A query to the selected Harmonicity object.
the standard deviation, expressed in dB.
The standard deviation between the times t1 and t2 is defined as
|1/(t2 - t1) ∫t1t2 dt (x(t) - μ)2|
where x(t) is the harmonicity (in dB) as a function of time, and μ its mean. For our discrete Harmonicity object, the standard deviation is approximated by
|1/(n-1) ∑i=m..m+n-1 (xi - μ)2|
where n is the number of frame centres between t1 and t2. Note the "minus 1".
© ppgb, November 7, 2004