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Proceedings Paper

1.5 to 5 micron radiometer for spectral contrast of objects in changing backgrounds in real time (Background Discrimination Radiometer or BDR)
Author(s): Dario Cabib; Amir Gil
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Paper Abstract

A digital FLIR (Forward Looking Infrared camera) in the 1.5 to 5 micron range can measure the contrast of selfemission of objects with respect to their background in real time: however, when such a measurement is carried out in a narrow spectral range through an interference filter the amount of unfiltered stray photons from the environment reaching the detector contributes a significant part of the total signal with respect to the filtered photons from the object of interest. The result is a significant reduction of dynamic range of the measurement and of the ability of the FLIR to measure large variation of signal in real time. A somewhat more advantageous instrument to measure the contrast of an object against its background in real time is proposed here: it is a non-imaging single-detector, 1.5 to 5 micron radiometer (BDR). A classical example of application is measuring the radiant intensity contrast of an airplane or missile in the background of sky during its flight. The instrument is built so that it can measure this contrast in one narrow or wide wavelength range as function of time or in successive wavelength ranges to provide contrast information in absolute units of irradiance (Watts/cm2) in different regions of the spectrum. Several filters can be accommodated in a wheel to provide the spectral capability. The reason for the ability of such configuration to avoid the dynamic range problem of the FLIR is the fact that in this detection method the detector is AC coupled and the electronic amplification acts only on the difference between the source and background signals. We present here the instrument's design and its calibration algorithm1.

Paper Details

Date Published: 27 August 2010
PDF: 8 pages
Proc. SPIE 7808, Infrared Remote Sensing and Instrumentation XVIII, 780812 (27 August 2010);
Show Author Affiliations
Dario Cabib, CI Systems (Israel) Ltd. (Israel)
Amir Gil, CI Systems (Israel) Ltd. (Israel)

Published in SPIE Proceedings Vol. 7808:
Infrared Remote Sensing and Instrumentation XVIII
Marija Strojnik; Gonzalo Paez, Editor(s)

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