Identifying of Noise Type and Estimating of Noise Level for InSAR Interferogram in the Wavelet Domain

摘要

In order to identify noise type of the InSAR interferogram and facilitate more effective interferogram processing, especially for interferogram filtering based on wavelet transform, a novel methodology for identifying noise type and estimating noise level was reported. This methodology combined a wavelet transform algorithm with a logarithmic transform algorithm, and carried on the thorough analysis for the characteristics of interferogram wavelet coefficients from two aspects of energy distribution and statistics. Firstly, energy distribution characteristics of low frequency son-band coefficients were researched before and after the logarithmic transform, so that noise type of interferogram can be identified. On this base, the noise level would be estimated by high frequency coefficients. From the analysis results obtained in this study, the conclusions can be made that noise of InSAR interferogram is the additive noise, high frequency coefficients show standard normal distribution, and the noise level could be estimated by HH son-band on one scale. These results provide more spaces for noise analysis and processing of InSAR interferogram based on the wavelet transform algorithm.