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.
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, ...)This function returns a list of three items:
a numeric vector corresponding to the time axis.
a numeric vector corresponding to the quefrency axis.
a numeric matrix corresponding to the the successive cepstral profiles computed along time.
an R object.
sampling frequency of wave (in Hz). Does not need to
be specified if embedded in wave.
channel of the R object, by default left channel (1).
if at is not null, length of the window for the analysis
(even number of points, by defaults = 512).
overlap between two successive windows (in %).
logical, if TRUE plots the cepstrogram
(by default TRUE).
logical, if TRUE plots a y-axis grid
(by default TRUE).
logical, if TRUE plots a dB colour scale on the right
side of the cesptrogram (by default TRUE).
logical, if TRUE overplots contour lines on the cepstrogram
(by default FALSE).
a set of levels which are used to partition the amplitude range of the cepstrogram (in dB).
a color palette function to be used to assign colors in the plot.
a set of levels which are used to partition the amplitude range for contour overplot (in dB).
colour for cont plotting.
background colour.
colour for grid plotting.
color of the axes.
color of the labels.
label of the time axis.
label of the quefrency axis.
label of the main title.
amplitude scale label.
font of the amplitude scale label.
cex of the amplitude scale label.
if TRUE plots time X-axis (by default TRUE).
if TRUE plots frequency Y-axis (by default TRUE).
modifications of the time X-axis limits.
modifications of the quefrency Y-axis limits (in ms).
other contour graphical parameters.
Jerome Sueur sueur@mnhn.fr.
It is unfortunately not possible to turn the y-axis to a frequency scale.
See spectro for the use of the graphical arguments.
Oppenheim, A.V. and Schafer, R.W. 2004. From frequency to quefrency: a history of the cepstrum. Signal Processing Magazine IEEE, 21: 95-106.
ceps, fund, autoc
data(sheep)
sheepc <- cutw(sheep, f=8000, from = 0.19, to = 2.3)
cepstro(sheepc,f=8000)
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