comparison toolboxes/MIRtoolbox1.3.2/AuditoryToolbox/CorrelogramPitch.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function [pitch,salience]=CorrelogramPitch(correlogram, width, sr, low, high);
+% pitch=CorrelogramPitch(correlogram, width [, sr, lowPitch, highPitch]) 
+% computes the pitch of a correlogram sequence by finding the time lag
+% with the largest correlation energy. 
+%  
+% (c) 1998 Interval Research Corporation
+
+if nargin < 3; sr=22254.54; end;
+if nargin < 4; low=0; end;
+if nargin < 5; high=inf; end;
+
+dropLow = floor(sr/high);
+if low > 0
+	dropHigh = min(width,ceil(sr/low));
+else
+	dropHigh = width;
+end
+
+[pixels frames] = size(correlogram);
+channels = pixels/width;
+if channels < 1 | floor(channels) ~= channels
+	error('Correlogram Size Error');
+end
+
+pitch = zeros(1,frames);
+salience = zeros(1,frames);
+for j=1:frames
+	% Get one frame from the correlogram, reshape it, and compute
+	% the sum (as a function of time lag) across all channels.
+	if channels == 1
+		summary=reshape(correlogram(:,j),channels,width);
+	else
+		summary=sum(reshape(correlogram(:,j),channels,width));
+	end
+	zeroLag = summary(1);
+	% Now we need to find the first pitch past the peak at zero
+	% lag.  The following lines smooth the summary pitch a bit, then
+	% look for the first point where the summary goes back up.  
+	% Everything up to this point is zeroed out.
+	windowLength=16;
+	sumfilt=filter(ones(1,windowLength),[1],summary);
+	sumdif=sumfilt(2:width)-sumfilt(1:width-1);
+	sumdif(1:windowLength) = zeros(1,windowLength);
+	valleys=find(sumdif>0);
+	summary(1:valleys(1)) = zeros(1,valleys(1));
+	summary(1:dropLow) = zeros(1,dropLow);
+	summary(dropHigh:width) = zeros(1,width-dropHigh+1);
+	plot(summary);
+	drawnow;
+	% Now find the location of the biggest peak and call this the pitch
+	[m p] = max(summary);
+	pitch(j) = sr/(p-1);
+	salience(j) = m/zeroLag;
+end