<title>512x512 high-speed grayscale optical correlator</title>

Abstract

Jet Propulsion Laboratory has developed a new 512 X 512 high-speed grayscale optical correlator (GOC) for real-time automatic target recognition (ATR) applications. As compared with a previous developed 128 X 128 grayscale optical correlator, the utilization of a pair of high-resolution input spatial light modulator (SLM) has increased the input field of view by 16 times. The use of a matching high- resolution filter SLM has increased the sharpness of the correlation peak. Key features of this GOC include: a grayscale input SLM (Kopin 640 X 480, 8-bit) to accommodate direct interface with the input imaging sensor. A real-valued (bipolar-amplitude) filter SLM (512 X 512, 4-bit) to enable use of a MACH (Maximum Average Correlation Height) composite correlation filter algorithm, compact and portable. This GOC architecture has greatly improve the system complexity by removing the need of preprocessing (binarization) the input, and the powerful MACH composite filter has greatly reduced the number of filter templates. In this paper, the criterion of selection of both input and filter SLM will be discussed. System analysis of building a compact correlator will also be provided. Experimental ATR verification of the 512 X 512 GOC will also be illustrated.