Iris scanning determines the outline of the iris in the colored area of the eye, even though the color of the iris has no relation to the biometric. Iris outlines are fashioned at random. As a consequence, the outlines of the iris in a person's left and right eyes are not the same, and so are outlines of the iris of identical twins. Iris scanning can be employed rapidly for both recognition and validation functions because the iris is extremely unique and strong.
Retinal scans evaluate the outlines of the blood vessels in the back of the eye. The mechanism consists of a source of light shone into the eye of a user who has to be situated in very close vicinity and absolutely stationary of the mechanism. Because users believe the technology to be invasive to some extent, retinal scanning has not acquired regard; at present retinal scanning mechanisms are not available for sale.
Voice or speaker identification employs vocal individuality to recognize people using a pass-phrase. A telephone or microphone can be set up as an antenna, which caused it be a comparatively cheap and easily installable technology. However, voice identification can be influenced by ecological causes such as surrounding sound. This technology has been the focal end of significant endeavors by the telecommunications industry plus the United States government's intelligence agencies, which keep on working on increasing consistency.
- Davies, Graham and Sonya Thasen. (August 2000). “Closed-Circuit Television: How Effective an Identification Aid?” British Journal of Psychology, 91:3.
- Phillips, P. J., Alvin Martin, C.L. Wilson, and Mark Przybocki. (February 2000). “An Introduction to Evaluating Biometric Systems,” Computer.