A high-resolution SWIR camera via compressed sensing

Images from a novel shortwave infrared (SWIR, 900 nm to 1.7 mu m) camera system are presented. Custom electronics and software are combined with a digital micromirror device (DMD) and a single-element sensor; the latter are commercial off-the-shelf devices, which together create a lower-cost imaging system than is otherwise available in this wavelength regime. A compressive sensing (CS) encoding schema is applied to the DMD to modulate the light that has entered the camera. This modulated light is directed to a single-element sensor and an ensemble of measurements is collected. With the data ensemble and knowledge of the CS encoding, images are computationally reconstructed. The hardware and software combination makes it possible to create images with the resolution of the DMD while employing a substantially lower-cost sensor subsystem than would otherwise be required by the use of traditional focal plane arrays (FPAs). In addition to the basic camera architecture, we also discuss a technique that uses the adaptive functionality of the DMD to search and identify regions of interest. We demonstrate adaptive CS in solar exclusion experiments where bright pixels, which would otherwise reduce dynamic range in the images, are automatically removed.