Abstract

The remote sensing community continues to pursue advanced sensor designs and post processing techniques that improve upon the spatial quality of collected overhead imagery. Unfortunately, spaceborne applications frequently encounter launch vehicle fairing and weight constraints that limit the size of the primary aperture that can be utilized for a given application. Sparse aperture telescopes provide a potential avenue for overcoming some of the size and weight issues associated with deploying a large monolithic mirror system. These telescope systems are constructed of smaller subapertures which are phased to form a common image field and thereby synthesize a larger effective primary diameter to obtain higher spatial resolution than that achievable with a single subaperture. Much of the research conducted to date in this sparse aperture arena has focused on the panchromatic image quality performance of various optical configurations through approaches that make use of resampled, gray-scale imagery products. The research effort performed in conjunction with this dissertation focused on laying the groundwork for synthetic model-based approaches for evaluating the optical performance of sparse aperture collection systems with enhanced spectral fidelity and a polychromatic object scene. It entailed a fundamental investigation and demonstration of the first-principles physics required to model such imaging systems. This theoretical development ultimately led to the generation of a modeling concept that more rigorously addresses the spectral characteristics of classic sparse aperture optical configurations used in remote sensing applications. To demonstrate the proposed theoretical foundation, a proof-of-concept digital model was implemented that incorporates essential components of the fundamental physical processes involved with typical sparse aperture collection systems, including any potential spectral effects unique to these design configurations. In addition to modeling the detected imagery derived from the collection system, there was also an interest in exploring the quality implications of image restoration techniques typically required for sparse aperture imaging systems. Several variations of the classic Wiener-Helstrom filter were implemented and investigated in response to this research objective. The basic restoration methodologies pursued in this effort provide a foundation for research into more advanced techniques in the future. Finally, a top-level sensitivity study of the image quality performance of various sparse aperture pupil configurations subjected to varying levels of subaperture dephasing and/or aberrations was performed. This exploration of the trade space focused on a panchromatic detection scenario and attempted to bound the performance region where unique spectral quality issues are observed for the unconventional collection telescopes targeted through this research effort.

Library of Congress Subject Headings

Image processing--Mathematical models; Imaging systems--Mathematical models; Optics--Mathematics

Publication Date

2004

Document Type

Dissertation

Student Type

Graduate

Degree Name

Imaging Science (Ph.D.)

Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)

Advisor

John Schott

Advisor/Committee Member

Roger Easton

Advisor/Committee Member

Robert Fiete

Campus

RIT – Main Campus

Plan Codes

IMGS-MS

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