Interferometric SAR Phase Filtering in the Wavelet Domain Using Simultaneous Detection and Estimation

In this paper, two interferometric SAR (InSAR) phase-filtering methods are proposed. These methods are performed in the wavelet domain and employ the simultaneous detection and estimation technique. In the wavelet domain, closed-form estimator and detector equations are derived, based upon a quadratic cost function, to minimize the combined risk of detection and estimation and, thus, the least square errors. Both methods occur within the wavelet domain; however, the first method employs the wavelet packet, while the second method is performed in the undecimated wavelet domain. A major characteristic of InSAR phase data is that the noise level is spatially variable, and the proposed methods have a particularly good comparative performance in these situations. Tests are performed using simulated phase data and show that the proposed methods have lower root-mean-square error and less noisy fringes in the filtering results than those of three existing “state-of-the-art” wavelet-domain phase-filtering methods. Tests using real InSAR data also demonstrate the superiority of the proposed methods in terms of visual and quantitative evaluation.