RGB 与 (RGB转 YCbCr再转为 RGB)的图像   不可逆，能够从 矩阵的逆运算看出来。

附上 matlab 代码：

  clc,clear;

Source=imread('1.jpg');%读入原始RGB图像

figure(1);

subplot(1,2,1);

imshow(Source):title('original image');%显示图像

[r c d]=size(Source);%计算图像大小

%------计算红色分量并显示分解图------%

R(:,:,1)=Source(:,:,1);

R(:,:,2)=zeros(r,c);

R(:,:,3)=zeros(r,c);

R=uint8(R);

whos;

figure(2);

subplot(1,3,1);

imshow(R)

title('Red Component');

%-------计算绿色分量并显示分解图-------%

G(:,:,2)=Source(:,:,2);

G(:,:,1)=zeros(r,c);

G(:,:,3)=zeros(r,c);

G=uint8(G);

figure(2);

subplot(1,3,2);

imshow(G)

title('Green Component');

%--------计算蓝色分量并显示分解图-------%

B(:,:,3)=Source(:,:,3);

B(:,:,1)=zeros(r,c);

B(:,:,2)=zeros(r,c);

B=uint8(B);

figure(2);

subplot(1,3,3)

imshow(B)

title('Blue Component');

%------------合成-------------%

Comp(:,:,1)=R(:,:,1);

Comp(:,:,2)=G(:,:,2);

Comp(:,:,3)=B(:,:,3);

figure(5);

subplot(1,2,2);

imshow(Comp):title('composition image');

Y=0.213*R+0.715*G+0.072*B;

Cb=0.511*B-0.117*R-0.394*G+128;

Cr=0.511*R-0.464*G-0.047*B+128;

%red=Y+1.402*(Cr-128);

%green=Y-0.34414*(Cb-128)-0.71414*(Cr-128);

%blue=Y+1.772*(Cb-128);

red = 1.164*(Y-16)+1.793*(Cr-128);

green = 1.164*(Y-16)-0.534*(Cr-128)-0.213*(Cb-128);

blue =1.164*(Y-16)+2.115*(Cb-128);

Comp2(:,:,1)=red(:,:,1);

Comp2(:,:,2)=green(:,:,2);

Comp2(:,:,3)=blue(:,:,3);

Comp5(:,:,1)=Y(:,:,1);

Comp5(:,:,2)=Cb(:,:,2);

Comp5(:,:,3)=Cr(:,:,3);

figure(5);imshow(Comp5);title('显示11YCBcr');

figure(1);subplot(1,2,2);imshow(Comp2);title('RGB转换为YCrCb后又转换为RGB的图像');

RD=R(:,:,1)-red(:,:,1);

GD=G(:,:,2)-green(:,:,2);

BD=B(:,:,3)-blue(:,:,3);

figure(4);subplot(1,3,1);imshow(RD);title('红色分量差异');

subplot(1,3,2);imshow(GD);title('绿色分量差异');

subplot(1,3,3);imshow(BD);title('蓝色分量差异');