Geo-located networks are analyzed in various domains such as supply chain management. When simulating supply chain processes or when testing geo-visualization techniques, synthetic test datasets are needed. However, r...
详细信息
ISBN:
(纸本)9781509056989
Geo-located networks are analyzed in various domains such as supply chain management. When simulating supply chain processes or when testing geo-visualization techniques, synthetic test datasets are needed. However, real world data are difficult to obtain and artificial data are cumbersome to create manually. In this paper, we present an interactive visual tree network generator that not only generates a network, but also attaches geo-locations to its nodes. We designed a modular rulebased system to control the generation process. A user can interactively use rules to parametrize the data generation process. The user can visually explore and adjust results intermediately after each generation iteration.
In this paper we compare the time and space complexity of editing operations on two data structures which are suitable for visualizing huge point clouds. The first data structure was introduced by Scheiblauer and Wimm...
详细信息
ISBN:
(纸本)9788086943749
In this paper we compare the time and space complexity of editing operations on two data structures which are suitable for visualizing huge point clouds. The first data structure was introduced by Scheiblauer and Wimmer [SW11] and uses only the original points from a source data set for building a level-of-detail hierarchy that can be used for rendering points clouds. The second data structure introduced by Wand et al. [WBB+07] requires additional points for the level-of-detail hierarchy and therefore needs more memory when stored on disk. Both data structures are based on an octree hierarchy and allow for deleting and inserting points. Besides analyzing and comparing these two data structures we also introduce an improvement to the points deleting algorithm for the data structure of Wand et al. [WBB+07], which thus allows for a more efficient node loading strategy during rendering.
Any sufficiently smooth, positive, real-valued function psi : S-2 -> IR+ on a sphere S-2 can be expanded by a Laplace expansion into a sum of spherical harmonics. Given the Laplace expansion coefficients, we provid...
详细信息
Any sufficiently smooth, positive, real-valued function psi : S-2 -> IR+ on a sphere S-2 can be expanded by a Laplace expansion into a sum of spherical harmonics. Given the Laplace expansion coefficients, we provide a CPU and GPU-based algorithm that renders the radial graph of psi in a fast and efficient way by ray-casting the glyph of psi in the fragment shader of a GPU. The proposed rendering algorithm has proven highly useful in the visualization of high angular resolution diffusion imaging (HARDI) data. Our implementation of the rendering algorithm can display simultaneously thousands of glyphs depicting the local diffusivity of water. The rendering is fast enough to allow for interactive manipulation of large HARDI data sets.
作者：
Schaufler, GSturzlinger, WGUP
Johannes Kepler Universität Linz Altenbergerstr.69 A-4040 Linz Austria/Europe schaufler@gup.uni-linz.ac.at
Despite recent advances in rendering hardware, large and complex virtual environments cannot be displayed with a sufficiently high frame rate, because of limitations in the available rendering performance. This paper ...
详细信息
Despite recent advances in rendering hardware, large and complex virtual environments cannot be displayed with a sufficiently high frame rate, because of limitations in the available rendering performance. This paper presents a new approach of software accelerated rendering which draws from the concepts of impostors, hierarchical scene subdivision and levels of detail. So far software optimization in real-time rendering has merely considered individual objects. This work is actually optimizing the rendering of the whole virtual environment by implementing a three dimensional image cache. It speeds up rendering for large portions of the scene by exploiting the coherence inherent in any smooth frame sequence. The implementation of the three dimensional image cache is discussed and the savings in rendering load achievable on a suitable hardware platform are presented.
Algebraic Point Set Surfaces (APSS) define a smooth surface from a set of points using local moving least-squares (MLS) fitting of algebraic spheres. In this paper we first revisit the spherical fitting problem and pr...
详细信息
Algebraic Point Set Surfaces (APSS) define a smooth surface from a set of points using local moving least-squares (MLS) fitting of algebraic spheres. In this paper we first revisit the spherical fitting problem and provide a new, more generic solution that includes intuitive parameters for curvature control of the fitted spheres. As a second contribution we present a novel real-time rendering system of such surfaces using a dynamic up-sampling strategy combined with a conventional splatting algorithm for high quality rendering. Our approach also includes a new view dependent geometric error tailored to efficient and adaptive up-sampling of the surface. One of the key features of our system is its high degree of flexibility that enables us to achieve high performance even for highly dynamic data or complex models by exploiting temporal coherence at the primitive level. We also address the issue of efficient spatial search data structures with respect to construction, access and GPU friendliness. Finally, we present an efficient parallel GPU implementation of the algorithms and search structures.
Control over what is in focus and what is not in focus in an image is an important artistic tool. The range of depth in a 3D scene that is imaged in sufficient focus through an optics system, such as a camera lens, is...
详细信息
ISBN:
(纸本)9781568814704
Control over what is in focus and what is not in focus in an image is an important artistic tool. The range of depth in a 3D scene that is imaged in sufficient focus through an optics system, such as a camera lens, is called depth of field. Without depth of field, the entire scene appears completely in sharp focus, leading to an unnatural, overly crisp appearance. Current techniques for rendering depth of field in computer graphics are either slow or suffer from artifacts, or restrict the choice of point spread function (PSF). In this paper, we present a new image filter based on rectangle spreading which is constant time per pixel. When used in a layered depth of field framework, our filter eliminates the intensity leakage and depth discontinuity artifacts that occur in previous methods. We also present several extensions to our rectangle spreading method to allow flexibility in the appearance of the blur through control over the PSF.
Depth and visual hulls are useful for quick reconstruction and rendering of a 3D object based on a number of reference views. However, for many scenes, especially multi-object, these hulls may contain significant arti...
详细信息
Depth and visual hulls are useful for quick reconstruction and rendering of a 3D object based on a number of reference views. However, for many scenes, especially multi-object, these hulls may contain significant artifacts known as phantom geometry. In depth hulls the phantom geometry appears behind the scene objects in regions occluded from all the reference views. In visual hulls the phantom geometry may also appear in front of the objects because there is not enough information to unambiguously imply the object positions. In this work we identify which parts of the depth and visual hull might constitute phantom geometry. We define the notion of reduced depth hull and reduced visual hull as the parts of the corresponding hull that are phantom-free. We analyze the role of the depth information in identification of the phantom geometry. Based on this, we provide an algorithm for rendering the reduced depth hull at interactive frame-rates and suggest an approach for rendering the reduced visual hull. The rendering algorithms take advantage of modern GPU programming techniques. Our techniques bypass explicit reconstruction of the hulls, rendering the reduced depth or visual hull directly from the reference views.
暂无评论