Potential of Using Phase Correlation in Distributed Scatterer InSAR Applied to Built Scenarios
Institute of Space and Earth Information Science, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong 999077, China
Key Lab of Poyang Lake Wetland and Watershed Research of Ministry of Education, School of Geography and Environment, Jiangxi Normal University, Nanchang 330022, China
Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518063, China
Department of Geography and Resource Management, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong 999077, China
Department of Space Microwave Remote Sensing System, The Institute of Electronics, Chinese Academy of Science, Beijing 100190, China
University of Chinese Academy of Sciences, Beijing 100049, China
Authors to whom correspondence should be addressed.
Remote Sens. 2020, 12(4), 686; https://doi.org/10.3390/rs12040686
Received: 23 December 2019 / Revised: 14 February 2020 / Accepted: 15 February 2020 / Published: 19 February 2020
(This article belongs to the Special Issue InSAR in Remote Sensing)
The improved spatial resolution of Synthetic Aperture Radar (SAR) images from newly launched sensors has promoted a more frequent use of distributed scatterer (DS) interferometry (DSI) in urban monitoring, pursuing sufficient and detailed measurements. However, the commonly used statistical methods for homogeneous pixel clustering by exploring amplitude information are firstly, computationally intensive; furthermore, their necessity when applied to high-coherent built scenarios is little discussed in the literature. This paper explores the potential of using phase information for the detection of homogeneous pixels on built surfaces. We propose a simple phase-correlated pixel (PCP) clustering and introduce a coherence-weighted phase link (WPL), i.e., PCPWPL, to pursue a faster processing of interferogram phase denoising. Rather than relying on the statistical tests of amplitude characteristics, we exploit vector correlation in the complex domain to identify PCPs with similar phase observations, thus, avoiding the intensive hypothesis test. A coherence-weighted phase linking is applied for DS phase reconstruction. The estimation of geophysical parameters, e.g., deformation, is completed using an integrated network of persistent scatterers (PS) and DS. Efficiency of the proposed method is fairly illustrated by both synthetic and real data experiments. Pros and cons of the proposed PCPWPL were analyzed with the comparison to a conventional amplitude-based strategy using an X-band CosmoSkyMed dataset. It is demonstrated that the use of phase correlation is sufficient for DS monitoring in built scenarios, with equivalent measurement quantity and cheaper computational cost.