wpcoef (Wavelet Toolbox)

Wavelet packet coefficients.

X = wpcoef(S,D,N)
X = wpcoef(S,D)

Description

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

X = wpcoef(S,D,N) returns the coefficients associated with the node N. S is the tree structure and D the data structure (see maketree). If N doesn't exist,
X = [ ];

X = wpcoef(S,D) is equivalent to X = wpcoef(S,D,0).

Examples

% 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. 
    [t,d] = wpdec(x,3,'db1','shannon');

% Plot tree structure. 
    plottree(t)




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

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