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WT2DStruct(2) Scilab Function WT2DStruct(2)
NAME
WT2DStruct - Retrieve the Structure of a 2D DWT
Author: Bertrand Guiheneuf
This routine retrieve the structure informations contained in a 2D Wavelet
Transform.
Usage
[ScIndex, ScLength]=WT2DStruct(wt)
Input parameters
o wt : real unidimensional matrix [m,n] Contains the wavelet transform
(obtained with FWT2D).
Output parameters
o index : real matrix [NbIter,4] Contains the indexes (in wt) of the
projection of the signal on the multiresolution subspaces
o length : real matrix [NbIter,2] Contains the dimensions of each pro-
jection
Description
Introduction
This routine is used to retreive the structure information of a wavelet
transform. It must be used in all routine that might work on a wavelet
transform whose structure is not passed as an imput parameter. (That should
be the case of all routines taking a Wavelet Transform as input parameter
to minimize the input).see FWT2D.
Parameters
Input must be a real matrix. It's generally obtained with FWT2D. It con-
tains the wavelet transform. index contains the indexes of the first coef-
ficient of each output. At each scale Scale, the output indexes are:
index(Scale,1) : HL index(Scale,2) : LH index(Scale,3) : HH index(Scale,4)
: LL on the last scale and 0 otherwise length contains the dimensions
(height, width) of each output at a given Iteration.
Example
a=rand(256,256); q=MakeQMF('daubechies',4); wt = FWT2D(a,8,q); (a few days
pass...) wti, wtl=WT2DStruct(wt); wtl
See Also
FWT2D, IWT2D, WT2Dext, WT2DVisu
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