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Proceedings Paper

Passive IR polarization measurements applied to rough surfaces consisting of cenosphere particles covered with gold
Author(s): Goeran Forssell; Eva Hedborg-Karlsson
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Paper Abstract

Using passive IR polarization enhances the possibility to detect man made objects. Usually, man made objects consist of flat surfaces which polarize the emitted and reflected radiation, thereby increasing the contrast relative to an almost completely depolarized background. This makes reconnaissance and surveillance sensors and warners more efficient. In order to protect an object from being detected by a polarization sensitive sensor the surface of the object should be less sensitive to polarization. This is achieved by increasing the surface roughness. In this paper describes the use of cenosphere particles to increase the surface roughness and hence reducing the polarization. At the same time it is important to decide the value of the emissivity due to the need of contrast reduction. Evaporating gold with different coverage on the surface does this. The equipment used here consist of two IR Thermovision cameras, one for the wavelength region 3-5 μm and the other for the region 8-12μm. By applying linear polarizing filters in front of the cameras, it is possible to measure the emissivity curves. The emissivity of the used cenosphere samples varies between about 0.90 and 0.23. For all samples the radiation is close to Lambertian and they all depolarize the radiation completely.

Paper Details

Date Published: 25 September 2002
PDF: 12 pages
Proc. SPIE 4819, Polarization Measurement, Analysis, and Applications V, (25 September 2002); doi: 10.1117/12.450924
Show Author Affiliations
Goeran Forssell, Swedish Defence Research Agency (Sweden)
Eva Hedborg-Karlsson, Swedish Defence Research Agency (Sweden)

Published in SPIE Proceedings Vol. 4819:
Polarization Measurement, Analysis, and Applications V
Dennis H. Goldstein; David B. Chenault, Editor(s)

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