Browsing by Author "Feng, Powei"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Functional representation and manipulation of shapes with applications in surface and solid modeling
    (2013-09-16) Feng, Powei; Warren, Joe; Goldman, Ron; O'Malley, Marcia K.
    Real-valued functions have wide applications in various areas within computer graphics. In this work, we examine three representation of shapes using functions. In particular, we study the classical B-spline representation of piece-wise polynomials in the univariate domain. We provide a generalization of B-spline to the bivariate domain using intuition gained from the univariate construction. We also study the popular scheme of representing 3D density distribution using a uniform, rectilinear grid, where we provide a novel contouring scheme that culls occluded inner geometries. Lastly, we examine a ray-based representation for 3D indicator functions called ray-rep, for which we present a novel meshing scheme with multi-material extensions.
  • Thumbnail Image
    Item
    Segmentation and visualization of volume maps
    (2010) Feng, Powei; Warren, Joe
    Volume data is a simple and often-used representation for exchanging and processing data in various scientific domains, such as medicine and molecular biology. The segmentation of volume data is an essential part of data interpretation. Researchers have extensively studied the problem of segmentation focusing on efficient algorithms for segmenting and rendering volumes. Our contribution is two-fold. First, we propose a tri-linear classification method that can implemented on the GPU to reduce artifacts and jaggedness along the material boundaries that appear when rendering segmented volumes. Our representation provides sub-voxel accuracy for representing segmented materials. Second, we demonstrate our interactive painting-based segmentation tool, which can be used to rapidly produce an intuitive segmentation. We compare our tool against known results and show that we can generate similar segmentations using a simple and intuitive control scheme.