OPTRA proposes an open-architecture spectral gas sensor based on compressive sensing concepts employed for both spatial and spectral domains. Our matched spectral filter (MSF) core can be used as a single point detector in either point or standoff configurations or it can be coupled with a compressive imaging module for molecular imaging. The MSF core employs a digital micromirror device (DMD) to apply reference spectra to a spatially dispersed spectrum; the dot product measured with a single element photodetector is proportional to the probability of the compound corresponding to the reference spectrum being present. The MSF can also be used for quantification via grayscaling of the DMD. This approach effectively performs multicomponent spectral analysis in hardware rather than software thereby reducing data bandwidth requirements. The MFS will be designed for the 3-5.5 micron spectral range enabling detection and quantification of a range of greenhouse gases and other air pollutants. This solution represents a significant cost and size reduction relative to commercially available spectrometers operating in this spectral range, as it does not require a focal plane array or interferometer. Under the Phase I effort we will design, build, and test the MSF core configured for point detection.