Identification and estimation of InSAR interferogram noise based on wavelet transform

Abstract

To identify the type of noise in an Interferometric Syntheic Aperture Radar (InSAR) interferogram and facilitate more effective data processing, especially for interferogram filtering based on wavelet transform, we developed a novel method for identifying the noise type and estimating the noise level. This method combines wavelet transform with logarithmic transformation and includes an in-depth analysis of the characteristics of interferogram wavelet coefficients from the viewpoints of energy distribution and statistical interpretation. First, we investigated the energy distribution characteristics of low-frequency subband wavelet coefficients before and after the logarithmic transformation to identify the noise type of the interferogram. On this basis, the noise level could be estimated using high-frequency subband wavelet coefficients. From the analysis results of this study, we conclude that the noise type of the InSAR interferogram is additive noise, the high-frequency coefficients show a Gaussian distribution, and the noise level can be estimated by a high-frequency subband on one scale. These results provide further scope for noise analysis and processing of InSAR interferograms based on wavelet transform.