基于DCT变换的信息隐藏(数字水印)嵌入算法的设计(Matlab)

隐藏信息嵌入程序，老师写的！

%------------------------------------------------------------------%
% 基于DCT变换的信息隐藏(数字水印)嵌入算法的设计____2007.06.19 %% %% %
%-----------------------------------------------------------=------%
clear all;
close all;
clc
%-----------------读入"W"，并进行WPP处理---------------------
wm0=imread('watermark.bmp');
% wm0=imresize(wm0,[64 64]);
[Mm,Nm]=size(wm0) ; %计算水印图象的高度和宽度
n=Mm*Nm;
subplot(131)
imshow(wm0);
title('my watermark');
wm=double(wm0);
for i=1:Mm
for j=1:Nm
if wm(i,j)==0
wm(i,j)=-1;
end
end
end

%-----------------------读入"C"，并进行CPP处理--------------------------
% cover_image=imread('cameraman.tif');
cover_image=imread('lena.bmp');
[Mc,Nc]=size(cover_image); %计算载体图象的高度和宽度
subplot(132);
imshow(cover_image);
title('my coverimage');
cover_image=double(cover_image);%读入原始宿主图象，并转换为双精度数组

%------------------分块DCT变换,嵌入水印----------------------------

%设置水印嵌入强度
% k=369;
k=70;
%设置嵌入位置
x=3;
y=5;
%设定图象的分块大小为8*8
blocksize=8;
c=Mc/blocksize;
d=Nc/blocksize;
m=c*d;%计算图象划分的图象块

%判断载体图像尺寸是否适合水印大小
if n>m
error('^_^ Dear classmates~~~~~~The watermark is too large to be imbeded into the coverimage,hehe~~~');
end

%分块DCT变换，嵌入水印
for j=1:c
for i=1:d
dct_block=dct2(cover_image((1+(j-1)*8):j*8,(1+(i-1)*8):i*8));
dct_block(x,y)=k*wm(j,i);
watermarked_image((1+(j-1)*8):j*8,(1+(i-1)*8):i*8)=idct2(dct_block);
end
end
%------------------------------------------------------------------

%生成并输出嵌入水印后的图象
imwrite(uint8(watermarked_image),'watermarked_image.bmp','bmp');
%显示嵌入水印后的图象
subplot(133);
imshow(uint8(watermarked_image))
title('watermarkedImage')

隐藏信息提取程序，我写的！

clear all ;
close all ;
clc

%定义一个空空间来存储提取的水印
wm_image=zeros(32,32);
% subplot(122);
% imshow(wm_image);

%read the marked image and transfer it to double precise
%-------------------------------------------------------
watermarked_image=imread('watermarked_image.bmp');
[M_marked,N_marked]=size(watermarked_image);
subplot(121);
imshow(watermarked_image);
title('The marked image') ;
watermarked_image=double(watermarked_image);

blocksize=8;
k=1/70;
x=3;
y=5;

c=M_marked/blocksize;
d=N_marked/blocksize;

for j=1:c
for i=1:d
dct_markedblock=dct2(watermarked_image((1+(j-1)*8):j*8,(1+(i-1)*8):i*8));
if k*dct_markedblock(x,y)>0
wm_image(j,i)=1;
else
vm_image(j,i)=0;
end
end
end
subplot(122);
imshow(wm_image);
title('mark image');

imwrite((wm_image),'MYwm_image.bmp','bmp');