autoc: Short-term autocorrelation of a time wave

In seewave: Sound Analysis and Synthesis

Short-term autocorrelation of a time wave

Description

This function returns the fundamental frequency of a harmonic time wave. This is achieved by computing a correlation of the signal with itself after a time delay.

Usage

autoc(wave, f, channel = 1, wl = 512, fmin, fmax, threshold = NULL, plot = TRUE,
xlab = "Time (s)", ylab = "Frequency (kHz)", ylim = c(0, f/2000), pb =
FALSE, ...)

Arguments

wave	an R object.
f	sampling frequency of wave (in Hz). Does not need to be specified if embedded in wave.
channel	channel of the R object, by default left channel (1).
wl	length of the window for the analysis (even number of points, by default = 512).
fmin	the minimum frequency to detect (in Hz). See details.
fmax	the maximum frequency to detect (in Hz). See details
threshold	amplitude threshold for signal detection (in %).
plot	logical, if TRUE plots the fundamental frequency against time (by default TRUE).
xlab	title of the x-axis.
ylab	title of the y-axis.
ylim	the range of y values.
pb	if TRUE returns a text progress bar in the console.
...	other plot graphical parameters.

Details

'fmin' and 'fmax' can help by reducing computing time but can also produce less accurate results.

Value

When plot is FALSE, autoc returns a two-column matrix, the first column corresponding to time in seconds (x-axis) and the second column corresponding to to fundamental frequency in kHz (y-axis).
NA corresponds to pause sections in wave (see threshold).

Author(s)

Jerome Sueur [e-mail] and Thierry Aubin [e-mail]

References

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

See Also

ceps, acf

Examples

data(sheep)
# fundamental frequency of a sheep
res <- autoc(sheep, f=8000, threshold=5, fmin=100, fmax=700, plot=FALSE)
spectro(sheep, f=8000, ovlp=75, scale=FALSE)
points(res, pch=20)
legend(0.5, 3.6, "Fundamental frequency", pch=20, bty=0, cex=0.7)

seewave documentation built on Oct. 19, 2023, 5:07 p.m.