Abstract: Arrangements and methods are described employing input optical intensity to output spatial position mapping, for performing optical computing or logic processing functions. An electro-optical device which receives discrete input optical object beams of different intensity levels and a separate readout optical beam, diffracts portions of the readout optical beam to unique spatial positions in two dimensional space, each portion as a function of the intensity of individual discrete input beams or of combinations of the intensities of the input beams. A spatial filter having discrete apertures at selected ones of the unique spatial positions transmits the selected diffracted optical outputs for implementing logic or computing functions.