Patent ID: 8320643

Claim:
A face authentication device comprising: a first extraction unit which extracts a feature data item from an input face image data item; a face image data registration unit which registers a face image data item imaged under a prescribed imaging condition in it; a second extraction unit which extracts a feature data item from the face image data item registered in the face image data registration unit; a first calculation unit which checks the feature data items each extracted by the first and second extraction units against each other to calculate a similarity between both feature data items; a feature data storage for storing a plurality of feature data items each extracted from a plurality of face image data items of a plurality of persons imaged under an almost identical condition to the prescribed imaging condition; a second calculation unit which checks the feature data item extracted by the first extraction unit against the feature data items stored in the feature data storage to calculate similarities between feature data items, each time the input face image data item is inputted; a threshold setting unit which sets a threshold for judging whether the input face image data item and the face image data item registered in the face image data registration unit are of an identical person or not based on the similarities calculated by the second calculation unit, each time the input face image data item is inputted; and a determination unit which determines whether the input face image data item and the face image data item registered in the face image data registration unit are of an identical person or not by comparing the threshold set by the threshold setting unit and the similarity calculated by the first calculation unit.