function varargout = Entropie(varargin)
% Calcul de l'entropie d'une image
% 
% INPUT:
% - image PxQ
%
% OUTPUT:
% - valeur numérique : entropie
%
% Plugin for OpenIsaac
% version 1
% © 2011-2018 Sié Ouattara / Alain Clément - Université d'Angers

%---------------------------------------------------------------------------------------------------

% Copyright 2007 - 2018 Université d'Angers - Author: Alain Clément
%
% This program is free software; you can redistribute it and/or modify it under the terms of the GNU
% General Public License as published by the Free Software Foundation; either version 3 of the
% License, or any later version. This program is distributed in the hope that it will be useful, but
% WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
% PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received
% a copy of the GNU General Public License along with this program; if not, write to the Free
% Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

%---------------------------------------------------------------------------------------------------

% PLUGIN PARAMETERS
if (nargin == 1) && strcmp(varargin{1},'-f')
    % input
	varargout{1} = {'IMG','image'};
    % sortie            
	varargout{2} = {'DATA','entropie'};
	return
end	

% INPUT
ObjIMG = varargin{1};

%---------------------------------------------------------------------------------------------------

[~,counts] = IsaacModule('IsaacHistN',double(IsaacIMG_img2mat(ObjIMG)));
p = counts/sum(counts);
entrop = -p'*log2(p); % attention opération matricielle : ordre impératif

%---------------------------------------------------------------------------------------------------

% OUTPUT
varargout{1} = IsaacDATA('VALN',entrop,'entropie');