www.gusucode.com > wavelet 源码程序 matlab案例代码 > wavelet/ObtainProjectionOntoScalingSpaceExample.m

    %% Obtain Projection onto Scaling Space
% Obtain the MODWT of an ECG signal down to the maximum level and obtain 
% the projection of the ECG signal onto the scaling space at level 3.
%%
% Load the ECG data.

% Copyright 2015 The MathWorks, Inc.

load wecg;
%%
% Obtain the MODWT.
wtecg = modwt(wecg);
%%
% Obtain the projection of the ECG signal onto $V_3$, the scaling space
% at level three by using the |imodwt| function.

v3proj = imodwt(wtecg,3);
%%
% Plot the original signal and the projection.
subplot(2,1,1)
plot(wecg)
title('Original Signal')
subplot(2,1,2)
plot(v3proj)
title('Projection onto V3')
%%
% Note that the spikes characteristic of the R waves in the ECG are missing
% in the $V_3$ approximation. You can see the missing details by examining
% the wavelete coefficients at level three.
%%
% Plot the level-three wavelet coefficients.
figure
plot(wtecg(3,:))
title('Level-Three Wavelet Coefficients')