feixianxing.m

数字图象加密程序（编写的数字图象加密程序）

clear all;

Image=double(imread('e:\work\lena.jpg'));

figure(1)
subplot(2,2,1)
imshow(Image,[]);%显示原始图像
title('原始图像');
Image=uint8(Image);
figure(1)
subplot(2,2,2)
imhist(Image);
title('原始图像的直方图');

Image=double(Image);
key1=3.9;
key2=0.7;
Kimage=double(zeros(size(Image)));
Kimage1=double(zeros(size(Image)));
Kimage2=double(zeros(size(Image)));
Kimage3=double(zeros(size(Image)));
key=0;
% Himage=zeros(size(Image));

Ih=size(Image,1);%图像的长度
Iw=size(Image,2);%图像的宽度
% Kimage(1)=key2;
for(i=1:Ih)
        for(j=1:Iw)
            key2=key1*(key2*(1-key2));
%             key=mod((key2*256),256);
            Kimage1(i,j)=key2;
            Kimage2(i,j)=key2;
            Kimage3(i,j)=key2;
        end
end

for(i=1:Ih)
        for(j=1:Iw)
             Kimage(i,j)=Kimage1(i,j)*Kimage2(i,j)+(1-Kimage1(i,j))*Kimage3(i,j);
%              Image(i,j)=mod((Kimage(i,j)+Image(i,j)),256);
         end
end
m=double(zeros(size(257)));
for(i=1:257)
    m(i)=sin(((i-1)*pi)/512);
end
for(i=1:Ih)
    for(j=1:Iw)
        for(k=0:256)
            while (Kimage(i,j)<m(k+1))&(Kimage(i,j)>=m(k))
                Kimage(i,j)=k;
            end
%             break
        end
        Image(i,j)=mod((Kimage(i,j)+Image(i,j)),256);
    end
end

     
% Image=mod((Kimage+Image),256);
figure(1)
subplot(2,2,3)
imshow(Image,[]);
title('加密图像');
Image=uint8(Image);
figure(1)
subplot(2,2,4)
imhist(Image);
title('加密图像的直方图');