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corenv

Cross-correlation between two time wave envelopes

Description

This function tests the similarity between two time wave envelopes by returning their maximal correlation and the time shift related to it.

Usage

corenv(wave1, wave2, f, channel=c(1,1), envt="hil", msmooth = NULL, ksmooth = NULL,
ssmooth = 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", pb = FALSE, ...)

Arguments

`wave1`	a first R object.
`wave2`	a second R object.
`f`	sampling frequency of `wave` (in Hz). Does not need to be specified if embedded in `wave`.
`channel`	channel of the R objects, by default left channel (1) for each object.
`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`.
`ssmooth`	sum smooth. 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).
`pb`	if `TRUE` returns a text progress bar in the console.
`...`	other `plot` graphical parameters.

Details

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.

Value

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`.

Author(s)

Jerome Sueur

Examples

## Not run: 
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)

## End(Not run)

seewave

Sound Analysis and Synthesis

v2.1.6

GPL (>= 2)

Authors

Jerome Sueur <sueur@mnhn.fr> [cre, au], Thierry Aubin [au], Caroline Simonis [au], Laurent Lellouch [main ctrb], Ethan C. Brown [ctrb], Marion Depraetere [ctrb], Camille Desjonqueres [ctrb], Francois Fabianek [ctrb], Amandine Gasc [ctrb], Eric Kasten [ctrb], Stefanie LaZerte [ctrb], Jonathan Lees [ctrb], Jean Marchal [ctrb], Andre Mikulec [ctrb], Sandrine Pavoine [ctrb], David Pinaud [ctrb], Alicia Stotz [ctrb], Luis J. Villanueva-Rivera [ctrb], Zev Ross [ctrb], Carl G. Witthoft [ctrb], Hristo Zhivomirov [ctrb].

Initial release

2020-06-28