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pesq2mos

PURPOSE ^

PESQ2MOS convert PESQ speech quality scores to MOS m=(p)

SYNOPSIS ^

function m=pesq2mos(p)

DESCRIPTION ^

PESQ2MOS convert PESQ speech quality scores to MOS m=(p)
Inputs:    p  is a matrix of PESQ scores

Outputs:   m  is a matrix, the same size as p, of MOS scores

 The PESQ measure is defined in [2]. The mapping function, defined in [3],
 converts raw PESQ scores (which lie in the range -0.5 to 4.5) onto the
 MOS-LQO (Mean Opinion Score - Listening Quality Objective [2]) scale in the
 range 1 to 5. The MOS scale is defined in [1] as
           5=Excellent, 4=Good, 3=Fair, 2=Poor, 1=Bad.

 Refs: [1]    ITU-T. Methods for subjective determination of transmission quality.
           Recommendation P.800, Aug. 1996.
       [2]    ITU-T. Mean opinion score (MOS) terminology.
           Recommendation P.800.1, July 2006.
       [2]    ITU-T. Perceptual evaluation of speech quality (PESQ), an objective
           method for end-to-end speech quality assessment of narrowband telephone
           networks and speech codecs. Recommendation P.862, Feb. 2001.
       [3]    ITU-T. Mapping function for transforming P.862 raw result scores to MOS-LQO.
           Recommendation P.862.1, Nov. 2003.

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function m=pesq2mos(p)
0002 %PESQ2MOS convert PESQ speech quality scores to MOS m=(p)
0003 %Inputs:    p  is a matrix of PESQ scores
0004 %
0005 %Outputs:   m  is a matrix, the same size as p, of MOS scores
0006 %
0007 % The PESQ measure is defined in [2]. The mapping function, defined in [3],
0008 % converts raw PESQ scores (which lie in the range -0.5 to 4.5) onto the
0009 % MOS-LQO (Mean Opinion Score - Listening Quality Objective [2]) scale in the
0010 % range 1 to 5. The MOS scale is defined in [1] as
0011 %           5=Excellent, 4=Good, 3=Fair, 2=Poor, 1=Bad.
0012 %
0013 % Refs: [1]    ITU-T. Methods for subjective determination of transmission quality.
0014 %           Recommendation P.800, Aug. 1996.
0015 %       [2]    ITU-T. Mean opinion score (MOS) terminology.
0016 %           Recommendation P.800.1, July 2006.
0017 %       [2]    ITU-T. Perceptual evaluation of speech quality (PESQ), an objective
0018 %           method for end-to-end speech quality assessment of narrowband telephone
0019 %           networks and speech codecs. Recommendation P.862, Feb. 2001.
0020 %       [3]    ITU-T. Mapping function for transforming P.862 raw result scores to MOS-LQO.
0021 %           Recommendation P.862.1, Nov. 2003.
0022 
0023 %      Copyright (C) Mike Brookes 2012-2013
0024 %      Version: $Id: pesq2mos.m 3289 2013-08-01 13:56:02Z dmb $
0025 %
0026 %   VOICEBOX is a MATLAB toolbox for speech processing.
0027 %   Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html
0028 %
0029 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0030 %   This program is free software; you can redistribute it and/or modify
0031 %   it under the terms of the GNU General Public License as published by
0032 %   the Free Software Foundation; either version 2 of the License, or
0033 %   (at your option) any later version.
0034 %
0035 %   This program is distributed in the hope that it will be useful,
0036 %   but WITHOUT ANY WARRANTY; without even the implied warranty of
0037 %   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0038 %   GNU General Public License for more details.
0039 %
0040 %   You can obtain a copy of the GNU General Public License from
0041 %   http://www.gnu.org/copyleft/gpl.html or by writing to
0042 %   Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA.
0043 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0044 persistent a b c d
0045 if isempty(a)
0046     a=0.999;
0047     b=4.999-a;
0048     c=-1.4945;
0049     d=4.6607;
0050 end
0051 if nargout>0
0052     m=a+b./(1+exp(c*p+d));
0053 else
0054     if nargin<1 || isempty(p)
0055         pp=linspace(-0.5,4.5,100);
0056     else
0057         pp=p;
0058     end
0059     plot(pp,pesq2mos(pp));
0060     xlabel('PESQ (P.862)');
0061     ylabel('Mean Opimion Score (MOS)');
0062 end

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