Modified sigma filter for processing images corrupted by multiplicative and impulsive noise

A new modification of sigma filter is proposed and tested in this paper. This modification is suitable for processing images corrupted by Gaussian multiplicative and impulsive noises and it avoids some typical disadvantages of the standard sigma filter while possessing robust properties. The test images include both simulated and real radar images. It is seen that the proposed modification provides improved speckle suppression efficiency and less bias for homogeneous regions of images.