Analysis on noise reduction method for interferometric SAR image

Noise in SAR interferogram brings much trouble in phase unwrapping. It will also influence the accuracy of digital elevation models. Based on realization of complex mean filtering, pivoting mean filtering, pivoting median filtering three noise reduction algorithms, their computations are analyzed and the effect of noise reduction is given out. In order to get the most optimized balance between computation and effect of noise reduction, a new noise reduction idea - second-time or multiple combined noise reduction is proposed. The algorithm can comprehend the merits of several noise reduction methods. It can preserve edge information well and decrease phase noise dramatically at the cost of adding a little computation. Based on computer simulation, certain terrain is set and the effect of noise reduction of new method is verified. The variance of before and after combined noise reduction is given out. The effect of three-time or more combined noise reduction is not obvious because noise has been reduced by second-time noise reduction. We do not recommend 4 or more-time combined noise reduction for its large computation. ERS-frac12 real data are also used to verify the validity of the new algorithm