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Start date: 2011 × End date: 2019 × Author: Pauly, Mark ×

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Now showing 1 - 10 of 12
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    Dynamic 2D/3D Registration
    (The Eurographics Association, 2014) Bouaziz, Sofien; Tagliasacchi, Andrea; Pauly, Mark; Nicolas Holzschuch and Karol Myszkowski
    Image and geometry registration algorithms are an essential component of many computer graphics and computer vision systems. With recent technological advances in RGB-D sensors, such as the Microsoft Kinect or Asus Xtion Live, robust algorithms that combine 2D image and 3D geometry registration have become an active area of research. The goal of this course is to introduce the basics of 2D/3D registration algorithms and to provide theoretical explanations and practical tools to design computer vision and computer graphics systems based on RGB-D devices. To illustrate the theory and demonstrate practical relevance, we briefly discuss three applications: rigid scanning, non-rigid modeling, and realtime face tracking. Our course targets researchers and computer graphics practitioners with a background in computer graphics and/or computer vision. An up-to-date version of the course notes as well as slides and source code can be found at http://lgg.epfl.ch/2d3dRegistration.
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    Self Tuning Texture Optimization
    (The Eurographics Association and John Wiley & Sons Ltd., 2015) Kaspar, Alexandre; Neubert, Boris; Lischinski, Dani; Pauly, Mark; Kopf, Johannes; Olga Sorkine-Hornung and Michael Wimmer
    The goal of example-based texture synthesis methods is to generate arbitrarily large textures from limited exemplars in order to fit the exact dimensions and resolution required for a specific modeling task. The challenge is to faithfully capture all of the visual characteristics of the exemplar texture, without introducing obvious repetitions or unnatural looking visual elements. While existing non-parametric synthesis methods have made remarkable progress towards this goal, most such methods have been demonstrated only on relatively low-resolution exemplars. Real-world high resolution textures often contain texture details at multiple scales, which these methods have difficulty reproducing faithfully. In this work, we present a new general-purpose and fully automatic selftuning non-parametric texture synthesis method that extends Texture Optimization by introducing several key improvements that result in superior synthesis ability. Our method is able to self-tune its various parameters and weights and focuses on addressing three challenging aspects of texture synthesis: (i) irregular large scale structures are faithfully reproduced through the use of automatically generated and weighted guidance channels; (ii) repetition and smoothing of texture patches is avoided by new spatial uniformity constraints; (iii) a smart initialization strategy is used in order to improve the synthesis of regular and near-regular textures, without affecting textures that do not exhibit regularities. We demonstrate the versatility and robustness of our completely automatic approach on a variety of challenging high-resolution texture exemplars.
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    Fabrication-aware Design with Intersecting Planar Pieces
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Schwartzburg, Yuliy; Pauly, Mark; I. Navazo, P. Poulin
    We propose a computational design approach to generate 3D models composed of interlocking planar pieces. We show how intricate 3D forms can be created by sliding the pieces into each other along straight slits, leading to a simple construction that does not require glue, screws, or other means of support. To facilitate the design process, we present an abstraction model that formalizes the main geometric constraints imposed by fabrication and assembly, and incorporates conditions on the rigidity of the resulting structure.We show that the tight coupling of constraints makes manual design highly nontrivial and introduce an optimization method to automate constraint satisfaction based on an analysis of the constraint relation graph. This algorithm ensures that the planar parts can be fabricated and assembled. We demonstrate the versatility of our approach by creating 3D toy models, an architectural design study, and several examples of functional furniture.
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    Symmetry in Shapes - Theory and Practice
    (The Eurographics Association, 2013) Mitra, Niloy; Ovsjanikov, Maksim; Pauly, Mark; Wand, Michael; Ceylan, Duygu; Diego Gutierrez and Karol Myszkowski
    Part I: What is symmetry? Part II: Extrinsic symmetry detection Part III: Intrinsic symmetries Part IV: Representations and applications Conclusions, wrap-up
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    Thumbnail Galleries for Procedural Models
    (The Eurographics Association and John Wiley and Sons Ltd., 2014) Lienhard, Stefan; Specht, Matthias; Neubert, Boris; Pauly, Mark; Müller, Pascal; B. Levy and J. Kautz
    Procedural modeling allows for the generation of innumerable variations of models from a parameterized, conditional or stochastic rule set. Due to the abstractness, complexity and stochastic nature of rule sets, it is often very difficult to have an understanding of the diversity of models that a given rule set defines. We address this problem by presenting a novel system to automatically generate, cluster, rank, and select a series of representative thumbnail images out of a rule set. We introduce a set of view attributes that can be used to measure the suitability of an image to represent a model, and allow for comparison of different models derived from the same rule set. To find the best thumbnails, we exploit these view attributes on images of models obtained by stochastically sampling the parameter space of the rule set. The resulting thumbnail gallery gives a representative visual impression of the procedural modeling potential of the rule set. Performance is discussed by means of a number of distinct examples and compared to state-of-the-art approaches.
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    Factored Facade Acquisition using Symmetric Line Arrangements
    (The Eurographics Association and John Wiley and Sons Ltd., 2012) Ceylan, Duygu; Mitra, Niloy J.; Li, Hao; Weise, Thibaut; Pauly, Mark; P. Cignoni and T. Ertl
    We introduce a novel framework for image-based 3D reconstruction of urban buildings based on symmetry priors. Starting from image-level edges, we generate a sparse and approximate set of consistent 3D lines. These lines are then used to simultaneously detect symmetric line arrangements while refining the estimated 3D model. Operating both on 2D image data and intermediate 3D feature representations, we perform iterative feature consolidation and effective outlier pruning, thus eliminating reconstruction artifacts arising from ambiguous or wrong stereo matches. We exploit non-local coherence of symmetric elements to generate precise model reconstructions, even in the presence of a significant amount of outlier image-edges arising from reflections, shadows, outlier objects, etc. We evaluate our algorithm on several challenging test scenarios, both synthetic and real. Beyond reconstruction, the extracted symmetry patterns are useful towards interactive and intuitive model manipulations.
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    SAFE: Structure-aware Facade Editing
    (The Eurographics Association and John Wiley and Sons Ltd., 2014) Dang, Minh; Ceylan, Duygu; Neubert, Boris; Pauly, Mark; B. Levy and J. Kautz
    Many man-made objects, in particular building facades, exhibit dominant structural relations such as symmetry and regularity. When editing these shapes, a common objective is to preserve these relations. However, often there are numerous plausible editing results that all preserve the desired structural relations of the input, creating ambiguity. We propose an interactive facade editing framework that explores this structural ambiguity. We first analyze the input in a semi-automatic manner to detect different groupings of the facade elements and the relations among them. We then provide an incremental editing process where a set of variations that preserve the detected relations in a particular grouping are generated at each step. Starting from one input example, our system can quickly generate various facade configurations
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    Dynamic Geometry Processing
    (The Eurographics Association, 2012) Chang, Will; Li, Hao; Mitra, Niloy; Pauly, Mark; Wand, Michael; Renato Pajarola and Michela Spagnuolo
    Throughout the last few years, acquisition and processing of dynamic geometry has already received quite an amount of attention in the computer vision and graphics research community. Recently, the topic has gained a significant boost due to the availability of commodity devices for dynamic geometry acquisition: The introduction of the Microsoft ''Kinect'' device made this kind of technology broadly available, being very well received by both researchers and end-users, and even more development in this direction can probably be expected for the near future. The tutorial on ''Dynamic Geometry Processing'' considers the problem of processing such dynamic range data effectively and efficiently. The tutorial introduces basic processing techniques for analyzing and matching range data. It introduces models for correspondence estimation and presents the according basic algorithmic building blocks. Furthermore, it discusses the current state-of-the-art by looking at example approaches for processing and real-time tracking of dynamic data. In addition, the tutorial will also identify and discuss future challenges in the field, aiming at inspiring future work in this exciting area of research.
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    Automatic Generation of Constructable Brick Sculptures
    (The Eurographics Association, 2013) Testuz, Romain; Schwartzburg, Yuliy; Pauly, Mark; M.- A. Otaduy and O. Sorkine
    Fabrication of LEGO R models in large scale requires careful pre-planning to produce constructable and stable models. We propose a system that, starting with a voxelization of a 3D mesh, merges voxels to form larger bricks, and then analyzes and repairs structural problems, finally outputting a set of building instructions. We also present extensions such as producing hollow models, fulfilling limits on the number of bricks of each size, and including colors. Results (both real and virtual) and timings show significant improvements over previous work.
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    Exploring Local Modifications for Constrained Meshes
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Deng, Bailin; Bouaziz, Sofien; Deuss, Mario; Zhang, Juyong; Schwartzburg, Yuliy; Pauly, Mark; I. Navazo, P. Poulin
    Mesh editing under constraints is a challenging task with numerous applications in geometric modeling, industrial design, and architectural form finding. Recent methods support constraint-based exploration of meshes with fixed connectivity, but commonly lack local control. Because constraints are often globally coupled, a local modification by the user can have global effects on the surface, making iterative design exploration and refinement difficult. Simply fixing a local region of interest a priori is problematic, as it is not clear in advance which parts of the mesh need to be modified to obtain an aesthetically pleasing solution that satisfies all constraints. We propose a novel framework for exploring local modifications of constrained meshes. Our solution consists of three steps. First, a user specifies target positions for one or more vertices. Our algorithm computes a sparse set of displacement vectors that satisfies the constraints and yields a smooth deformation. Then we build a linear subspace to allow realtime exploration of local variations that satisfy the constraints approximately. Finally, after interactive exploration, the result is optimized to fully satisfy the set of constraints. We evaluate our framework on meshes where each face is constrained to be planar.