We have developed a technique, using sensor feedback measurements, to adaptively control a tunable optical filter to reject laser energy being transmitted to a focal plane array (FPA). Laser energy at the focal plane can mask a target or spoof a track processor. The technique is based on processing pixel counts (densities of detectors exceeding detection threshold) generated by laser energy at the focal plane. An algorithm, using the pixel count, controls the spectral wavelength and bandwidth of a dual tunable Fabry-Perot (DTFP) optical filter to reduce this undesired energy. This paper describes the algorithm used to control the DTFP and the model and methodology used to verify the DTFP control algorithm performance. Results show the feasibility of using an adaptive spectral selection technique for laser rejection. The importance of control loop sensitivity and out-of-band leakage to achieve the best sensor performance was clearly demonstrated.

Date Published: 10 August 1983
PDF: 12 pages
Proc. SPIE 0350, Focal Plane Methodologies III, (10 August 1983); doi: 10.1117/12.933897

Published in SPIE Proceedings Vol. 0350:
Focal Plane Methodologies III
William S. Chan; John T. Hall, Editor(s)