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. plot(wpt)
% Read packet (2,1) coefficients. cfs = wpcoef(wpt,[2 1]); figure(1); subplot(212); plot(cfs); title('Packet (2,1) coefficients');