
A query to the selected Intensity object.
the standard deviation (in dB) of the intensity values of the frames within a specified time domain.
The standard deviation between the times t_{1} and t_{2} is defined as
√ {1/(t_{2}  t_{1}) ∫_{t1}^{t2} dt (x(t)  μ)^{2}} 
where x(t) is the intensity (in dB) as a function of time, and μ its mean. For our discrete Intensity object, the standard deviation is approximated by
√ {1/(n1) ∑_{i=m..m+n1} (x_{i}  μ)^{2}} 
where n is the number of frames between t_{1} and t_{2}. Note the "minus 1".
© ppgb, November 7, 2004