Non-subsampled shearlet transformation-based high-resolution three-SAR image speckle reduction method

Abstract

The invention discloses a non-subsampled shearlet transformation-based high-resolution three-SAR image speckle reduction method. The method comprises the steps of S1, converting an image noise model;S2, performing shear wave conversion; S3, processing a high-frequency coefficient by a wavelet hard threshold value; S4, shearing and reconstructing; S5, performing exponential transformation. According to the method disclosed by the invention, high-resolution three-SAR images with the good sparsity can be processed by adopting shear waves with the optimal sparse representation. Therefore, the non-subsampled shear wave transformation is adopted to replace the traditional shear wave transformation. The frequency spectrum aliasing phenomenon caused by the sampling operation is avoided. The gooddirectionality of shear waves is effectively utilized, so that the edge detail part of an image can be effectively reserved. Meanwhile, for the potential noise characteristic of a high-frequency wavelet coefficient, a wavelet hard threshold algorithm is adopted to process the noise. Therefore, the effect of filtering and removing spots is effectively achieved.

Description

technical field [0001] The invention belongs to the technical field of image processing, and in particular relates to a method for reducing speckle in a high-resolution three-point SAR image based on non-subsampling Shearlet transform. Background technique [0002] The Gaofen-3 satellite is not restricted by weather conditions such as cloud and rain, and can monitor and monitor the global ocean and land resources around the clock. Serving marine, disaster reduction, water conservancy, meteorology and many other fields. However, due to the coherent imaging method, the high-resolution three-dimensional SAR image will also produce bright and dark spots, which seriously affect the interpretation of the image. Therefore, it is particularly important to be able to effectively filter out the image spots and at the same time retain the edge information. [0003] The high-resolution three SAR image is a high-resolution SAR image with obvious details such as edges, points, and textur...

AI Technical Summary

Problems solved by technology

However, the traditional shear wave processing includes sampling operation, and the sampling operation of the image after speckle reduction will cause spectrum aliasing, resulting in information in several directions in one direction, which seriously damages the good directionality of shear wave.

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