gusucode.com > 《MATLAB图像与视频处理实用案例详解》代码 > 《MATLAB图像与视频处理实用案例详解》代码/第 19 章 基于语音识别的信号灯图像模拟控制技术/voicebox/distispf.m
function d=distispf(pf1,pf2,mode) %DISTISPF calculates the Itakura-Saito 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 Itakura-Saito spectral distance is the average over +ve and -ve frequency of % % pf1/pf2 - log(pf1/pf2) - 1 = exp(v) - v - 1 where v=log(pf1/pf2) % % The Itakura-Saito distance is asymmetric: pf1>pf2 contributes more to the distance than pf2>pf1. % A symmetrical version is the COSH distance: distchpf(x,y)=(distispf(x,y)+distispf(y,x))/2 % The Itakura-Saito distance can also be calculated directly from AR coefficients; providing np is large % enough, the values of d0 and d1 in the following will be very similar: % % np=255; d0=distisar(ar1,ar2); d1=distispf(lpcar2pf(ar1,np),lpcar2pf(ar2,np)) % % Ref: A.H.Gray Jr and J.D.Markel, "Distance measures for speech processing", IEEE ASSP-24(5): 380-391, Oct 1976 % L. Rabiner abd B-H Juang, "Fundamentals of Speech Recognition", Section 4.5, Prentice-Hall 1993, ISBN 0-13-015157-2 % F.Itakura & S.Saito, "A statistical method for estimation of speech spectral density and formant frequencies", % Electronics & Communications in Japan, 53A: 36-43, 1970. % Copyright (C) Mike Brookes 1997 % Version: $Id: distispf.m,v 1.4 2007/05/04 07:01:38 dmb Exp $ % % VOICEBOX is a MATLAB toolbox for speech processing. % Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 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 2 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 can obtain a copy of the GNU General Public License from % http://www.gnu.org/copyleft/gpl.html or by writing to % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% [nf1,p2]=size(pf1); p1=p2-1; nf2=size(pf2,1); if nargin<3 | isempty(mode) mode='0'; end if any(mode=='d') | (mode~='x' & nf1==nf2) nx=min(nf1,nf2); r=pf1(1:nx,:)./pf2(1:nx,:); q=r-log(r); d=(sum(q(:,2:p1),2)+0.5*(q(:,1)+q(:,p2)))/p1-1; else r=permute(pf1(:,:,ones(1,nf2)),[1 3 2])./permute(pf2(:,:,ones(1,nf1)),[3 1 2]); q=r-log(r); d=(sum(q(:,:,2:p1),3)+0.5*(q(:,:,1)+q(:,:,p2)))/p1-1; end