www.gusucode.com > wavelet 源码程序 matlab案例代码 > wavelet/VisualizingWaveletsWaveletPacketsandWaveletFiltersExample.m
%% Visualizing Wavelets, Wavelet Packets, and Wavelet Filters % This example shows how to use |wfilters|, |wavefun|, and |wpfun| to obtain % the filters, wavelet, or wavelet packets corresponding to a particular % wavelet family. You can visualize 2-D separable wavelets with |wavefun2|. %% % Obtain the decomposition (analysis) and reconstruction (synthesis) filters % for the biorthogonal spline wavelet filters with 3 vanishing moments in % the reconstruction filter and 5 vanishing moments in the decomposition % filter. [LoD,HiD,LoR,HiR] = wfilters('bior3.5'); subplot(221); stem(LoD,'markerfacecolor',[0 0 1]); title('Lowpass Decomposition Filter'); subplot(222); stem(LoR,'markerfacecolor',[0 0 1]); title('Lowpass Reconstruction Filter'); subplot(223); stem(HiD,'markerfacecolor',[0 0 1]); title('Highpass Decomposition Filter'); subplot(224); stem(HiR,'markerfacecolor',[0 0 1]); title('Highpass Reconstruction Filter'); %% % Visualize the real-valued Morlet wavelet. There is no associated scaling % function. figure; [psi,xval] = wavefun('morl'); plot(xval,psi,'linewidth',2); title('$\psi(x) = e^{-x^2/2} \cos{(5x)}$','Interpreter','latex',... 'fontsize',14); %% % Obtain the first 4 wavelet packets for the Daubechies least-asymmetric % wavelet with 4 vanishing moments, |sym4|. [wpws,x] = wpfun('sym4',4,10); for nn = 1:size(wpws,1) subplot(3,2,nn) plot(x,wpws(nn,:)); axis tight; title(['W',num2str(nn-1)]); end