title: Shape representation and classification using the poisson equation.
abstract: We present a novel approach that allows us to reliably compute many useful properties of a silhouette. Our approach assigns, for every internal point of the silhouette, a value reflecting the mean time required for a random walk beginning at the point to hit the boundaries. This function can be computed by solving Poisson's equation, with the silhouette contours providing boundary conditions. We show how this function can be used to reliably extract various shape properties including part structure and rough skeleton, local orientation and aspect ratio of different parts, and convex and concave sections of the boundaries. In addition to this, we discuss properties of the solution and show how to efficiently compute this solution using multigrid algorithms. We demonstrate the utility of the extracted properties by using them for shape classification and retrieval.
authors.affiliation: Department of Computer Science and Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel. lena.gorelick@weizmann.ac.il
authors.forename: Lena
authors.initials: L
authors.lastname: Gorelick
authors.forename: Meirav
authors.initials: M
authors.lastname: Galun
authors.forename: Eitan
authors.initials: E
authors.lastname: Sharon
authors.forename: Ronen
authors.initials: R
authors.lastname: Basri
authors.forename: Achi
authors.initials: A
authors.lastname: Brandt
mesh_terms: D000465:Algorithms; D001185:Artificial Intelligence; D016000:Cluster Analysis; D003198:Computer Simulation; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D016247:Information Storage and Retrieval / Q000379:methods*; D015233:Models, Statistical; D010363:Pattern Recognition, Automated / Q000379:methods*; D016012:Poisson Distribution; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity