We have constructed a correlator using a gray scale amplitude modulator for an input device and a gray scale phase modulator in the filter plane. The spatial light modulators used in the correlator are two of the three liquid crystal cells from a commercially available color projection television. The cells (twisted nematic liquid crystals) may be operated in an amplitude mostly or phase mostly mode by selecting the polarization of the light and the operating bias voltage. We show the Jones matrix analysis of the laboratory measurements and the corresponding operating curves. Signal to noise ratios on the order of 100:1 have been observed for some test objects using simple phase mostly filters.

Date Published: 24 August 1992
PDF: 9 pages
Proc. SPIE 1704, Advances in Optical Information Processing V, (24 August 1992); doi: 10.1117/12.139897

Published in SPIE Proceedings Vol. 1704:
Advances in Optical Information Processing V
Dennis R. Pape, Editor(s)