about pitch coherence

[zoulingqi]

hello,
In your code:
Exp[i] = Exp[i]/sqrt(1e-15+Ex[i]*Ep[i]).
while bandE[i]=sqrt(sum[i]) in the function compute_band_corr.

I think the code should be
if(Ex[i]*Ep[i]==0)
Exp[i] = 0;(or 1?)
else
Exp[i] = Exp[i]/(1e-15+Ex[i]*Ep[i]).
And this can only make pitch coherence{Exp[i]} be 1,when signal{X} and it's periodic component {P} are exactly the same。

[jzi040941]

I've checked the code in the function compute_band_corr didn't apply sqrt
if I change it to bandE[i]=sqrt(sum[i]) than I think
the equation Exp[i] = Exp[i]/sqrt(1e-15+Ex[i]*Ep[i]). should remain sqrt
otherwise your answer Exp[i] = Exp[i]/(1e-15+Ex[i]*Ep[i]) (without sqrt) is right

I'm not sure about which Exp[i] value should I take 0 or 1 in case of exception that Ex[i] or Ep[i] is 0.
how about changing 1e-15 to very small epsilon 1e-37 would be nice solution
I think it won't ruin Exp value that much but also prevent zero division error.

wait for your suggestion thanks.

[zoulingqi]

sorry,I confused the two functions.
"bandE[i]=sqrt(sum[i])"is in the fuction compute_band_energy.
Ex[i] and Ep[i] is already the ||x|| and ||p||,so Exp[i] should equal to Exp[i]/(1e-37+Ex[i]*Ep[i]) instead of Exp[i]/sqrt(1e-37+Ex[i]*Ep[i]).

void compute_band_energy(float *bandE, const kiss_fft_cpx *X) {
......
......
for (i=0;i<NB_BANDS;i++)
{
bandE[i] = sqrt(sum[i]);
}
}