rgbtoyiq.m

一个基于离散余弦变换的水印算法的matlab程序（嵌入、提取）

%RGBtoYIQ.m
function Y=RGBtoYIQ(I)
% RGBtoYIQ to YIQ representation

if (~isrgb(I))
   error ('La imagen I no es una imagen color en RGB')
end

matConv= [0.299  0.587  0.114
    	    0.596 -0.275 -0.321
	    0.212 -0.523  0.311];
RGBtoY=matConv(1,:);
RGBtoI=matConv(2,:);
RGBtoQ=matConv(3,:);

RenI=double(I(:,:,1));
GenI=double(I(:,:,2));
BenI=double(I(:,:,3));

Y=zeros(size(I));
Y(:,:,1)=RGBtoY(1)*RenI + RGBtoY(2)*GenI + RGBtoY(3)*BenI;
Y(:,:,2)=RGBtoI(1)*RenI + RGBtoI(2)*GenI + RGBtoI(3)*BenI;
Y(:,:,3)=RGBtoQ(1)*RenI + RGBtoQ(2)*GenI + RGBtoQ(3)*BenI;