rgb2hsi.rar_HSI到RGB_rgb to hsi_rgb2hsi_颜色_颜色模型 MATLAB

function hsi=rgb2hsi(rgb) %RGB2HSI Converts an RGB image to HSI % HSI=RGB2HSI(rgb) converts an RGB image to HSI. The input image is % assumed to be of size M-by-N-by-3, where the third dimension accounts % for three image planes:red, green, and blue, in that order. If all RGB % component images are equal, the HSI conversion is undefined. Ths input % image can be of class double (with values in the rang[0,1]), uint8, or % uint16. % The output image, HSI, is of class double, where: % hsi(:,:,1)= hue image normalized values to the range [0,1] by % dividing all angle values by 2*pi. % hsi(:,:,2)=saturation image, in the range [0,1]. % hsi(:,:,3)=intensity image, in the range [0,1]. %Extract the individual component images. 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; %Combine all three results into an hsi image. hsi=cat(3,H,S,I);