diff extra codes/f0detectionyin.m @ 3:1c0f36c348d4

extra code for matlab

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/extra codes/f0detectionyin.m	Sat Apr 20 13:03:01 2013 +0100
@@ -0,0 +1,60 @@
+function f0 = f0detectionyin(x,fs,ws,minf0,maxf0) 
+% x: input signal, fs: sampling rate, ws: integration window length, minf0: minimum f0, maxf0: maximum f0 
+% f0: fundamental frequency detected in Hz 
+maxlag = ws-2;                            % maximum lag 
+th = 0.1;                                 % set threshold 
+d = zeros(maxlag,1);                      % init variable 
+d2 = zeros(maxlag,1);                     % init variable 
+% compute d(tau) 
+x1 = x(1:ws);  
+cumsumx = sum(x1.^2); 
+cumsumxl = cumsumx; 
+xy = xcorr(x(1:ws*2),x1); 
+xy = xy(ws*2+1:ws*3-2); 
+for lag=0:maxlag-1 
+    d(1+lag) = cumsumx + cumsumxl - 2*xy(1+lag); 
+    cumsumxl = cumsumxl - x(1+lag).^2 + x(1+lag+ws+1)^2; 
+end 
+cumsum = 0; 
+% compute d'(tau) 
+d2(1) = 1; 
+for lag=1:maxlag-1 
+    cumsum = cumsum + d(1+lag); 
+    d2(1+lag) = d(1+lag)*lag./cumsum; 
+end 
+% limit the search to the target range 
+minf0lag = 1+round(fs./minf0);            % compute lag corresponding to minf0 
+maxf0lag = 1+round(fs./maxf0);            % compute lag corresponding to maxf0 
+if (maxf0lag>1 && maxf0lag<maxlag) 
+    d2(1:maxf0lag) = 100;                 % avoid lags shorter than maxf0lag 
+end 
+if (minf0lag>1 && minf0lag<maxlag) 
+        d2(minf0lag:end) = 100;               % avoid lags larger than minf0lag 
+end 
+% find the best candidate 
+mloc = 1 + find((d2(2:end-1)<d2(3:end)).*(d2(2:end-1)<d2(1:end-2)));  % minima 
+candf0lag = 0; 
+if (length(mloc)>0) 
+    I = find(d2(mloc)<th); 
+    if (length(I)>0) 
+        candf0lag = mloc(I(1)); 
+    else 
+        [Y,I2] = min(d2(mloc)); 
+        candf0lag = mloc(I2); 
+    end 
+    candf0lag = candf0lag;                % this is zero-based indexing     
+    if (candf0lag>1 & candf0lag<maxlag) 
+        % parabolic interpolation 
+        lval = d2(candf0lag-1);  
+        val = d2(candf0lag);  
+        rval= d2(candf0lag+1);  
+        candf0lag = candf0lag + .5*(lval-rval)./(lval-2*val+rval);   
+    end 
+end         
+ac = min(d2);  
+f0lag = candf0lag-1;                      % convert to zero-based indexing 
+f0 = fs./f0lag;                           % compute candidate frequency in Hz 
+if (ac > 0.2)                             % voiced/unvoiced threshold 
+    f0 = 0;                               % set to unvoiced 
+end 
+ 
\ No newline at end of file