Vander-lugt correlator converting to joint-transform correlator

Abstract

A module, capable of being mounted on a printed circuit board, containing optical components necessary for optical correlation and a unique folded light path technique for conversion from a Vander Lugt optical correlator to a joint-transform optical correlator, or visa versa, with no electronic changes required. The folded optical path permits a polarizing filter to be positioned in the beam path reflected by a filter SLM but before a correlation detector means when the correlator is in a Vander Lugt mode and permits the polarizing filter to be removed, and an auxilliary mirror or other optical components positioned in the beam path to eliminate the filter SLM and to direct the beam path toward the correlation detector means when the optical correlator is to become a two-cycle joint-transform optical correlator and simultaneously match the Fourier transform plane to the detector plane of the detector means. The polarizing filter is mounted on the module cover for ease of placement and for ease of removal, while the mirror or other optical components are mounted on another module cover for ease of placement at the required precise point in the folded optical path and ease of removal. In lieu of changing covers, the mirror and other optical components as the case may be may be moved, as by sliding, pivoting or rotating, for the conversion of the Vander Lugt correlator to the joint-transform correlator and visa versa.