DISTCHPF calculates the cosh spectral distance between power spectra D=(PF1,PF2,MODE) Inputs: PF1,PF2 Power spectra to be compared. Each row represents a power spectrum: the first and last columns represent the DC and Nyquist terms respectively. PF1 and PF2 must have the same number of columns. MODE Character string selecting the following options: 'x' Calculate the full distance matrix from every row of PF1 to every row of PF2 'd' Calculate only the distance between corresponding rows of PF1 and PF2 The default is 'd' if PF1 and PF2 have the same number of rows otherwise 'x'. Output: D If MODE='d' then D is a column vector with the same number of rows as the shorter of PF1 and PF2. If MODE='x' then D is a matrix with the same number of rows as PF1 and the same number of columns as PF2'. The COSH spectral distance is the average over +ve and -ve frequency of cosh(log(p1/p2))-1 = (p1-p2)^2/(2p1*p2) = (p1/p2 + p2/p1)/2 - 1 The COSH distance is a symmetrical version of the Itakura-Saito distance: distchpf(x,y)=(distispf(x,y)+distispf(y,x))/2

0001 function d=distchpf(pf1,pf2,mode) 0002 %DISTCHPF calculates the cosh spectral distance between power spectra D=(PF1,PF2,MODE) 0003 % 0004 % Inputs: PF1,PF2 Power spectra to be compared. Each row represents a power spectrum: the first 0005 % and last columns represent the DC and Nyquist terms respectively. 0006 % PF1 and PF2 must have the same number of columns. 0007 % 0008 % MODE Character string selecting the following options: 0009 % 'x' Calculate the full distance matrix from every row of PF1 to every row of PF2 0010 % 'd' Calculate only the distance between corresponding rows of PF1 and PF2 0011 % The default is 'd' if PF1 and PF2 have the same number of rows otherwise 'x'. 0012 % 0013 % Output: D If MODE='d' then D is a column vector with the same number of rows as the shorter of PF1 and PF2. 0014 % If MODE='x' then D is a matrix with the same number of rows as PF1 and the same number of columns as PF2'. 0015 % 0016 % The COSH spectral distance is the average over +ve and -ve frequency of 0017 % 0018 % cosh(log(p1/p2))-1 = (p1-p2)^2/(2p1*p2) = (p1/p2 + p2/p1)/2 - 1 0019 % 0020 % The COSH distance is a symmetrical version of the Itakura-Saito distance: distchpf(x,y)=(distispf(x,y)+distispf(y,x))/2 0021 0022 % The Cosh distance can also be calculated directly from AR coefficients; providing np is large 0023 % enough, the values of d0 and d1 in the following will be very similar: 0024 % 0025 % np=255; d0=distchar(ar1,ar2); d1=distchpf(lpcar2pf(ar1,np),lpcar2pf(ar2,np)) 0026 % 0027 0028 % Ref: A.H.Gray Jr and J.D.Markel, "Distance measures for speech processing", IEEE ASSP-24(5): 380-391, Oct 1976 0029 % L. Rabiner abd B-H Juang, "Fundamentals of Speech Recognition", Section 4.5, Prentice-Hall 1993, ISBN 0-13-015157-2 0030 0031 % Copyright (C) Mike Brookes 1997 0032 % Version: $Id: distchpf.m 713 2011-10-16 14:45:43Z dmb $ 0033 % 0034 % VOICEBOX is a MATLAB toolbox for speech processing. 0035 % Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html 0036 % 0037 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0038 % This program is free software; you can redistribute it and/or modify 0039 % it under the terms of the GNU General Public License as published by 0040 % the Free Software Foundation; either version 2 of the License, or 0041 % (at your option) any later version. 0042 % 0043 % This program is distributed in the hope that it will be useful, 0044 % but WITHOUT ANY WARRANTY; without even the implied warranty of 0045 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 0046 % GNU General Public License for more details. 0047 % 0048 % You can obtain a copy of the GNU General Public License from 0049 % http://www.gnu.org/copyleft/gpl.html or by writing to 0050 % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. 0051 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0052 0053 [nf1,p2]=size(pf1); 0054 p1=p2-1; 0055 nf2=size(pf2,1); 0056 if nargin<3 | isempty(mode) mode='0'; end 0057 if any(mode=='d') | (mode~='x' & nf1==nf2) 0058 nx=min(nf1,nf2); 0059 r=pf1(1:nx,:)./pf2(1:nx,:); 0060 q=r+r.^(-1); 0061 d=(2*sum(q(:,2:p1),2)+q(:,1)+q(:,p2))/(4*p1)-1; 0062 else 0063 r=permute(pf1(:,:,ones(1,nf2)),[1 3 2])./permute(pf2(:,:,ones(1,nf1)),[3 1 2]); 0064 q=r+r.^(-1); 0065 d=(2*sum(q(:,:,2:p1),3)+q(:,:,1)+q(:,:,p2))/(4*p1)-1; 0066 end

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