Programmer Guide/Command Reference/EVAL/formants: Difference between revisions

Revision as of 14:54, 20 April 2011

Format tracking algorithm.

Usage

formants(cf, ca, f0, mflag, bias, lmin)

cf

a matrix containing the frequencies of the formant candidates in Hz

ca

a matrix containing the amplitudes of formant candidates in dB

each row of cf/ca contains the candidates of one frame
number of frames: N=nrow(cf)
maximum number of candidates M=ncol(cf)
ca must be a matrix with the same dimensions as cf or a scalar (if amplitudes should not be used for formant tracking)

f0

f0 vector

f0 must be a vector with length N containing the f0 values or a scalar (if f0 should not be used for formant tracking)
if f0 is supplied, the formant tracking is only applied to voiced regions

mflag

selects the tracking method

currently only one method (mflag=0) is implemented (see sp-atom FORMANTS for more details)
a second method using a formant modell is under development

Result: A matrix with N rows and L columns. Each column l contains the formant track with order l+1. L is the maximum formant order or the maximum number of parallel tracks.
See also: f0ac, lpc, cepstrum, ipeaks, FORMANTS

@@ Line 14: / Line 14: @@
 ::*currently only one method (''mflag''=0) is implemented (see [[Programmer_Guide/SPU_Reference/FORMANTS|sp-atom FORMANTS]] for more details)
 ::*a second method using a formant modell is under development
-:;<var>bias</var>:tracking bias in Hz; This value is used to check if two candidates can be connected (<code>|cf[i1,j1]-cf[i2,j2]) / (cf[i1,j1]+cf[i2,j2]+2*bias)</code> must be lower than '''0.1''').
+:;<var>bias</var>:tracking bias in Hz
 :;<var>lmin</var>:the minimum length of a track in frames
-;Result: The f0 vector. The vector contains the f0 values in Hz. The vector length depends mainly on the length of the signal vector ''x'' and the hopsize ''dt''. For unvoiced frames the f0 values are set to zero.
+;Result: A matrix with N rows and L columns. Each column ''l'' contains the formant track with order ''l+1''. L is the maximum formant order or the maximum number of parallel tracks.
 ;See also: [[../f0ac|f0ac]], [[../lpc|lpc]], [[../cepstrum|cepstrum]], [[../ipeaks|ipeaks]],  [[Programmer_Guide/SPU_Reference/FORMANTS|FORMANTS]]
 [[../#Functions|<function list>]]