spectro {seewave} | R Documentation |
This function returns a two-dimension spectrographic representation of a time wave. The function corresponds to short-term Fourier transform. An amplitude contour plot can be overlaid.
spectro(wave, f, wl = 512, wn = "hanning", zp = 0, ovlp = 0, plot = TRUE, grid = TRUE, osc = FALSE, scale = TRUE, cont = FALSE, collevels = seq(-30, 0, 1), palette = spectro.colors, contlevels = seq(-30, 0, 10), colcont = "black", colbg = "white", colgrid = "black", colaxis = "black", collab="black", plot.title = title(main = "", xlab = "Time (s)", ylab = "Frequency (kHz)"), scalelab = "Amplitude\n(dB)", scalefontlab = 1, scalecexlab =0.75, axisX = TRUE, axisY = TRUE, tlim = NULL, trel = TRUE, flim = NULL, flimd = NULL, listen=FALSE, ...)
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 |
window length for the analysis (even number of points). (by default = 512) |
zp |
zero-padding (even number of points), see Details . |
ovlp |
overlap between two successive windows (in %). |
wn |
window name, see ftwindow (by default "hanning" ). |
plot |
logical, if TRUE plots the spectrogram
(by default TRUE ). |
grid |
logical, if TRUE plots a y-axis grid
(by default TRUE ). |
osc |
logical, if TRUE plots an oscillogram beneath
the spectrogram (by default FALSE ). |
scale |
logical, if TRUE plots a dB colour scale on the right
side of the spectrogram (by default TRUE ). |
cont |
logical, if TRUE overplots contour lines on the spectrogram
(by default FALSE ). |
collevels |
a set of levels which are used to partition the amplitude range of the spectrogram (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 |
logical, if TRUE plots time X-axis (by default TRUE ). |
axisY |
logical, if TRUE plots frequency Y-axis (by default TRUE ). |
tlim |
modifications of the time X-axis limits. |
trel |
time X-axis with a relative scale when tlim is not null,
i.e. relative to wave . |
flim |
modifications of the frequency Y-axis limits. |
flimd |
dynamic modifications of the frequency Y-axis limits. New wl
and ovlp arguments are applied to increase time/frequency resolution. |
listen |
if TRUE the sound is played back (by default FALSE ). |
... |
other contour and oscillo
graphical parameters. |
Following Heisenberg uncertainty principle, the short-term Fourier transform
cannot be precised in both time and frequency. The temporal and frequency
precisions of the function are actually dependent of the wl
value.
Choosing a high wl
value will increase the frequency resolution but
reduce the temporal one, and vice versa. The frequency precision is
obtained by calculating the ratio f
/wl
,
and the temporal precision is obtained by calculating the reverse ratio
wl
/f
. This problem can be reduced in some way with zp
that
adds 0 values on both sides of the analysis window. This increases frequency
resolution without altering time resolution.
Any colour palette can be used. In particular, it is possible to use other
palettes coming with seewave: temp.colors
,
rev.gray.colors.1
,
rev.gray.colors.2
, rev.heat.colors
,
rev.terrain.colors
, rev.topo.colors
,
rev.cm.colors
corresponding to the reverse of heat.colors
,
terrain.colors
, topo.colors
, cm.colors
.
Use locator
to identify points.
If plot
is FALSE
, this function returns a matrix. Each column
corresponds to a Fourier transform of length wl
/2.
This function is based on fft
, contour
and
filled.contour
Jerome Sueur sueur@mnhn.fr and Caroline Simonis csimonis@mnhn.fr.
Hopp, S. L., Owren, M. J. and Evans, C. S. (Eds) 1998. Animal acoustic communication. Springer, Berlin, Heidelberg.
spectro3D
, dynspec
,
oscillo
, dBscale
, fft
.
data(tico) data(pellucens) # simple plots spectro(tico,f=22050) spectro(tico,f=22050,osc=TRUE) spectro(tico,f=22050,scale=FALSE) spectro(tico,f=22050,osc=TRUE,scale=FALSE) # manipulating wl op<-par(mfrow=c(2,2)) spectro(tico,f=22050,wl=256,scale=FALSE) title("wl = 256") spectro(tico,f=22050,wl=512,scale=FALSE) title("wl = 512") spectro(tico,f=22050,wl=1024,scale=FALSE) title("wl = 1024") spectro(tico,f=22050,wl=4096,scale=FALSE) title("wl = 4096") par(op) # vertical zoom using flim spectro(tico,f=22050, ylim=c(2,6)) spectro(tico,f=22050, ylimd=c(2,6)) # a full plot pellu2<-cutw(pellucens,f=22050,from=1,plot=FALSE) spectro(pellu2,f=22050,ovlp=85,zp=16,osc=TRUE, cont=TRUE,contlevels=seq(-30,0,20),colcont="red", lwd=1.5,lty=2,palette=rev.terrain.colors) # black and white spectrogram spectro(pellu2,f=22050,ovlp=85,zp=16, palette=rev.gray.colors.1) # colour modifications data(sheep) spectro(sheep,f=8000,palette=temp.colors,collevels=seq(-115,0,1)) spectro(pellu2,f=22050,ovlp=85,zp=16, palette=rev.cm.colors,osc=TRUE,colwave="orchid1") spectro(pellu2,f=22050,ovlp=85,zp=16,osc=TRUE,palette=rev.heat.colors, colbg="black",colgrid="white", colwave="white",colaxis="white",collab="white")