RGB轉為HSI的MATLAB程式 rgb2hsi

這個程式更清楚一些：

function hsi = rgb2hsi(rgb) rgb=im2double(rgb); r=rgb(:,:,1); g=rgb(:,:,2); b=rgb(:,:,3); %Implement the conversion equations  num = 0.5*((r-g)+(r-b)); den = sqrt((r-g).^2+(r-b).*(g-b)); theta=acos(num./(den+eps));

H=theta; H(b>g)=2*pi-H(b>g); H=H/(2*pi);

num=min(min(r,g),b); den = r+g+b; den(den==0)=eps; S=1-3.*num./den; H(S==0)=0; I=(r+g+b)/3; %combin all three results into an hsi image hsi = cat(3,H,S,I);