Polarization Effects on Infrared Target Contrast

• Main Author: Pontes, Marcos C.
• Other Authors: NAVAL POSTGRADUATE SCHOOL MONTEREY CA
• Format: Text
• Language: English
• Published: 1998
• Subjects: Photography; Infrared Detection and Detectors; *POLARIZATION; *INFRARED RADIATION; TARGET SIGNATURES; THESES; NORTH ATLANTIC OCEAN; ASPECT ANGLE; SAN DIEGO BAY; PHOTOGRAPHIC CONTRAST; *THERMAL IMAGING; TARGET CONTRAST; Loma; North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/ADA353099; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA353099

An analysis has been carried out of a data base of polarized long wave infrared images of the instrumented Research Vessel POINT SUR recorded over a period of two days during the EOPACE measurements series in San Diego Bay in 1996. The measurements were made from a land site on Point Loma with an AGA780 sensor with internally mounted polarization filters. The objectives of the analysis were to determine a possible influence of target aspect angle on the polarization signature, to compare polarization contrast improvement in San Diego Bay with previous measurements in the North Atlantic, and to validate by measurement the estimation of unpolarized signature from vertical and horizontal components. 5508 images representing 70 cases with vertical, horizontal and unpolarized sequences were analyzed. Using a horizontal polarizer, target to background contrast improvement was found with a mean of 1.08 (8%) compared with the 15% found in previous measurements. Estimated unpolarized signatures from vertical and horizontal components agreed with unpolarized measurements with a slope coefficient of .85 to .99. Target signature for major ship facets and for total ship showed no discernable degree of polarization. A total of 37 IDL programs developed for this analysis can be assembled as a package for future data processing.