Speckle reduction in synthetic aperture radar imagery using wavelets

In this paper, a method using the wavelet transform and the multiresolution analysis to remove the speckle effect in Synthetic Aperture Radar imagery is proposed. This technique allows the filtering of the most speckled structures and the improvement of the performances of a classical Wiener filter. Results on one example are presented. They confirm the efficiency of the multiresolution approach, as described in Cauneau and Ranchin' .The choice of the algorithm of wavelet transform and of the number of scales treated are discussed. The efficiency of the "a trous" algorithm is due to the isotropy of the wavelet used. This non-directional wavelet allows an improvement of the radiometric resolution without degrading significantly the geometrical resolution. Perspectives for an improvement of the quality of the speckle reduction are explored.