clear all;close all;clc;img=imread('Lena_cai.jpg');imshow(img);mean1=mean(mean(img(:,:,1)));mean2=mean(mean(img(:,:,2)));mean3=mean(mean(img(:,:,3)));me=mean(mean(mean(img)));img(:,:,1)=me/mean1*img(:,:,1);img(:,:,2)=me/mean2*img(:,:,2);img(:,:,3)=me/mean3*img(:,:,3);figure,imshow(img);

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