HSI-RGB.zip_HSI RGB_hsi

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:

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);

%Combine all three results into an hsi image.

hsi=cat(3,H,S,I);

function rgb=hsi2rgb(hsi)

%HSI2RGB Converts an HSI image to RGB.

% HSI2RGB Converts an HSI image to RGB, where HSI is assumed to be of

% class double with:

% 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].