Weighted least-squares algorithm for phase unwrapping based on confidence level in frequency domain

Shaohua Wang; Jie Yu; Cankun Yang; Shuai Jiao; Jun Fan; Yanyan Wan

doi:10.1117/12.2205700

17 December 2015 Weighted least-squares algorithm for phase unwrapping based on confidence level in frequency domain

Shaohua Wang, Jie Yu, Cankun Yang, Shuai Jiao, Jun Fan, Yanyan Wan

Proceedings Volume 9811, MIPPR 2015: Multispectral Image Acquisition, Processing, and Analysis; 98110Q (2015) https://doi.org/10.1117/12.2205700
Event: Ninth International Symposium on Multispectral Image Processing and Pattern Recognition (MIPPR2015), 2015, Enshi, China

Abstract

Phase unwrapping is a key step in InSAR (Synthetic Aperture Radar Interferometry) processing, and its result may directly affect the accuracy of DEM (Digital Elevation Model) and ground deformation. However, the decoherence phenomenon such as shadows and layover, in the area of severe land subsidence where the terrain is steep and the slope changes greatly, will cause error transmission in the differential wrapped phase information, leading to inaccurate unwrapping phase. In order to eliminate the effect of the noise and reduce the effect of less sampling which caused by topographical factors, a weighted least-squares method based on confidence level in frequency domain is used in this study. This method considered to express the terrain slope in the interferogram as the partial phase frequency in range and azimuth direction, then integrated them into the confidence level. The parameter was used as the constraints of the nonlinear least squares phase unwrapping algorithm, to smooth the un-requirements unwrapped phase gradient and improve the accuracy of phase unwrapping. Finally, comparing with interferometric data of the Beijing subsidence area obtained from TerraSAR verifies that the algorithm has higher accuracy and stability than the normal weighted least-square phase unwrapping algorithms, and could consider to terrain factors.

Citation Download Citation

Shaohua Wang, Jie Yu, Cankun Yang, Shuai Jiao, Jun Fan, and Yanyan Wan "Weighted least-squares algorithm for phase unwrapping based on confidence level in frequency domain", Proc. SPIE 9811, MIPPR 2015: Multispectral Image Acquisition, Processing, and Analysis, 98110Q (17 December 2015); https://doi.org/10.1117/12.2205700

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