Adaptive Anisotropic Diffusion Method for Polarimetric SAR Speckle Filtering

In this paper, we present an adaptive anisotropic diffusion (AD) method for the speckle filtering of polarimetric synthetic aperture radar (PolSAR) images. One of the main innovations of our work is that we employ a likelihood-ratio test method to measure the equality of two polarimetric covariance matrices to control the diffusivity, and thus consider the full polarimetric information and the statistical traits of PolSAR data in the diffusion process. Meanwhile, to overcome the drawback of the conventional AD methods, we integrate the local homogeneity information into the diffusion model to adaptively control the generosity of the filtering. Experiments were conducted on a simulated image and two airborne PolSAR images to illustrate the filtering performance, and the results show that the proposed method effectively reduces speckle, retains edges, and targets, and preserves the polarimetric scattering mechanisms.