getthewatermark.m

利用matlab将一个图片作为水印插入另一个图片

function [pickedMark]=getTheWaterMark(newImage,numOfBlock,markSize)

fun=@dct2;
metrix=[1 1;1 2];
dctImage=blkproc(newImage,[8 8],fun);
for i=1:numOfBlock
    for j=1:numOfBlock
         if (dctImage((i-1)*8+2,(j-1)*8+6)>(dctImage((i-1)*8+1,(j-1)*8+6)+dctImage((i-1)*8+2,(j-1)*8+5)...
             +dctImage((i-1)*8+2,(j-1)*8+7)+dctImage((i-1)*8+3,(j-1)*8+6))/4)
             waterMark((i-1)*2+1,(j-1)*2+1)=1;
         else 
              waterMark((i-1)*2+1,(j-1)*2+1)=0;
         end
         
         if (dctImage((i-1)*8+4,(j-1)*8+5)>(dctImage((i-1)*8+3,(j-1)*8+5)+dctImage((i-1)*8+5,(j-1)*8+5)...
             +dctImage((i-1)*8+4,(j-1)*8+4)+dctImage((i-1)*8+4,(j-1)*8+6))/4)
             waterMark((i-1)*2+1,(j-1)*2+2)=1;
         else 
              waterMark((i-1)*2+1,(j-1)*2+2)=0;
         end

          if (dctImage((i-1)*8+6,(j-1)*8+4)>(dctImage((i-1)*8+5,(j-1)*8+4)+dctImage((i-1)*8+7,(j-1)*8+4)...
             +dctImage((i-1)*8+6,(j-1)*8+3)+dctImage((i-1)*8+6,(j-1)*8+5))/4)
             waterMark((i-1)*2+2,(j-1)*2+1)=1;
         else 
              waterMark((i-1)*2+2,(j-1)*2+1)=0;
         end
         
          if (dctImage((i-1)*8+7,(j-1)*8+2)>(dctImage((i-1)*8+6,(j-1)*8+2)+dctImage((i-1)*8+8,(j-1)*8+2)...
             +dctImage((i-1)*8+7,(j-1)*8+1)+dctImage((i-1)*8+7,(j-1)*8+3))/4)
             waterMark((i-1)*2+2,(j-1)*2+2)=1;
         else 
              waterMark((i-1)*2+2,(j-1)*2+2)=0;
         end
     end
 end
 
 %inverse the arnold transform        
for i=1:5
    for j=1:markSize
        for k=1:markSize
            tmp=[j;k];
            tmp=metrix\tmp;
            tmp=mod(tmp,markSize);
            if(tmp(1)==0)
                tmp(1)=markSize;
            end
            if(tmp(2)==0)
                tmp(2)=markSize;
            end
            pickedMark(tmp(1),tmp(2))=waterMark(j,k);
        end
    end
end