This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English version of the page.

Note: This page has been translated by MathWorks. Click here to see
To view all translated materials including this page, select Country from the country navigator on the bottom of this page.


Entropy update (wavelet packet)


T = entrupd(T,ENT)
T = entrupd(T,ENT,PAR)


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).


% 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 =
    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 =
    937 488 320 241 175 170 163

See Also

| |

Introduced before R2006a