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Proceedings Paper

Weighted least squares phase unwrapping by means of multigrid techniques
Author(s): Mark D. Pritt
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Paper Abstract

The weighted least squares approach to phase unwrapping, an extension of the unweighted least squares approach, is a robust and accurate method for phase unwrapping. This approach zero-weights portions of the phase data to avoid unwrapping across regions of corrupted phase, which are typically caused by the SAR phenomena of layover and radar shadow. Recently the first practical method for accomplishing this weighted phase unwrapping was introduced. This method is based on preconditioned conjugate gradients (PCGs). We present a new method that is an extension of our multigrid algorithm for unweighted least squares phase unwrapping. This new method features a carefully defined operator for transferring the phase weights to the coarse grids of the multigrid scheme. The algorithm converges in only a few multigrid cycles, and on phase data that contain severe discontinuities or shear we demonstrate that it is up to 25 times faster than the PCG algorithm. We also present methods for defining the initial phase weights, thus yielding a completely automated algorithm for fast and accurate phase unwrapping.

Paper Details

Date Published: 21 November 1995
PDF: 11 pages
Proc. SPIE 2584, Synthetic Aperture Radar and Passive Microwave Sensing, (21 November 1995); doi: 10.1117/12.227137
Show Author Affiliations
Mark D. Pritt, Loral Corp. (United States)

Published in SPIE Proceedings Vol. 2584:
Synthetic Aperture Radar and Passive Microwave Sensing
Giorgio Franceschetti; Christopher John Oliver; James C. Shiue; Shahram Tajbakhsh, Editor(s)

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