Sets the first \(n\) wavelet coefficients to NA
.
brick.wall(x, wf, method = "modwt")dwpt.brick.wall(x, wf, n.levels, method = "modwpt")
brick.wall.2d(x, method = "modwt")
Same object as x
only with some missing values.
DWT/MODWT/DWPT/MODWPT object
Character string; name of wavelet filter
Either dwt
or modwt
for
brick.wall
, or either dwpt
or modwpt
for
dwpt.brick.wall
Specifies the depth of the decomposition. This must be a number less than or equal to log(length(x),2).
B. Whitcher
The fact that observed time series are finite causes boundary issues. One
way to get around this is to simply remove any wavelet coefficient computed
involving the boundary. This is done here by replacing boundary wavelet
coefficients with NA
.
Lindsay, R. W., D. B. Percival and D. A. Rothrock (1996). The discrete wavelet transform and the scale anlaysis of the surface properties of sea ice, IEEE Transactions on Geoscience and Remote Sensing, 34, No. 3, 771-787.
Percival, D. B. and A. T. Walden (2000) Wavelet Methods for Time Series Analysis, Cambridge University Press.