Iris Recognition System

Abstract

Methods and apparatus are disclosed for identifying an eye, especially a human eye, on the basis of the visible features of the iris and pupil. The eye is first illuminated until the pupil reaches a predetermined size, at which an image of the iris and pupil is obtained. This image is then compared with stored image information for identification. The stored image information is previously obtained from an eye, the pupil of which was similarly brought to the same predetermined size. The illumination of the iris may include oblique illumination from several positions around the circumference of the iris. The illumination from each position may be relatively monochromatic, so that the resulting shadow will lack the color of the light source at that position, providing better contrast for elevation-depednent features. A system for performing iris recognition may include a processor which controls an illumination control circuit and a camera to obtain images at several predetermined sizes of the pupil.