Patent ID: 8565497

Claim:
A biometric authentication device comprising: a biometric information acquiring unit which acquires biometric input information of a user and generates a biometric input image representing the biometric input information; a storage unit which stores, for each of first prescribed number of registered users which have been preregistered, and stores, for each of a plurality of groups, a first group feature representing a feature of registered biometric information contained in the group, the plurality of groups being obtained by dividing a registered biometric image representing the registered biometric information of a registered user into a plurality of blocks, and classifying the plurality of blocks so that blocks which contain geometric features of the registered biometric information which are similar to each other, are classified into a same group; and a processing unit configured to perform a process including: dividing the biometric input image into a plurality of blocks; extracting, for each of the plurality of blocks in the biometric input image, a local feature representing a geometric feature of the biometric input information contained in the block; classifying the plurality of blocks in the biometric input image into the plurality of groups by blocks with the similar local feature; extracting, for each of the plurality of groups in the biometric input image, a second group feature representing the feature of the biometric input information contained in the group; calculating, from the plurality of groups set for the biometric input image and the plurality of groups set for each of a plurality of the registered biometric images, the difference between the second group feature and the first group feature for each group with the similar local feature, and calculating, depending on the difference, the degree of difference between each of the plurality of registered biometric information and the biometric input information, and selecting a second prescribed number, which is smaller than the first prescribed number, of registered biometric information in the ascending order of the degree of the difference; and matching the selected registered biometric information with the biometric input information.