Refined sigma filter for SAR image despeckling using reference image

Presented is a refined sigma filter for synthetic aperture radar (SAR) image despeckling, where a novel reference image is constructed to replace the original SAR image for the selection of homogeneous pixels. The reference image holds the advantages of containing almost the same amount of details as the original SAR image but with less speckle noise, and thus enables more accurate sigma selection. Results on synthetic and real SAR images show the effectiveness of the method on both detail preservation and speckle removal.