Share Email Print
cover

Proceedings Paper

Enhancement of optical detectability with polarization
Author(s): Walter G. Egan
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Low detectability is a major consideration for combat platforms. Exposed surfaces are painted or coated black to minimize optical or near infrared detectability; this is a fallacy in regard to polarization. The percent polarization of a diffuse (non specular) surface is inversely proportional to the surface reflectance (also known as albedo). Thus a dark surface with a reflectance of 2% can have a percent polarization of approximately 100%. (The percent polarization is the ratio of the difference between two orthogonal polarized measurements ratioed to the sum multiplied by 100). Experimental measurements of diffuse surfaces with albedos between 2% and 90% show this inverse relationship to be obeyed from the ultraviolet to the near infrared. Imagery has been obtained on various aircraft coatings that verify the inverse relationship between surface albedo and percent polarization in the green, red and near infrared wavelength bands. The imagery was obtained in the three bands with the Kodak digital cameras, which downloaded on to CD ROMs. Imagery has also been obtained on laboratory samples that verify the inverse relationship between albedo and polarization. The conclusion is that very high polarization of a dark aircraft enhances the detectability such that it is easily recognized optically using polarization. This effect has not been recognized in signature reduction. Imagery will be presented and the inverse relationship between surface albedo and percent polarization will be demonstrated.

Paper Details

Date Published: 14 July 1999
PDF: 11 pages
Proc. SPIE 3699, Targets and Backgrounds: Characterization and Representation V, (14 July 1999); doi: 10.1117/12.352963
Show Author Affiliations
Walter G. Egan, CUNY/York College (United States)


Published in SPIE Proceedings Vol. 3699:
Targets and Backgrounds: Characterization and Representation V
Wendell R. Watkins; Dieter Clement; William R. Reynolds, Editor(s)

© SPIE. Terms of Use
Back to Top