1 October 1990 Practical measurement of rain erosion and scatter from IR windows
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For a given image brightness, IRST range is limited by background noise. Mid-IA radiation from the sun contributes to background noise, even when the sun is well out of the field of view, because the illuminated IRST window scatters unwanted background radiation onto the detector. The level of scatter depends strongly on window degradation due to contamination and actual window damage incurred in flight, as well as inherent flaws in the window material. This paper presents scatter data taken at .67, 3.39 and 1 0.6 microns in a laboratory setting from several damaged germanium window samples. The data is compared to scatter levels from undamaged windows of other materials. Estimates made of the corresponding reduction in lAST range indicate that this can be a serious effect. Instrumentation has been developed that allows measurement of reflective scatter from aircraft sensor windows on the flight line. These measurements are compared to those obtained in the laboratory.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
John C. Stover, John C. Stover, "Practical measurement of rain erosion and scatter from IR windows", Proc. SPIE 1326, Window and Dome Technologies and Materials II, (1 October 1990); doi: 10.1117/12.22512; https://doi.org/10.1117/12.22512

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