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A list of current and past project with references to publications, talks and demo material.

 
Find below a list of my main projects (this is not an exhaustive list). Check the news, research reports or conference papers for more projects or short investigations.

Select a project from the list
 

  • Volume warping for adaptive isosurface extraction. - Last update April 10th, 2002
  • Space-optimized Texture Maps. - Last update March 10th, 2002
  • Mesh optimization using global error. - Last update March 15th, 2002
  • Properties of subdivision surfaces having 4-8 connectivity. - Last update Jan 10th, 2002
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    Additional publications are available in the docs section. If you're interested in development, please refer to this page.
     

    Volume warping for adaptive isosurface extraction
    Laurent Balmelli, Christopher Morris, Gabriel Taubin, Fausto Bernardini - IBM Research.

    We propose a novel methodology to generate adaptive isosurfaces that is easy to implement and allows the user to decide their degree of adaptivity as well as their choice of isosurface extraction algorithm. The method optimizes isosurface extraction by warping a volume to enlarge areas of high frequency and minimize areas of low frequency. Any extraction algorithm can then be used to generate a mesh which is subsequently unwarped. The resulting isosurface is represented by a mesh that is adaptively sampled in regions of significant details.
    Selected Publications and Talks
  • Volume warping for adaptive isosurface extraction, IBM Research report 22390 (full 3.1Mb/ No plates 1.1Mb).
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    Last update April 10th, 2002

    Space-optimized Texture Maps
    Laurent Balmelli, Gabriel Taubin, Fausto Bernardini - IBM Research.
    We propose a new texture optimization algorithm based on the reduction of the physical space allotted to the texture image. Our algorithm optimizes the use of texture space by computing a warping function for the image and new texture coordinates. Our method uniformly distributes frequency content of the image in the spatial domain. The resulting image can be resampled at lower rate while preserving its original details. (read more)
    Selected Publications and Talks
  • Space-optimized texture maps, to appear in Proceedings of Eurographics 2002.(1200dpi 3Mb, 100dpi, 600Kb), Additonal plates.
    		•  Demos, software
  • Space-optimized VRML models (zip file).
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    For more material, check here
    Last update March 10th, 2002


    Mesh optimization using global error
    Laurent Balmelli - IBM Research,
    Martin Vetterli - Communication System Laboratory, Ecole Polytechnique Federale, Swizterland.

    We propose an algorithm to decompose a mesh into a control mesh and a series of embedded detail meshes. Hence, the output representation is adaptive and progressive. We use a tree-driven, fine to coarse approach to simplify the mesh using vertex decimation. Previous approaches use local error and greedy strategies to simplify meshes. Our method uses global error and a generalized vertex decimation technique borrowed from optimal tree pruning algorithms used in compression. Although global error is used, our algorithm has cost O(n log n). We show that a direct approach using the same error criterion has at least cost O(n^2).
    Selected Publications and Talks
  • Mesh optimization using global error with application to geometry simplification, Preprint from Journal of Graphic Models, January 2003, Academic Press.
  • Efficient approach to adaptive 4-8 mesh generation, Talk given at Princeton, Sept 2001.
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    For more material, check here
    Last update March 15th, 2002

    Properties of subdivision surfaces having 4-8 connectivity
    Laurent Balmelli - IBM Research,
    Thomas Liebling - Operation Research Laboratory, Ecole Polytechnique Federale, Swizterland,
    Martin Vetterli - Communication System Laboratory, Ecole Polytechnique Federale, Swizterland.

    We present computational results when computing approximations of 4-8 meshes using vertex decimation or vertex insertion. We prove that a vertex decimation and vertex insertion leading to a conforming mesh has cost O(log n) on average, where n is the number of vertices used to describe the surface. We introduce the notion of merging domain, as a set of vertices to be removed jointly in order to obtain a conforming mesh after decimation. We show that the intersection between two merging domains can be computed in O(log^2 n) operations. We use the latter result to show that one can keep track of the global error in O(log^2 n) time in surface simplification algorithms having a fine to coarse approach.
    Selected Publications and Talks
  • Computational analysis of 4-8 meshes with application to surface simplification using global error, CCCG'01, Aug 2001.
  • Talk given at the Canadian Conference in Computational Geometry, Aug 2001.
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    Last update Jan 10th, 2002