Dissertation/Thesis Abstract

Image Reconstruction for Interferometric Imaging of Geosynchronous Satellites
by DeSantis, Zachary J., Ph.D., University of Rochester, 2017, 143; 10623793
Abstract (Summary)

Imaging distant objects at a high resolution has always presented a challenge due to the diffraction limit. Larger apertures improve the resolution, but at some point the cost of engineering, building, and correcting phase aberrations of large apertures become prohibitive. Interferometric imaging uses the Van Cittert-Zernike theorem to form an image from measurements of spatial coherence. This effectively allows the synthesis of a large aperture from two or more smaller telescopes to improve the resolution. We apply this method to imaging geosynchronous satellites with a ground-based system. Imaging a dim object from the ground presents unique challenges. The atmosphere creates errors in the phase measurements. The measurements are taken simultaneously across a large bandwidth of light. The atmospheric piston error, therefore, manifests as a linear phase error across the spectral measurements. Because the objects are faint, many of the measurements are expected to have a poor signal-to-noise ratio (SNR). This eliminates possibility of use of commonly used techniques like closure phase, which is a standard technique in astronomical interferometric imaging for making partial phase measurements in the presence of atmospheric error. The bulk of our work has been focused on forming an image, using sub-Nyquist sampled data, in the presence of these linear phase errors without relying on closure phase techniques. We present an image reconstruction algorithm that successfully forms an image in the presence of these linear phase errors. We demonstrate our algorithm’s success in both simulation and in laboratory experiments.

Indexing (document details)
Advisor: Fienup, James R.
Commitee: Alonso, Miguel A., Sharma, Gaurav, Zavislan, James M.
School: University of Rochester
Department: Hajim School of Engineering and Applied Sciences
School Location: United States -- New York
Source: DAI-B 79/02(E), Dissertation Abstracts International
Subjects: Optics
Keywords: Image reconstruction, Interferometric imaging
Publication Number: 10623793
ISBN: 978-0-355-39566-2
Copyright © 2020 ProQuest LLC. All rights reserved. Terms and Conditions Privacy Policy Cookie Policy