Matched Spectral Filter Imager

OPTRA proposes the development of an imaging spectrometer for greenhouse gas and volcanic gas imaging based on matched spectral filtering and compressive imaging. The matched spectral filter compressive imager (MSF-CI) system will be capable of simultaneously imaging and quantifying a series of compounds of interest via passive IR spectroscopy from an airborne or space-based platform.The MSF-CI operates in the 3-5.5 micron spectral range and employs two digital micromirror devices (DMDs) – one to encode the spatial information and a second to encode the spectral information – a dispersive spectrometer, and a single element thermoelectrically cooled mercury cadmium telluride detector. The proposed system offers a significant cost advantage relative to both imagers and hyperspectral imagers presently available in this spectral range as it does not require a costly infrared focal plane array (FPA). Moreover, the MSF-CI makes efficient use of compressive sensing and matched spectral filtering, resulting in minimized data bandwidth while preserving the information of interest. In addition, the use of the DMD in place of a conventional FPA offers significantly better image uniformity, pixel operability, signal to noise at low light levels, and dynamic range. The overall package is expected to be compact and rugged, making it ideal for airborne/space based applications. The proposed Phase I effort will produce a breadboard MSF-CI system which will be characterized and used for a carbon dioxide imaging demonstration. More »