Accession Number : AD0918832

Title :   Feasibility Investigation of Polarization Techniques for Surface-Cloud Discrimination with an Active Optical System.

Descriptive Note : Final rept. 15 Dec 72-30 Jun 73,

Corporate Author : TENNESSEE UNIV SPACE INST TULLAHOMA

Personal Author(s) : Kohl, R. H. ; Partin, R. L. ; Flaherty, M. I. ; Dunnill, W. A.

Report Date : DEC 1973

Pagination or Media Count : 86

Abstract : A limited, theoretical and experimental investigation was conducted of the feasibility of using polarization of near infrared light to discriminate between the returns received from clouds and those received from terrain surfaces. The two concepts investigated utilize emission of linearly polarized light. The simpler concept detects the perpendicularly polarized component of the return alone while the other, which will work in situations where the former will not, detects both polarization components of the return and utilizes their ratio. Limited, uncalibrated data, taken in flight at distances of up to 1600 feet over many types of natural and man-made terrain, indicate the marked success of both concepts under the fair weather cumulus cloud conditions existing at the time. Troublesome situations, both encountered and predicted, are pointed out. Information is given on the experimental methods used along with information on the selection of polarizers. A recommendation for a second generation device technique is also made.

Descriptors :   *INFRARED DETECTORS), *POLARIZING FILTERS), (*TARGET DISCRIMINATION, (*NEAR INFRARED RADIATION, INFRARED TRANSMITTERS, RETROREFLECTORS, CLOUDS, SURFACE TARGETS, DEPOLARIZATION, GALLIUM ARSENIDE LASERS, INFRARED PULSES, CUMULUS CLOUDS, TERRAIN, OPTICAL PROPERTIES, INFRARED EQUIPMENT, AIRBORNE, BACKSCATTERING, POLARIZATION, ASPHALT, CONCRETE, SURFACE ROUGHNESS, ATMOSPHERIC CONDENSATION, ATMOSPHERIC PRECIPITATION, WATER VAPOR, TREES, GRASSLANDS, DUST CLOUDS, SMOKE, RATIOS, PERFORMANCE(ENGINEERING), THEORY, FEASIBILITY STUDIES, EXPERIMENTAL DATA, SIGNAL TO NOISE RATIO, SUNLIGHT, BEAM SPLITTING.

Subject Categories : Infrared Detection and Detectors
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE