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Wavelet packet coefficients


X = wpcoef(T,N)
X = wpcoef(T)


wpcoef is a one- or two-dimensional wavelet packet analysis function.

X = wpcoef(T,N) returns the coefficients associated with the node N of the wavelet packet tree T. If N doesn't exist, X = [ ];

X = wpcoef(T) is equivalent to X = wpcoef(T,0).


% The current extension mode is zero-padding (see dwtmode).

% Load signal. 
load noisdopp; x = noisdopp;

figure(1); subplot(211); 
plot(x); title('Original signal');

% Decompose x at depth 3 with db1 wavelet packets 
% using Shannon entropy. 
wpt = wpdec(x,3,'db1');

% Plot wavelet packet tree wpt. 

% Read packet (2,1) coefficients. 
cfs = wpcoef(wpt,[2 1]);

figure(1); subplot(212); 
plot(cfs); title('Packet (2,1) coefficients');

Introduced before R2006a