Abstract: An optical data correlator for the analysis of images of random fields is provided which comprises a light source for projecting a beam of light along a preselected optical axis, a first lens system for receiving the beam and focusing it onto a first image, a second lens system for receiving light transmitted by the first image and focusing the light so transmitted onto a second image, a third lens system for receiving light transmitted by the second image and projecting this transmitted light onto a photodetector, and suitable electronics including an amplifier and an analog-to-digital converter for analyzing the output of the photodetector and displaying the output in useful form. Spatial filters may be included to define the projected beam, and an alignment system preferably attachable to the second image may be included to selectively position the second image.