atrous(x, wavelet="s8", n.levels=6, dual=F, analysis.filter=NULL)
"d4", "s8".
See
wavelet for a list of all available wavelet names.
For user-provided filters, input the values in
analysis.filter below.
n.levels is bigger than
ml, where
ml is the maximum possible level,
computed from the
max.level function, then
n.levels is set to
ml and
a warning message is given.
filter argument in
wave.filter for
details.
atrous, inheriting from the classes
nd.dwt.list
,
dwt.list,
wpt.list,
wp.list, and
crystal.list.
See
crystal.list.object for details.
The
atrous transform is closely related to the non-decimated
discrete wavelet transform.
Refer to the function
nd.dwt and the
section "Non-Decimated Wavelets" in the
S+WAVELETS User's Manual
for more details about the
atrous function.
Subscripting is not fully supported. Cannot reconstruct from
[[.
Signal
x is assumed to be periodic. Other boundary rules are
not available for
atrous.
Dutilleux, P. (1987). An Implementation of the "algorithme a trous" to Compute the Wavelet Transform. In Wavelets: Time-Frequency Methods and Phase Space. Edited by Combes, J. M. and Grossman, A., Tchamitchian, Ph., Springer-Verlag. Shensa, M. J. (1992). The Discrete Wavelet Transform: Wedding the A Trous and Mallat Algorithms. IEEE Transactions on Signal Processing, 40 (10), 2464-2482.
z1 <- atrous(glint, wavelet="s8", n.levels=5) z2 <- nd.dwt(glint, wavelet="s8", n.levels=5) par(mfrow=c(1,2)) plot(z1) # plot A Trous coefficients plot(z2) # plot non-decimate DWT coefficients