Planar curve segmentation for recognition of partially occluded shapes

2D shape boundary segmentation is required as a fundamental and important stage in the recognition process of partially occluded objects. The authors introduce a segmentation approach which is invariant to similarity transformation and in which partial occlusion has only marginal influence on the segmentation of the visible part. The basic concept is to transform the curve into another curve which intersects itself. Points of intersection of the new curve are retransformed to the original curve and serve as endpoints of segments. Properties of the transform are discussed, and conditions for the existence of intersection points are given. Simulation results, showing substantial immunity to noise, are presented, and advantages of the proposed method over conventional approaches relying on singular points of the curvature are discussed