BIOMETRIC FINGERPRINT TERMS D
D-Prime (D’)
A statistical measure of how well a system can discriminate between a signal and a non-signal.
Database
A collection of one or more computer files. For biometric systems, these files could consist of biometric sensor readings, templates, match results, related end user information, etc
Decision
The resultant action taken (either automated or manual) based on a comparison of a similarity score (or similar measure) and the system’s threshold.
Degrees of Freedom
A statistical measure of how unique biometric data is. Technically, it is the number of statistically independent features (parameters) contained in biometric data.
Delta Point
Part of a fingerprint pattern that looks similar to the Greek letter delta (_), as illustrated below. Technically, it is the point on a friction ridge at or nearest to the point of divergence of two type lines, and located at or directly in front of the point of divergence.
Detection and Identification Rate
The rate at which individuals, who are in a database, are properly identified in an open-set identification (watchlist) application.
Detection Error Trade-off (DET) Curve
A graphical plot of measured error rates, as illustrated below. DET curves typically plot matching error rates (false non-match rate vs. false match rate) or decision error rates (false reject rate vs. false accept rate).
Difference Score
A value returned by a biometric algorithm that indicates the degree of difference between a biometric sample and a
reference.