The SAR and SAS images are perturbed by a multiplicative noise called speckle, due to the coherent nature of the scattering phenomenon. This paper presents a new denoising method in the wavelet domain, which tends to reduce the speckle, preserving the structural features (like the discontinuities) and textural information of the scene. Due to the massive proliferation of SONAR images, the proposed technique is very appealing in ocean applications. In fact it is a pre-treatment required in any SONAR images analysis system. In this paper we propose the adaptation to the case of speckle noise of a denoising method developed by the authors in the case of additive white Gaussian noise. It is simple and fast. Some simulation results and comparisons prove the performance of the new algorithm.

Keywords: SONAR, MAP-filter, Double Tree Complex Wavelet Transform (DTCWT), Sensitivity