[R] wavethresh and multiresolutional decomposition (mallat)
Koen Hufkens
koen.hufkens at telenet.be
Tue Nov 8 16:15:03 CET 2005
Hi list,
I'm trying to calculate and playing around with multiresolutional
decomposition (MRD, Mallat 1989) using wavelets and the wavethresh3
package. Therefor I should "clear" all the unwanted wavelet coefficient
data from the wavelet coefficient matrix/vector? that's produced by
wavethresh3 and the imwd() command.
All data can be called for with waveletcoeff$wXLY where X and Y are the
level and the direction (horizontal, vertical, diagonal) in 2d wavelet
decompositions.
waveletcoeff$wXLY <- 0 will clear the vector and replace it with just
one 0 giving strange results when using the inverse wavelet transform.
So I was thinking of exporting waveletcoeff$wXLY to some variable, and
clearing it
somelevel <- waveletcoeff$wXLY
somelevel[1:n,] <- 0
decomposition$wXLY <- somelevel
But this gives as strange a result as just setting everything to 0 in
the first place.
So if anyone has any clues to how to do this and how to calculate the
MRD using R in general?
Cheers,
Koen
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