%主程序 clear all; close all; clc; %第一部分，信息嵌入 %准备 img=imread('pic.jpg'); imhide=imread('gray.jpg'); figure;imshow(img); title('原图片（RGB图片）'); figure;imshow(imhide);title('待嵌入图片（灰度图片）'); [m,n,h]=size(img); [mhide,nhide]=size(imhide); imgR=img(:,:,1); imgG=img(:,:,2); imgB=img(:,:,3); imgRline=imgR(:); imgGline=imgG(:); imgBline=imgB(:); imhideline=imhide(:); yr=4; yg=5; yb=3; y=zeros(1,8); imhidelinebin=zeros(mhide*nhide*8,1); for ii=1:mhide*nhide [imhidelinebin(ii*8),imhidelinebin(ii*8-1),imhidelinebin(ii*8-2),imhidelinebin(ii*8-3),... imhidelinebin(ii*8-4),imhidelinebin(ii*8-5),imhidelinebin(ii*8-6),imhidelinebin(ii*8-7)]... =dec2bin_z(imhideline(ii)); end %开始嵌入 %R flag=0; embedSum=0; imgRlineNew=imgRline; for ii=1:m*n if(flag==1) break; end [y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)]=dec2bin_z(imgRline(ii)); fn=firstNzreo(y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)); embedNum=fn-yr; if embedNum>0 for jj=1:embedNum embedSum=embedSum+1; if embedSum>mhide*nhide*8 flag=1; break; end y(jj)=imhidelinebin(embedSum); end imgRlineNew(ii)=bin2dec_z(y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)); end end %开始嵌入 %G imgGlineNew=imgGline; for ii=1:m*n if(flag==1) break; end [y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)]=dec2bin_z(imgGline(ii)); fn=firstNzreo(y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)); embedNum=fn-yg; if embedNum>0 for jj=1:embedNum embedSum=embedSum+1; if embedSum>mhide*nhide*8 flag=1; break; end y(jj)=imhidelinebin(embedSum); end imgGlineNew(ii)=bin2dec_z(y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)); end end %B imgBlineNew=imgBline; for ii=1:m*n if(flag==1) break; end [y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)]=dec2bin_z(imgBline(ii)); fn=firstNzreo(y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)); embedNum=fn-yb; if embedNum>0 for jj=1:embedNum embedSum=embedSum+1; if embedSum>mhide*nhide*8 flag=1; break; end y(jj)=imhidelinebin(embedSum); end imgBlineNew(ii)=bin2dec_z(y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)); end end %嵌入完成，开始整合 imgNew=zeros(m,n,h); imgR2=reshape(imgRlineNew,[m,n]); imgG2=reshape(imgGlineNew,[m,n]); imgB2=reshape(imgBlineNew,[m,n]); imgNew(:,:,1)=imgR2; imgNew(:,:,2)=imgG2; imgNew(:,:,3)=imgB2; figure;imshow(uint8(imgNew));title('嵌入后的RGB图片'); imwrite(uint8(imgNew),'imgNew.jpg','quality',100);%即使保存了，即使保存的质量是100但是保存后的图片数据跟matlab里计算得的图片数据不一样了， %所以无法从保存后的imgNew.jpg里提取到任何水印 % r=imread('imgNew.jpg'); % r=double(r); % imgNew=double(imgNew); % dif=r-imgNew; % dif1=dif(:,:,1); %dif1不为0矩阵，所以matlab的imwrite存在失真 %第二部分，信息提取 %只有知道图片原来的形状，才能提取出完整的水印。 Imhidelinebin=zeros(8*mhide*nhide,1); %准备工作 ImgRline=imgR2(:); ImgGline=imgG2(:); ImgBline=imgB2(:); flag=0; extractSum=0; embedNum=0; y=zeros(8,1); %R for ii=1:m*n if flag==1 break; end [y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)]=dec2bin_z(ImgRline(ii)); fn=firstNzreo(y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)); embedNum=fn-yr; if embedNum>0 for jj=1:embedNum; extractSum=extractSum+1; if extractSum>8*mhide*nhide flag=1; break; end Imhidelinebin(extractSum)=y(jj); end end end %G for ii=1:m*n if flag==1 break; end [y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)]=dec2bin_z(ImgGline(ii)); fn=firstNzreo(y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)); embedNum=fn-yg; if embedNum>0 for jj=1:embedNum; extractSum=extractSum+1; if extractSum>8*mhide*Hide flag=1; break; end Imhidelinebin(extractSum)=y(jj); end end end %B for ii=1:m*n if flag==1 break; end [y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)]=dec2bin_z(ImgBline(ii)); fn=firstNzreo(y(8),y(7),y(6),y(5),y(4),y(3),y(2),y(1)); embedNum=fn-yb; if embedNum>0 for jj=1:embedNum; extractSum=extractSum+1; if extractSum>8*mhide*Hide flag=1; break; end Imhidelinebin(extractSum)=y(jj); end end end %在工作区看到embedSum跟extractSum相等，说明提取没有出错 %提取完毕，开始整合 Imhideline=zeros(mhide*nhide,1); for ii=1:mhide*nhide Imhideline(ii)=bin2dec_z(Imhidelinebin(ii*8),Imhidelinebin(ii*8-1),Imhidelinebin(ii*8-2),Imhidelinebin(ii*8-3),... Imhidelinebin(ii*8-4),Imhidelinebin(ii*8-5),Imhidelinebin(ii*8-6),Imhidelinebin(ii*8-7)); end Imhide=reshape(Imhideline,[mhide,nhide]); figure;imshow(uint8(Imhide));title('提取出的灰度图片'); dif=double(Imhide)-double(imhide);%dif为零矩阵，说明没有误差%function firstNzreo %第一个不是零的位置 function po=firstNzreo(y8,y7,y6,y5,y4,y3,y2,y1) if y8~=0 po=8; elseif y7~=0 po=7; elseif y6~=0 po=6; elseif y5~=0 po=5; elseif y4~=0 po=4; elseif y3~=0 po=3; elseif y2~=0 po=2; else po=1; end
%function bin2dec_z %二进制转十进制 function dec=bin2dec_z(y8,y7,y6,y5,y4,y3,y2,y1) dec=y1+2*y2+4*y3+8*y4+16*y5+32*y6+64*y7+128*y8; end
%function bin2dec_z %十进制转二进制 function [y8,y7,y6,y5,y4,y3,y2,y1]=dec2bin_z(dec) y1=mod(dec,2); dec=(dec-y1)/2; y2=mod(dec,2); dec=(dec-y2)/2; y3=mod(dec,2); dec=(dec-y3)/2; y4=mod(dec,2); dec=(dec-y4)/2; y5=mod(dec,2); dec=(dec-y5)/2; y6=mod(dec,2); dec=(dec-y6)/2; y7=mod(dec,2); dec=(dec-y7)/2; y8=mod(dec,2); end
参考 ：
谢建全, 阳春华. 大容量的信息隐藏算法[J]. 计算机工程, 2008, 34(8):167-169
文章来源: LSB隐写算法的扩展延伸――大容量的信息隐藏算法