Speckle Reduction in SAR Images Based on the First Moment (L1) Norm

Due to expanding applications of the SAR (Synthetic Aperture Radar) images and the effect of Speckle noise in reducing the Interpretability of the SAR images, Speckle noise reduction is very important. In this paper, an Adaptive Filter has been proposed to reduce the speckle noise. In this filter, L1 norm (first moment) has been used to identify pixels that have been severely affected by Speckle phenomenon. In the Proposed method, the nearest degree of previous gray level --within the allowable limit-- instead mean of kernel has been placed in the pixels. In This paper it is tried to determine the best mode for the proposed filter as a damping factor in the used images. The results have been compared then to the results obtained by other widely-used adaptive filters including Lee, Gamma, Frost and Touzi. The results of this comparison showed that the proposed filter with the mean signal to noise ratio (SNR) above 14 offers better results than the above-mentioned filters with the maximum value 10.13.