tomwalters@0: % method of class @signal
tomwalters@0: % function sig=crosscorrelate(sig1,sig2,[delay_start],[delay_stop],[normalization_mode])
tomwalters@0: %
tomwalters@0: % calculates the cross corrlelation between the signals sig1 and sig2. The
tomwalters@0: % return value is a signal that covers the correlation between the two
tomwalters@0: % signals between delay_start and delay_stop.
tomwalters@0: %
tomwalters@0: %   INPUT VALUES:
tomwalters@0: %       sig1: original @signal
tomwalters@0: %       sig2: @signal to correlate with
tomwalters@0: %		delay_start: start of the correlation : default -length(sig)
tomwalters@0: %		delay_stop: longest delay of the correlation : default length(sig)
tomwalters@0: % 		normalization_mode: normalizateion: default: 'biased' (see help 'xcorr')
tomwalters@0: % 		
tomwalters@0: %   RETURN VALUE:
tomwalters@0: % 		@sig: the correlation values at each delay
tomwalters@0: %
bleeck@3: % This external file is included as part of the 'aim-mat' distribution package
bleeck@3: % (c) 2011, University of Southampton
bleeck@3: % Maintained by Stefan Bleeck (bleeck@gmail.com)
bleeck@3: % download of current version is on the soundsoftware site: 
bleeck@3: % http://code.soundsoftware.ac.uk/projects/aimmat
bleeck@3: % documentation and everything is on http://www.acousticscale.org
bleeck@3: 
tomwalters@0: 
tomwalters@0: function sig=crosscorrelate(sig1,sig2,delay_start,delay_stop,normalization_mode)
tomwalters@0: 
tomwalters@0: if nargin < 5
tomwalters@0: 	normalization_mode='biased';
tomwalters@0: end
tomwalters@0: if nargin < 4
tomwalters@0: 	l1=getlength(sig1);
tomwalters@0: 	l2=getlength(sig2);
tomwalters@0: 	delay_stop=min(l1,l2); % the smaller of both length
tomwalters@0: end
tomwalters@0: if nargin < 3
tomwalters@0: 	delay_start=-delay_stop;	% the 
tomwalters@0: end
tomwalters@0: 
tomwalters@0: % by this time the signal is shifted
tomwalters@0: deltatime=delay_stop+delay_start;
tomwalters@0: 
tomwalters@0: values1=getvalues(sig1);
tomwalters@0: values2=getvalues(sig2);
tomwalters@0: 
tomwalters@0: sr=getsr(sig1);
tomwalters@0: maxlags1=delay_stop*sr;
tomwalters@0: maxlags2=-delay_start*sr;
tomwalters@0: 
tomwalters@0: maxlags=floor(max(maxlags1,maxlags2));
tomwalters@0: 
tomwalters@0: % do the crosscorrelation:
tomwalters@0: corrcovs=xcorr(values1,values2,maxlags,normalization_mode);
tomwalters@0: 
tomwalters@0: % return a signal:
tomwalters@0: sig=signal(corrcovs,sr);
tomwalters@0: if deltatime > 0
tomwalters@0: 	sig=getpart(sig,deltatime);	% compensate for a possible asymmetric shift
tomwalters@0: else
tomwalters@0: 	sig=getpart(sig,0,delay_stop-delay_start);	% compensate for a possible asymmetric shift
tomwalters@0: end
tomwalters@0: sig=setstarttime(sig,delay_start);
tomwalters@0: sig=setname(sig,'CrossCorrelation');
tomwalters@0: sig=setunit_x(sig,'delay (ms)');
tomwalters@0: 
tomwalters@0: 
tomwalters@0: 
tomwalters@0: 
tomwalters@0: 
tomwalters@0: