cp.molecule, cpt, dwt, nd.dwt, rob.dwt, wp.molecule, wpt
.
time.freq.plot(x, plot=T, power.stretch=0, ...) time.scale.plot(x, plot=T, power.stretch=0, ...)
TRUE
, a time-frequency plane plot will be provided.
stretch.image
is
TRUE
.
If
power.stretch=0
, then image is transformed
with
log(abs(x)+1)
.
Otherwise, the image is transformed with
(abs(x))^power.stretch
.
image
.
x, y
and
z
suitable for input to
image
.
A time-frequency plane plot is also known as the "scalogram"
(when based on the wavelet
transform) and the "spectrogram" (when based on the Fourier transform). It
plots the modulus of the coefficients as rectangles (known as Heisenberg boxes)
in the time-frequency plane. The center of each rectangle is determined by the
functions
center
and
freq.center
. The area of each rectangle is the same
with the width and height given by the functions
bandwidth
and
freq.bandwidth
.
Coifman, R., Meyer, Y., Quake, S. and Wickerhauser, M. V. (1990). Signal processing and compression with wavelet packets. Technical report, Yale University.
xx <- make.signal("linchirp", 512) ww <- wp.table(xx, wavelet="s8") bb <- best.basis(ww) # select the best basis time.freq.plot(bb) # time-frequency plane plot for the best basis ww.dwt <- as.dwt(ww) # extract DWT coefficients from the full table time.freq.plot(ww.dwt) # time-frequency plane plot for DWT