DCT数字水印嵌入与提取过程

clear all; clc; start_time=cputime; %%%%%%%%%%%% 读取水印图像 %%%%%%%% I=imread('mark.bmp'); %%%%%%%%%%显示水印图像%%%%%%%%%%%%% figure(1); subplot(2,3,1); imshow(I),title('水印图像') dimI=size(I); rm=dimI(1);cm=dimI(2); %%%%%%%%%%%%%%% 以下生成水印信息 %%%%%%%% mark=I; alpha=15, k1=randn(1,8); k2=randn(1,8); a0=imread('lena.bmp'); psnr_cover=double(a0); subplot(2,3,2),imshow(a0,[]),title('载体图像'); [r,c]=size(a0); cda0=blkproc(a0,[8,8],'dct2'); %%%%%%%%%%%%%%%%%%嵌入 %%%%%%%%%% cda1=cda0; for i=1:rm for j=1:cm x=(i-1)*8;y=(j-1)*8; if mark(i,j)==1 k=k1; else k=k2; end cda1(x+1,y+8)=cda0(x+1,y+8)+alpha*k(1); cda1(x+2,y+7)=cda0(x+2,y+7)+alpha*k(2); cda1(x+3,y+6)=cda0(x+3,y+6)+alpha*k(3); cda1(x+4,y+5)=cda0(x+4,y+5)+alpha*k(4); cda1(x+5,y+4)=cda0(x+5,y+4)+alpha*k(5); cda1(x+6,y+3)=cda0(x+6,y+3)+alpha*k(6); cda1(x+7,y+2)=cda0(x+7,y+2)+alpha*k(7); cda1(x+8,y+1)=cda0(x+8,y+1)+alpha*k(8); end end %%%%% 嵌入水印后图像 %%%%%%%%%%%%%% a1=blkproc(cda1,[8,8],'idct2'); a_1=uint8(a1); imwrite(a_1,'withmark.bmp','bmp'); subplot(2,3,3),imshow(a1,[]),title('嵌入水印后的图像'); disp('嵌入水印处理时间'); embed_time=cputime-start_time, %%%%%% 攻击实验 测试鲁棒性 %%%%%%%%%%% disp('对嵌入水印的图像的攻击实验，请输入选择项：'); disp('1--添加白噪声'); disp('2--高斯低通滤波'); disp('3--JPEG 压缩'); disp('4--图像剪切'); disp('5--旋转10度'); disp('6--直接检测水印'); disp('其他--不攻击'); d=input('请输入选择（1-6）:'); start_time=cputime; figure(1); switch d case 6 subplot(2,3,4); imshow(a1,[]); title('未受攻击的含水印图像'); M1=a1; case 1 WImage2=a1; noise0=20*randn(size(WImage2)); WImage2=WImage2+noise0; subplot(2,3,4); imshow(WImage2,[]); title('加入白噪声后图像'); M1=WImage2; M_1=uint8(M1); imwrite(M_1,'whitenoise.bmp','bmp'); case 2 WImage3=a1; H=fspecial('gaussian',[4,4],0.2); WImage3=imfilter(WImage3,H); subplot(2,3,4); imshow(WImage3,[]); title('高斯低通滤波后图像'); M1=WImage3; M_1=uint8(M1); imwrite(M_1,'gaussian.bmp','bmp'); case 4 WImage4=a1; WImage4(1:64,1:512)=512; WImage4cl=mat2gray(WImage4); subplot(2,3,4); imshow(WImage4cl); title('部分剪切后图像'); figure(1); M1=WImage4cl; case 3 WImage5=a1; WImage5=im2double(WImage5); cnum=10; dctm=dctmtx(8); P1=dctm; P2=dctm.'; imageDCT=blkproc(WImage5,[8,8],'P1*x*P2',dctm,dctm.'); DCTvar=im2col(imageDCT,[8,8],'distinct').'; n=size(DCTvar,1); DCTvar=(sum(DCTvar.*DCTvar)-(sum(DCTvar)/n).^2)/n; [dum,order]=sort(DCTvar); cnum=64-cnum; mask=ones(8,8); mask(order(1:cnum))=zeros(1,cnum); im88=zeros(9,9); im88(1:8,1:8)=mask; im128128=kron(im88(1:8,1:8),ones(16)); dctm=dctmtx(8); P1=dctm.'; P2=mask(1:8,1:8); P3=dctm; WImage5=blkproc(imageDCT,[8,8],'P1*(x.*P2)*P3',dctm.',mask(1:8,1:8),dctm); WImage5cl=mat2gray(WImage5); subplot(2,3,4); imshow(WImage5cl); title('经JPEG压缩后图像'); M1=WImage5cl; case 5 WImage6=a1; WImage6=imrotate(WImage6,10,'bilinear','crop'); WImage6cl=mat2gray(WImage6); %figure(2); subplot(2,3,4); imshow(WImage6cl); title('旋转10度后图像'); %figure(1); M1=WImage6cl; otherwise disp('你输入的是无效数字，图像未受攻击，将直接检测水印'); subplot(2,3,4); imshow(a1,[]); title('未受攻击的含水印图像'); M1=a1; end %%%%%%%%%%%%%%%% 提取水印 %%%%% psnr_watermarked=M1; dca1=blkproc(M1,[8,8],'dct2'); p=zeros(1,8); for i=1:dimI(1) for j=1:dimI(2) % j=1:32 x=(i-1)*8;y=(j-1)*8; p(1)=dca1(x+1,y+8); p(2)=dca1(x+2,y+7); p(3)=dca1(x+3,y+6); p(4)=dca1(x+4,y+5); p(5)=dca1(x+5,y+4); p(6)=dca1(x+6,y+3); p(7)=dca1(x+7,y+2); p(8)=dca1(x+8,y+1); if corr2(p,k1)>corr2(p,k2),warning off MATLAB:divideByZero; mark1(i,j)=1; else mark1(i,j)=0; end end end subplot(2,3,5); imshow(mark1,[]),title('提取的水印图像'); subplot(2,3,6); imwrite(mark1,'getmark.bmp','bmp'); imshow(mark),title('原嵌入水印'); %%%% time %%%%%%% disp('攻击与提取处理时间') attack_recover_time=cputime-start_time, %%%%% psnr %%%%%%% disp('载体图像与含水印图像峰值信噪比') psnrvalue=PSNR(psnr_cover,psnr_watermarked), %%%%%%% Oringinal mark and mark test %%%%%%%%%% disp('原水印图像与提取水印图像互相关系数') NC=NC(mark1,mark)