The PROM - A Status Report

Abstract
The PROM is a solid-state, rapidly recyclable, image storage device having a number of applications in image and signal processing. Some of its important characteristics include 1/10-wave optical surface quality, 100-1p/mm three-bar resolution, 10 ergs/cm2 light sensitivity, and image plane contrast of 10 4 :1. One of the unique features of the PROM is that the bias level of stored patterns can be adjusted through application of an external voltage, resulting in image contrast inversion or enhancement. This same operation (baseline subtraction) is used to null the zero order in an optical Fourier transform, achieving a Fourier plane signal-to-noise ratio approaching 106:1. This paper reports on the current status of this device and a number of applications for which it has been tested in several areas of image and signal processing. Results are shown for coherent optical processing by computer-controlled Fourier plane filtering and real-time image correlation, and signal processing systems are described which couple the PROM with an acousto-optic raster recorder to perform spectrum analysis and correlation on radio frequency signals.