How is the False Identification Rate (FIR) calculated?
During an identification, the recognition biometric features are compared to many references and possibly, the similarity value will exceed the threshold for more than one reference. This is non-critical if only granting access, but can be very problematic if the correct assignment of personal data to the biometric characteristic is required (Example: access to a bank account via ATM). The probability for the identification of further (by definition false) candidates (independent of the correct reference) can be calculated from the FAR since these candidates would represent false acceptances in the case of verification. Its value is given by: 1 – (1 – FAR1)N-1 ~ (N – 1) FAR1 whereby FAR1 is the False Acceptance Rate for a system with one reference. N represents the number of references. The approximation (right side) applies in the case that the resulting value lies considerably under 1. The False Identification Rate can first be calculated after selecting one of the candidates. One st
