OPTICAL-PROCESSING USING A BIREFRINGENCE-BASED SPATIAL FILTER

It is well known that a suitably shaped birefringent material, placed between two polarizers, exhibits a spatial variation in amplitude transmittance. The present article explores the possibility of using such an arrangement as a spatial frequency filter. The advantage of such filters is that the nature of filtering achievable can be changed by rotating any of the two polarizers. The specific case of a biconvex quartz lens as a spatial frequency filter is considered and techniques for real-time edge enhancement and periodic noise removal are discussed. Experimental results are also presented.