Reduction of sidelobes in the responses of optimal filters implemented on some SLMs

Spatial light modulators (SLMs) are used to implement optical correlation filters for real time pattern recognition. These SLMs have characteristics that are of limited range in the complex plane. Methods have been proposed to design optimal filters implementable on these constrained SLMs. In an earlier work it was observed and reported that the response of these optimal filters for some constrained SLMs contained large sidelobes in the correlation plane. As these sidelobes can cause false detection for pattern recognition they need to be eliminated. In the present paper, we propose a solution to reduce them by appropriate postprocessing. Satisfactory results for high-contrast SLM are obtained in numerical simulation experiments