A generalized biometric identification system model

Commonly-held knowledge and oft-repeated descriptions of biometric identification systems are more complicated than necessary because of the lack of a generally accepted system model. A good example is the supposed difference between "identification" and "verification". We present a system model applicable to all biometric systems showing the relationship between "verification" and "identification" and "enrollment" and "operation", illustrating where commonalities exist between seemingly disparate systems, and suggesting where interface standards might be useful. Further, we develop a general mathematical formulation to show "verification" to be the degenerate case of M-to-N matching, with N=1. Similarly, "PIN-less verification" is recognized as the degenerate case with small N with M=1, and "identification" can be seen as the more general case with small M and large N.