基于 GMM 的 GB-InSAR 图像 PS 点选择方法

Permanent scatterer (PS) selection is a crucial step in the processing of ground-based interferometric synthetic aperture radar (GB-InSAR).Existing methods rely on amplitude stability, phase stability or high coherence between pixels to select PS. Amplitude stability and phase stability are sensitive to phase fluctuations and may not well represent phase errors in some cases. The methods based on high coherence can easily lead to false detections due to their reliance on local windows. To address these issues, this paper analyzes the differences in the distribution characteristics of interferometric phases between PS and non-PS in GB-InSAR. A new PS selection method based on Gaussian mixture model (GMM) is proposed. The method firstly selects enough PS as prior reference PS. Then, GMM is used to fit the probability distribution of the interferometric phases of the reference PS. Finally, the PS and non-PS are distinguished based on the matching degree between the interferometric phase series of all image pixels and the GMM. The results of measured data show that, comparing to the traditional methods based on amplitude and phase stability, when the number of obtained PS is close, the proposed method yields stronger coherence and higher degree of aggregating of phase series among the obtained PS. The PS obtained by GMM are with less residues than other methods. This demonstrates the method's ability to accurately select PS.