tpwd: Tensor product 2D wavelet transform

In wavethresh: Wavelets Statistics and Transforms

Tensor product 2D wavelet transform

Description

Performs the tensor product 2D wavelet transform. This is a related, but different, 2D wavelet transform compared to imwd.

Usage

tpwd(image, filter.number = 10, family = "DaubLeAsymm", verbose = FALSE)

Arguments

image	The image you wish to subject to the tensor product WT
filter.number	The smoothness of wavelet, see filter.select
family	The wavelet family you wish to use
verbose	Whether or not you wish to print out informative messages

Details

The transform works by first taking the regular 1D wavelet transform across all columns in the image and storing these coefficients line by line back into the image. Then to this new image we apply the regular 1D wavelet transform across all rows in the image.

Hence, the top-left coefficient is the smoothed version both horizontally and vertically. The left-most row contains the image smoothed horiztonally, but then detail picked up amongst the horizontal smooths vertically.

Suggested by Rainer von Sachs.

Value

A list with the following components:

tpwd	A matrix with the same dimensions as the input image, but containing the tensor product wavelet transform coefficients.
filter.number	The filter number used
family	The wavelet family used
type	The type of transform used
bc	The boundary conditions used
date	When the transform occurred

Author(s)

G P Nason

See Also

imwd,tpwr

Examples

data(lennon)
ltpwd <- tpwd(lennon)
## Not run: image(log(abs(ltpwd$tpwd)), col=grey(seq(from=0, to=1, length=100)))

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