Error: Missing variable or function.求高手指点
%基于傅立叶域的数字水印%注意:水印必须为40*40的二值图像
%因为40阶的二维arnold置乱周期为30,所以嵌入时置乱8次,提取时置乱22.可以根据自己的需要更改.
%嵌入源码
clc
clear all;
% 保存开始时间
start_time=cputime;
iTimes=8; %置乱次数
k=1.1; % 设置嵌入强度系数
blocksize=8; % 块的大小
filter_m=[1,1,1,1,1,1,1,1; % 滤波矩阵
1,1,1,1,1,1,1,1;
1,1,0,0,0,0,1,1;
1,1,0,0,0,0,1,1;
0,0,0,0,0,0,0,0;
0,0,0,0,0,0,0,0;
0,0,0,0,0,0,0,0;
0,0,0,0,0,0,0,0;];
% 读入原始图像
file_name='C:\MATLAB7\work\yuantu.bmp';
cover_object=double(imread(file_name))/255;
% 原始图像矩阵的行数与列数
Mc=size(cover_object,1);
Nc=size(cover_object,2);
% 最大嵌入信息量
max_message=Mc*Nc/(blocksize^2);
% 读入水印图像
file_name='C:\MATLAB7\work\watermark.bmp';
message=double(imread(file_name));
%水印图像矩阵的行数与列数
Mm=size(message,1);
Nm=size(message,2);
% 检查水印信息是否过大
ifMm*Nm>max_message
error('水印信息过大')
end
%对水印图像进行Arnold置乱
if Mm~=Nm
error('水印矩阵必须为方阵');
end
if Mm~=40
error('必须为40*40大小,或者修改置乱次数');
end
tempImg=message;
for n=1:iTimes % 次数
for u=1:Mm
for v=1:Nm
temp=tempImg(u,v);
ax=mod(u+v,Mm)+1;
ay=mod(u+2*v,Nm)+1;
outImg(ax,ay)=temp;
end
end
tempImg=outImg;
end
message_vector=reshape(outImg,1,Mm*Nm)
% 将cover_object（原图矩阵）写入watermarked_image
watermarked_image=cover_object;
%置随机数发生器的状态为1100
key=1100;
rand('state',key);
% 产生伪随机序列
pn_sequence_zero=round(2*(rand(1,sum(sum(filter_m)))-0.5));
pn_sequence_one=round(2*(rand(1,sum(sum(filter_m)))-0.5));
% 将图像分块
x=1;
y=1;
h=waitbar(0,'嵌入水印，请等待');
for (kk = 1:length(message_vector))
% 做傅立叶变换
fft_block=fft2(cover_object(y:y+blocksize-1,x:x+blocksize-1));
%计算幅值
abs_block=fftshift(abs(fft_block));
%计算相位
angle_block=angle(fft_block);
% 当message_vector=0且filter_m=1时用伪随机序列pn_sequence_zero叠加abs_block
% 当message_vector=1且filter_m=1时用伪随机序列pn_sequence_one叠加abs_block
ll=1;
if (message_vector(kk)==0)
for ii=1:blocksize
for jj=1:blocksize
if (filter_m(ii,jj)==1)
abs_block_o=abs_block(ii,jj);
abs_block(ii,jj)=abs_block(ii,jj)*(1+k*pn_sequence_zero(ll));
abs_block(blocksize-ii+1,blocksize-jj+1)=abs_block(blocksize-ii+1,blocksize-jj+1)+…
abs_block(ii,jj)-abs_block_o;
ll=ll+1;
end
end
end
else
for ii=1:blocksize
for jj=1:blocksize
if (filter_m(ii,jj)==1)
abs_block_o=abs_block(ii,jj);
abs_block(ii,jj)=abs_block(ii,jj)*(1+k*pn_sequence_one(ll));
abs_block(blocksize-ii+1,blocksize-jj+1)=abs_block(blocksize-ii+1,blocksize-jj+1)+…
abs_block(ii,jj)-abs_block_o;
ll=ll+1;
end
end
end
end
% 进行傅立叶逆变换
abs_block=fftshift(abs_block);
watermarked_image(y:y+blocksize-1,x:x+blocksize-1)=…
abs(ifft2(abs_block.*exp(i*angle_block)));
% 移动到下一块
if (x+blocksize) >= Nc
x=1;
y=y+blocksize;
else
x=x+blocksize;
end
waitbar(kk/length(message_vector),h);
end
close(h);
% 转换为uint8，并写入
watermarked_image_int=uint8(watermarked_image*255);
imwrite(watermarked_image_int,'dft2_watermarked.bmp','bmp');
% 计算运行时间
elapsed_time=cputime-start_time,
% 计算psnr
PSNR=psnr(cover_object,watermarked_image),
% 显示水印，嵌入水印图像与原始图像
figure(1)
subplot(1,2,1)
imshow(message,[]);
title('原始水印');
subplot(1,2,2);
imshow(tempImg,[]);
title('置乱水印');
figure(2)
subplot(1,2,1)
imshow(watermarked_image,[]);
name='嵌入水印图像';
title(strcat(num2str(name),' k=',num2str(k),' PSNR=',num2str(PSNR)));
subplot(1,2,2)
imshow(cover_object,[])
title('原始图像');
??? abs_block(blocksize-ii+1,blocksize-jj+1)=abs_block(blocksize-ii+1,blocksize-jj+1)+…;
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Error: Missing variable or function.
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