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, envt="hil", msmooth = NULL, ksmooth = NULL, plot = TRUE, plotval = TRUE, method = "spearman", col = "black", colval = "red", cexval = 1, fontval = 1, xlab = "Time (s)", ylab = "Coefficient of correlation (r)", type = "l", ...)
wave1 |
data or a Sample object generated loading a wav file
with loadSample (package Sound) describing a first time wave. |
wave2 |
data or a Sample object generated loading a wav file
with loadSample (package Sound) describing a second time wave. |
f |
sampling frequency of wave1 and wave1 (in Hz).
Does not need to be specified if wave1 and/or wave2 are/is (a)
Sample object(s). |
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 . |
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. |
type |
if plot is TRUE , type of plot that should be drawn.
See plot for details (by default "l" for lines). |
... |
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 |
a two-column matrix, the first colum corresponding to the time
shift (frequency x-axis) and the second column corresponding to the successive
r correlation values between env1 and env2 (correlation y-axis). |
rmax |
the maximum correlation value between x and y . |
p |
the p value corresponding to rmax . |
t |
the time offset corresponding to rmax . |
Jerome Sueur sueur@mnhn.fr
env
,corspec
,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)