基于DCT变换的信息隐藏(数字水印)嵌入算法的设计(Matlab)

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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');
 
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