METHOD AND APPARATUS FOR ACQUIRING BIOMETRIC IMAGE

摘要

A compact and inexpensive method and apparatus for illuminating and acquiring a digital image of a biometric feature such as a fingerprint, palm print, footprint, or some subset or multiple of such features. A source of illumination (11) is introduced into an exposed edge of a transparent optical window (13) that is essentially smooth and generally flat with spaced apart surfaces. The illumination propagates between the surfaces of a flat or slightly curved transparent window (13) via total internal reflection (15) to obliquely illuminate a biometric feature (12) when in contact with the window (13). A digital camera (17) views the obliquely illuminated biometric feature (12) to record an image of it which can then be compared with registered images for matching and control purposes.