digitalencypt.m

给定一副图像和一段文字

clear;
I=imread('Beidalou.bmp');
%in = fix(double(I)/2)*2;
in=double(I);
code = imread('code.bmp'); 
                                    
Code = (double(code))/255;                       %把uint8型强制转为double型，方便下面运算

[s1,s2] = size(Code);
[t1,t2] = size(I);
U=zeros(320,240,3);
%嵌入过程
for i=1:s1
    for j=1:s2
        U(i,j,1)=in(i,j,1)+Code(i,j,1);
        U(i,j,2)=in(i,j,2)+Code(i,j,2);
        U(i,j,3)=in(i,j,3)+Code(i,j,3);
    end
end

for i=1:t1
    for j=1:t2
        if i<=s1&&j<=s2
            out(i,j,1)=U(i,j,1);
            out(i,j,2)=U(i,j,1);
            out(i,j,3)=U(i,j,1);
        else
            out(i,j,1)=I(i,j,1);
            out(i,j,2)=I(i,j,1);
            out(i,j,3)=I(i,j,1);
        end
    end
end
%out=uint8(out);
%imshow(out);
                                                   
imwrite(out,'Encrypted_Beidalou','bmp');                          %把嵌入水印后的图读出到Encrypted_Beidalou中
toBeDecoded = imread('Encrypted_Beidalou');
%提取过程
toBeDecoded = double(toBeDecoded);
for i=1:s1
    for j=1:s2
        decode(i,j,1)=(toBeDecoded(i,j,1)-(fix(toBeDecoded(i,j,1)/2))*2)*255;
        decode(i,j,2)=(toBeDecoded(i,j,2)-(fix(toBeDecoded(i,j,2)/2))*2)*255;
        decode(i,j,3)=(toBeDecoded(i,j,3)-(fix(toBeDecoded(i,j,3)/2))*2)*255;
    end
end
                                                              
%decode = uint8(decode);                                              
figure,imshow(decode);                                            %decode存放数字解出的水印