53 Keywords: speckle filtering, SAR images, wavelets transformation, MMCV filter, EMD decomposition ABSTRACT: This paper presents three methods for reducing speckle noise in SAR images. The first one, proposed by North (North & Wu 2001), is based on filtering by Minimum Coefficient of Variation (MCV) based on mathematical morphology. This method use a non-linear filter that uses local measurements of the noise in the image to guide a low pass filtering operation to act only over regions where the original signal is estimated to be homogeneous. Speckle is therefore reduced in these areas but the edges between them remain intact. The second one, proposed by Chunming (Chunming & al 2002), consists on empirical modal decomposition (EMD). It is a recent introduced tool for decomposing data into so-called Intrinsic Mode Functions (IMF). This method decomposes an image in four recursive images (vertical, horizontal, right diagonal et left diagonal) and do in the same time an appropriate smoothing by the EMD method. The reconstruction of the image is done by detecting the edge direction. The last one, proposed by Duskunovic (Duskunovic & al 2000) is based on the Daubechies wavelets decomposition with denoising detail images. This method is based on the analysis of the detail images, obtained from the wavelet decomposition of the original image. The goal of the analysis is to determine the position of real edges in the image so that false edges and noise can be removed. Comparison of these three filtering techniques with existing methods show us that they were a good compromise between reducing speckle noise, texture conservation, and edge preserving. We have done a comparative study based on statistical criteria (mean, Standard-Deviation, Speckle Index) and Visual aspect. The results obtained by these three methods tested on SAR images of Algiers city, show that we have a good reduction of speckle noise with preserving edges. 1 INTRODUCTION Synthetic aperture radar (SAR) images are becoming more widely used in remote sensing applications. SAR uses microwave radiation to illuminate the earth’s surface, and therefore overcomes some problems associated with conventional visual remote sensing imagery. For example, SAR is not affected by cloud cover variation. The coherent microwave illumination, however, generates a multiplicative speckle noise that corrupts SAR images. We have used the properties of this speckle noise to implement two methods by IDL language (Interactive Data Language) to reduce the noise without blurring edge or other features. Many filtering algorithms have been developed to reduce speckle on SAR imagery. Nevertheless, speckle suppression and detail preservation remain the two key issues in speckle filtering. Most commonly used speckle filters have good speckle-smoothing capabilities. However, the resulting images are subject to degradation of spatial and radiometric resolution, which can result in the loss Implementation of new methods of speckle noise reduction in SAR images L. Bouchemakh*, Y. Smara*, M. Benali & Z. Ben Cheikh *Image Processing Laboratory, Faculty of Electronics and Computer science, Houari Boumediene University of Sciences and Technology (USTHB), B.P. 32, El Alia, Bab Ezzouar, 16111 Algiers Algeria lbouchemakh@usthb.dz, y.smara@lycos.com