Patent US 5,229,764

A system activating and analyzing the biometric data from a plurality of biometrically-oriented personal identification devices at intermittent intervals selectively allows or prevents continued use of a particular protected system or device by a particular individual. The system is a continuous biometric authentication matrix which can employ any number of any variety of biometric personal identification devices including thumbscan, digital photo, voiceprints, fingerprints, and so on. The system acts as a continuously functioning "gate" between a system to be protected and a prospective user. A prospective user's biometric data is stored for reference. When the prospective user attempts to use the protected system or device, he or she must interface with the system, which then compares the prospective user's biometric data to the reference data. This comparison must not only be acceptably close in similarity in order to gain access to the protected system, it must also continue to be close in subsequent comparisons in order for access to the protected system or device to continue. The accept/reject threshold for individual biometric sensor devices is adjustable, as is the accept/reject threshold for the overall combination of biometric sensors.