test.m

一个基于dct变换的数字水印算法的源程序,可供进行数字水印学习和研究的学生及科研工作者学习参考

function test
ck1=clock();
tao=0;
ZT=imread('biao256.bmp');
[m n]=size(ZT);
[Q watermarked]=dct_ema(ZT,tao);
     imwrite(uint8(watermarked),'watermarked.bmp','bmp');
     imwrite(uint8(watermarked),'attack.jpg','jpg','quality',90);
   dif=watermarked-double(ZT);
   psnr=10*log10(255*255*m*n/sum(sum(dif.*dif)))
     attacked=imread('attack.jpg','jpg');
%    attacked=watermarked;
%       attacked(144:160,144:160)=0;
       attacked(90:102,70:78)=255;
       imshow(uint8(attacked));
     imwrite(uint8(attacked),'attack.bmp','bmp');
QQ=dct_deta(attacked,tao);
sum(xor(Q,QQ))
ck2=clock();
 totaltime=ck2-ck1
%%%对于表格只能抗轻微的压缩最多抗到90