| Wavelet Toolbox | |
Entropy update (wavelet packet)
Syntax
Description
entrupd is a one- or two-dimensional wavelet packet utility.
T = entrupd(T,ENT) or T = entrupd(T,ENT,PAR) returns for a given wavelet packet tree T, the updated tree using the entropy function ENT with the optional parameter PAR (see wenergy for more information).
Examples
% The current extension mode is zero-padding (see dwtmode).
% Load signal.
load noisdopp; x = noisdopp;
% Decompose x at depth 2 with db1 wavelet packets
% using shannon entropy.
t = wpdec(x,2,'db1','shannon');
% Read entropy of all the nodes.
nodes = allnodes(t);
ent = read(t,'ent',nodes);
ent'
ent =
1.0e+04 *
-5.8615 -6.8204 -0.0350 -7.7901 -0.0497 -0.0205 -0.0138
% Update nodes entropy.
t = entrupd(t,'threshold',0.5);
nent = read(t,'ent');
nent'
nent =
937 488 320 241 175 170 163
See Also
wenergy, wpdec, wpdec2
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