert W.; Florence Bertails-Descoubes and Stelian Coros and Shinjiro Sueda
    We propose a sketch-based posing system for rigged 3D characters that allows artists to create custom sketch abstractions on top of a character's actual shape. A sketch abstraction is composed of rigged curves that form an iconographic 2D representation of the character from a particular viewpoint. When provided with a new input sketch, our optimization system minimizes a nonlinear iterative closest point energy to find the rigging parameters that best align the character's sketch abstraction to the input sketch. A custom regularization term addresses the underconstrained nature of the problem to select favorable poses. Although our system supports arbitrary black-box rigs, we show how to optimize computations when rigging formulas and derivatives are available. We demonstrate our system's flexibility with examples showing different artist-designed sketch abstractions for both full body posing and the customization of individual components of a modular character. Finally, we show that simple sketch abstractions can be built on the fly by projecting a drawn curve onto the character's mesh. Redrawing the curve allows the user to dynamically pose the character. Taken together, our system enables a new form of intuitive sketch-based posing in which the character designer has the freedom to prescribe the sketch abstraction that is most meaningful for the character.
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    Interactive Generation of Realistic Facial Wrinkles from Sketchy Drawings
    (The Eurographics Association and John Wiley & Sons Ltd., 2015) Kim, Hyeon-Joong; Ă–ztireli, A. Cengiz; Shin, Il-Kyu; Gross, Markus; Choi, Soo-Mi; Olga Sorkine-Hornung and Michael Wimmer
    Synthesizing facial wrinkles has been tackled either by a long process of manual sculpting on 3D models, or using automatic methods that do not allow for user interaction or artistic expression. In this paper, we propose a method that accepts interactive sketchy drawings depicting wrinkle patterns, and synthesizes realistic looking wrinkles on faces. The method inherits the simplicity of sketching, making it possible for artists as well as novice users to generate realistic facial detail very efficiently, allowing fast preview for physical makeup, or aging simulations for fun and professional applications. All strokes are used to infer the wrinkles, retaining the expressiveness of the sketches and realism of the final result at the same time. This is achieved by designing novel multi-scale statistics tailored to the wrinkle geometry and coupled to the sketch interpretation method. The statistics capture the crosssectional profiles of wrinkles at different scales and parts of a face. The strokes are augmented with the statistics extracted from given example face models, and applied to an input face model interactively. The interface gives the user control over the shapes and scales of wrinkles via sketching while adding extra details required for realism automatically.
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    Panoramic Video from Unstructured Camera Arrays
    (The Eurographics Association and John Wiley & Sons Ltd., 2015) Perazzi, Federico; Sorkine-Hornung, Alexander; Zimmer, Henning; Kaufmann, Peter; Wang, Oliver; Watson, Scott; Gross, Markus; Olga Sorkine-Hornung and Michael Wimmer
    We describe an algorithm for generating panoramic video from unstructured camera arrays. Artifact-free panorama stitching is impeded by parallax between input views. Common strategies such as multi-level blending or minimum energy seams produce seamless results on quasi-static input. However, on video input these approaches introduce noticeable visual artifacts due to lack of global temporal and spatial coherence. In this paper we extend the basic concept of local warping for parallax removal. Firstly, we introduce an error measure with increased sensitivity to stitching artifacts in regions with pronounced structure. Using this measure, our method efficiently finds an optimal ordering of pair-wise warps for robust stitching with minimal parallax artifacts. Weighted extrapolation of warps in non-overlap regions ensures temporal stability, while at the same time avoiding visual discontinuities around transitions between views. Remaining global deformation introduced by the warps is spread over the entire panorama domain using constrained relaxation, while staying as close as possible to the original input views. In combination, these contributions form the first system for spatiotemporally stable panoramic video stitching from unstructured camera array input.