Patent ID: 6490375
Filing Date: 2002-12-03
Classification: G06K

Abstract:
A method for finding a peak in a characteristic surface of an image, the characteristic surface having an array of characteristic values, each of the characteristic values having adjacent characteristic values providing neighbors, and each of the characteristic values having extended neighbors, the extended neighbors being adjacent to the respective neighbors while also being not adjacent to each of the respective characteristic values, the characteristic values being slowly changing and the characteristic values being derived from the image, the image having an array of pixels, the method comprising:processing the image, before measuring the characteristic values of the image, so as to substantially eliminate dependence between a characteristic value of the peak and the characteristic values of the extended neighbors of the peak, so as to provide a processed image; measuring the characteristic values of respective sub-regions of the processed image, each of the sub-regions having an origin position; associating the characteristic values of each of the sub-regions of the processed image with the characteristic surface at the respective origin positions of each of the sub-regions, so as to provide the characteristic surface; finding local peaks in the characteristic surface; comparing the characteristic values of the local peaks with the characteristic values of at least a portion of the respective extended neighbors of each of the local peaks; and selecting as the peak, one of the local peaks with a characteristic value substantially greater than any one of the characteristic values of the at least a portion of the extended neighbors of the peak.