Speckle Suppression Method for SAR Image Based on Noise Distribution Constraint in Sparse Domain

Abstract

The invention discloses an SAR (Synthetic Aperture Radar) image spot-inhibiting method based on spare domain noise distribution constraint, which mainly solves the problem that existing spot-inhibiting method cannot keep image texture details and radiation characteristic at the same time. The method comprises the following steps: 1, carrying out logarithm transformation on an original SAR image, dividing the transformed image into overlapped sub image blocks which are same in size and clustering the image blocks by a K mean value clustering method; 2, solving a sparse representation sub dictionary of each cluster by a principal component analysis method and calculating an estimated value of a sparse representation coefficient of a noise-free sub image corresponding to each sub image block by non-local mean value algorithm; 3, solving the final noise-free sparse representation coefficient by soft threshold shrinking algorithm and obtaining the de-noised sub image blocks through reverse sparse transformation; and 4, splicing the sub image blocks and carrying out reverse logarithm transformation to obtain the spot-inhibited SAR image. The method disclosed by the invention is strong in coherent spot inhibiting ability, and the image texture details and radiation characteristic are kept well, so that the method can be used for target identification and characteristic extraction.

Description

Technical field [0001] The invention belongs to the technical field of image processing, and specifically is a method for suppressing the speckle of synthetic aperture radar SAR image, which can be used for target recognition and feature extraction. Background technique [0002] Synthetic Aperture Radar is an active microwave remote sensing device with all-weather and all-weather imaging capabilities, and has been widely used in military and civilian applications. However, the coherent imaging mechanism of SAR results in strong coherent speckle noise in the imaging results, which makes target identification and feature extraction very difficult. Therefore, it is necessary to expand the coherent speckle suppression work of SAR images. [0003] There are two main targets for SAR image speckle suppression. One is to effectively suppress the coherent speckle noise in the homogeneous region of the image, and the other is to preserve the details of the scene's edge, texture, and point ta...

AI Technical Summary

Problems solved by technology

This method can better maintain the texture and details of the image while suppressing the coherence speckle, but it has a very obvious loss of radiation characteristics.

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