Fusion method of SAR (Synthetic Aperture Radar) images and visible light images on the basis of NSCT (Non Subsampled Contourlet Transform)

Abstract

The invention relates to a fusion method of SAR (Synthetic Aperture Radar) images and visible light images on the basis of NSCT (Non Subsampled Contourlet Transform). The fusion method is characterized by comprising the following steps of: firstly, carrying out NSCT decomposition on the SAR images and the visible light images respectively; then adopting different fusion rules to carry out fusion treatment on NSCT low-frequency and high-frequency subband coefficients, wherein according to the decomposition coefficient characteristics of noise and signals in an NSCT domain, carrying out hard-threshold denoising on the NSCT high-frequency subband coefficient of the SAR images under the maximum decomposition scale, then respectively adopting different fusion rules to carry out fusion processing on the NSCT high-frequency subband coefficient under the maximum decomposition scale and other decomposition scales by adopting the coefficients with threshold processing as the basis; and finally,carrying out NSCT reverse transformation on the fused NSCT coefficients and obtaining fused images. The fusion method takes denoising as the basis of the fusion rule design, considers noise suppression while fusion treatment is carried out, is simple and easy to operate, can be used for obtaining a good fusion effect and is especially more applicable to the SAR images and the visible light imageswith serious spot and noise pollution.

Description

technical field [0001] The present invention relates to a fusion method of a Synthetic Aperture Radar (SAR) image and a visible light image based on Nonsubsampled Contourlet Transform (Nonsubsampled Contourlet Transform, NSCT). The fusion rules of important features can be applied to various military or civilian image processing systems. Background technique [0002] With the rapid development of aerospace technology, in the field of remote sensing measurement, a single visible light remote sensing mode has gradually developed into a variety of sensor remote sensing modes. Especially in recent years, SAR remote sensing has attracted more and more attention. As an active remote sensing system , SAR is very sensitive to the geometric characteristics of the target, which is often reflected on the image as a very dark or bright point or area, while visible light is more sensitive to the physical and chemical properties of the target (such as reflectivity, albedo, color), and the...

AI Technical Summary

Problems solved by technology

For the fusion of SAR and visible light images, most of them deal with image sources with little noise interference or image fusion after denoising. There are few reports on the fusion methods of SAR and visible light images with serious noise directly.

[0004] The commonly used NSCT-based image fusion methods at this stage are image fusion methods at the pixel level, and the fusion rules adopted are based on pixel points and window rules. These methods have the following problems for the fusion of SAR images and visible light images: 1 ) The NSCT decomposition coefficients are only divided into low-frequency and high-frequency, without a finer distinction, and the fusion rules are relatively rough; 2) The ability to suppress noise is poor. If the fusion method does not consider the factor of suppressing noise, it will have a serious impact on the fusion result , and if the filtering and denoising process is performed before fusion, the important feature information of the image will be blurred; 3) noise suppression and fusion are generally taken as two independent steps, which wastes storage space and takes more time. many

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