%装入原图像1
load woman %读入图像
I=X
%小波函数
type = 'db1' %选择小波类型
% 2维离散Daubechies小波变换
[CA1, CH1, CV1, CD1] = dwt2(I,type) %小波变换
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 %水印参数
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 ) %如果C1>阈值
marked1(counter1,counter2) = randn(1,1) %marked1为水印图像
NEWC1(counter1, counter2) = double( C1(counter1, counter2) ) +alpha * abs( double( C1(counter1, counter2) ) ) * marked1(counter1,counter2) %NEWC1为加入水印后的小波域
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) %显示原始图像
axis('square')
title('原始图像')
subplot(1,2,2)
imshow(R1/250)%显示小波变换后图像
axis('square')
title('Daubechies小波变换后图像')
figure(2)
imshow(watermark1*10^16)%显示水印图像
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 ) %当NEWC1大于阈值时提取水印
NEWC1X(counter1, counter2) = NEWC1(counter1, counter2)
else
NEWC1X(counter1, counter2) = 0
end
end
end
NEWC1X = reshape(NEWC1X, M1*N1, 1)%锐化
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, '--')%显示原始的加水印图像
title('原始的加水印图像')
xlabel('水印')
ylabel('检测响应')
在matlab的库里面没有pfilters这个函数,是你自己定义的吧?这个函数用来处理pfilt这个字符串的,通过这个字符串获得你滤波的系数h和g,然后送到另外一个自己定义的函数lpdec中。不知道这么说能不能帮到你
使用imnoise函数X=imread('D:\matlab7.1\toolbox\images\imdemos\greens.jpg')
Y=imnoise(X,'gaussian')%%默认均值为0,方差为0.01
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A double-class image must have values between zero and one,这个问题是你的图像是double型,但是你的图像的数值不是0-1之间,给他除以255即可!
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