1 clear all;
 2 close all;
 3 clc;
 4 
 5 img=imread('lena_color.jpg');
 6 img=mat2gray(img);  %任意区间映射到[0,1];
 7 [m n dim]=size(img);
 8 imshow(img);
 9 %%图像的RGB
10 R=img(:,:,1);
11 G=img(:,:,2);
12 B=img(:,:,3);
13 
14 %%RGB2YUV
15 Y=zeros(m,n);   %亮度
16 U=zeros(m,n);   %彩度
17 V=zeros(m,n);   %浓度
18 matrix=[0.299 0.587 0.114;
19         -0.14713 -0.28886 0.436;
20         0.615 -0.51498 -0.10001];
21 for i=1:m
22    for j=1:n 
23         tmp=matrix*[R(i,j) G(i,j) B(i,j)]';
24         Y(i,j)=tmp(1);
25         U(i,j)=tmp(2);
26         V(i,j)=tmp(3);
27    end
28 end
29 
30 %%YUV2RGB
31 matrix=inv(matrix);
32 for i=1:m
33    for j=1:n 
34         tmp=matrix*[Y(i,j) U(i,j) V(i,j)]';
35         R(i,j)=tmp(1);
36         G(i,j)=tmp(2);
37         B(i,j)=tmp(3);
38    end
39 end
40 
41 %%如果正反变换都没错的话，那么图像是不变的
42 img(:,:,1)=R;
43 img(:,:,2)=G;
44 img(:,:,3)=B;
45 figure;
46 imshow(img)