BIOMETRIC AUTHENTICATION DEVICE, BIOMETRIC AUTHENTICATION METHOD, AND COMPUTER PROGRAM FOR BIOMETRIC AUTHENTICATION

A biometric authentication device includes: a biometric information acquisition unit which generates a first input biometric image representing the biometric information of a user, a storage unit which stores data relating to registered biometric information of at least one registered user, and a processing unit. The processing unit realizes a quality judgment function which judges if the first input biometric image is suitable or not for use for comparison of the biometric information represented in the first input biometric image with the registered biometric information, a selection function which selects registered biometric information which is similar to biometric information represented in the first input biometric image among registered biometric information when the first input biometric image is judged unsuitable, and a matching process function which compares the user's biometric information represented in a second input biometric image with the selected registered biometric information.