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Wavelab Toolbox >> Wavelab Toolbox > 2-d Wavelet- and Cosine- Packet Tools > Best2dBasis

Best2dBasis

Coifman-Wickerhauser Best-2d-Basis Algorithm

Calling Sequence

[btree,vtree] = Best2dBasis(sqtree,D)

Parameters

Inputs:

sqtree:

stat-quadtree (output by Calc2dStatTree)

D :

maximum depth of tree-search

Outputs:

btree :

basis-quadtree of best basis

vtree :

value of components of best basis, vtree(1) holds value of best basis

Description

The best-basis algorithm is used to pick out the ``best'' basis from all the possible bases in the packet table. Here ``best'' means minimizing an additive measure of information, called entropy by Coifman and Wickerhauser.

Once the stat-quadtree of entropy values is created, Best2dBasis selects the best basis using the pruning algorithm described in Wickerhauser's book.

Yale University has filed a patent application for this algorithm. Commercial Development based on this algorithm should be cleared by Yale University. Contact them for licensing information.

Examples

// get best basis for ``image''
// use Coiflet 3 filter and CW Entropy
[n,D] = quadlength(image);
qmf = MakeONFilter('Coiflet',3);
sqtree = Calc2dStatTree('WP',image,D,qmf,'Entropy');
[btree,vtree] = Best2dBasis(sqtree,D);

See also

Bibliography

Wickerhauser, M.V. _Adapted_Wavelet_Analysis_. AK Peters (1994).

Authors

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