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