Patent ID: 6195448
Filing Date: 2001-02-27
Classification: G06K

Abstract:
An optical finger image system comprising:a platen having a touching surface to receive and support a finger to be interrogated,a light beam source providing an interrogating light beam, said light beam providing a trace at said touching surface, said trace having a maximum width and a maximum length, the maximum width being less than or equal to the maximum length, said width of said trace being no greater than approximately 2h.sub.min /tan .PHI., wherein h.sub.min is a minimum depth of a valley portion of the finger,said light beam source being oriented with respect to said platen such that said light beam forms a predetermined angle .PHI. with said touching surface, said light beam illuminating a surface of a finger applied thereto,imaging optics optically downstream from said platen for directing onto an image plane light from said interrogating light beam scattered by a finger on said touching surface, anda photoelectric transducer at said image plane, light detected by said photoelectric transducer being restricted to light falling within a window area, said window area being positioned such that an illuminated ridge portion of said finger is imaged within said window, said predetermined angle .PHI. being sufficiently small such that any image of an illuminated valley floor portion of said finger is projected outside said window area.