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.TH "WT2DStruct" 2 " 01 June 1997" "Fractales Group" "Scilab Function"
.so ../sci.an
.SH NAME
WT2DStruct - Retrieve the Structure of a 2D DWT
.sp
Author: Bertrand Guiheneuf
.sp
This routine retrieve the structure informations contained in a 2D Wavelet Transform.
.sp
.sp
.SH Usage
\f(CR[\fPScIndex, ScLength\f(CR]\fP=WT2DStruct(wt)
.SH Input parameters
.RS
.TP
o
\fBwt\fP : real unidimensional matrix \f(CR[\fPm,n\f(CR]\fP
Contains the wavelet transform (obtained with FWT2D).
.RE
.SH Output parameters
.RS
.TP
o
\fBindex\fP : real matrix \f(CR[\fPNbIter,4\f(CR]\fP
Contains the indexes (in wt) of the projection of the signal on the multiresolution subspaces
.TP
o
\fBlength\fP : real matrix \f(CR[\fPNbIter,2\f(CR]\fP
Contains the dimensions of each projection
.RE
.SH Description
.SH 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.
.SH Parameters
\fIInput\fP must be a real matrix. It's generally obtained with FWT2D. It contains the wavelet transform.
\fIindex\fP contains the indexes of the first coefficient of each output. At each scale \fIScale\fP, 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
\fIlength\fP contains the dimensions (height, width) of each output at a given Iteration.
.SH Example
a=rand(256,256);
q=MakeQMF('daubechies',4);
wt = FWT2D(a,8,q);
(a few days pass...)
wti, wtl=WT2DStruct(wt);
wtl
.SH See Also
FWT2D, IWT2D, WT2Dext, WT2DVisu
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