Recognition of Partially Occluded Shapes Using Boundary Matching in Distance Image
Hong-Chih Liu, Mandyam D. Srinath · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1990
A new translation and rotation invariant algorithm to identify and locate occluded objects in an image is presented. The points of local maxima and minima of the curvature function extracted from a digitized image of the object and smoothed by a Gaussian filter are used as control points and the object boundary is approximated by straight-line segments connecting these points. A two-pass boundary matching procedure is used to match the control points of the test shape to those of the object to be recognized. The matching is done from local to global, that is, from matching one segment pair to matching groups of segment pairs. The possible translational and rotational parameters (0, Ax, Ay) between the two shapes is recorded and a distance transformation used to determine the set which yields the best match. The algo-rithm has been successfully used to locate a set of tools from occluded images.