SAR‐IRGF: A novel improved rolling guidance filter for the synthetic aperture radar image

Abstract

Inspired by the framework of the rolling guidance filter (RGF), a novel improved RGF for synthetic aperture radar (SAR) images is proposed in this letter, named SAR-IRGF. Based on the model of additive noise, the RGF has the complete control of detailed smoothing under a scale measure for optical images. However, the speckle is well known as a multiplicative noise, which invalidates the RGF for SAR images. In this letter, an appropriate edge guidance is utilized to optimize the RGF for SAR image denoising. Compared with the original version, better convergence is achieved. Experimental results on natural Ku-band airborne SAR images show that the proposed SAR-IRGF reduces more speckle while sharpening the edges effectively. Simultaneously, the SAR-IRGF demonstrates a significant nearly 5.5-fold improvement than RGF in the equivalent number of looks (ENL).