34-Issue 2

Permanent URI for this collection

https://diglib.eg.org/handle/10.2312/12150

Browse

Browsing 34-Issue 2 by Subject "and systems"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Designing Camera Networks by Convex Quadratic Programming
    (The Eurographics Association and John Wiley & Sons Ltd., 2015) Ghanem, Bernard; Cao, Yuanhao; Wonka, Peter; Olga Sorkine-Hornung and Michael Wimmer
    In this paper, we study the problem of automatic camera placement for computer graphics and computer vision applications. We extend the problem formulations of previous work by proposing a novel way to incorporate visibility constraints and camera-to-camera relationships. For example, the placement solution can be encouraged to have cameras that image the same important locations from different viewing directions, which can enable reconstruction and surveillance tasks to perform better. We show that the general camera placement problem can be formulated mathematically as a convex binary quadratic program (BQP) under linear constraints. Moreover, we propose an optimization strategy with a favorable trade-off between speed and solution quality. Our solution is almost as fast as a greedy treatment of the problem, but the quality is significantly higher, so much so that it is comparable to exact solutions that take orders of magnitude more computation time. Because it is computationally attractive, our method also allows users to explore the space of solutions for variations in input parameters. To evaluate its effectiveness, we show a range of 3D results on real-world floorplans (garage, hotel, mall, and airport).
  • Thumbnail Image
    Item
    Interactive Disassembly Planning for Complex Objects
    (The Eurographics Association and John Wiley & Sons Ltd., 2015) Kerbl, Bernhard; Kalkofen, Denis; Steinberger, Markus; Schmalstieg, Dieter; Olga Sorkine-Hornung and Michael Wimmer
    We present an approach for the automatic generation, interactive exploration and real-time modification of disassembly procedures for complex, multipartite CAD data sets. In order to lift the performance barriers prohibiting interactive disassembly planning, we run a detailed analysis on the input model to identify recurring part constellations and efficiently determine blocked part motions in parallel on the GPU. Building on the extracted information, we present an interface for computing and editing extensive disassembly sequences in real-time while considering user-defined constraints and avoiding unstable configurations. To evaluate the performance of our C++/CUDA implementation, we use a variety of openly available CAD data sets, ranging from simple to highly complex. In contrast to previous approaches, our work enables interactive disassembly planning for objects which consist of several thousand parts and require cascaded translations during part removal.
  • Thumbnail Image
    Item
    Template Assembly for Detailed Urban Reconstruction
    (The Eurographics Association and John Wiley & Sons Ltd., 2015) Nan, Liangliang; Jiang, Caigui; Ghanem, Bernard; Wonka, Peter; Olga Sorkine-Hornung and Michael Wimmer
    We propose a new framework to reconstruct building details by automatically assembling 3D templates on coarse textured building models. In a preprocessing step, we generate an initial coarse model to approximate a point cloud computed using Structure from Motion and Multi View Stereo, and we model a set of 3D templates of facade details. Next, we optimize the initial coarse model to enforce consistency between geometry and appearance (texture images). Then, building details are reconstructed by assembling templates on the textured faces of the coarse model. The 3D templates are automatically chosen and located by our optimization-based template assembly algorithm that balances image matching and structural regularity. In the results, we demonstrate how our framework can enrich the details of coarse models using various data sets.