Abstract: A system and method match a search print with one or more file prints stored in a database, wherein each of said prints including minutiae. The system and method receive a minutiae match report which includes a list of file prints which are possible matches with the search print. The minutiae match report is based on at least a comparison of coordinate locations and angles of rotation of the minutiae in the file prints with the minutiae in the search prints. The system and method determine an offset between a first singularity in the search print and a corresponding first singularity in the file print. Additionally, the system and method determines a first angle between at least one singularity in the search print and at least one minutia of the search print. A second angle between a corresponding at least one singularity in the file print and a corresponding at least one minutia of the file print is determined.

Abstract: Illumination for the platen of a finger receiving imaging prism is provided from a source mounted below the prism and reflected to the platen surface at an angle greater than the critical angle, through a beam folding input prism that is positioned primarily below and behind a front edge of the platen. Transmitting and scanning optics of the system are positioned behind and below the imaging prism, and an output prism is bonded to the imaging prism to receive light reflected from the platen, to shift the path of this reflected light downwardly and to direct it rearwardly toward system optics. The beam from the output prism is fed through an F-Theta scanning lens to a scanning mirror mounted on a scanning galvanometer that causes the fingerprint image to precisely scan across a linear array of print camera sensors that are repetitively sampled to provide a readout of the entire surface of the prism platen for reading a slap print.

Abstract: A scanning fingerprint reader provides a set of digital data representing interface topology of a fingerprint pressed against a platen (20). The platen (20) is formed by one surface of a prism (10) utilizing total internal reflection of an illuminating beam (30) directed at an interior surface of the prism. The beam (37) that is output from the prism is fed through a scanning lens (40) to a scanning mirror (48) that causes the fingerprint image (68) to scan across a linear array (60) of CCD sensors that is repetitively sampled to provide a print readout of the entire surface of the prism for reading a slap print. The signal from the CCD array is read out and digitized (72,74,76) to provide a serial bit stream (78) representing the set of multiple fingerprints on the platen. An optical architecture (40,48,56) employing dual telecentricity eliminates keystoning distortion.