A flexible design for coded aperture snapshot spectral imager

By the success of compressive sensing (CS), coded aperture snapshot spectral imager (CASSI) computationally obtains 3D spectral images from 2D compressive measurement. In CASSI, each pixel of the detector captures spectral information only from one voxel in each band with binary weights (i.e., 0 or 1), which limits the variety of superposition relationship among the 3D voxels in the underlying scene. Moreover, the correspondence of each pixel of detector to each pixel of coded aperture cannot be readily achieved in the presence of dispersive prism, due to the small pixel sizes of these elements (often in micrometer). In this paper, we propose a flexible design to improve the performance of CASSI with currently employed optical elements in CASSI. Specifically, the proposed design integrates a kind of flexible alignment relationship along the coded aperture, the dispersive prism and the detector. Each measurement of the detector is manifested as the summation of several voxels in each band with random decimal weights and different measurements corresponds to overlapped voxels, which provides more sufficient superposition relationship of the scene information. This flexible design favors the sensing mechanism better satisfy the requirement of CS theory. Furthermore, the proposed design greatly reduces the alignment complexity and burden of system construction. Preliminary result achieves improved image quality, including higher PSNR and better perceptual effect, compared to the traditional design.