Abstract: To study surface targets, advances involving acquisition of synthetic aperture radar (SAR) images is important. This system is independent of sunlight and climate factors, but the images are contaminated with a multiplicative noise called speckle. It is due to the signal interference with the elements on the surface, and it gives a granulated aspect to the image that complicates its analysis and interpretation. Recently, non-local approaches have proved very powerful for image de noising. Unlike local filters, the nonlocal (NL) means decreases the noise while preserving resolution. De speckling techniques based on the nonlocal approach provide an excellent performance, but also exhibit a remarkable complexity, unsuitable for time-critical applications. This paper discusses the various techniques used to de speckle SAR images using non local

Keywords: Synthetic Aperture Radar (SAR), non local (NL) means, de speckling, Block matching 3D.