Compressive Hyperspectral Imager for Battlefield Event Detection from a Satellite Platform

ABSTRACT: The Air Force is seeking a hyperspectral imager capable of detecting missiles, aircraft and artillery fire from a satellite platform. OPTRA proposes to address this need through the development of a grating-based hyperspectral compressive imager. In this design, a grating would be used to diffract the incoming light from the energetic events. The diffracted orders would then be imaged onto a digital micromirror device (DMD). The DMD will be used to perform two distinct functions: order sorting and spatial filtering. The order sorting is accomplished by placing bandpass filters in front of two detectors: one collecting illumination from mirrors in the Son state and one collecting illumination from mirrors in the Soff state. These filters will have no overlap and will span the spectral range of the instrument, thus separating spectrally distinct overlaying orders. The DMDs will also be used for spatial filtering of the incoming light. A series of detector measurements will be made as a series of pseudo-random masks are applied to the DMD. Using these measurements, the image on the DMD can be reconstructed using the tenets of compressive imaging. Advantages of this approach include no moving parts and no infrared (IR) focal plane array (FPA). BENEFIT: High sensitivity (low per-pixel NEf'T]) owing to superior D* of single element photodetectors relative to focal plane arrays Higher dynamic range with significantly reduced problems with localized saturation Excellent uniformity with 100% Spixel operability Significantly lower cost of the single element detectors relative to an infrared focal plane arrays Commercial Applications: Unmanned aerial vehicle intelligence, surveillance and reconnaissance; Monitoring high crime areas for muzzle flash