corenv {seewave} | R Documentation |
This function tests the similarity between two time wave envelopes by returning their maximal correlation and the time shift related to it.
corenv(wave1, wave2, f, smooth = 20, plot = TRUE, plotval = TRUE, method = "spearman", col = "black", colval = "red", cexval = 1, fontval = 1, xlab = "Time (s)", ylab = "Coefficient of correlation (r)", ...)
wave1 |
data describing a first time wave. |
wave2 |
data describing a second time wave. |
f |
sampling frequency of wave1 and wave2 . |
smooth |
smoothes the envelopes of wave1 and wave2
by averaging the number of points selected. |
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 correlations between the envelopes of wave1
and wave2
are computed when regularly sliding forward and backward wave2
along
wave1
.
The maximal correlation is obtained at a particular shift (time offset).
This shift may be positive or negative.
The higher smooth
is set up,
the faster will be the computation but less precise the results will be.
The corresponding p value, obtained with cor.test
, is plotted.
Inverting wave1
and wave2
may give slight different results.
If plot
is FALSE
, corenv
returns a list containing four
components:
r |
the successive correlation values between x and y . |
rmax |
the maximum correlation value between x and y . |
p |
the p value corresponding to rmax . |
f |
the time offset corresponding to rmax . |
Jérôme Sueur jerome.sueur@ibaic.u-psud.fr
spec
,covspectro
,
cor
, cor.test
.
data(orni) # cross-correlation between two echemes of a cicada song wave1<-cutw(orni,f=22050,from=0.3,to=0.4,plot=FALSE) wave2<-cutw(orni,f=22050,from=0.58,to=0.68,plot=FALSE) corenv(wave1,wave2,f=22050,type="l",ylim=c(-0.7,1.1))