rgb2hsi.m

machine vision 工具箱

%RGB2HSI	Transform RGB to HSI color space
%
%	[h s i] = rgb2hsi(r, g, b)
%
%	Convert (r,g,b) color coordinates to HSI coordinates.
%
%	Copyright (c) Peter Corke, 1999  Machine Vision Toolbox for Matlab

function [h,s,i] = rgb2hsi(r,g,b)

	i = (r+g+b)/3;

% from Alan Roberts' FAQ
	rg = r-g;
	rb = r-b;
	gb = g-b;

	h = acos((0.5*rg + rb) ./ sqrt(rg.^2 + rb.*gb))*180/pi;

	a = [r g b];
	s = 1 - 3./i*min(a(:));