Title

Sensor hardening through translation of the detector from the focal plane

Author

Marc A. Finet

Date of Award

2012

Degree Name

M.S. in Electro-Optics

Department

Department of Electro-Optics and Photonics

Advisor/Chair

Advisor: Russell Hardie

Abstract

The defense industry has numerous detectors that provide critical imaging capability on tactical and reconnaissance platforms and have been shown to be susceptible to permanent damage from high energy pulsed lasers in both laboratory and field testing. Much of the materials research into this involves two different methods of providing pulsed laser damage protection: extrinsic limiter implementation and intrinsic detector hardening. This thesis focused on what gains could be made using another method: system defocus and detector redundancy. The work of this thesis revolved around hardening a camera system through defocusing the focal plane array (FPA) and then using image restoration algorithms to regain the image quality of the degraded images. This system, a three channel image splitting prism with lens mount, provided a unique opportunity to test multiple images of an identical scene with slight spatial misalignments, varying sensor defocus and precisely measured optical degradation as measured by the Point Spread Function. These defocused images were then restored using filters that utilized information from only a single channel (the Wiener Filter, Regularized Least Squares Filter, and Constrained Least Squares Filter) and across multiple channels (Multichannel Constrained Least Squares Filter). Results from the single channel filters were excellent and allowed significant sensor hardening without image degradation when compared to the unfiltered image. Results from the multichannel RLS filter as tested were disappointing when compared to those from the single channel however and could be expanded upon in future work.

Keywords

Image converters, Image reconstruction, Image registration

Rights Statement

Copyright 2012, author

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