CC: To DTW...

You can choose this command after selecting 2 objects with cepstral coefficients (two MFCC's or LFCC's). With this command you perform dynamic time warping.


First we calculate distances between cepstral coefficients:

The distance between frame i (from me) and j (from thee) is:
    wc · d1 + wle · d2 + wr · d3,
    where wc, wle & wr are user-supplied weights and
      d1 = ∑ (k=1..nCoefficients; (cik - cjk)2)
      d2 = (ci0 - cj0)2
      d3 = ∑ (k=1..nCoefficients; (rik - rjk)2), with
      rik the regression coefficient of the cepstral coefficients from the frames within a time span of dtr seconds. cij is j-th cepstral coefficient in frame i.

Next we find the optimum path through the distance matrix with a Viterbi-algorithm.

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© djmw, September 18, 1996