Correlation of digitally encoded patterns e.g. fingerprints - using holographic display of stored information compared with case pattern

摘要

Basically, a holograph containing a large number of patterns on a typically 10 x 10 cm plate is illuminated by means of a laser beam, which scans the surface by means of a suitable acoustically or electronically based scanning device. Between 10,000 and 90,000 patterns can be stored on such a plate. An optical amplifier, illuminated by a further laser beam projects the beam into an optical multiplexer and from there the output beams are projected through a film carrying the case study patterns on to an array of photo detector elements. The outputs of these are fed to a correlator unit.