BACKGROUND CHARACTERIZATION WITH A SCANNED FOURIER TRANSFORM SPECTROMETER

Abstract

Background scene characterization in the long wave infrared (LWIR) region of the electromagnetic spectrum is of particular interest for simulating the operational environment of passive standoff chemical detection systems. In conjunction with collections of local metrological data and temperature and water vapor profiles, spectrally resolved LWIR imagery, acquired using a scanned Fourier Transform Spectrometer, and boresighted visible imagery were collected during Fall 2005. Resulting spectra in the 700 – 1450 cm−1 frequency range were analyzed to provide estimates of the foreground/background temperature differential that can then be used as a metric to assess the information content in the resulting IR imagery. Measurements were performed at two geographical sites and over 100 GBs of raw data were accumulated. Through spatio-temporal analysis of the resulting temperature differential maps, we have derived strategies for optimizing scan patterns. These optimized strategies attempt to minimize the amount of redundant data thus providing shorter inter-sample times for temporally varying portions of the scene. Considerations include the first and second order spatial and temporal statistics as well as information content as quantified by average pixel entropy. This research was financed by the U.S. Army Joint Project Manager for Nuclear, Biological, and Chemical Contamination Avoidance under contract number N00024-03-D-6606.