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Hi All,
I'm writing to inquire why
the delta and delta delta feature are calculated in this way, as noticed in the
window coefficient configuration for HMGenS:
Assume the static feature is x( t
);
1. delta = -0.5*x( t-1 ) +
0*x( t ) + 0.5*x( t+1 ), intuitively
2. deltadelta = 1*x( t-1 )
+ (-2)*x( t ) + 1*x( t+1 ), how is this derived? {[x( t+1 ) -
x( t )]/1 - [x( t ) - x( t-1 )]/1}/1 ?
Another question is that I use the regression
formula on HTK book (5.16) to calculate the delta feature, and delta delta
feature is obtained by applying the formula again on delta. Does
HMGenS config file support setting the coefficients on a larger window scope,
e.g. 5 or 7 rather than 3 ?
Thanks.
Regards,
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