Time Series Phase Unwrapping Based on Graph Theory and Compressed Sensing
Abstract
Time Series SAR interferometry (InSAR) (TS-InSAR) has been widely applied to monitor the crustal deformation with centimeter- to millimeter-level accuracy. Phase unwrapping (PU) errors have proven to be one of the main sources of bias that hinder achieving such high accuracy. In this article, a new time series PU approach is developed to improve the unwrapping accuracy. The rationale behind the proposed method is to first improve the sparse unwrapping by mitigating the phase gradients in a 2-D network and then correcting the unwrapping errors in time, based on the triplet phase closure. Rather than the commonly used Delaunay network, we employ the all-pairs-shortest-path (APSP) algorithm from graph theory to maximize the temporal coherence of all edges and to approach the phase continuity assumption in the 2-D spatial domain. Next, we formulate the PU error correction in the 1-D temporal domain as compressed sensing (CS) problem, according to the sparsity of the remaining phase ambiguity cycles. We finally estimate phase ambiguity cycles by means of integer linear programming (ILP). The comprehensive comparisons using synthetic and real Sentinel-1 data covering Lost Hills, California, confirm the validity of the proposed 2-D + 1-D unwrapping approach and its superior performance compared to previous methods.
Additional Information
© 2021 IEEE. Manuscript received December 7, 2020; revised January 27, 2021 and March 1, 2021; accepted March 13, 2021. Date of publication March 26, 2021; date of current version December 13, 2021. This work was supported in part by the National Natural Science Foundation of China under Grant 41774003 and Grant 42074008, in part by the European Space Agency (ESA), Ministry of Science and Technology (MOST) of China Dragon 5 Project under Grant 59332, and in part by the Program of China Scholarship Council under Grant 202006710013. The Sentinel-1 data were provided by ESA/Copernicus. Thanks to GUROBI company, Beaverton, OR, USA, for providing the academic license of GUROBI software (License ID: 413287). All figures in this article were drawn by GMT6.1.0 software. The authors would like to thank three anonymous reviewers for their valuable comments.Attached Files
Accepted Version - 09387451.pdf
Submitted - essoar.10505085.1.pdf
Files
Name | Size | Download all |
---|---|---|
md5:5e2c0f5e897533631bb9097e469415c6
|
12.5 MB | Preview Download |
md5:1d7a7677b9092a443a571395e398e742
|
1.5 MB | Preview Download |
Additional details
- Eprint ID
- 108697
- Resolver ID
- CaltechAUTHORS:20210412-102922432
- 41774003
- National Natural Science Foundation of China
- 42074008
- National Natural Science Foundation of China
- European Space Agency (ESA)
- 59332
- Ministry of Science and Technology (Taipei)
- 202006710013
- China Scholarship Council
- Created
-
2021-04-13Created from EPrint's datestamp field
- Updated
-
2021-12-20Created from EPrint's last_modified field