Biometric score normalizer and method therefor

摘要

Apparatus, and a related method, for providing a standardized measure of accuracy of each biometric device (22) in a biometric identity authentication system (FIG. 2) having multiple users. The apparatus maintains a statistical database (30) that includes continually updated values of false acceptance rate and false rejection rate for each combination of user, biometric device and biometric device comparison score. False acceptance rate data are accumulated each time a user successfully accesses the system, by comparing the user's currently obtained biometric data with stored templates (28) of all other users of the same biometric device. The current user is thereby treated as an "impostor" with respect to the other users, and the probability of an impostor's obtaining each possible comparison score is computed with accumulated data each time a successful access is made to the system. The statistical database (30) also contains a false rejection rate for each combination of user, biometric device and biometric device comparison score. These data are accumulated during a test phase in which users' identities can be independently verified. During the test phase, a user's current biometric data are compared with a previously stored template (28) and the probability of obtaining each comparison score is continually computed. From these probabilities, false rejection rates are estimated for each user, biometric device and biometric comparison score. IMAGE