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Proceedings Paper

Infrared polarization measurements of targets and backgrounds in a marine environment
Author(s): Frank Cremer; Piet B. W. Schwering; Wim de Jong; Klamer Schutte; Arie N. de Jong
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Paper Abstract

The infrared (IR) radiation emitted or reflected in an off- normal direction from a smooth surface is partially polarized. This principle can be used for enhanced discrimination of targets from backgrounds in a marine environment. It has been shown that (man-made) targets do not demonstrate a pronounced polarization effect when observed from near normal direction whereas the sea background radiation has a certain degree of polarization in slant observation path. A measurement setup has been constructed for collecting polarized IR imagery. This setup contains a rotating polarization filter that rotates synchronously with the frame sync of the camera. Either a long wave IR (LWIR) or a mid wave IR (MWIR) camera can be mounted behind the rotating polarization filter. The synchronization allows a sequence of images to be taken with a predefined constant angle of rotation between the images. Out of this image sequence three independent Stokes images are constructed, containing the normal intensity part, the vertical/horizontal polarization and the diagonal polarization. Up to 20 full linearly polarized images can be acquired per second. Measurements are taken at the North Sea coast with this setup. The recorded images are analyzed to determine the influence of polarization on the detection of small targets in such an environment. Furthermore differences between polarization contrasts in MWIR are analyzed.

Paper Details

Date Published: 18 September 2001
PDF: 12 pages
Proc. SPIE 4370, Targets and Backgrounds VII: Characterization and Representation, (18 September 2001); doi: 10.1117/12.440074
Show Author Affiliations
Frank Cremer, TNO Physics and Electronics Lab. and Delft Univ. of Technology (Netherlands)
Piet B. W. Schwering, TNO Physics and Electronics Lab. (Netherlands)
Wim de Jong, TNO Physics and Electronics Lab. (Netherlands)
Klamer Schutte, TNO Physics and Electronics Lab. (Netherlands)
Arie N. de Jong, TNO Physics and Electronics Lab. (Netherlands)

Published in SPIE Proceedings Vol. 4370:
Targets and Backgrounds VII: Characterization and Representation
Wendell R. Watkins; Dieter Clement; William R. Reynolds, Editor(s)

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