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CN104200439B - Image super-resolution method based on adaptive filtering and regularization constraint - Google Patents

Image super-resolution method based on adaptive filtering and regularization constraint Download PDF

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CN104200439B
CN104200439B CN201410453238.XA CN201410453238A CN104200439B CN 104200439 B CN104200439 B CN 104200439B CN 201410453238 A CN201410453238 A CN 201410453238A CN 104200439 B CN104200439 B CN 104200439B
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董伟生
任京波
石光明
吴昊
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Xidian University
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Abstract

The invention discloses an image super-resolution method based on adaptive filtering and regularization constraint and mainly aims at solving the problems of blocking and virtual edges which are produced in an image super-resolution method based on constraint reconstruction in the prior art. The image super-resolution method based on adaptive filtering and regularization constraint comprises the implementation steps of firstly, inputting a high-resolution image, fuzzifying the high-resolution image, performing downsampling on the fuzzy image and performing interpolation on the low-resolution image, secondly, calculating an adaptive filter coefficient matrix to obtain a high-frequency image, thirdly optimizing the high-frequency image to obtain the optimal high-frequency image, and finally, optimizing the high-resolution image to obtain the optimal high-resolution image. The image super-resolution method based on the adaptive filtering and the regularization constraint is capable of performing super-resolution enlargement on the image by use of only one observation image and well keeping the edge and texture details of the image, and can be applied to image super-resolution reconstruction of a medical image, a video monitoring image and a remote sensing image.

Description

基于自适应滤波和正则约束的图像超分辨方法Image Super-resolution Method Based on Adaptive Filtering and Regular Constraint

技术领域technical field

本发明属于图像处理技术领域,更进一步涉及遥感图像、视频监控、医学图像领域中基于自适应滤波和正则约束的图像超分辨方法,本发明用于从一幅低分辨遥感图像、低分辨视频监控图像、低分辨医学图像中重建出高分辨图像,以提高图像的空间分辨率,并最大程度的保留图像边缘结构的准确性。The invention belongs to the technical field of image processing, and further relates to an image super-resolution method based on adaptive filtering and canonical constraints in the fields of remote sensing images, video monitoring, and medical images. High-resolution images are reconstructed from high-resolution images and low-resolution medical images to improve the spatial resolution of images and preserve the accuracy of image edge structures to the greatest extent.

背景技术Background technique

在遥感图像、视频监控、医学图像等成像领域中,为提高图像分辨率采用从一幅低分辨图像中重建出高分辨率图像的单幅图像超分辨率重建方法。目前,单幅图像主要基于稀疏表示和正则约束方法来实现超分辨率重建。In the imaging fields of remote sensing images, video surveillance, and medical images, a single image super-resolution reconstruction method that reconstructs a high-resolution image from a low-resolution image is used to improve image resolution. At present, single image is mainly based on sparse representation and regularized constraint methods to achieve super-resolution reconstruction.

Yang,J、Wright,J、Huang,T、Ma,Y.四人在文献“Image Super-Resolution ViaSparse Representation”(IEEE Trans.on Image Processing vol.19 no.11 pp.2861-2873 Nov.2010.)中公开了一种基于稀疏表示来实现单幅图像超分辨重建的方法。该方法是给定一幅低分辨的图像,将该图像划分成多个块,并对每一个低分辨率图像块稀疏编码,使其在低分辨数据中自适应的寻找到K个低分辨率块使表征误差最小且表征系数足够稀疏,然后线性组合低分辨率图像块对应的K个高分辨率图像块,融合所有的高分辨率图像块得到最终的高分辨率图像。该方法存在的不足是,稀疏编码过程计算复杂,并且该方法未对图像的边缘和纹理进行处理。Yang, J, Wright, J, Huang, T, Ma, Y. Four people in the literature "Image Super-Resolution ViaSparse Representation" (IEEE Trans. on Image Processing vol.19 no.11 pp.2861-2873 Nov.2010. ) discloses a method for realizing super-resolution reconstruction of a single image based on sparse representation. This method is given a low-resolution image, divides the image into multiple blocks, and sparsely encodes each low-resolution image block, so that it can adaptively find K low-resolution images in the low-resolution data block to minimize the representation error and the representation coefficients are sufficiently sparse, then linearly combine the K high-resolution image blocks corresponding to the low-resolution image blocks, and fuse all the high-resolution image blocks to obtain the final high-resolution image. The disadvantage of this method is that the sparse coding process is computationally complex, and this method does not process the edge and texture of the image.

Zuo,W、Lin,Z二人在文献“A Generalized Accelerated Accelerated ProximalGradient Approach for Total-Variation-Based Image Restoration”(IEEE Trans.onImage Processing vol.20 no.10 pp.2748-2759 Oct.2011.)中公开了一种用梯度光滑约束来求解超分辨问题的方法。该方法通过添加一个罚函数,使超分辨问题转变成一个优化问题,通过求解优化问题得到最终的高分辨图像。该方法存在的不足是,该方法模型需要建立在图像是分片光滑的假设下,这样的前提条件并不是所有图像都能满足,此外,这种方法还会引入图像的块效应,造成超分辨图像模糊。Zuo, W, Lin, Z in the document "A Generalized Accelerated Accelerated Proximal Gradient Approach for Total-Variation-Based Image Restoration" (IEEE Trans.onImage Processing vol.20 no.10 pp.2748-2759 Oct.2011.) A method for solving super-resolution problems with gradient smoothness constraints is disclosed. This method transforms the super-resolution problem into an optimization problem by adding a penalty function, and obtains the final high-resolution image by solving the optimization problem. The disadvantage of this method is that the model of this method needs to be established under the assumption that the image is sliced and smooth, and such a precondition cannot be satisfied for all images. In addition, this method will also introduce block effects of the image, resulting in super-resolution The image is blurry.

苏州新视线文化科技发展有限公司申请的专利“基于稀疏表示的图像超分辨率重建方法”(申请日:2013.07.16申请号:201310296581.3公开号:CN 103366347 A)中公开了一种基于稀疏表示的图像超分辨重建方法。该方法先计算低分辨率图像的梯度信息和高分辨率图像与低分辨率图像的残差信息,然后通过稀疏表达方法得到低分辨率特征集合和高分辨率特征集合,最后在高分辨率特征集合中找到对应的残差信息,将此残差信息融合到低分辨率图像上,获得高分辨图像。该方法存在的不足是,计算低分辨率特征集合和高分辨率特征集合的稀疏表达方法计算复杂度很高,实时性差,实际应用范围受到限制。The patent "Image Super-resolution Reconstruction Method Based on Sparse Representation" (application date: 2013.07.16, application number: 201310296581.3 publication number: CN 103366347 A) filed by Suzhou New Vision Culture Technology Development Co., Ltd. discloses a method based on sparse representation Image super-resolution reconstruction method. This method first calculates the gradient information of the low-resolution image and the residual information between the high-resolution image and the low-resolution image, then obtains the low-resolution feature set and the high-resolution feature set through the sparse expression method, and finally obtains the high-resolution feature set The corresponding residual information is found in the set, and the residual information is fused to the low-resolution image to obtain a high-resolution image. The shortcomings of this method are that the sparse representation method for calculating low-resolution feature sets and high-resolution feature sets has high computational complexity, poor real-time performance, and limited practical application range.

发明内容Contents of the invention

本发明的目的在于针对上述现有技术的不足,提出一种基于自适应滤波和正则约束的图像超分辨方法,通过优化约束图像的高频部分,使获得的高分辨率图像具有尖锐的边缘和丰富的纹理细节。The purpose of the present invention is to address the deficiencies of the above-mentioned prior art, and propose an image super-resolution method based on adaptive filtering and regular constraints, by optimizing the high-frequency part of the constrained image, the obtained high-resolution image has sharp edges and Rich texture details.

实现本发明的具体步骤如下:Realize the concrete steps of the present invention as follows:

(1)获得初始高分辨率遥感图像:(1) Obtain the initial high-resolution remote sensing image:

(1a)输入一幅高分辨率遥感图像;(1a) Input a high-resolution remote sensing image;

(1b)生成均值为0,方差为1.6,尺寸为7×7的高斯模糊矩阵;(1b) Generate a Gaussian blur matrix with a mean value of 0, a variance of 1.6, and a size of 7×7;

(1c)用高斯模糊矩阵卷积高分辨率遥感图像,得到高分辨率模糊遥感图像;(1c) Convolving the high-resolution remote sensing image with a Gaussian blur matrix to obtain a high-resolution blurred remote sensing image;

(1d)将高分辨率模糊遥感图像按水平方向和垂直方向各下采样3倍,得到低分辨率遥感图像;(1d) Downsampling the high-resolution fuzzy remote sensing image by 3 times in the horizontal and vertical directions respectively to obtain a low-resolution remote sensing image;

(1e)采用插值放大方法,将低分辨率遥感图像放大3倍,得到初始高分辨率图像;(1e) Enlarge the low-resolution remote sensing image by 3 times by using the interpolation amplification method to obtain the initial high-resolution image;

(2)计算自适应滤波器系数矩阵:(2) Calculate the adaptive filter coefficient matrix:

(2a)采用自适应滤波器生成方法,生成初始高分辨率遥感图像的自适应滤波器,得到自适应滤波器系数矩阵;(2a) Using an adaptive filter generation method to generate an adaptive filter for the initial high-resolution remote sensing image, and obtain an adaptive filter coefficient matrix;

(2b)利用下式,计算初始高频遥感图像:(2b) Use the following formula to calculate the initial high-frequency remote sensing image:

u0=k0-Fk0 u 0 =k 0 −Fk 0

其中,u0表示初始高频遥感图像,k0表示初始高分辨率遥感图像,F表示自适应滤波器系数矩阵;Among them, u 0 represents the initial high-frequency remote sensing image, k 0 represents the initial high-resolution remote sensing image, and F represents the adaptive filter coefficient matrix;

(3)获得最优高频遥感图像:(3) Obtain the optimal high-frequency remote sensing image:

(3a)将初始高分辨率遥感图像中相邻的两列像素两两作差,得到遥感图像的水平梯度算子;将初始高分辨率遥感图像中相邻的两行像素两两作差,得到图像的垂直梯度算子;(3a) Make a difference between two adjacent columns of pixels in the initial high-resolution remote sensing image to obtain the horizontal gradient operator of the remote sensing image; make a difference between two adjacent rows of pixels in the initial high-resolution remote sensing image, Get the vertical gradient operator of the image;

(3b)利用下式,计算高频遥感图像的全变分:(3b) Use the following formula to calculate the total variation of the high-frequency remote sensing image:

其中,Q表示高频遥感图像的全变分,D1和D2分别表示遥感图像的水平和垂直梯度算子,u表示高频遥感图像;Among them, Q represents the total variation of high-frequency remote sensing images, D 1 and D 2 represent the horizontal and vertical gradient operators of remote sensing images, respectively, and u represents high-frequency remote sensing images;

(3c)对高频遥感图像进行小波域变换,得到高频遥感图像的小波变换矩阵;(3c) performing wavelet domain transformation on the high-frequency remote sensing image to obtain a wavelet transform matrix of the high-frequency remote sensing image;

(3d)利用下式,计算高频遥感图像在小波域的投影矩阵:(3d) Calculate the projection matrix of the high-frequency remote sensing image in the wavelet domain by using the following formula:

B=ΨTuB= ΨTu

其中,B表示高频遥感图像在小波域的投影矩阵,ΨT表示高频遥感图像小波变换矩阵的转置矩阵,u表示高频遥感图像;Among them, B represents the projection matrix of the high-frequency remote sensing image in the wavelet domain, Ψ T represents the transpose matrix of the wavelet transformation matrix of the high-frequency remote sensing image, and u represents the high-frequency remote sensing image;

(3e)采用优化方程求解方法求解下式,获得最优高频遥感图像:(3e) Use the optimization equation solution method to solve the following equation to obtain the optimal high-frequency remote sensing image:

其中,U表示最优高频遥感图像;α1表示高频遥感图像全变分的正则化参数,α1=4.0e-5;α2表示高频遥感图像在小波域下投影的正则化参数,α2=3.0e-5;D1和D2分别表示遥感图像的水平和垂直梯度算子;u表示高频遥感图像;ΨT表示高频遥感图像的小波变换矩阵的转置矩阵;η表示高频遥感图像约束的惩罚因子,η=2;u0表示初始高频遥感图像;表示优化方程,||·||12表示取范式操作,||·||2表示取范式平方操作;Among them, U represents the optimal high-frequency remote sensing image; α 1 represents the regularization parameter of the total variation of the high-frequency remote sensing image, α 1 =4.0e -5 ; α 2 represents the regularization parameter of the projection of the high-frequency remote sensing image in the wavelet domain , α 2 =3.0e -5 ; D 1 and D 2 represent the horizontal and vertical gradient operators of the remote sensing image respectively; u represents the high-frequency remote sensing image; Ψ T represents the transpose matrix of the wavelet transform matrix of the high-frequency remote sensing image; η Represents the penalty factor of high-frequency remote sensing image constraints, η=2; u 0 represents the initial high-frequency remote sensing image; Indicates the optimization equation, ||·|| 12 represents the normal form operation, ||·|| 2 represents the normal form square operation;

(4)获得最优高分辨率遥感图像:(4) Obtain the optimal high-resolution remote sensing image:

(4a)对应低分辨率遥感图像像素和高分辨率遥感图像像素之间的位置关系,得到下采样矩阵;(4a) Corresponding to the positional relationship between the pixels of the low-resolution remote sensing image and the pixels of the high-resolution remote sensing image, a downsampling matrix is obtained;

(4b)采用优化方程等价转换求解方法求解下式,获得最优高分辨率遥感图像:(4b) Use the optimization equation equivalent conversion solution method to solve the following equation to obtain the optimal high-resolution remote sensing image:

其中,K表示最优高分辨率遥感图像;g表示低分辨率遥感图像;W表示下采样矩阵;H表示高斯模糊矩阵;k表示高分辨率遥感图像;β表示约束高分辨率遥感图像高频部分的惩罚因子,β=2;F表示自适应滤波器系数矩阵;U表示最优高频遥感图像;表示优化方程,||·||2表示取范式操作,||·||2表示取范式平方操作;Among them, K represents the optimal high-resolution remote sensing image; g represents the low-resolution remote sensing image; W represents the downsampling matrix; H represents the Gaussian blur matrix; k represents the high-resolution remote sensing image; Partial penalty factor, β=2; F represents the adaptive filter coefficient matrix; U represents the optimal high-frequency remote sensing image; Represents the optimization equation, ||·|| 2 represents the normal form operation, ||·|| 2 represents the normal form square operation;

(5)利用下式,计算最优高分辨率遥感图像和初始高分辨率遥感图像的相对误差:(5) Use the following formula to calculate the relative error between the optimal high-resolution remote sensing image and the initial high-resolution remote sensing image:

其中,γ表示最优高分辨率遥感图像和初始高分辨率遥感图像的相对误差,K表示最优高分辨率遥感图像;k0表示初始高分辨率遥感图像;||·||2表示取范式操作;Among them, γ represents the relative error between the optimal high-resolution remote sensing image and the initial high-resolution remote sensing image, K represents the optimal high-resolution remote sensing image; k 0 represents the initial high-resolution remote sensing image; ||·|| 2 represents the Paradigm operation;

(6)判断相对误差是否满足终止条件,如果是,执行步骤(8);否则,执行步骤(7);(6) Judging whether the relative error satisfies the termination condition, if yes, execute step (8); otherwise, execute step (7);

(7)数据更新:(7) Data update:

将最优高分辨率遥感图像的像素值赋值给初始高分辨率遥感图像的像素,执行步骤(2);Assign the pixel value of the optimal high-resolution remote sensing image to the pixel of the initial high-resolution remote sensing image, and perform step (2);

(8)输出最优高分辨率遥感图像。(8) Output the optimal high-resolution remote sensing image.

与现有技术相比,本发明具有以下优点:Compared with the prior art, the present invention has the following advantages:

第一,由于本发明仅需要输入一幅图像即可实现图像的高分辨率重建,重建图像时不再需要其它条件,克服了现有技术需要对输入图像附加分段光滑等苛刻条件,使得本发明提高了通用性。First, because the present invention only needs to input one image to realize the high-resolution reconstruction of the image, no other conditions are needed when reconstructing the image, and it overcomes the harsh conditions of the prior art that need to add segmental smoothness to the input image, making the present invention Invention increases versatility.

第二,由于本发明采用对高分辨率图像的高频部分进行优化运算,重建图像具有尖锐的边缘和丰富的纹理细节,克服了现有技术重建图像边缘模糊的缺点,使得本发明提高了图像的重建质量。Second, because the present invention optimizes the high-frequency part of the high-resolution image, the reconstructed image has sharp edges and rich texture details, which overcomes the shortcomings of the blurred edges of the reconstructed image in the prior art, making the present invention improve image quality. reconstruction quality.

第三,由于本发明利用优化运算来重建高分辨率图像,克服了现有技术稀疏编码运算复杂度高的缺点,使得本发明的计算复杂度低,优化运算收敛速率快,提高了效率。Third, because the present invention reconstructs high-resolution images using optimization operations, it overcomes the disadvantage of high computational complexity of sparse coding in the prior art, so that the present invention has low computational complexity, fast convergence rate of optimization operations, and improved efficiency.

附图说明Description of drawings

图1为本发明的流程图;Fig. 1 is a flowchart of the present invention;

图2为本发明步骤1生成的低分辨率图像的示意图;Fig. 2 is the schematic diagram of the low resolution image that step 1 of the present invention generates;

图3为本发明仿真实验1的效果图;Fig. 3 is the rendering of simulation experiment 1 of the present invention;

图4为本发明仿真实验2的效果图。FIG. 4 is an effect diagram of simulation experiment 2 of the present invention.

具体实施方式detailed description

下面结合附图对本发明作进一步的描述。The present invention will be further described below in conjunction with the accompanying drawings.

参照图1,本发明具体实施方式如下:With reference to Fig. 1, the embodiment of the present invention is as follows:

步骤1.获得初始高分辨率遥感图像。Step 1. Obtain an initial high-resolution remote sensing image.

输入一幅高分辨率遥感图像。本发明的实施例输入的遥感图像是从网络上任意获取。由MATLAB软件生成均值为0,方差为1.6,尺寸为7×7的高斯模糊矩阵。用生成的高斯模糊矩阵卷积输入的高分辨率遥感图像,得到高分辨率模糊遥感图像。紧接着将高分辨率模糊遥感图像按水平方向和垂直方向各下采样3倍,得到低分辨率遥感图像。Input a high-resolution remote sensing image. The remote sensing images input by the embodiments of the present invention are randomly obtained from the Internet. A Gaussian blur matrix with a mean value of 0, a variance of 1.6, and a size of 7×7 was generated by MATLAB software. The input high-resolution remote sensing image is convolved with the generated Gaussian blur matrix to obtain a high-resolution blurred remote sensing image. Then, the high-resolution fuzzy remote sensing image is down-sampled by 3 times in the horizontal direction and vertical direction respectively, and the low-resolution remote sensing image is obtained.

采用插值放大方法,将低分辨率遥感图像放大3倍,得到初始高分辨率遥感图像。The low-resolution remote sensing image is magnified three times by interpolation amplification method to obtain the initial high-resolution remote sensing image.

插值放大方法是指采用最近邻插值、双线性插值中的一种进行图像放大的方法。在本发明的实施例中,插值放大方法采用的是双线性插值方法。The interpolation magnification method refers to a method of image magnification using one of nearest neighbor interpolation and bilinear interpolation. In the embodiment of the present invention, the interpolation amplification method adopts a bilinear interpolation method.

步骤2.计算自适应滤波器系数矩阵。Step 2. Compute the adaptive filter coefficient matrix.

采用自适应滤波器生成方法,生成初始高分辨率遥感图像的自适应滤波器,得到自适应滤波器系数矩阵。The adaptive filter generation method is used to generate the adaptive filter of the initial high-resolution remote sensing image, and the adaptive filter coefficient matrix is obtained.

利用公式:u0=k0-Fk0,得到初始高频遥感图像,其中,u0表示初始高频遥感图像,k0表示初始高分辨率遥感图像,F表示自适应滤波器系数矩阵。The initial high-frequency remote sensing image is obtained by using the formula: u 0 =k 0 -Fk 0 , where u 0 represents the initial high-frequency remote sensing image, k 0 represents the initial high-resolution remote sensing image, and F represents the adaptive filter coefficient matrix.

自适应滤波器生成方法是指,采用非局部均值方法、基于图像引导方法中的一种生成方法。在本发明的实施例中采用非局部均值方法。The adaptive filter generation method refers to a generation method using a non-local mean method and an image-guided method. In an embodiment of the present invention a non-local mean method is employed.

步骤3.获得最优高频遥感图像。Step 3. Obtain the optimal high-frequency remote sensing image.

将初始高分辨率遥感图像中相邻的两列像素两两作差,得到遥感图像的水平梯度算子。将初始高分辨率遥感图像中相邻的两行像素两两作差,得到遥感图像的垂直梯度算子。The horizontal gradient operator of the remote sensing image is obtained by taking the difference between two adjacent columns of pixels in the initial high-resolution remote sensing image. The vertical gradient operator of the remote sensing image is obtained by taking the difference between two adjacent rows of pixels in the initial high-resolution remote sensing image.

利用公式:得到高频遥感图像的全变分,其中,Q表示高频遥感图像的全变分,D1和D2分别表示遥感图像的水平和垂直梯度算子,u表示高频遥感图像。对高频遥感图像进行小波域变换,得到高频遥感图像的小波变换矩阵。Use the formula: The total variation of the high-frequency remote sensing image is obtained, where Q represents the total variation of the high-frequency remote sensing image, D 1 and D 2 represent the horizontal and vertical gradient operators of the remote sensing image, and u represents the high-frequency remote sensing image. The wavelet domain transform is carried out on the high-frequency remote sensing image, and the wavelet transform matrix of the high-frequency remote sensing image is obtained.

利用公式:B=ΨTu,得到高频遥感图像在小波域的投影矩阵,其中,B表示高频遥感图像在小波域的投影矩阵,ΨT表示高频遥感图像小波变换矩阵的转置矩阵,u表示高频遥感图像。Using the formula: B = Ψ T u, the projection matrix of the high-frequency remote sensing image in the wavelet domain is obtained, where B represents the projection matrix of the high-frequency remote sensing image in the wavelet domain, and Ψ T represents the transposition matrix of the wavelet transform matrix of the high-frequency remote sensing image , u represents the high-frequency remote sensing image.

采用优化方程求解方法求解下式,获得最优高频遥感图像:The optimal high-frequency remote sensing image is obtained by solving the following formula with the optimization equation solution method:

其中,U表示最优高频遥感图像;α1表示高频遥感图像全变分的正则化参数,α1=4.0e-5;α2表示高频遥感图像在小波域下投影的正则化参数,α2=3.0e-5;D1和D2分别表示遥感图像的水平和垂直梯度算子;u表示高频遥感图像;ΨT表示高频遥感图像的小波变换矩阵的转置矩阵;η表示高频遥感图像约束的惩罚因子,η=2;u0表示初始高频遥感图像;表示优化方程,||·||1,2表示取范式操作,||·||2表示取范式平方操作。优化方程求解方法是指,采用联合交替迭代法、迭代收缩法、两步迭代收缩法、加权最小二乘法中的任意一种求解方法。Among them, U represents the optimal high-frequency remote sensing image; α 1 represents the regularization parameter of the total variation of the high-frequency remote sensing image, α 1 =4.0e -5 ; α 2 represents the regularization parameter of the projection of the high-frequency remote sensing image in the wavelet domain , α 2 =3.0e -5 ; D 1 and D 2 represent the horizontal and vertical gradient operators of the remote sensing image respectively; u represents the high-frequency remote sensing image; Ψ T represents the transpose matrix of the wavelet transform matrix of the high-frequency remote sensing image; η Represents the penalty factor of high-frequency remote sensing image constraints, η=2; u 0 represents the initial high-frequency remote sensing image; Represents the optimization equation, ||·|| 1,2 represents the normal form operation, ||·|| 2 represents the normal form square operation. The method of solving the optimization equation refers to the use of any one of the joint alternate iteration method, iterative contraction method, two-step iterative contraction method, and weighted least squares method.

本发明的实施例采用联合交替迭代法,联合交替迭代具体步骤为以下五步:Embodiments of the present invention adopt the joint alternate iteration method, and the specific steps of the joint alternate iteration are the following five steps:

第一步,设置初始参数,开始迭代运算。The first step is to set the initial parameters and start the iterative operation.

设置最大迭代次数为20次,设置阈值为10-4Set the maximum number of iterations to 20, and set the threshold to 10 -4 .

第二步,利用下式,计算高频图像梯度域的逼近矩阵:In the second step, the approximation matrix of the high-frequency image gradient domain is calculated using the following formula:

其中,w1和w2分别表示高频遥感图像的水平梯度和垂直梯度的逼近矩阵;σ1表示逼近高频遥感图像的水平梯度和垂直梯度时的惩罚因子;α1表示高频遥感图像全变分的正则化参数;λ11和λ12表示辅助变量,其初始值为0;u表示高频遥感图像;D1和D2分别表示遥感图像的水平和垂直梯度算子;|·|表示取绝对值操作;max(·)表示取最大值操作;sgn(·)表示取符号算子操作。Among them, w 1 and w 2 represent the approximation matrix of the horizontal gradient and vertical gradient of the high-frequency remote sensing image respectively; σ 1 represents the penalty factor when approximating the horizontal gradient and vertical gradient of the high-frequency remote sensing image; α 1 represents the full Variational regularization parameters; λ 11 and λ 12 represent auxiliary variables, whose initial value is 0; u represents high-frequency remote sensing images; D 1 and D 2 represent the horizontal and vertical gradient operators of remote sensing images, respectively; |·| Take the absolute value operation; max(·) means take the maximum value operation; sgn(·) means take the sign operator operation.

第三步,利用下式,计算高频遥感图像小波变换系数的逼近矩阵:The third step is to calculate the approximation matrix of the wavelet transform coefficients of the high-frequency remote sensing image using the following formula:

其中,z表示高频遥感图像小波变换系数的逼近矩阵;ΨT表示高频遥感图像的小波变换矩阵的转置矩阵;u表示高频遥感图像;σ2表示逼近高频遥感图像小波变换系数时的惩罚因子;α2表示高频遥感图像在小波域下投影的正则化参数;λ2表示辅助变量,其初始值为0;|·|表示取绝对值操作;max(·)表示取最大值操作;sgn(·)表示取符号算子操作。Among them, z represents the approximation matrix of the wavelet transform coefficient of the high - frequency remote sensing image; Ψ T represents the transpose matrix of the wavelet transform matrix of the high-frequency remote sensing image; u represents the high-frequency remote sensing image; α 2 represents the regularization parameter of the projection of high-frequency remote sensing images in the wavelet domain; λ 2 represents the auxiliary variable, whose initial value is 0; |·| represents the absolute value operation; max(·) represents the maximum value operation; sgn(·) represents the symbolic operator operation.

求解最优高频遥感图像的优化方程等价为求解下面的一元一次方程:The optimization equation for solving the optimal high-frequency remote sensing image is equivalent to solving the following linear equation in one variable:

上述的一元一次方程可以利用二维快速离散傅里叶变换和逆变换进行高效求解,其中,表示合并D1矩阵和D2矩阵,D1和D2分别表示遥感图像的水平和垂直梯度算子;表示合并w1矩阵和w2矩阵,w1和w2分别表示高频遥感图像的水平梯度和垂直梯度的逼近矩阵;σ1表示逼近高频遥感图像的水平梯度和垂直梯度时的惩罚因子,σ2表示逼近高频遥感图像小波变换系数时的惩罚因子;u表示高频遥感图像;Ψ表示高频遥感图像的小波变换矩阵;z表示高频遥感图像小波变换系数的逼近矩阵;λ2表示辅助变量;η表示高频遥感图像约束的惩罚因子;u0表示初始高频遥感图像。The above one-dimensional linear equation can be efficiently solved by using two-dimensional fast discrete Fourier transform and inverse transform, where, Indicates the combination of D 1 matrix and D 2 matrix, D 1 and D 2 respectively represent the horizontal and vertical gradient operators of the remote sensing image; Represents the combination of w 1 matrix and w 2 matrix, w 1 and w 2 represent the approximation matrix of the horizontal gradient and vertical gradient of high-frequency remote sensing images respectively; σ 1 represents the penalty factor when approximating the horizontal gradient and vertical gradient of high-frequency remote sensing images, σ 2 represents the penalty factor when approaching the wavelet transform coefficients of high-frequency remote sensing images; u represents high-frequency remote sensing images; Ψ represents the wavelet transform matrix of high-frequency remote sensing images; z represents the approximation matrix of wavelet transform coefficients of high-frequency remote sensing images ; Auxiliary variable; η represents the penalty factor of high-frequency remote sensing image constraints; u 0 represents the initial high-frequency remote sensing image.

第四步,更新参数:The fourth step is to update the parameters:

利用下列各式,对参数进行更新:The parameters are updated using the following formulas:

其中,表示第k次迭代的参数值,表示第k+1次迭代的参数值;分别表示第k次和第k+1次迭代的参数值;表示一个固定参数,在实施例中取ρ=1.618;D1和D2分别表示遥感图像的水平和垂直梯度算子;w1和w2分别表示高频遥感图像的水平梯度和垂直梯度的逼近矩阵;u表示高频遥感图像;ΨT表示高频遥感图像的小波变换矩阵的转置矩阵;z表示高频遥感图像小波变换系数的逼近矩阵;表示一个固定参数,在实施例中取μ=1.022。in, with Indicates the parameter value of the kth iteration, with Indicates the parameter value of the k+1th iteration; with Represent the parameter values of the kth and k+1th iterations, respectively; Represents a fixed parameter, ρ=1.618 in the embodiment; D 1 and D 2 represent the horizontal and vertical gradient operators of the remote sensing image respectively; w 1 and w 2 represent the approximation of the horizontal gradient and the vertical gradient of the high-frequency remote sensing image respectively matrix; u represents the high-frequency remote sensing image; Ψ T represents the transpose matrix of the wavelet transform matrix of the high-frequency remote sensing image; z represents the approximation matrix of the wavelet transform coefficient of the high-frequency remote sensing image; represents a fixed parameter, and μ=1.022 is taken in the embodiment.

第五步,利用以下联合交替迭代终止条件,判断是否终止迭代:The fifth step is to use the following joint alternate iteration termination conditions to determine whether to terminate the iteration:

联合交替迭代终止条件1.达到初始设置的最大迭代次数,本发明的实施例中最大迭代次数为20次;Joint alternate iteration termination condition 1. reaches the maximum number of iterations initially set, and the maximum number of iterations is 20 times in the embodiment of the present invention;

联合交替迭代终止条件2.利用下式,判断相邻两次迭代时高频信息的相对变化率是否小于等于给定的阈值:Joint alternate iteration termination condition 2. Use the following formula to determine whether the relative change rate of high-frequency information is less than or equal to a given threshold during two adjacent iterations:

其中,uk表示第k次迭代的高频遥感图像,uk+1表示第k+1次迭代的高频遥感图像,ζ表示阈值,实施例中取ζ=10-4,||·||2表示取范式操作。Among them, u k represents the high-frequency remote sensing image of the k-th iteration, u k+1 represents the high-frequency remote sensing image of the k+1-th iteration, ζ represents the threshold, and in the embodiment, ζ=10 -4 , ||·| | 2 means to take the normal form operation.

只要满足联合交替迭代终止条件1和联合交替迭代终止条件2中的任意一个条件,则终止迭代,转至步骤4,否则,转至第二步,继续迭代。As long as any one of joint alternating iteration termination condition 1 and joint alternating iteration termination condition 2 is satisfied, the iteration is terminated and go to step 4, otherwise, go to the second step and continue iteration.

步骤4.获得最优高分辨率遥感图像。Step 4. Obtain the optimal high-resolution remote sensing image.

对应低分辨率遥感图像像素和高分辨率遥感图像像素之间的位置关系,得到下采样矩阵。Corresponding to the positional relationship between the pixels of the low-resolution remote sensing image and the pixels of the high-resolution remote sensing image, the downsampling matrix is obtained.

采用优化方程等价转换求解方法求解下式,获得最优高分辨率遥感图像:The optimal high-resolution remote sensing image is obtained by solving the following equation by using the optimization equation equivalent conversion solution method:

其中,K表示最优高分辨率遥感图像;g表示低分辨率遥感图像;W表示下采样矩阵;H表示高斯模糊矩阵;k表示高分辨率遥感图像;β表示高分辨率遥感图像约束的惩罚因子,β=2;F表示自适应滤波器系数矩阵;U表示最优高频遥感图像;表示优化方程,||·||2表示取范式操作,||·||2表示取范式平方操作。优化方程等价转换求解方法是指,采用等价转换方法,将优化方程转换成一次线性方程的方法。Among them, K represents the optimal high-resolution remote sensing image; g represents the low-resolution remote sensing image; W represents the downsampling matrix; H represents the Gaussian blur matrix; k represents the high-resolution remote sensing image; β represents the penalty of the high-resolution remote sensing image constraint Factor, β=2; F represents the adaptive filter coefficient matrix; U represents the optimal high-frequency remote sensing image; Indicates the optimization equation, ||·|| 2 represents the normal form operation, and ||·|| 2 represents the normal form square operation. The optimization equation equivalent conversion solution method refers to the method of converting the optimization equation into a linear equation by using the equivalent conversion method.

步骤5.利用下式,计算最优高分辨率遥感图像和初始高分辨率遥感图像的相对误差。Step 5. Using the following formula, calculate the relative error between the optimal high-resolution remote sensing image and the initial high-resolution remote sensing image.

其中,γ表示最优高分辨率遥感图像和初始高分辨率遥感图像的相对误差,K表示最优高分辨率遥感图像;k0表示初始高分辨率遥感图像;||·||2表示取范式操作。Among them, γ represents the relative error between the optimal high-resolution remote sensing image and the initial high-resolution remote sensing image, K represents the optimal high-resolution remote sensing image; k 0 represents the initial high-resolution remote sensing image; ||·|| 2 represents the Paradigm operation.

步骤6.判断相对误差是否满足终止条件,如果是,执行步骤8;否则,执行步骤7。Step 6. Judging whether the relative error satisfies the termination condition, if yes, execute step 8; otherwise, execute step 7.

本发明设置的终止条件为:γ≤ε,其中,ε为容忍极限,其值取值范围为ε∈(10-6,10-2)的正数。本发明的实施例中取ε=10-4The termination condition set in the present invention is: γ≤ε, where ε is a tolerance limit, and its value range is a positive number of ε∈(10 −6 , 10 −2 ). In the embodiment of the present invention, ε=10 -4 is taken.

步骤7.数据更新。Step 7. Data update.

将最优高分辨率遥感图像的像素值赋值给初始高分辨率遥感图像的像素,执行步骤2。Assign the pixel values of the optimal high-resolution remote sensing image to the pixels of the initial high-resolution remote sensing image, and perform step 2.

步骤8.输出最优高分辨率遥感图像。Step 8. Output the optimal high-resolution remote sensing image.

下面结合实施例对本发明的图像超分辨率效果做进一步的描述:The image super-resolution effect of the present invention will be further described below in conjunction with the embodiments:

1.仿真实验条件:1. Simulation experiment conditions:

本发明的仿真实验运行系统采用Intel(R)Core(TM)i7-2600 CPU 650@3.40GHz,64位Windows操作系统,仿真软件采用MATLAB(R2013b)。The simulation experiment operating system of the present invention adopts Intel(R) Core(TM) i7-2600 CPU 650@3.40GHz, 64-bit Windows operating system, and the simulation software adopts MATLAB(R2013b).

2.仿真实验内容:2. Simulation experiment content:

在本发明的实施例中,统一设定参数为固定值,令α1=4.0e-5,α2=3.0e-5,η=2,β=2,ε=10-5In the embodiment of the present invention, the uniformly set parameters are fixed values, such that α 1 =4.0e -5 , α 2 =3.0e -5 , η=2, β=2, ε=10 -5 .

图2是两幅低分辨率遥感图像的示意图。从网络上任意下载两幅灰度遥感图像作为仿真实验的高分辨率遥感图像。用高斯模糊矩阵分别卷积两幅高分辨率遥感图像,得到两幅高分辨率模糊遥感图像。紧接着将高分辨率模糊遥感图像按水平方向和垂直方向各下采样3倍,得到两幅低分辨率遥感图像。图2(a)用于仿真实验1,图2(b)用于仿真实验2。Figure 2 is a schematic diagram of two low-resolution remote sensing images. Two grayscale remote sensing images are downloaded from the Internet as high-resolution remote sensing images for the simulation experiment. Two high-resolution remote sensing images are convoluted with Gaussian blur matrix to obtain two high-resolution blurred remote sensing images. Next, the high-resolution fuzzy remote sensing image is down-sampled by 3 times in the horizontal direction and vertical direction respectively, and two low-resolution remote sensing images are obtained. Figure 2(a) is used for simulation experiment 1, and Figure 2(b) is used for simulation experiment 2.

图3是仿真实验1的效果图。图3(a)是利用现有技术双线性插值得到的最优高分辨率图像。图3(b)是利用Zuo,W、Lin,Z二人在文献“A Generalized AcceleratedAccelerated Proximal Gradient Approach for Total-Variation-Based ImageRestoration”(IEEE Trans.on Image Processing vol.20 no.10 pp.2748-2759Oct.2011.)中提出的图像超分辨方法得到的最优高分辨率图像。图3(c)是利用Yang,J、Wright,J、Huang,T、Ma,Y.四人在文献“Image Super-Resolution Via SparseRepresentation”(IEEE Trans.on Image Processing vol.19 no.11 pp.2861-2873Nov.2010.)中提出的超分辨方法得到的最优高分辨率图像。图3(d)是利用本发明方法得到的最优高分辨率图像。Fig. 3 is the effect diagram of simulation experiment 1. Figure 3(a) is the optimal high-resolution image obtained by bilinear interpolation in the prior art. Figure 3(b) is based on Zuo, W, Lin, and Z in the literature "A Generalized Accelerated Accelerated Proximal Gradient Approach for Total-Variation-Based Image Restoration" (IEEE Trans.on Image Processing vol.20 no.10 pp.2748- 2759Oct.2011.) The optimal high-resolution image obtained by the image super-resolution method proposed in 2759Oct.2011.). Figure 3(c) is based on Yang, J, Wright, J, Huang, T, Ma, Y. Four people in the document "Image Super-Resolution Via Sparse Representation" (IEEE Trans. on Image Processing vol.19 no.11 pp. 2861-2873Nov.2010.) The optimal high-resolution image obtained by the super-resolution method proposed in 2861-2873Nov.2010.). Fig. 3(d) is the optimal high-resolution image obtained by the method of the present invention.

图4是仿真实验2的效果图。图4(a)是利用现有技术双线性插值得到的最优高分辨率图像。图4(b)是利用Zuo,W、Lin,Z二人在文献“A Generalized AcceleratedAccelerated Proximal Gradient Approach for Total-Variation-Based ImageRestoration”(IEEE Trans.on Image Processing vol.20 no.10 pp.2748-2759Oct.2011.)中提出的图像超分辨方法得到的最优高分辨率图像。图4(c)是利用Yang,J、Wright,J、Huang,T、Ma,Y.四人在文献“Image Super-Resolution Via SparseRepresentation”(IEEE Trans.on Image Processing vol.19 no.11 pp.2861-2873Nov.2010.)中提出的超分辨方法得到的最优高分辨率图像。图4(d)是利用本发明方法得到的最优高分辨率图像。FIG. 4 is an effect diagram of simulation experiment 2. Fig. 4(a) is the optimal high-resolution image obtained by bilinear interpolation in the prior art. Figure 4(b) is based on Zuo, W, Lin, and Z in the literature "A Generalized Accelerated Accelerated Proximal Gradient Approach for Total-Variation-Based Image Restoration" (IEEE Trans.on Image Processing vol.20 no.10 pp.2748- 2759Oct.2011.) The optimal high-resolution image obtained by the image super-resolution method proposed in 2759Oct.2011.). Figure 4(c) is based on Yang, J, Wright, J, Huang, T, Ma, Y. Four people in the document "Image Super-Resolution Via Sparse Representation" (IEEE Trans. on Image Processing vol.19 no.11 pp. 2861-2873Nov.2010.) The optimal high-resolution image obtained by the super-resolution method proposed in 2861-2873Nov.2010.). Fig. 4(d) is the optimal high-resolution image obtained by the method of the present invention.

3.仿真结果分析:3. Simulation result analysis:

本发明的实施例中,采用峰值信噪比指标来评价实验结果:In the embodiments of the present invention, the peak signal-to-noise ratio index is used to evaluate the experimental results:

其中,PSNR表示峰值信噪比,K表示为最优高分辨率图像,k0表示为利用观测的低分辨率图像进行超分辨放大得到的高分辨率图像,log10(·)表示取对数操作,∑(·)表示求和操作,||·||2表示取范式操作。Among them, PSNR represents the peak signal-to-noise ratio, K represents the optimal high-resolution image, k 0 represents the high-resolution image obtained by super-resolution amplification using the observed low-resolution image, and log 10 ( ) represents the logarithm operation, ∑(·) represents the sum operation, ||·|| 2 represents the normal form operation.

图3中各幅图像的峰值信噪比依次为(单位dB):25.08、29.49、25.34、32.42。The peak signal-to-noise ratios of each image in Fig. 3 are (in dB): 25.08, 29.49, 25.34, 32.42.

图4中各幅图像的峰值信噪比依次为(单位dB):21.86、24.65、22.13、26.36。The peak signal-to-noise ratios of the images in Fig. 4 are (in dB): 21.86, 24.65, 22.13, and 26.36.

峰值信噪比的值越大则超分辨方法的性能越好。图3(d)的峰值信噪比大于图3(a)、图3(b)、图3(c),图4(d)的峰值信噪比大于图4(a)、图4(b)、图4(c),由此可见,本发明的超分辨方法好于另外的三种现有技术。The larger the peak signal-to-noise ratio, the better the performance of the super-resolution method. The peak signal-to-noise ratio of Figure 3(d) is greater than that of Figure 3(a), Figure 3(b), and Figure 3(c), and the peak signal-to-noise ratio of Figure 4(d) is greater than that of Figure 4(a), Figure 4(b ), Fig. 4(c), it can be seen that the super-resolution method of the present invention is better than the other three prior art methods.

从图3和图4可以进一步看出,图3(a)和图4(a)的视觉效果最差。图3(b)和图4(b)的图像比较清晰,但是物体的边缘出现块状效应比较明显。图3(c)和图4(c)中图像的块状效应较图3(b)和图4(b)有所抑制,但图像整体有些模糊,边缘不够清晰。图3(d)和图4(d)中的图像基本没有块状效应,图像的纹理清晰,边缘效果很好,图像的高频信息恢复的较好。It can be further seen from Figure 3 and Figure 4 that the visual effects of Figure 3(a) and Figure 4(a) are the worst. The images in Figure 3(b) and Figure 4(b) are relatively clear, but the block effect at the edge of the object is more obvious. The blocky effect of the image in Figure 3(c) and Figure 4(c) is suppressed compared with that in Figure 3(b) and Figure 4(b), but the overall image is somewhat blurred and the edges are not clear enough. The images in Figure 3(d) and Figure 4(d) basically have no block effect, the texture of the image is clear, the edge effect is good, and the high-frequency information of the image is restored well.

综上所述,本发明的图像超分辨方法不仅峰值信噪比结果较好,而且视觉效果也很好。To sum up, the image super-resolution method of the present invention not only has better peak signal-to-noise ratio results, but also has good visual effects.

Claims (6)

1.一种基于自适应滤波和正则约束的图像超分辨方法,包括以下步骤:1. An image super-resolution method based on adaptive filtering and regular constraints, comprising the following steps: (1)获得初始高分辨率遥感图像:(1) Obtain the initial high-resolution remote sensing image: (1a)输入一幅高分辨率遥感图像;(1a) Input a high-resolution remote sensing image; (1b)生成均值为0,方差为1.6,尺寸为7×7的高斯模糊矩阵;(1b) Generate a Gaussian blur matrix with a mean value of 0, a variance of 1.6, and a size of 7×7; (1c)用高斯模糊矩阵卷积高分辨率遥感图像,得到高分辨率模糊遥感图像;(1c) Convolving the high-resolution remote sensing image with a Gaussian blur matrix to obtain a high-resolution blurred remote sensing image; (1d)将高分辨率模糊遥感图像按水平方向和垂直方向各下采样3倍,得到低分辨率遥感图像;(1d) Downsampling the high-resolution fuzzy remote sensing image by 3 times in the horizontal and vertical directions respectively to obtain a low-resolution remote sensing image; (1e)采用插值放大方法,将低分辨率遥感图像放大3倍,得到初始高分辨率遥感图像;(1e) Enlarge the low-resolution remote sensing image by 3 times by using the interpolation amplification method to obtain the initial high-resolution remote sensing image; (2)计算自适应滤波器系数矩阵:(2) Calculate the adaptive filter coefficient matrix: (2a)采用自适应滤波器生成方法,生成初始高分辨率遥感图像的自适应滤波器,得到自适应滤波器系数矩阵;(2a) Using an adaptive filter generation method to generate an adaptive filter for the initial high-resolution remote sensing image, and obtain an adaptive filter coefficient matrix; (2b)利用下式,计算初始高频遥感图像:(2b) Use the following formula to calculate the initial high-frequency remote sensing image: u0=k0-Fk0 u 0 =k 0 −Fk 0 其中,u0表示初始高频遥感图像,k0表示初始高分辨率遥感图像,F表示自适应滤波器系数矩阵;Among them, u 0 represents the initial high-frequency remote sensing image, k 0 represents the initial high-resolution remote sensing image, and F represents the adaptive filter coefficient matrix; (3)获得最优高频遥感图像:(3) Obtain the optimal high-frequency remote sensing image: (3a)将初始高分辨率遥感图像中相邻的两列像素两两作差,得到遥感图像的水平梯度算子;将初始高分辨率遥感图像中相邻的两行像素两两作差,得到遥感图像的垂直梯度算子;(3a) Make a difference between two adjacent columns of pixels in the initial high-resolution remote sensing image to obtain the horizontal gradient operator of the remote sensing image; make a pairwise difference between two adjacent rows of pixels in the initial high-resolution remote sensing image, Obtain the vertical gradient operator of the remote sensing image; (3b)利用下式,计算高频遥感图像的全变分:(3b) Use the following formula to calculate the total variation of the high-frequency remote sensing image: QQ == ΣΣ ii == 11 22 || || DD. ii uu || || 11 其中,Q表示高频遥感图像的全变分,D1和D2分别表示遥感图像的水平和垂直梯度算子,u表示高频遥感图像;Among them, Q represents the total variation of high-frequency remote sensing images, D 1 and D 2 represent the horizontal and vertical gradient operators of remote sensing images, respectively, and u represents high-frequency remote sensing images; (3c)对高频遥感图像进行小波域变换,得到高频遥感图像的小波变换矩阵;(3c) performing wavelet domain transformation on the high-frequency remote sensing image to obtain a wavelet transform matrix of the high-frequency remote sensing image; (3d)利用下式,计算高频遥感图像在小波域的投影矩阵:(3d) Calculate the projection matrix of the high-frequency remote sensing image in the wavelet domain by using the following formula: B=ΨTuB= ΨTu 其中,B表示高频遥感图像在小波域的投影矩阵,ΨT表示高频遥感图像小波变换矩阵的转置矩阵,u表示高频遥感图像;Among them, B represents the projection matrix of the high-frequency remote sensing image in the wavelet domain, Ψ T represents the transpose matrix of the wavelet transformation matrix of the high-frequency remote sensing image, and u represents the high-frequency remote sensing image; (3e)采用优化方程求解方法求解下式,获得最优高频遥感图像:(3e) Use the optimization equation solution method to solve the following equation to obtain the optimal high-frequency remote sensing image: Uu == argarg minmin uu {{ αα 11 ΣΣ ii == 11 22 || || DD. ii uu || || 11 ++ αα 22 || || ΨΨ TT uu || || 11 ++ ηη 22 || || uu -- uu 00 || || 22 22 }} 其中,U表示最优高频遥感图像;α1表示高频遥感图像全变分的正则化参数,α1=4.0e-5;α2表示高频遥感图像在小波域下投影的正则化参数,α2=3.0e-5;D1和D2分别表示遥感图像的水平和垂直梯度算子;u表示高频遥感图像;ΨT表示高频遥感图像的小波变换矩阵的转置矩阵;η表示高频遥感图像约束的惩罚因子,η=2;u0表示初始高频遥感图像;表示优化方程,||·||1,2表示取范式操作,||·||2表示取范式平方操作;Among them, U represents the optimal high-frequency remote sensing image; α 1 represents the regularization parameter of the total variation of the high-frequency remote sensing image, α 1 =4.0e -5 ; α 2 represents the regularization parameter of the projection of the high-frequency remote sensing image in the wavelet domain , α 2 =3.0e -5 ; D 1 and D 2 represent the horizontal and vertical gradient operators of the remote sensing image respectively; u represents the high-frequency remote sensing image; Ψ T represents the transpose matrix of the wavelet transform matrix of the high-frequency remote sensing image; η Represents the penalty factor of high-frequency remote sensing image constraints, η=2; u 0 represents the initial high-frequency remote sensing image; Represents the optimization equation, ||·|| 1, 2 represents the normal form operation, ||·|| 2 represents the normal form square operation; (4)获得最优高分辨率遥感图像:(4) Obtain the optimal high-resolution remote sensing image: (4a)对应低分辨率遥感图像像素和高分辨率遥感图像像素之间的位置关系,得到下采样矩阵;(4a) Corresponding to the positional relationship between the pixels of the low-resolution remote sensing image and the pixels of the high-resolution remote sensing image, a downsampling matrix is obtained; (4b)采用优化方程等价转换求解方法求解下式,获得最优高分辨率遥感图像:(4b) Use the optimization equation equivalent conversion solution method to solve the following equation to obtain the optimal high-resolution remote sensing image: KK == argarg mm ii nno kk {{ || || gg -- WW Hh kk || || 22 22 ++ ββ 22 || || (( kk -- Ff kk )) -- Uu || || 22 22 }} 其中,K表示最优高分辨率遥感图像;g表示低分辨率遥感图像;W表示下采样矩阵;H表示高斯模糊矩阵;k表示高分辨率遥感图像;β表示约束高分辨率遥感图像高频部分的惩罚因子,β=2;F表示自适应滤波器系数矩阵;U表示最优高频遥感图像;表示优化方程,||·||2表示取范式操作,||·||2表示取范式平方操作;Among them, K represents the optimal high-resolution remote sensing image; g represents the low-resolution remote sensing image; W represents the downsampling matrix; H represents the Gaussian blur matrix; k represents the high-resolution remote sensing image; Partial penalty factor, β=2; F represents the adaptive filter coefficient matrix; U represents the optimal high-frequency remote sensing image; Represents the optimization equation, ||·|| 2 represents the normal form operation, ||·|| 2 represents the normal form square operation; (5)利用下式,计算最优高分辨率遥感图像和初始高分辨率遥感图像的相对误差:(5) Use the following formula to calculate the relative error between the optimal high-resolution remote sensing image and the initial high-resolution remote sensing image: γγ == || || KK -- kk 00 || || 22 || || KK || || 22 其中,γ表示最优高分辨率遥感图像和初始高分辨率遥感图像的相对误差,K表示最优高分辨率遥感图像;k0表示初始高分辨率遥感图像;||·||2表示取范式操作;Among them, γ represents the relative error between the optimal high-resolution remote sensing image and the initial high-resolution remote sensing image, K represents the optimal high-resolution remote sensing image; k 0 represents the initial high-resolution remote sensing image; ||·|| 2 represents the Paradigm operation; (6)判断相对误差是否满足终止条件,如果是,执行步骤(8);否则,执行步骤(7);(6) Judging whether the relative error satisfies the termination condition, if yes, execute step (8); otherwise, execute step (7); (7)数据更新:(7) Data update: 将最优高分辨率遥感图像的像素值赋值给初始高分辨率遥感图像的像素,执行步骤(2);Assign the pixel value of the optimal high-resolution remote sensing image to the pixel of the initial high-resolution remote sensing image, and perform step (2); (8)输出最优高分辨率遥感图像。(8) Output the optimal high-resolution remote sensing image. 2.根据权利要求1所述的基于自适应滤波和正则约束的图像超分辨方法,其特征在于,步骤(1e)中所述的插值放大方法是指,采用最近邻插值、双线性插值中的一种进行遥感图像放大的方法。2. The image super-resolution method based on adaptive filtering and regular constraints according to claim 1, characterized in that, the interpolation amplification method described in step (1e) refers to the use of nearest neighbor interpolation, bilinear interpolation A method for zooming in on remote sensing images. 3.根据权利要求1所述的基于自适应滤波和正则约束的图像超分辨方法,其特征在于,步骤(2a)中所述的自适应滤波器生成方法是指,采用非局部均值方法。3. The image super-resolution method based on adaptive filtering and regular constraints according to claim 1, characterized in that the adaptive filter generation method described in step (2a) refers to the use of a non-local mean method. 4.根据权利要求1所述的基于自适应滤波和正则约束的图像超分辨方法,其特征在于,步骤(3e)中所述的优化方程求解方法是指,采用联合交替迭代法、迭代收缩法、加权最小二乘法中的任意一种求解方法。4. the image superresolution method based on adaptive filtering and regular constraint according to claim 1, is characterized in that, the optimization equation solution method described in step (3e) refers to, adopts joint alternating iteration method, iterative contraction method , any one of the weighted least squares methods. 5.根据权利要求1所述的基于自适应滤波和正则约束的图像超分辨方法,其特征在于,步骤(4b)中所述的优化方程等价转换求解方法是指,采用等价转换方法,将优化方程转换成一次线性方程的方法。5. the image super-resolution method based on adaptive filtering and regular constraint according to claim 1, is characterized in that, the optimization equation described in the step (4b) is equivalent to conversion solution method refers to, adopts equivalent conversion method, A method for converting an optimization equation into a linear equation. 6.根据权利要求1所述的基于自适应滤波和正则约束的图像超分辨方法,其特征在于,步骤(6)中所述的终止条件是指γ≤ε,其中,γ表示最优高分辨遥感图像和初始高分辨率遥感图像的相对误差,ε表示容忍极限,其值取值范围为ε∈(10-6,10-2)的正数。6. The image super-resolution method based on adaptive filtering and regular constraints according to claim 1, wherein the termination condition described in step (6) refers to γ≤ε, where γ represents the optimal high-resolution The relative error between the remote sensing image and the initial high-resolution remote sensing image, ε represents the tolerance limit, and its value range is a positive number of ε∈(10 -6 ,10 -2 ).
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