%基于小波變換的心電信號的降噪
ecg=fopen('ECG1.dat','r');
N=1201;
data=fread(ecg,N,'int16');
data=data/10000;
fclose(ecg);
x=data;
wavename='db5';
level=4;
[c,l]=wavedec(x,level,wavename);
alpha=1.5;
sorh='h';
[thr,nkeep]=wdcbm(c,l,alpha);%使用硬閾值給信號降噪
[xc,cxc,lxc,perf0,perfl2]=wdencmp('lvd',c,l,wavename,level,thr,sorh);
t1=0:0.004:(length(x)-1)*0.004;
subplot(211);
plot(t1,x);
title('從人體采集的原始的ECG信號');
subplot(212);
plot(t1,xc);
title('Birge-Massart策略閾值降噪后的ECG信號（wname=db5 level=4）');