SAR interferometry: confronting incoherence in phase unwrapping

摘要

Automated phase unwrapping of a highly incoherent differential interferogram of the Arthur's Pass earthquake of 1994 has illustrated many challenges to the use of interferometric SAR in the New Zealand environment. Though severe decorrelation between interferometric pairs is common in New Zealand, processing of images for differential interferometry is motivated by the geologically active landscape. The weighted full multigrid (WFMG) phase unwrapping method of Pritt has been implemented for its robust, global operation. This paper examines the opposing requirements to block out the distorting effect of incoherence, and yet to retain valuable connections between coherent regions. Using both synthesised examples and the Arthur's Pass differential interferogram to illustrate, we propose a modification to the WFMG algorithm, which improves its performance for highly incoherent interferograms.