Higher order discretization model for Coded Aperture Spectral Imaging Systems

Date
2015
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University of Delaware
Abstract
Coded Aperture Snapshot Spectral Imaging Systems (CASSI) sense the 3D spatio-spectral information of a scene using a single 2-dimensional focal plane array (FPA) snapshot. The compressive CASSI measurements are often modeled as the summation of coded and shifted versions of the spectral voxels of the underlying scene. This coarse approximation of the analog CASSI sensing phenomena is then compensated by calibration preprocessing prior to signal reconstruction. This thesis develops a higher order precision model for the optical sensing in CASSI that includes a more accurate discretization of the underlying signals, leading to image reconstructions less dependent on calibration. Further, the higher order model results in improved image quality reconstruction of the underlying scene than that achieved by the traditional model. The proposed higher precision computational model is also more suitable for recongurable multi-frame CASSI systems where multiple coded apertures are used sequentially to capture the hyperspectral scene. Several simulations and experimental measurements demonstrate the benefits of the new discretization model.
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