denoise {rwt} | R Documentation |
Denoise the signal x
using the 2-band wavelet system described
by the filter h
using either the traditional discrete wavelet
transform (DWT) or the linear shift invariant discrete wavelet
transform (also known as the undecimated DWT (UDWT)).
denoise(x, h, type, option) denoise.dwt(x, h, option = default.dwt.option) denoise.udwt(x, h, option = default.udwt.option)
x |
1D or 2D signal to be denoised | ||
h |
Scaling filter to be applied | ||
type |
Type of transform. Valid values are:
| ||
option |
List containing desired transformation settings |
The transformation settings in the option
list are:
TRUE
, threshold the low-pass component.thld = c*MAD(noise_estimate)
MAD.VARIANCE.ESTIMATOR | Mean absolute deviation |
STD.VARIANCE.ESTIMATOR | Classical numerical std estimate |
SOFT.THRESHOLD.TYPE | Soft thresholding |
HARD.THRESHOLD.TYPE | Hard thresholding |
MAX.DECOMPOSITION
will allow
maximal decomposition.
CALC.THRESHOLD.TO.USE
will disable the
variance.estimator
setting.
Returns a list with components:
xd |
Estimate of noise free signal |
xn |
Estimated noise signal (x -xd ) |
option |
List of actual parameters used. It is configured
the same way as the input option list with an additional
element - option[[7]] = type .
|
Both denoise.dwt
and denoise.udwt
are convenience routines
that call the denoise
routine with appropriate default arguments.
P. Roebuck, roebuck@mdanderson.org
~put references to the literature/web site here ~
sig <- makesig(SIGNAL.DOPPLER) h <- daubcqf(6) ret.dwt <- denoise.dwt(sig$x, h$h.0)