Synthetic aperture radar image denoising method based on non-down sampling profile wave

Abstract

The present invention discloses a denoising method of synthetic aperture radar image based on a non-lower sampling configuration wave, which is mainly to solve the problem that the image detail is difficult to keep effectively by the existing method, the new method comprises: (1) inputting a SAR image X and performing the L layer non-lower sampling configuration wave transformation; (2) calculating speckle noise variance of subband in each high-frequency direction of different dimensions; (3) distinguishing the high-frequency direction subband coefficients into the signal or the noise transformation coefficients by the local average value mean[C1, i(a, b)] high-frequency direction subband coefficient C1 and the i (a, b); (4) reserving the signal part in the judged high-frequency direction subband coefficient C1 and i (a, b) to obtain the denoised high-frequency direction subband coefficient C1 and i <*> (a, b); (5) performing the non-lower sampling configuration wave inverse transformation for the low-frequency subband and the denoised high-frequency direction subband coefficient C1 and I <*> (a, b) to obtain the denoised SAR image X <*>. The invention can effectively eliminate the coherent speckle noise, meanwhile can effectively keep the image detail, the denoised image has no shake and distortion and can be used for the preprocessing stage of the synthetic aperture radar image.

Description

technical field [0001] The invention belongs to the technical field of image processing, and relates to the application of the technology in the field of synthetic aperture radar Synthetic Aperture Radar image, that is, the field of SAR image denoising, specifically a method for denoising synthetic aperture radar images based on non-subsampling contourlets . This method can be used in the preprocessing stage of SAR images. Background technique [0002] Synthetic aperture radar can image all-weather and all-weather, and has high spatial resolution and strong penetrating ability. SAR images have been widely used in both military and civilian applications. However, due to the inherent coherent speckle noise, SAR images cannot effectively reflect the scattering characteristics of ground objects, which seriously affects the image quality and causes great difficulties for automatic image interpretation. SAR image denoising is a key step in SAR image processing and analysis, and...

AI Technical Summary

Problems solved by technology

Regardless of whether the SAR image is denoised in the downsampling or non-downsampling wavelet transform domain, the resulting image often cannot well retain the details of the original SAR image, and wavelet analysis is not the optimal function in two-dimensional space. The representation method cannot well describe the geometric information with line singularity in the image

Most of the existing SAR image denoising methods based on the transform domain simply convert the multiplicative speckle noise into additive noise through logarithmic transformation to estimate the denoising threshold, resulting in insufficient denoising

Images