imwd.object: 2d Wavelet Decomposition Object

Description

These are objects of class "imwd". They represent a decomposition of a 2D function with respect to a 2D wavelet basis.

Arguments

Value

The following components must be included in a legitimate imwd object.
nlevelsnumber of levels in wavelet decomposition. If you raise 2 to the power of nlevels then you get the dimension of the image that you originally started with.
fl.dbaseThe first last database associated with the decomposition. For images, this list is not very useful as each level's components is stored as a list component, rather than being packaged up in a single vector as in the 1D case. Nevertheless the internals still need to know about fl.dbase to get the computations correct.
filterA filter object as returned by "filter.select". This component records the filter used in the decomposition. The reconstruction routines use this component to find out what filter to use in reconstruction.
wNLxThe object will probably contain many components with names of this form. These are all the wavelet coefficients of the decomposition. In "wNLx" the "N" refers to the level number and the "x" refers to the direction of the coefficients with "1" being horizontal, "2" being vertical and "3" being diagonal. Note that the levels should be in numerically decreasing order, so if nlevels is 5, then there will be w5L1, w5L2, w5L3 first, then down to w1L1, w1L2, and w1L3. Note that these coefficients store their data according to the first.last database fl.dbase$first.last.d, so refer to them using this, see first.last.
w0LconstantThis is the coefficient of the bottom level scaling function coefficient. So for example, if you used Haar wavelets this would be the sample mean of the data (scaled by some factor depending on the number of levels, nlevels).
bcThis component details how the boundaries were treated in the decomposition.

GENERATION

This class of objects is typically returned from imwd(.) to represent a wavelet decomposition of an image (or other 2D function).

METHODS

The "imwd" class of objects has methods for the following generic functions: plot, threshold, summary, print, draw, imwr, compress.

RELEASE

Details

In previous releases the original image was stored as the "original" component of a imwd object. This is not done now as the resulting objects were excessively large.