[OPTICAL REVIEW Vol. 8, No. 2 (2001) 112-119]

Rewritable Broad-Band Color Filters for Spectral Image Analysis

Kanae MIYAZAWA,1 Markku HAUTA-KASARI2 and Satoru TOYOOKA1,*

1Graduate School of Science and Engineering, Saitama University, 255, Shimo-okubo, Urawa, Saitama, 338-8570 Japan, 2Department of Computer Science, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland

(Received December 14, 2000; Accepted January 4, 2001)

We propose an optical system to implement rewritable transparent broad-band color filters. The filter consists of a linear variable filter and a liquid crystal spatial light modulator in which an expected filter function is written. A time-integrated intensity image was taken while the filter was passing the lens aperture of a CCD camera. The averaged norm error between the implemented and the expected filter functions was about 5.4%. The system was applied to spectral estimation in a two-dimensional color image.

Key words : spectral imaging system, rewritable broad-band color filter, linear variable filter, liquid crystal spatial light modulator