H {seewave}

Total entropy

Description

This function estimates the total entropy of a time wave.

Usage

H(wave, f, channel = 1, wl = 512, envt="hil", msmooth = NULL, ksmooth = NULL)

Arguments

wave

an R object.

f

sampling frequency of wave (in Hz). Does not need to be specified if embedded in wave.

channel

channel of the R object, by default left channel (1).

wl

window length for spectral entropy analysis (even number of points). See sh.

envt

the type of envelope to be used: either "abs" for absolute amplitude envelope or "hil" for Hilbert amplitude envelope. See env.

msmooth

a vector of length 2 to smooth the amplitude envelope with a mean sliding window. The first component is the window length (in number of points). The second component is the overlap between successive windows (in %). See env.

ksmooth

kernel smooth via kernel. See env.

Details

This function computes the product between the values obtained with sh and th functions.
This then gives a global (time and frequency) estimation of signal entropy.
The frequency mean spectrum and the amplitude envelope needed for computing respectively sh and th are automatically generated. They can be controlled through wl and smooth arguments respectively. See examples below and examples in sh and th for implications on the results.

Value

A single value varying between 0 and 1 is returned. The value has no unit.

Note

The entropy of a noisy signal will tend towards 1 whereas the entropy of a pure tone signal will tend towards 0.

Author(s)

Jerome Sueur [e-mail]

References

Sueur, J., Pavoine, S., Hamerlynck, O. & Duvail, S. (2008) - Rapid acoustic survey for biodiversity appraisal. PLoS ONE, 3(12): e4065.

See Also

sh, th, csh

Examples

data(orni)
H(orni,f=22050)
# changing the spectral parameter (wl)
H(orni,f=22050,wl=1024)
# changing the temporal parameter (msmooth)
H(orni,f=22050,msmooth=c(20,0))