Patent ID: 8155395
Filing Date: 2012-04-10
Classification: G06K

Abstract:
1. An iris authentication apparatus comprising: iris area extraction means for extracting iris areas from a sensed registration eyeball image and a sensed collation eyeball image; a registration pattern generating means for, when said iris area extraction means extracts an iris area from the registration eyeball image, generating a registration iris pattern image by performing polar coordinate transformation of an image in the extracted iris area; a collation pattern generating means for, when said iris area extraction means extracts an iris area from the collation eyeball image, generating a collation iris pattern image by performing polar coordinate transformation of an image in the extracted iris area; and a collation means for collating the registration iris pattern image output from said registration pattern generating means and the collation iris pattern image output from said collation pattern generating means, wherein said collation means comprises: a rectangular area cutting means for cutting out a plurality of rectangular areas from the registration iris pattern image output from said registration pattern generating means and the collation iris pattern image output from said collation pattern generating means so as not to include any non-iris portion, a correlation value calculation means for obtaining a plurality of band-limited phase-only correlation (BLPOC) values between rectangular areas common to the registration iris pattern image output from said registration pattern generating means and the collation iris pattern image output from said collation pattern generating means, and a collation determination means for collating the two images on the basis of a plurality of the band-limited phase-only correlation (BPLOC) values output from said correlation value calculation means, said correlation value calculation means determines, in association with said plurality of rectangular areas, a plurality of first collation scores that are based on a BLPOC of the collation iris pattern image before enlargement or reduction thereof with the registration iris pattern image, and a plurality of second collation scores that are based on BLPOC of the collation iris pattern image after enlargement or reduction thereof in the angular direction or the radial direction in the eyeball image with the registration iris pattern image, wherein a mismatch occurs if a first determination collation score, which is obtained from said plurality of first collation scores associated with said plurality of rectangular areas, is smaller than a predetermined first reference value: wherein a match occurs if said first determination collation score is not smaller than a predetermined second reference value; wherein a mismatch occurs if said first determination collation score is not smaller than said first reference value but smaller than said second reference value and if a second determination collation score which is obtained from said plurality of second collation scores associated with said plurality of rectangular areas is smaller than said second reference value; and wherein a match occurs if said first determination collation score is not smaller than said first reference value but smaller than said second reference value and if said second determination collation score is not smaller than said second reference value.