A PolSAR image despeckle filter based on evidence theory
Saïd Kharbouche · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2010
Images issued from a SAR (Synthetic Aperture Radar) sensor are effected by a specific noise called speckle; therefore, many studies have been dedicated to modulate this noise with the aim to be able to reduce its effects. But, studies in the area of polarimetric SAR (PolSAR) images despeckling are still poor and don't take advantage correctly of polarimetric information. In this way, this paper describes an original and efficient method of despeckling PolSAR images in order to improve the visualization and the extraction of planimetric features. The proposed filter, takes into account all polarization modes for each polarization mode despeckling. So, for a pixel in a single polarization mode, the modification of its radiometric value will be supervised by it adjacent pixels in the same polarization mode and also by their equivalent pixels in other polarization modes. Furthermore, to avoid error propagation, the filter will be very cautious in modification of radiometric values in such way that it runs in many iterations modifying the less ambiguous pixels firstly and leaves the rest of the pixels for the next iterations for a possible modification. To combine the information resulting from each polarization mode and make a decision, the proposed filter calls some rules of the Evidence Theory. The experimentation was done on Radarsat-2 images of the Arctic and Quebec regions of Canada, and the results show clearly the benefit and the high performance of this despeckling approach.