SAR (synthetic aperture radar) image coherent speckle suppression method

Abstract

The present invention provides an SAR (synthetic aperture radar) image coherent speckle suppression method. According to the method, the probability density function of multiplicative noises and prior information are utilized to construct the approximation term, diffusion term and sparse constraint of a model; a sparse partial differential equation model is established; and alternate optimization is adopted to obtain a solution, so that a coherent speckle-suppressed SAR image can be obtained. With the sparse partial differential equation-based SAR image coherent speckle suppression method of the invention adopted, the defects of a traditional filtering method and a partial differential equation method can be eliminated; and the coherent speckles of the image can be suppressed, the radiation resolution of the SAR image can be improved, and at the same time, the edge information and scattering characteristics of a radar target can be well retained, the quality improvement of the SAR image can be realized effectively, the numerical solution of the model can be obtained robustly, and therefore, the method is easy to implement.

Description

technical field [0001] The invention relates to an image processing method, in particular to a SAR image coherent spot suppression method. Background technique [0002] Synthetic aperture radar is a coherent imaging system. When it images distributed targets, the echoes of a large number of scattered points in the same spatial resolution unit have interference phenomenon, which is manifested as coherent speckle noise on the SAR image. Speckle noise not only reduces the radiation resolution of SAR images, but also adversely affects the subsequent applications of SAR images such as edge detection, image segmentation, and object classification. Therefore, speckle suppression is an important part of improving the quality of SAR images. [0003] At present, there are mainly two technical approaches for coherent speckle suppression methods, one is multi-view processing, and the other is filtering processing. Multi-look processing usually reduces the spatial resolution of SAR imag...

AI Technical Summary

Problems solved by technology

However, since the above partial differential model was first proposed for the additive noise of optical images, it needs to be improved when it is applied to the multiplicative coherent speckle noise of SAR images. The electromagnetic scattering characteristics of optical images vary greatly, and partial differential equations cannot well maintain the scattering characteristics of radar targets

[0005] The sparse partial differential equation method is an improvement of the partial differential equation method, which is used to solve the stable solution of the dynamic equation, and cannot be directly applied to coherent speckle suppression in SAR images

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