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Spectral rolloff point for audio signals and auditory spectrograms

`rolloffPoint = spectralRolloffPoint(x,f)`

`rolloffPoint = spectralRolloffPoint(x,f,Name,Value)`

returns the spectral rolloff point of the signal, `rolloffPoint`

= spectralRolloffPoint(`x`

,`f`

)`x`

, over time. How the
function interprets `x`

depends on the shape of
`f`

.

specifies options using one or more `rolloffPoint`

= spectralRolloffPoint(`x`

,`f`

,`Name,Value`

)`Name,Value`

pair arguments.

The spectral rolloff point is calculated as described in [1]:

$$\text{rolloffPoint}=i$$

such that

$$\sum _{k={b}_{1}}^{i}{s}_{k}}=\kappa {\displaystyle \sum _{k={b}_{1}}^{{b}_{2}}{s}_{k}$$

where

*s*is the spectral value at bin_{k}*k*.*b*_{1}and*b*_{2}are the band edges, in bins, over which to calculate the spectral spread.*κ*is the percentage of total energy contained between*b*_{1}and*i*. You can set*κ*using`Threshold`

.

[1] Scheirer, E., and M. Slaney,
"Construction and Evaluation of a Robust Multifeature Speech/Music Discriminator,"
*IEEE International Conference on Acoustics, Speech, and Signal
Processing*. Volume 2, 1997, pp. 1221–1224.