THE AUDITORY MODELING TOOLBOX

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TAKANEN2013_DIRECTIONMAPPING - Map the directional cues to directions

Program code:

function [msoAngles,lsoAngles,wbMsoAngles] = takanen2013_directionmapping(mso,lso,contraMso,wbMmso)
%TAKANEN2013_DIRECTIONMAPPING Map the directional cues to directions                 
%   Usage: [msoAngles,lsoAngles,wbMsoAngles] = takanen2013_directionmapping(mso,lso,contraMso,wbMmso)
%
%   Input parameters:
%        mso       : output of the MSO model projecting to left or right
%                    hemisphere
%        lso       : output of the LSO model projecting to left or right
%                    hemisphere
%        contraMso : output of the MSO model projecting to opposite
%                    hemisphere
%        wbMso     : output of the wideband MSO model projecting to left
%                    or right hemisphere
%
%   Output parameters:
%        msoAngles   : direction estimates provided by the model of MSO
%        lsoAngles   : direction estimates provided by the model of MSO
%        wbMsoAngles : direction estimates provided by the wideband MSO
%                      model
%
%   This function maps the outputs of the models of MSO and LSO into
%   azimuth angles ranging from -90 to 90 in 10 degree resolution using a
%   a set of reference values computed using monophonic signals and
%   measured HRTFs of the corresponding directions. More detailed
%   description about the process can be found in Takanen, Santala, Pulkki
%   2013 (Sec. 3.2.5)
%
%   See also: takanen2013, takanen2013_mso, takanen2013_lso,
%             takanen2013_wbmso
%
%   References:
%     M. Takanen, O. Santala, and V. Pulkki. Visualization of functional
%     count-comparison-based binaural auditory model output. Hearing
%     research, 309:147--163, 2014. PMID: 24513586.
%     
%
%   Url: http://amtoolbox.org/amt-1.2.0/doc/modelstages/takanen2013_directionmapping.php

% Copyright (C) 2009-2022 Piotr Majdak, Clara Hollomey, and the AMT team.
% This file is part of Auditory Modeling Toolbox (AMT) version 1.2.0
%
% 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
% (at your option) 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, see <http://www.gnu.org/licenses/>.

%   AUTHOR: Marko Takanen, Olli Santala, Ville Pulkki
%
%   COPYRIGHT (C) 2013 Aalto University
%                      School of Electrical Engineering
%                      Department of Signal Processing and Acoustics
%                      Espoo, Finland


%% ------ Computation ----------------------------------------------------
%load the precomputed set of reference values
x=amt_load('takanen2013','lookuptable.mat');
referencevalues=x.referencevalues;
dims = size(mso);

%initialize the output values
msoAngles = zeros(dims(1),dims(2));
lsoAngles=msoAngles;
wbMsoAngles =msoAngles;

nAngles = length(referencevalues.angles);
for freqInd =1:dims(2)
    %find the closest match to the cue value amongst the reference values 
    %in the lookup table
    temp = abs((lso(:,freqInd)*ones(1,nAngles))-(ones(dims(1),1)*referencevalues.lso(:,freqInd)'));
    %set the direction corresponding to the found reference value as the
    %direction estimate
    [~,ind] = min(temp,[],2);
    lsoAngles(:,freqInd) = referencevalues.angles(ind);

    %otherwise similar approach as above is used for MSO, except for the
    %fact that contralateral MSO cues are used to solve some ambiguities in
    %direction estimation
    temp = abs((mso(:,freqInd)*ones(1,nAngles))-(ones(dims(1),1)*referencevalues.mso(:,freqInd)'))+...
        abs((contraMso(:,freqInd)*ones(1,nAngles))-(ones(dims(1),1)*referencevalues.contramso(:,freqInd)'));
    [~,ind] = min(temp,[],2);
    msoAngles(:,freqInd) = referencevalues.angles(ind);

    %direction mapping for wideband MSO
    temp = abs((wbMmso(:,freqInd)*ones(1,nAngles))-(ones(dims(1),1)*referencevalues.wbmso(:,freqInd)'));
    [~,ind] = min(temp,[],2);
    wbMsoAngles(:,freqInd) = referencevalues.angles(ind);
end