Performance trade-offs of infrared spectral imagers: II

IR spectral imagers are being considered for air to ground target detection applications. The targets can be detected not only by the exploitation of target to background color but also by the high spectral band to band correlation of many background. Detection of low contrast targets in high thermal clutter backgrounds can therefore be improved by using IR spectral sensors as opposed to broad or narrow band IR sensor. However, the improvement requires a high quality IR spectral sensor. A previous paper explored the trade-offs of some parameters associated with the requirement for low sensor noise levels - namely, instantaneous field of view, aperture diameter, spectral frame rate, number of detector pixels, area coverage rate, spectral bandwidth, and integration time. This paper explores the trade-offs of some parameters associated with the requirement for the preservation of high spectral band to band correlation - namely, spatial ground resolution, spatial registration of spectral bands, and sensor noise level. The Aerospace Corporation Spatially Enhanced Broadband Array Spectrography System was used to collect high quality spectral imagery of vegetated backgrounds at Redstone Arsenal, Alabama. This imagery is analyzed to determine background spectral band to band correlation and coherence. The degradation of correlation as ground spatial resolution, spatial registration accuracy, and sensor noise level are varied was then studied. The result can be used to help set sensor requirements for ground resolution, spatial registration, and noise level.