cepstro: 2D-cepstrogram of a time wave

In seewave: Sound Analysis and Synthesis

2D-cepstrogram of a time wave

Description

This function returns a two-dimension cepstrographic representation of a time wave. The function corresponds to a short-term cepstral transform. An amplitude contour plot can be overlaid.

Usage

cepstro(wave, f, channel = 1, wl = 512, ovlp = 0, plot = TRUE, grid = TRUE,
scale = TRUE, cont = FALSE, collevels = seq(0, 1, 0.01),
palette = reverse.heat.colors, contlevels = seq(0, 1, 0.01),
colcont = "black", colbg="white", colgrid = "black",
colaxis = "black", collab = "black",
xlab = "Time (s)", ylab = "Quefrency (ms)",
scalelab = "Amplitude", main = NULL, scalefontlab = 1, scalecexlab = 0.75,
axisX = TRUE, axisY = TRUE, tlim = NULL, qlim = NULL, ...)

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	if at is not null, length of the window for the analysis (even number of points, by defaults = 512).
ovlp	overlap between two successive windows (in %).
plot	logical, if TRUE plots the cepstrogram (by default TRUE).
grid	logical, if TRUE plots a y-axis grid (by default TRUE).
scale	logical, if TRUE plots a dB colour scale on the right side of the cesptrogram (by default TRUE).
cont	logical, if TRUE overplots contour lines on the cepstrogram (by default FALSE).
collevels	a set of levels which are used to partition the amplitude range of the cepstrogram (in dB).
palette	a color palette function to be used to assign colors in the plot.
contlevels	a set of levels which are used to partition the amplitude range for contour overplot (in dB).
colcont	colour for cont plotting.
colbg	background colour.
colgrid	colour for grid plotting.
colaxis	color of the axes.
collab	color of the labels.
xlab	label of the time axis.
ylab	label of the quefrency axis.
main	label of the main title.
scalelab	amplitude scale label.
scalefontlab	font of the amplitude scale label.
scalecexlab	cex of the amplitude scale label.
axisX	if TRUE plots time X-axis (by default TRUE).
axisY	if TRUE plots frequency Y-axis (by default TRUE).
tlim	modifications of the time X-axis limits.
qlim	modifications of the quefrency Y-axis limits (in ms).
...	other contour graphical parameters.

Details

It is unfortunately not possible to turn the y-axis to a frequency scale.
See spectro for the use of the graphical arguments.

Value

This function returns a list of three items:

time	a numeric vector corresponding to the time axis.
freq	a numeric vector corresponding to the quefrency axis.
amp	a numeric matrix corresponding to the the successive cepstral profiles computed along time.

Note

This function is based on ceps.

Author(s)

Jerome Sueur [e-mail].

References

Oppenheim, A.V. and Schafer, R.W. 2004. From frequency to quefrency: a history of the cepstrum. Signal Processing Magazine IEEE, 21: 95-106.

See Also

ceps, fund, autoc

Examples

data(sheep)
sheepc <- cutw(sheep, f=8000, from = 0.19, to = 2.3)
cepstro(sheepc,f=8000)

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