Image extraction method and apparatus, and image recognition method and apparatus, for extracting/recognizing specific image from input image signal

摘要

A circumscribing rectangle is obtained for a black continuous image part using a two-tone image signal. If it is determined (in S105) that the image part is possibly one which is obtained as a result of rotating the object, lengths of sides of the image part are compared with threshold values (in S106 and S108). If it is determined (in S105) that the image part is not one which is obtained as a result of rotating the object, the height and horizontal length of the circumscribing rectangle are compared with the threshold values (in S107 and S108). Thus, it is determined (in S115 and S116) whether or not the image part is identical to the object. An RGB chromaticity histogram is produced for each of small regions of an input color image (in S202A). Each of the chromaticity histograms of the small regions is compared with reference ones (in S202A). As a result of the comparison, an identification number of the reference histogram having the highest similarity to that of the small region among those constituting the input image is given to the small region (in S204). A histogram of the identification numbers thus is produced for the input color image (in S204). The thus-produced histogram is used to determine (in S205) which one of a plurality of objects is identical to the input color image.