Choice of Infrared Waveband for a Dual Spectrum (Visible/Infrared) Imaging Line Scanner (Revised)

This report documents the results of a study to determine the optimum infrared IR band over which to operate for a common aperture configuration a dual band EOIR imaging line scanner for airborne tactical operations. Performance requirements include wide-angle, real-time, remotely-viewable, registrable fusible, and simultaneous visible and infrared imagery. The sensor must have a lateral field of view of 120 to 160 degrees and be capable of operating at aircraft speeds up to 600 kn and altitudes as low as 200 ft. Factors considered in the analysis included the spectral distribution of radiation from scenes of interest, spectral atmospheric transmission, spectral detectivity of available detectors, climate considerations, effects of diffraction on resolution, availability of optical materials, detector cooling, complimentarity of imaged target information, and effects of atmospheric aerosols. It was concluded that the long wavelength IR band nominally 8 to 13 microns would be optimum.