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Proceedings Paper

Field test results of standoff chemical detection using the FIRST
Author(s): Thomas S. Spisz; Patricia K. Murphy; Christopher C. Carter; Alison K. Carr; Alexandre Vallières; Martin Chamberland
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Paper Abstract

The FIRST, a commercial hyperspectral imager developed by Telops, features high sensitivity in a compact and robust package. This sensor provides hypercubes of spectral radiance of up to 320x256 pixels at 0.35mrad spatial resolution over the 8 - 12 &mgr;m spectral range at user selectable spectral resolutions of up to 0.25 cm-1. The measurements are converted into "chemical maps" by the use of powerful algorithms using both spatial and spectral information. The FIRST has been used at several field tests for the standoff detection and identification of chemicals. During these tests, the sensor is usually operated at 4 cm-1 of spectral resolution and the image size is tailored according to the dissemination. Algorithms based on a combination of clutter-matched filters and spectral angle mapper have been developed and used to process the measured data. The algorithms combine sub-band selection to minimize the correlation between the spectral signatures in the library and careful selection of the thresholds to reduce the level of false alarms. The output of the algorithms is the image of the clouds superimposed on the broadband thermal image. JHU/APL has developed a processing approach that adapts to different backgrounds, yields low probability of false alarm, and performs well in the presence of "hot" pixels. The algorithm combines background/noise suppression techniques, spectral detection techniques, such as the spectral angle mapper and the matched filter, and automatic adaptive threshold techniques. This paper will present the successful standoff detection and identification of various chemical compounds using a variety of field measurements. Images of chemical disseminations will be presented, with some of them including mixtures of 2 different chemicals.

Paper Details

Date Published: 27 April 2007
PDF: 12 pages
Proc. SPIE 6554, Chemical and Biological Sensing VIII, 655408 (27 April 2007);
Show Author Affiliations
Thomas S. Spisz, Johns Hopkins Univ. Applied Physics Lab. (United States)
Patricia K. Murphy, Johns Hopkins Univ. Applied Physics Lab. (United States)
Christopher C. Carter, Johns Hopkins Univ. Applied Physics Lab. (United States)
Alison K. Carr, Johns Hopkins Univ. Applied Physics Lab. (United States)
Alexandre Vallières, Telops, Inc. (Canada)
Martin Chamberland, Telops, Inc. (Canada)

Published in SPIE Proceedings Vol. 6554:
Chemical and Biological Sensing VIII
Augustus W. Fountain III, Editor(s)

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