Fingerprint authentication with input image validation based on the analysis of the spatial distribution of the brightness

摘要

A fingerprint authentication device comprises input finger characteristic judging portion 13. The input finger characteristic judging portion 13 judges whether the input data is proper or not on the basis of spatial distribution of brightness in an fingerprint image represented by the input data. An observation line deciding portion decides an observation line on the fingerprint image. A peak envelope calculating portion graphs the brightness against positions on the observation line and draws envelopes of line graphs each of which links local maximums or local minimums of the brightness. A discriminative value calculating portion calculates discriminative values by the use of a brightness distribution function and peak envelop functions. A deciding portion decides whether the input image is proper or not by the use of the discriminative values together with the discriminative coefficient preliminary calculated.