hsl2hsv

hsl2hsv - Convert hue-saturation-luminance colors to hue-saturation-value.

  USAGE

    y = hsl2hsv(x)

    x              Nx3 RGB matrix (values in [0..1])

0001 function y = hsl2hsv(x)
0002 
0003 %hsl2hsv - Convert hue-saturation-luminance colors to hue-saturation-value.
0004 %
0005 %  USAGE
0006 %
0007 %    y = hsl2hsv(x)
0008 %
0009 %    x              Nx3 RGB matrix (values in [0..1])
0010 
0011 % Copyright (C) 2013 by Michaël Zugaro
0012 %
0013 % This program is free software; you can redistribute it and/or modify
0014 % it under the terms of the GNU General Public License as published by
0015 % the Free Software Foundation; either version 3 of the License, or
0016 % (at your option) any later version.
0017 
0018 % Check number of parameters
0019 if nargin < 1,
0020   error('Incorrect number of parameters (type ''help <a href="matlab:help hsl2hsv">hsl2hsv</a>'' for details).');
0021 end
0022 if ~isdmatrix(x) || size(x,2) ~= 3 || any(x(:)<0) || any(x(:)>1),
0023   error('Incorrect HSL matrix (type ''help <a href="matlab:help hsl2hsv">hsl2hsv</a>'' for details).');
0024 end
0025 
0026 % Convert from HSL to HSV
0027 
0028 h = x(:,1);
0029 s = x(:,2);
0030 l = x(:,3);
0031 
0032 H = h;
0033 S = s;
0034 in = l <= 0.5;
0035 S(in) = S(in) .* l(in);
0036 S(~in) = S(~in) .* (1-l(~in));
0037 V = l + S;
0038 in = V > 0;
0039 S(in) = 2 * S(in) ./ V(in);
0040 S(~in) = 0;
0041 
0042 
0043 y = Clip([H S V],0,1);
0044 
0045 
0046 %  in = l <= 0.5;
0047 %  s(in) = s(in) .* l(in);
0048 %  s(~in) = s(~in) .* (1-l(~in));
0049 %  l = l + s;
0050 %
0051 %  in = l > 0;
0052 %  s(in) = 2 * s(in) ./ l(in);
0053 %  s(~in) = 0;
0054 %
0055 %  H = h;
0056 %  S = s;
0057 %  V = l;