dtw.m

DTW算法

function dist = dtw(t,r)
% Compare two model using a efficient DTW
% inputs:
%   test -- test model
%   ref  -- reference model
%
% output:
%   dist -- matching score

%      Copyright (C) Qiang He, 2001
%
%   This file is part of MATLAB speech recognition software. Homepage is at:
%     http://go.163.com/energy/speech.htm
%
%   About the author:
%     Qiang He (Ph.D.)
%     E.E., Tsinghua University, Beijing, P.R.C., 100084
%     Email: [e-mail]
%     WWW  : http://go.163.com/energy
%     Tel  : [phone]
%     
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%   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
%   ftp://prep.ai.mit.edu/pub/gnu/COPYING-2.0 or by writing to
%   Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

n = size(t,1);
m = size(r,1);

% frame match distance matrix
d = zeros(n,m);

for i = 1:n
for j = 1:m
	d(i,j) = sum((t(i,:)-r(j,:)).^2);
end
end

% accumulate distance matrix
D =  ones(n,m) * realmax;
D(1,1) = d(1,1);

% dynamic programming
for i = 2:n
for j = 1:m
	D1 = D(i-1,j);

	if j>1
		D2 = D(i-1,j-1);
    else
        D2 = realmax;
	end

	if j>2
		D3 = D(i-1,j-2);
    else
        D3 = realmax;
	end

	D(i,j) = d(i,j) + min([D1,D2,D3]);
end
end

dist = D(n,m);