Snapshot Spectral and Color Imaging Using a Regular Digital Camera with a Monochromatic Image Sensor

Abstract

“Spectral imaging” (SI) refers to the acquisition of the three-dimensional (3D) spectral cube of spatial and spectral data of a source object at a limited number of wavelengths in a given wavelength range. “Snapshot spectral imaging” (SSI) refers to the instantaneous acquisition (in a single “shot”) of the spectral cube, a process suitable for fast changing objects. Known SSI devices exhibit large total track length (TTL), weight and production costs and relatively low optical throughput. We present a simple SSI camera based on a regular digital camera with (i) an added diffusing and dispersing “phase-only” static optical element at the entrance pupil ("diffuser") and (ii) tailored compressed sensing (CS) methods for digital processing of the diffused and dispersed (DD) image recorded on the image sensor. The diffuser is designed to mix the spectral cube data spectrally and spatially and thus to enable convergence in its reconstruction by CS-based algorithms. In addition to performing SSI, this SSI camera is capable to perform color imaging using a "monochromatic" or "gray-scale" image sensor without color filter arrays.