Patent ID: 6067379
Filing Date: 2000-05-23
Classification: G06K,G06T

Abstract:
An apparatus for identifying a linear pattern, having an expected radius less than or equal to a value r, in an image signal, I, said apparatus comprising:A. projection means for generating a projection signal, P, representative of a projection of said image signal along an axis substantially aligned with an expected orientation of said linear pattern, where said projection signal, P, is comprised of elements P.sub.i, where i is an integer between 1 and a length of said image signal along said axis,B. mirror symmetry filter means, coupled with said projection means, responsive to said radius and said projection signal for filtering that projection signal to generate a mirror symmetry signal, S, representative of the degree of symmetry of the projection signal P about each point therein,C. notch detector means, coupled with said mirror symmetry filter means, for operating on said mirror symmetry signal to generate a peak location signal emphasizing a peak corresponding to a location of a center of said linear pattern, andD. peak locating means, coupled with said notch detector means, for identifying a peak in said peak location signal, and for estimating from a location of that peak a location of a center of said linear pattern.