Spectral Zooming and Resolution Limits of Spatial Spectral Compressive Spectral Imagers

The recently introduced Spatial Spectral Compressive Spectral Imager (SSCSI) has been proposed as an alternative to carry out spatial and spectral coding using a binary ON-OFF coded aperture. In SSCSI, the pixel pitch size of the coded aperture, as well as its location with respect to the detector array, plays a critical role in the quality of image reconstruction. In this paper, a rigorous discretization model for this architecture is developed, based on a light propagation analysis across the imager. The attainable spatial and spectral resolution, and the various parameters affecting them, is derived through this process. Much like the displacement of zoom lens components leads to higher spatial resolution of a scene, a shift of the coded aperture in the SSCSI in reference to the detector leads to higher spectral resolution. This allows the recovery of spectrally detailed datacubes by physically displacing the mask toward the spectral plane. To prove the underlying concepts, computer simulations and experimental data are presented in this paper.