Weighted least squares phase unwrapping by means of multigrid techniques

Mark D. Pritt

doi:10.1117/12.227137

21 November 1995 Weighted least squares phase unwrapping by means of multigrid techniques

Mark D. Pritt

Proceedings Volume 2584, Synthetic Aperture Radar and Passive Microwave Sensing; (1995) https://doi.org/10.1117/12.227137
Event: Satellite Remote Sensing II, 1995, Paris, France

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.

Citation Download Citation

Mark D. Pritt "Weighted least squares phase unwrapping by means of multigrid techniques", Proc. SPIE 2584, Synthetic Aperture Radar and Passive Microwave Sensing, (21 November 1995); https://doi.org/10.1117/12.227137

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