我对matlab不怎么懂。。。要求能用字符串做为水印嵌入到图像中 ，，，急这里先谢谢大家了。。
代码如下 帮帮忙
clear;
%装入原图像1
f1='';
[f1,p]=uigetfile('*.jpg;*.bmp;*.tif;*.gif','打开原始图像文件');
addpath(p);
if f1==0;
return;
end;
I=imread(f1); %把原始图像转换成矩阵
save image;
load image;
%小波函数
type = 'db1';
% 2维离散Daubechies小波变换
[CA1, CH1, CV1, CD1] = dwt2(I,type);
C1 = [CH1 CV1 CD1];
%系数矩阵大小
[length1, width1] = size(CA1);
[M1, N1] = size(C1);
% 定义阈值T1
T1 =50;
alpha = 0.2;
%在图像中加入水印
for counter2 = 1: 1: N1
for counter1 = 1: 1: M1
if( C1(counter1, counter2) > T1 )
marked1(counter1,counter2) = randn(1,1);
NEWC1(counter1, counter2) = double( C1(counter1, counter2) ) +alpha * abs( double( C1(counter1, counter2) ) ) * marked1(counter1,counter2) ;
else
marked1(counter1, counter2) = 0;
NEWC1(counter1, counter2) = double( C1(counter1, counter2) );
end;
end;
end;
%重构图像
NEWCH1 = NEWC1(1:length1, 1:width1);
NEWCV1 = NEWC1(1:length1, width1+1:2*width1);
NEWCD1 = NEWC1(1:length1, 2*width1+1:3*width1);
R1 = double( idwt2(CA1, NEWCH1, NEWCV1, NEWCD1, type) );
%分离水印
watermark1 = double(R1) - double(I);
figure(1);
subplot(1,2,1);
image(I);
axis('square');
title('原始图像');
subplot(1,2,2);
imshow(R1/250);
axis('square');
title('Daubechies小波变换后图像');
figure(2);
imshow(watermark1*10^16);
axis('square');
title('水印图像');
% 水印检测
newmarked1 = reshape(marked1, M1*N1, 1);
% 检测阈值
T2 = 60;
for counter2 = 1: 1: N1
for counter1 = 1: 1: M1
if( NEWC1(counter1, counter2) >T2 )
NEWC1X(counter1, counter2) = NEWC1(counter1, counter2);
else
NEWC1X(counter1, counter2) = 0;
end;
end;
end;
NEWC1X = reshape(NEWC1X, M1*N1, 1);
correlation1 = zeros(1000,1);
for corrcounter = 1: 1: 1000
if( corrcounter == 500)
correlation1(corrcounter,1) = NEWC1X'*newmarked1 / (M1*N1);
else
rnmark = randn(M1*N1,1);
correlation1(corrcounter,1) = NEWC1X'*rnmark / (M1*N1);
end;
end;
% 计算阈值
originalthreshold = 0;
for counter2 = 1: 1: N1
for counter1 = 1: 1: M1
if( NEWC1(counter1, counter2) > T2 )
originalthreshold = originalthreshold + abs( NEWC1(counter1, counter2) );
end;
end;
end;
originalthreshold = originalthreshold * alpha / (2*M1*N1);
corrcounter = 1000;
originalthresholdvector = ones(corrcounter,1) * originalthreshold;
figure(3);
plot(correlation1, '-');
hold on;
plot(originalthresholdvector, '--');
title('原始的加水印图像');
xlabel('水印');
ylabel('检测响应');
[此贴子已经被作者于2006-5-20 16:50:31编辑过]
