The terms "Biometrics" and "Biometry" have been used since early in the 20th century to refer to the field of development of statistical and mathematical methods applicable to data analysis problems in the biological sciences. Recently, the term "Biometrics" has also been used to refer to the emerging field of technology devoted to identification of individuals using biological traits, such as those based on retinal or iris scanning, fingerprints, or face recognition.

    There are two different ways to recognize a person: verification and identification. Verification (Am I who I claim I am?) involves confirming or denying a person's claimed identity. On the other hand, in identification, the system has to recognize a person (Who am I? ) from a list of N users in the template database. Identification is a more challenging problem because it involves 1:N matching compared to 1:1 matching for verification.