Method for producing correct fingerprints

摘要

The conventional method of producing fingerprints by total internal reflection using a right-angle prism does not give true size images. In this case an anamorphic real image is formed by the Scheimpflug condition with keystone distortion. A method of combining a single prism with the right-angle prism for anamorphic stretching to get the correct fingerprint image is described. The method of constructing such a type of an optical system is discussed in detail. The method is useful to directly obtain the correct fingerprints using a CCD camera. (c) 2008 Optical Society of America.