Accession Number : ADA289731

Title :   The Detection of Oil Slicks at Night with Airborne Infrared Imagers.

Descriptive Note : Final rept. Oct 93-Apr 94,

Corporate Author : MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB

Personal Author(s) : Daniels, G. M. ; Hover, G. L.

PDF Url : ADA289731

Report Date : DEC 1994

Pagination or Media Count : 84

Abstract : The detection of oil slicks on the ocean is a Coast Guard priority. Daytime detection in clear weather is routine; but nighttime detection requires sophisticated imaging sensors. Infrared imagers have demonstrated some capability to detect oil slicks at night in the marine environment. Infrared imagers sense the thermal radiation, and its variations, in a scene rather than the reflected radiation. Gimbal-mounted thermal imagers operating in the 8-12 micron region are currently flown on Coast Guard aircraft. This study compared the performance of these imagers with hand-held imagers operating in the 3-5 micron region. The comparison was primarily theoretical with semi-quantitative support from an uncalibrated data base of infrared images taken wit various sensors. It was found theoretically, and supported by image data, that the 8-12 micron instruments produced images with better water-oil contrast at night. This differential behavior was theoretically predicted to hold over a wide range of environmental conditions. The differential behavior was traced to the fact that the optical properties of water and oil are more different in the 8-12 than in the 3-5 micron bands. The utility of night-vision imagers or low-light level TVs was also assessed. Calculations indicated that typical water-oil contrasts would not be seen with current sensors. Image data appearing to contradict this conclusion was found to be defective in the sense that the conditions of the experiments were not representative of operational conditions. It is recommended that: the use of 8-12 micron imagers be continued for oil slick searches at night and the potential of new night-time imaging devices be assessed.

Descriptors :   *AIRBORNE, *INFRARED IMAGE TUBES, DATA BASES, RADIATION, OPTICAL PROPERTIES, DETECTION, DETECTORS, WATER, REFLECTION, WATER POLLUTION, INFRARED IMAGES, IMAGES, DAY, MOUNTS, NIGHT, NIGHT VISION DEVICES, BEHAVIOR, OCEANS, RANGE(EXTREMES), OCEAN ENVIRONMENTS, HAND HELD, THERMAL RADIATION, LOW LIGHT LEVELS, COAST GUARD AIRCRAFT, OIL SPILLS, COAST GUARD, GIMBALS, TIMING DEVICES, CLEAR WEATHER.

Subject Categories : Infrared Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE