seewave (version 2.2.4)

covspectro: Covariance between two spectrograms

Description

This function tests the similarity between two spectrograms by returning their maximal covariance and the time shift related to it.

Usage

covspectro(wave1, wave2, f, channel = c(1,1), wl = 512, wn = "hanning", n,
plot = TRUE, plotval = TRUE,
method = "spearman", col = "black", colval = "red", cexval = 1,
fontval = 1, xlab = "Time (s)",
ylab = "Normalised covariance (cov)", type = "l", pb = FALSE, ...)

Value

If plot is FALSE, covspectro returns a list containing three components:

cov

the successive covariance values between wave1 and wave2.

covmax

the maximum covariance between wave1 and wave2.

t

the time offset corresponding to cov.

Details

Successive covariances between the spectrogram of wave1 and the spectrogram of wave2 are computed when regularly sliding forward and backward wave2 along wave1.
The maximal covariance is obtained at a particular shift (time offset). This shift may be positive or negative.
n sets in how many steps wave2 will be slided along wave1. Time process can be then decreased by setting low n value.
Inverting wave1 and wave2 may give slight different results.

References

Hopp, S. L., Owren, M. J. and Evans, C. S. (Eds) 1998. Animal acoustic communication. Springer, Berlin, Heidelberg.

See Also

corspec, corenv, spectro, cor,

Examples

# covariance between two notes of a birdsong
if (FALSE) {
data(tico)
note1<-cutw(tico, f=22050, from=0.5, to=0.9)
note2<-cutw(tico, f=22050, from=0.9, to=1.3)
covspectro(note1,note2,f=22050,n=37)
}