covspectro {seewave} | R Documentation |
This function tests the similarity between two spectrograms by returning their maximal covariance and the time shift related to it.
covspectro(wave1, wave2, f, 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)", ...)
wave1 |
data or a Sample object created loading a wav file
with loadSample (package Sound) describing a first time wave. |
wave2 |
data or a Sample object created loading a wav file
with loadSample (package Sound) describing a second time wave. |
f |
sampling frequency of wave1 and wave2 (in Hz). |
wl |
length of the window for the analysis (even number of points). |
wn |
window name, see ftwindow (by default "hanning" ). |
n |
number of covariances computed between wave1 and wave2
when sliding wave2 along wave1 . |
plot |
logical, if TRUE plots r values against frequency shift
(by default TRUE ). |
plotval |
logical, if TRUE adds to the plot maximum R value
and frequency offset (by default TRUE ). |
method |
a character string indicating which correlation coefficient is
to be computed ("pearson", "spearman", or "kendall")
(see cor ). |
col |
colour of r values. |
colval |
colour of r max and frequency offset values. |
cexval |
character size of r max and frequency offset values. |
fontval |
font of r max and frequency offset values. |
xlab |
title of the frequency axis. |
ylab |
title of the r axis. |
... |
other plot graphical parameters. |
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.
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 . |
Jérôme Sueur jerome.sueur@univ-tours.fr
Hopp, S. L., Owren, M. J. and Evans, C. S. (Eds) 1998. Animal acoustic communication. Springer, Berlin, Heidelberg.
corspec
, corenv
, spectro
,
cor
,
# covariance between two echemes of a cicada calling song data(orni) orni1<-cutw(orni,f=22050,from=0,to=0.1,plot=FALSE) orni2<-cutw(orni,f=22050,from=0.15,to=0.25,plot=FALSE) covspectro(orni1,orni2,f=22050,wl=512,n=37,type="l")