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].