mark.txt

添加水印

首先读入原始图象并设置参数，然后嵌入水印信息，程序代码如下：
clear
%

size=256;block=8;blockno=size/block;LENGTH=size*size/64;

Alpha1=0.02;  Alpha2=0.1; T1=3; I=zeros(size,size); D=zeros(size,size); BW=zeros(size,size); block_dct1=zeros(block,block);

 

%产生水印序列并对其排序

randn('seed',10);watermark1=randn(1,LENGTH);

subplot(2,2,1);plot(watermark1);title('watermarc:Gaussian noise');

subplot(2,2,3);
title('edge of origine image')
[Y0,I0]=sort(watermark1);
%

%读入原图象
trueImage=imread('H:\Documents and Settings\sunhw\My Documents\My Pictures\biaozhun.bmp');
alfa=.1;
LENGTH=2500;
subplot(2,2,2);
imshow(trueImage);
title('origine image:I');
%
%对原图象进行DCT变换
dctF1=dct2('H:\Documents and Settings\sunhw\My Documents\My Pictures\biaozhun.bmp');
[m,n]=size(dctF1);
%
%找出水印嵌入位置（幅值较大的n个频域成分）
A=dctF1(:);
[Y1,I1]=sort(A);
x=m*n;
k=LENGTH;
M=zeros(x,1);
%
%修改幅值较大的n个频域成分的幅值，嵌入水印（因为两个问题不同，所以有两个注释符）
for i=1:x
   if k>=1
    M(x)=Y1(x)*(1+alfa*Y0(k));
    k=k-1;
   else
    M(x)=Y1(x);
   end
   x=x-1;
end
N=zeros(x,1);
x=m*n;
for i=1:x
    N(I1(i))=M(i);
end
a=1;
for j=1:n
  for i=1:m
    dctF2(i,j)=N(a);
    a=a+1;
  end
end
%
%DCT反变换，得到嵌入水印的图象
idctF1=idct2(dctF2);
subplot(2,2,4);
imshow(log(abs(idctF1)),[ ]);
title('embeded image:D');
%end