USE OF A PRIORI INFORMATION FOR IMPROVED TOMOGRAPHIC IMAGING IN CODED-APERTURE SYSTEMS.

Persistent Link:
http://hdl.handle.net/10150/184470
Title:
USE OF A PRIORI INFORMATION FOR IMPROVED TOMOGRAPHIC IMAGING IN CODED-APERTURE SYSTEMS.
Author:
GINDI, GENE ROBERT.
Issue Date:
1982
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Coded-aperture imaging offers a method of classical tomographic imaging by encoding the distance of a point from the detector by the lateral scale of the point response function. An estimate, termed a layergram, of the transverse sections of the object can be obtained by performing a simple correlation operation on the detector data. The estimate of one transverse plane contains artifacts contributed by source points from all other planes. These artifacts can be partially removed by a nonlinear algorithm which incorporates a priori knowledge of total integrated object activity per transverse plane, positivity of the quantity being measured, and lateral extent of the object in each plane. The algorithm is iterative and contains, at each step, a linear operation followed by the imposition of a constraint. The use of this class of algorithms is tested by simulating a coded-aperture imaging situation using a one-dimensional code and two-dimensional (one axis perpendicular to aperture) object. Results show nearly perfect reconstructions in noise-free cases for the codes tested. If finite detector resolution and Poisson source noise are taken into account, the reconstructions are still significantly improved relative to the layergram. The algorithm lends itself to implementation on an optical-digital hybrid computer. The problems inherent in a prototype device are characterized and results of its performance are presented.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Tomography -- Data processing.; Image processing.; Imaging systems in medicine -- Data processing.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Optical Sciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Barrett, Harry

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleUSE OF A PRIORI INFORMATION FOR IMPROVED TOMOGRAPHIC IMAGING IN CODED-APERTURE SYSTEMS.en_US
dc.creatorGINDI, GENE ROBERT.en_US
dc.contributor.authorGINDI, GENE ROBERT.en_US
dc.date.issued1982en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractCoded-aperture imaging offers a method of classical tomographic imaging by encoding the distance of a point from the detector by the lateral scale of the point response function. An estimate, termed a layergram, of the transverse sections of the object can be obtained by performing a simple correlation operation on the detector data. The estimate of one transverse plane contains artifacts contributed by source points from all other planes. These artifacts can be partially removed by a nonlinear algorithm which incorporates a priori knowledge of total integrated object activity per transverse plane, positivity of the quantity being measured, and lateral extent of the object in each plane. The algorithm is iterative and contains, at each step, a linear operation followed by the imposition of a constraint. The use of this class of algorithms is tested by simulating a coded-aperture imaging situation using a one-dimensional code and two-dimensional (one axis perpendicular to aperture) object. Results show nearly perfect reconstructions in noise-free cases for the codes tested. If finite detector resolution and Poisson source noise are taken into account, the reconstructions are still significantly improved relative to the layergram. The algorithm lends itself to implementation on an optical-digital hybrid computer. The problems inherent in a prototype device are characterized and results of its performance are presented.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectTomography -- Data processing.en_US
dc.subjectImage processing.en_US
dc.subjectImaging systems in medicine -- Data processing.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineOptical Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorBarrett, Harryen_US
dc.identifier.proquest8227351en_US
dc.identifier.oclc682948435en_US
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