Extracting parametric descriptions of circular GCs from a pair of contours for 3-D shapes recognition

This paper addresses the issue of recognizing 3-D shapes of objects from their 2-D contour pairs. A shape model, that is represented by a family of spheres of varying radii with their centers on its axis, is developed for the shape class of circular generalized cylinders (GCs) with a space-curved axis. Quasi-invariant property of the shape model is defined, and is used to recover the 3-D shapes of the shape class by solving the problem of stereo matching between their contour pairs. The recovered shapes are segmented into their parts and represented by a set of the parametrically describable parts and spatial relations between them, so that they may be used for recognition even under occluded environments.