OPTICAL-PROCESSING WITH FEEDBACK USING SMART-PIXEL SPATIAL LIGHT MODULATORS

A spatial light modulator is often used as the basic element in real-t ime recognition architectures. However, many of the devices suffer fro m poor uniformity and/or nonlinearities that affect the overall perfor mance of any real-time recognition scheme. We propose using optical fe edback as a method of improving device performance. We demonstrate bot h positive and negative feedback separately through a mixture of on-bo ard electronic processors and optical polarization intensity encoding. Placing the spatial light modulator in a positive feedback system cau ses the system to act like a memory. Placing the spatial light modulat or in a negative feedback system makes the spatial light modulator res ponse more analog, which in turn leads to improved uniformity. (C) 199 8 Society of Photo-Optical instrumentation Engineers. [S0091-3286(98)0 2103-5].