Possibilities and limitations of coded aperture imaging

Silva, Ronald L. (1981). Possibilities and limitations of coded aperture imaging. PHD thesis, Aston University.

Abstract

We have simulated the performance of various apertures used in Coded Aperture Imaging - optically. Coded pictures of extended and continuous-tone planar objects from the Annulus, Twin Annulus, Fresnel Zone Plate and the Uniformly Redundant Array have been decoded using a noncoherent correlation process. We have compared the tomographic capabilities of the Twin Annulus with the Uniformly Redundant Arrays based on quadratic residues and m-sequences. We discuss the ways of reducing the 'd. c.' background of the various apertures used. The non-ideal System-Point-Spread-Function inherent in a noncoherent optical correlation process produces artifacts in the reconstruction. Artifacts are also introduced as a result of unwanted cross-correlation terms from out-of-focus planes. We find that the URN based on m-sequences exhibits good spatial resolution and out-of-focus behaviour when imaging extended objects.

Divisions: Engineering & Applied Sciences
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Institution: Aston University
Uncontrolled Keywords: Possibilities,limitations,coded aperture imaging,twin annulus,biomedical imaging,y-ray imaging,tomography
Completed Date: 1981

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