Sar image speckle reduction method based on anisotropic diffusion and mutual information homogeneity measure

Abstract

The invention discloses SAR image speckle reduction algorithm based on anisotropic diffusion and mutual information homogeneity measuring degrees, which mainly overcomes shortcomings that most of existing speckle reduction algorithm cannot effectively reserve structural features in images while noise in homogeneity regions is removed. A realization method of the SAR image speckle reduction algorithm includes (1), computing the mutual information homogeneity measuring degree of each pixel in an inputted image; (2), constructing diffusion coefficients of anisotropic diffusion equations by the aid of the mutual information homogeneity measuring degrees; (3), realizing isotropic diffusion for a homogenous region by the aid of the newly built diffusion coefficient, and realizing anisotropic diffusion for edge regions; and (4), outputting a final noise-reduced image after iteration diffusion is realized for the image by certain times. Compared with an existing method for realizing anisotropic diffusion speckle reduction and an existing method for reducing speckles in space and wavelet domains, the SAR image speckle reduction algorithm has the advantages that structural and detail features in the image can be effectively reserved while a noise smoothing effect of the homogenous region is strengthened, noise reduction performances in various aspects are remarkably improved, and the SAR image speckle reduction algorithm can be used for dividing and classifying SAR images and identifying targets.

Description

technical field [0001] The invention belongs to the technical field of image processing, and relates to a SAR image coherent spot suppression method, which can be used for SAR image segmentation, classification and target recognition. Background technique [0002] The basic goal of the speckle suppression algorithm for SAR images is to preserve the edge, texture and strong reflection point targets of the image under the premise of suppressing the speckle noise in the uniform area of ​​the image. Aiming at the multiplicative characteristic of speckle noise in SAR images, many speckle reduction algorithms have been developed. Such algorithms can be roughly divided into spatial domain filtering algorithms and transform domain filtering algorithms. Typical spatial domain filtering algorithms include Lee filter, Kuan filter and Frost filter; typical transform domain filtering algorithms include wavelet domain, contourlet domain, and curvelet domain filtering algorithms. However...

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