This document discusses computer controlled biometric based access control. It defines biometrics as using unique physiological characteristics to identify individuals, most commonly used for security. Biometric systems use traits like fingerprints, iris scans, signatures etc. to authenticate a person's identity. The process involves capturing a raw biometric, extracting distinguishing characteristics, and enrolling the processed sample for future comparison during authentication in a verification or identification system. Biometric characteristics must be universal, invariant over time, measurable without waiting, singular, acceptable, reducible, reliable, private, comparable and satisfy other requirements for effective identification.