wp.object: Wavelet Packet decomposition objects.

In wavethresh: Wavelets Statistics and Transforms

Wavelet Packet decomposition objects.

Description

These are objects of classes wp They represent a decomposition of a function with respect to a set of wavelet packet functions.

Details

To retain your sanity we recommend that wavelet packets be extracted in one of two ways:

• use getpacket.wp to obtain individual packets.

• use accessD.wp to obtain all coefficients at a particular resolution level.

You can obtain the coefficients directly from the wp$wp component but you have to understand their organization described above.

Value

The following components must be included in a legitimate ‘wp’ object.

wp	a matrix containing the wavelet packet coefficients. Each row of the matrix contains coefficients with respect to a particular resolution level. There are nlevelsWT(wp)+1 rows in the matrix. Row nlevels(wp)+1 (the “bottom”) row contains the “original” data used to produce the wavelet packet coefficients. Rows nlevels(wp) to row 1 contain coefficients at resolution levels nlevels(wp)-1 to 0 (so the first row contains coefficients at resolution level 0). The columns contain the coefficients with respect to packets. A different packet length exists at each resolution level. The packet length at resolution level i is given by 2^i. However, the getpacket.wp function should be used to access individual packets from a wp object.
nlevelsWT	The number of levels in the wavelet packet decomposition. If you raise 2 to the power of nlevels you get the number of data points used in the decomposition.
filter	a list containing the details of the filter that did the decomposition (equivalent to the return value from the filter.select function).
date	The date that the transform was performed or the wp was modified.

GENERATION

This class of objects is returned from the wp function to represent a wavelet packet decomposition of a function. Many other functions return an object of class wp.

METHODS

The wp class of objects has methods for the following generic functions: InvBasis, MaNoVe, accessC, accessD, basisplot, draw. getpacket, nlevelsWT, plot, print, putC, putD, putpacket, summary, threshold.

RELEASE

Version 3.5.3 Copyright Guy Nason 1994

Author(s)

G P Nason

See Also

wp

wavethresh documentation built on Sept. 11, 2024, 9:33 p.m.