Date of Award

12-1994

Document Type

Thesis

Degree Name

Master of Science in Electrical Engineering

Department

Department of Electrical and Computer Engineering

First Advisor

Byron Welsh, PhD

Abstract

The U.S. Air Force has a continuing mission to obtain imagery of earth-orbiting objects. One of the means for obtaining this imagery is through the use of ground-based observatories. A fundamental problem associated with imaging objects through the atmosphere is that atmospheric turbulence inflicts a large, random aberration on the telescope which effectively limits the realizable resolution to that of a much smaller telescope. Several approaches have been taken to overcome these effects including pure post processing, pure adaptive optics, and hybrid techniques involving both adaptive optics and image post processing. One key result from past approaches is that partially compensated systems can be used in conjunction with image processing to overcome most of the optical effects of atmospheric turbulence while retaining nearly the performance of a fully compensated system. One hybrid approach is compensated deconvolution from wavefront sensing (CDWFS). This method uses wavefront sensor measurements in conjunction with short exposure images to improve the effective optical performance. This thesis formulates and executes a plan which allows fundamental questions regarding partially compensated adaptive optics performance to be answered. Specifically, imaging of extended objects using the CDWFS technique is investigated, through simulation. The simulation results demonstrate that the CDWFS technique can be used to reduce the required closed-loop bandwidth of an imaging system, permitting longer integration times in the wavefront sensor, and thus allowing dimmer objects to be imaged without the use of an artificial guidestar.

AFIT Designator

AFIT-GE-ENG-94D-29

DTIC Accession Number

ADA289490

Comments

The author's Vita page is omitted.

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