SYSTEM FOR OUTPUT PLANE CALIBRATION OF AN OPTICAL CORRELATOR

A system for calibrating the output correlation plane of an optical correlator for positional and nonlinearity information to determine the position of an input image in an input image plane of the optical correlator. The optical correlator operates on the principle of projecting the Fourier transform of an input image onto at least one matched filter having recorded thereon the Fourier transform hologram of an image of interest. The inverse Fourier transform of the correlated optical signal is then projected onto a detector to determine the correlation of the input image with the image of interest. A calibration image is positioned in the input image plane of the optical correlator, and includes a two dimensional array of substantially identical targets, with the precise location of each identical target in the input image plane being known. At least one matched filter is placed in the optical correlator, and has recorded thereon the Fourier transform hologram of the identical target. The positions of the resultant optical signals in the output correlation plane are then correlated with the position of the two dimensional array of identical targets in the input image plane to calibrate the output correlation plane of the optical correlator for positional information and nonlinearity. The calibration system of the present invention enables an optical correlator system to be precisely calibrated in a way that the system can continue to operate using the same optical computing array. The calibration system can be used with any prescribed input format, e.g. 35 mm, 70 mm, 5", etc.