cepstro {seewave}R Documentation

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, wl = 512, ovlp = 0, plot = TRUE, grid = TRUE,
scale = TRUE, cont = FALSE, collevels = seq(0, 1, 0.01),
palette = rev.heat.colors, contlevels = seq(0, 1, 0.01),
colcont = "black", colbg="white", colgrid = "black",
colaxis = "black", collab = "black",
plot.title = title(main = "", xlab = "Time (s)", ylab = "Quefrency (kHz)"),
scalelab = "Amplitude", scalefontlab = 1, scalecexlab = 0.75,
axisX = TRUE, axisY = TRUE, ...)

Arguments

wave data describing a time wave or a Sample object generated loading a wav file with loadSample (package sound).
f sampling frequency of wave (in Hz). Does not need to be specified if wave is a Sample object.
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, see Details.
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.
plot.title statements which add titles to the plot.
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).
... 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

When plot is FALSE, a matrix is returned with the successive cepstral profiles computed along time.

Note

This function is based on ceps.

Author(s)

Jerome Sueur sueur@mnhn.fr.

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)
cepstro(sheep,f=8000)

[Package seewave version 1.5.0 Index]