TransNorm(data, NormMethod)

%function [data, mi, norms] = TransNorm(data, NormMethod);
%
%This function normalizes the data of the Biodata object in an alternative
%way. First TransNorm will substract the minimum value of each spectrum.
%Afterwards the normalisation is executed. One can choose to normalize by
%dividing all values of one spectrum
%    - with the maximum value of that spectrum
%    - with the length (or norm) of that vector
%
%Input parameters:
%    - data: the datamatrix
%    - NormMethod: method of normalisation: if
%         'Max': division by the maximum value of each spectrum
%         'Len': division by norm of each spectrum after substraction of 
%             the minimum value
%
%Output parameters:
%    - data: the normalized spectra
%    - mi: the minima of the spectra
%    - norms: the normalisation factor
%
%Example:
%    load data
%    xaxis = 1:size(data,2);
%    subplot (3,1,1);
%    plot (xaxis, data);
%    title ('Original dataset');
%    subplot (3, 1, 2);
%    plot (xaxis, TransNorm (data, 'Max'));
%    title ('Normalized by maximum');
%    subplot (3, 1, 3);
%    plot (xaxis, TransNorm (data, 'Len'));
%    title ('Normalized by vector length');

%The Biodata toolbox for MATLAB: a spectral database system for storing and
%processing spectra
%C 2005-2008, Kris De Gussem, Raman Spectroscopy Research Group, Department
%of analytical chemistry, Ghent University
%C 2009 Kris De Gussem
%
%This file is part of Biodata.
%
%Biodata 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
%(at your option) any later version.
%
%Biodata 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 Biodata.  If not, see <http://www.gnu.org/licenses/>.

%Copyright (c) 2005-2009, Kris De Gussem
%All rights reserved.
%
%Redistribution and use in source and binary forms, with or without 
%modification, are permitted provided that the following conditions are 
%met:
%
%    * Redistributions of source code must retain the above copyright 
%      notice, this list of conditions and the following disclaimer.
%    * Redistributions in binary form must reproduce the above copyright 
%      notice, this list of conditions and the following disclaimer in 
%      the documentation and/or other materials provided with the distribution
%    * Neither the name of Raman Spectroscopy Research Group, Department of
%	  analytical chemistry, Ghent University nor the names 
%      of its contributors may be used to endorse or promote products derived 
%      from this software without specific prior written permission.
%      
%THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
%AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
%IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
%ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
%LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
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%POSSIBILITY OF SUCH DAMAGE.

function [data, mi, norms] = TransNorm(data, NormMethod)
switch nargin
    case 1
        NormMethod = 'Len';
    case 2
        
    otherwise
        error ('Biodata:msg', 'Wrong number of input parameters...');
end

si = size (data,2);
mi = min (data, [], 2);
data = data - repmat (mi, 1, si);
switch NormMethod
    case 'Max'
        norms = max(data,[], 2);
        data = data ./ repmat (norms, 1, size (data,2));
    case 'Len'
        [data, norms] = normaliz (data);
    otherwise
        error ('Biodata:msg', 'Unsupported value for normalization method. See help Biodata/TransNorm...')
end