Terms and Definitions

For the purpose of this document, the following terms and definitions apply.

Algorithm	A sequence of instructions that tell a biometric system how to solve a particular problem. An algorithm will have a finite number of steps and is typically used by the biometric engine (i.e. the biometric system software) to compute whether a biometric sample and template match.
Biometric data	Data encoding a feature or features used in biometric verification.
Comparison	The process of comparing a biometric sample with a previously stored reference template or templates.
Comparison score	Numerical value resulting from a comparison.
Enrollment	The process of collecting biometric samples from a person and the subsequent preparation and storage of biometric reference templates representing that person’s identity.
Extraction	The process of converting a captured biometric sample into biometric data so that it can be compared to a reference template; sometimes called ‘characterization’.
False match	Comparison decision of ‘match’ for a biometric probe and a biometric reference that are from different biometric capture subjects.
False match rate	Expected probability that a captured biometric sample will be falsely declared to match to a single, randomly-selected, non-self biometric reference.
False non-match	Comparison decision of ‘non-match’ for a biometric probe and a biometric reference that are from the same biometric capture subject and of the same biometric characteristic.
False non-match rate	Proportion of the completed biometric mated comparison trials that result in a false non-match.
Fingerprint image	Area of friction skin on the fleshy surface of a finger located horizontally between the two edges of the fingernail and vertically between the first joint and the tip of a finger. It contains a unique pattern of friction ridge and valley information commonly referred to as a “fingerprint”.
Match / Matching	The process of comparing a biometric sample against a previously stored template and scoring the level of similarity.
Minutiae	Friction ridge characteristics that are used to individualize a fingerprint. Minutiae occur at points where a single friction ridge deviates from an uninterrupted flow. Deviation may take the form of ending, bifurcation, or a more complicated “composite” type.
One-to-many search	Process in which a biometric probe of one biometric data subject is searched against the biometric references of more than one biometric data subject to return a candidate list or a comparison decision.
One-to-one comparison	Process in which a biometric probe from one biometric data subject is compared to a biometric reference from one biometric data subject to produce a comparison score.
Template / Reference template	Data, which represents the biometric measurement of an enrollee, used by a biometric system for comparison against subsequently submitted biometric samples. NOTE - this term is not restricted to mean only data used in any particular recognition method, such as template matching.
Threshold	Numerical value (or set of values) at which a decision boundary exists

Abbreviated Terms

For the purpose of this document, the following abbreviations apply.

API	Application Programming Interface
ANSI	American National Standards Institute
GPU	Graphical Processing Unit
ISO	International Organization for Standardization
NIST	National Institute of Standards And Technology
PAD	Presentation attack detection
SDK	Software Development Kit