DCT实现水印嵌入与提取(带攻击)

问题：

想要用DCT技术，在Matlib上实现水印的隐藏和提取（带GUI界面），且加上一些攻击(噪声、旋转、裁剪)，以及用NC值评判！

流程#

选择载体#

[filename,pathname]=uigetfile({'*.bmp';'*.jpg';'*.*'},'选择图片');%文件选择，这里可以选择可以打开的图片格式
str=[pathname filename];%被选择的文件路径
[handles.I,handles.map]=imread(str);%读取图片
zai=imread(str);
%zai=[handles.I,handles.map];
psnr_cover=double(zai);
guidata(hObject,handles);%图像串行化，保存在hObject,这样我整个页面都能取到handles的值
axes(handles.axes1);%把显示范围限定在axes1
imshow(zai,[]);%显示图片

选择要嵌入的水印#

[filename,pathname]=uigetfile({'*.bmp';'*.jpg';'*.*'},'选择图片');%文件选择，这里可以选择可以打开的图片格式
str=[pathname filename];%被选择的文件路径
[handles.I,handles.map]=imread(str);%读取图片
%water=[handles.I,handles.map];
global water;
water=imread(str);
water=rgb2gray(water);
water=double(water)/255; 
water=ceil(water);
%guidata(hObject,handles);%图像串行化，保存在hObject,这样我整个页面都能取到handles的值
axes(handles.axes4);%把显示范围限定在axes4
imshow(water);%显示图片
dimI=size(water);
global rm;
global cm;
rm=dimI(1);cm=dimI(2);

嵌入#

start_time=cputime;
global water;
global rm;
global cm;
cda0=blkproc(handles.I,[8,8],'dct2');
mark=water;
alpha=10;
global k1;
global k2;
k1=randn(1,8);
k2=randn(1,8);
[r,c]=size(handles.I);
cda1=cda0;   % cda1 = 256_256
for i=1:rm  % i=1:32
    for j=1:cm  % j=1:32
        x=(i-1)*8;y=(j-1)*8;
        if mark(i,j)==1
            k=k1;
        else
            k=k2;
        end
        cda1(x+1,y+8)=cda0(x+1,y+8)+alpha*k(1);
        cda1(x+2,y+7)=cda0(x+2,y+7)+alpha*k(2);
        cda1(x+3,y+6)=cda0(x+3,y+6)+alpha*k(3);
        cda1(x+4,y+5)=cda0(x+4,y+5)+alpha*k(4);
        cda1(x+5,y+4)=cda0(x+5,y+4)+alpha*k(5);
        cda1(x+6,y+3)=cda0(x+6,y+3)+alpha*k(6);
        cda1(x+7,y+2)=cda0(x+7,y+2)+alpha*k(7);
        cda1(x+8,y+1)=cda0(x+8,y+1)+alpha*k(8);
    end
end
global a1;
a1=blkproc(cda1,[8,8],'idct2');
a_1=uint8(a1);
 
axes(handles.axes5);%把显示范围限定在axes5s
imshow(a_1);%显示图片
%imwrite(a_1,'嵌入水印后的图.bmp','bmp');
%subplot(2,3,3),imshow(a1,[]),title('嵌入水印后的图像');
%disp('嵌入水印处理时间')
embed_time=cputime-start_time
set(handles.text13,'string',num2str(embed_time));
p0=a_1;

攻击#

1、白噪声攻击

gong=a1;
noise0=1*randn(size(gong));
gong=uint8(gong+noise0);

2、椒盐噪声

1	`gong=imnoise(uint8(a1),` `'salt & pepper', 0.01);%添加密度为0.01的椒盐噪声`

3、旋转

1	`gong=uint8(imrotate(uint8(a1),30,'nearest','crop'));`

4、裁剪

%原图进行分色并剪切
gong=a1;
I_r= gong(:,:,1);
I_r(1:128,1:128)=255;
%三色通道合并
gong(:,:,1) = I_r;
gong=uint8(gong);

提取#

global k1;
global gong;
global k2;
global water;
dimI=size(water);
 
psnr_watermarked=double(gong);
dca1=blkproc(gong,[8,8],'dct2');
p=zeros(1,8);
for i=1:dimI(1) %行
    for j=1:dimI(2)  % j=1:32列
        x=(i-1)*8;y=(j-1)*8;
        p(1)=dca1(x+1,y+8);
        p(2)=dca1(x+2,y+7);
        p(3)=dca1(x+3,y+6);
        p(4)=dca1(x+4,y+5);
        p(5)=dca1(x+5,y+4);
        p(6)=dca1(x+6,y+3);
        p(7)=dca1(x+7,y+2);
        p(8)=dca1(x+8,y+1);
        if corr2(p,k1)>corr2(p,k2),warning off MATLAB:divideByZero;
            mark1(i,j)=1;
        else
            mark1(i,j)=0;
        end
    end
end
axes(handles.axes7);%把显示范围限定在axes5s
imshow(mark1);%显示图片
embed_time=cputime-start_time;
set(handles.text14,'string',num2str(embed_time));
 
NC=nc(mark1,water)  %调用nc.m子函数
set(handles.text15,'string',num2str(NC));