Feedback/Rationale
Access is granted only if the probability of a match between the raw data and reference data exceeds a certain threshold level. Thus, impostors should generate lower scores than the threshold, while authorized users generate higher ones. However, the opposite sometimes occurs. Thus, a combination of uncorrelated modalities (e.g., the use of vein patterns with fingerprints or iris recognition) generally provides a significant improvement in false acceptance rate (FAR) and false rejection rate (FRR) performance rates over a combination of correlated modalities (e.g., prints from different fingers).
