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Visualization and Computer Graphics, IEEE Transactions on

Issue 1 • Date Jan.-March 2001

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Displaying Results 1 - 8 of 8
  • Reviewers list 2000

    Page(s): 94 - 96
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    Freely Available from IEEE
  • “Meshsweeper”: dynamic point-to-polygonal mesh distance and applications

    Page(s): 47 - 61
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1808 KB) |  | HTML iconHTML  

    We introduce a new algorithm for computing the distance from a point to an arbitrary polygonal mesh. Our algorithm uses a multiresolution hierarchy of bounding volumes generated by geometric simplification. Our algorithm is dynamic, exploiting coherence between subsequent queries using a priority process and achieving constant time queries in some cases. It can be applied to meshes that transform rigidly or deform nonrigidly. We illustrate our algorithm with a simulation of particle dynamics and collisions with a deformable mesh, the computation of distance maps and offset surfaces, the computation of an approximation to the expensive Hausdorff distance between two shapes, and the detection of self-intersections. We also report comparison results between our algorithm and an alternative algorithm using an octree, upon which our method permits an order-of-magnitude speed-up View full abstract»

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  • Terrain decimation through Quadtree Morphing

    Page(s): 62 - 69
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1036 KB) |  | HTML iconHTML  

    We present a new terrain decimation technique called a Quadtree Morph, or Q-morph. The new approach eliminates the usual popping artifacts associated with polygon reduction, replacing them with less objectionable smooth morphing. We show that Q-morphing is fast enough to create a view-dependent terrain model for each frame in an interactive environment. In contrast to most Geomorph algorithms, Q-morphing does not use a time step to interpolate between geometric configurations. Instead, the geometry motion in a Q-morph is based solely on the position of the viewer View full abstract»

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  • Nonlinear multiresolution techniques with applications to scientific visualization in a haptic environment

    Page(s): 76 - 93
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1180 KB) |  | HTML iconHTML  

    This paper develops nonlinear multiresolution techniques for scientific visualization utilizing haptic methods. The visualization of data is critical to many areas of scientific pursuit. Scientific visualization is generally accomplished through computer graphic techniques. Recent advances in haptic technologies allow visual techniques to be augmented with haptic methods. The kinesthetic feedback provided through haptic techniques provides a second modality for visualization and allows for active exploration. Moreover, haptic methods can be utilized by individuals with visual impairments. Haptic representations of large data sets, however, can be confusing to a user, especially if a visual representation is not available or cannot be used. This paper develops a multiresolution data decomposition method based on the affine median filter. This results in a hybrid structure that can be tuned to yield a decomposition that varies from a linear wavelet decomposition to that produced by the median filter. The performance of this hybrid structure is analyzed utilizing deterministic signals and statistically in the frequency domain. This analysis and qualitative and quantitative implementation results show that the affine median decomposition has advantages over previously proposed methods. In addition to multiresolution decomposition development, analysis, and results, haptic implementation methods are presented View full abstract»

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  • Fast isosurface generation using the volume thinning algorithm

    Page(s): 32 - 46
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1472 KB) |  | HTML iconHTML  

    One of the most effective techniques for developing efficient isosurfacing algorithms is the reduction of visits to nonisosurface cells. Recent algorithms have drastically reduced the unnecessary cost of visiting nonisosurface cells. The experimental results show almost optimal performance in their isosurfacing processes. However, most of them have a bottleneck in that they require more than O(n) computation time for their preprocessing, where n denotes the total number of cells. We propose an efficient isosurfacing technique, which can be applied to unstructured as well as structured volumes and which does not require more than O(n) computation time for its preprocessing. A preprocessing step generates an extrema skeleton, which consists of cells and connects all extremum points, by the volume thinning algorithm. All disjoint parts of every isosurface intersect at least one cell in the extrema skeleton. Our implementation generates isosurfaces by searching for isosurface cells in the extrema skeleton and then recursively visiting their adjacent isosurface cells, while it skips most of the nonisosurface cells. The computation time of the preprocessing is estimated as O(n). The computation time of the isosurfacing process is estimated as O(n1/3m+k), where k denotes the number of isosurface cells and m denotes the number of extremum points since the number of cells in an extrema skeleton is estimated as O(n1/3m) View full abstract»

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  • A graphical representation of the state spaces of hierarchical level-of-detail scene descriptions

    Page(s): 70 - 75
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB) |  | HTML iconHTML  

    We present a new graphical representation of the level-of-detail state spaces generated by hierarchical geometric scene descriptions with multiple levels of detail. These level-of-detail graphs permit the analytical investigation of the hierarchical level-of-detail optimization problem that arises for such descriptions. As an example of their use, we prove the equivalence of two hierarchical level-of-detail algorithms View full abstract»

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  • On simulated annealing and the construction of linear spline approximations for scattered data

    Page(s): 17 - 31
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2648 KB) |  | HTML iconHTML  

    We describe a method to create optimal linear spline approximations to arbitrary functions of one or two variables, given as scattered data without known connectivity. We start with an initial approximation consisting of a fixed number of vertices and improve this approximation by choosing different vertices, governed by a simulated annealing algorithm. In the case of one variable, the approximation is defined by line segments; in the case of two variables, the vertices are connected to define a Delaunay triangulation of the selected subset of sites in the plane. In a second version of this algorithm, specifically designed for the bivariate case, we choose vertex sets and also change the triangulation to achieve both optimal vertex placement and optimal triangulation. We then create a hierarchy of linear spline approximations, each one being a superset of all lower-resolution ones View full abstract»

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  • Parameterization and reconstruction from 3D scattered points based on neural network and PDE techniques

    Page(s): 1 - 16
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1808 KB) |  | HTML iconHTML  

    Reverse engineering ordinarily uses laser scanners since they can sample 3D data quickly and accurately relative to other systems. These laser scanner systems, however, yield an enormous amount of irregular and scattered digitized point data that requires intensive reconstruction processing. Reconstruction of freeform objects consists of two main stages: parameterization and surface fitting. Selection of an appropriate parameterization is essential for topology reconstruction as well as surface fitness. Current parameterization methods have topological problems that lead to undesired surface fitting results, such as noisy self-intersecting surfaces. Such problems are particularly common with concave shapes whose parametric grid is self-intersecting, resulting in a fitted surface that considerably twists and changes its original shape. In such cases, other parameterization approaches should be used in order to guarantee non-self-intersecting behavior. The parameterization method described in this paper is based on two stages: 2D initial parameterization; and 3D adaptive parameterization. Two methods were developed for the first stage: partial differential equation (PDE) parameterization and neural network self organizing maps (SOM) parameterization. The Gradient Descent Algorithm (GDA) and Random Surface Error Correction (RSEC), both of which are iterative surface fitting methods, were developed and implemented View full abstract»

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Aims & Scope

Visualization techniques and methodologies; visualization systems and software; volume visualization; flow visualization; multivariate visualization; modeling and surfaces; rendering; animation; user interfaces; visual progranuning; applications.

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Meet Our Editors

Editor-in-Chief
Ming Lin
Department of Computer Science
University of North Carolina