Interferometric SAR Phase Noise Reduction: theory, methods and evaluation

摘要

Phase is the most important information in InSAR (Interferometry SAR) interferogram to derive height or surface deformation. Due to various decorrelation factors, such as spatial, temporal, spectral, thermal noise and so on, there is much phase noise in InSAR interferogram. The phase noise degrades the visual quality of the interferogram not only, also increases the errors of the results derived from the InSAR interferogram, obstruct the phase unwrapping. There are many methods to decrease speckle noise in SAR intensity image, however, which usually could not directly apply to the InSAR interferogram without modification because of the wrap of the phase in InSAR interferogram. The paper first discussed the theoretical models for phase noise, and then summarized several traditional noise reduction methods that are extended to apply to InSAR interferogram. Then, we improved the adaptive phase filtering proposed by R. Goldstein and C. Werner. How to evaluate the phase filtering effect is as difficult and important as filtering itself, in this paper, we made qualitative and quantitative evaluation by real and simulated noisy interferogram, and discussed the relationship between coherence and filtering.