【特征提取】心电信号PTT+HRV+PRV含Matlab源码

1 简介

提取心电信号PTT+HRV+PRV

2 部分代码

clc;
clear all;
close all;
x=load('day2_0917.txt');
%% ECG signal
y=x(1:95000,1); % ECG signal
figure,plot(y);
title('ECG signal');
xlabel('time');
ylabel('amplitude');
hold on
%% PPG signal
z=x(200:95000,2); % PPG signal
plot(z,'r');
title('PPG signal');
xlabel('time');
ylabel('amplitude');
%% peak detection of ECG
j=1;
n=length(y);
for i=2:n-1
if y(i)> y(i-1) && y(i)>= y(i+1) && y(i)> 0.45*max(y)
val(j)= y(i);
pos(j)=i;
j=j+1;
end
end
ecg_peaks=j-1;
ecg_pos=pos./1000;
plot(pos,val,'*r');
title('ECG peak');
%% peak detection of PPG
m=1;
n=length(z);
for i=2:n-1
if z(i)> z(i-1) && z(i)>= z(i+1) && z(i)> 0.45*max(z)
val(m)= z(i);
pos1(m)=i;
m=m+1;
end
end
ppg_peaks=m-1;
ppg_pos=pos1./1000;
ppg_val=val;
plot(pos1,val,'*g');
title('ECG & PPG signal');
legend('ECG signal','PPG signal');
%% HRV
j=1;
for i=1:ecg_peaks-1
e(j)= ecg_pos(i+1)-ecg_pos(i);% gives RR interval
j=j+1;
end
hr=60./mean(e); % 60/ mean of RR interval
hrv= (60./e); % 60/ each RR interval
figure,stairs(hrv);
title('HRV');
xlabel('samples');
ylabel('hrv');
%% PRV
k=1;
for i=1:ppg_peaks-1
f(k)= ppg_pos(i+1)-ppg_pos(i);
k=k+1;
end
pr=60./mean(f);
prv= 60./f;
figure,stairs(prv);
title('PRV');
xlabel('samples');
ylabel('prv');
%% PTT
ptt=(ppg_pos-ecg_pos);
figure,stairs(ptt);
title('PTT');
xlabel('ptt');
ylabel('time');
%% notch detection
%%moving average filter
av=smooth(z,150);
%%differentiation
p=100*diff(av,1); % (signal,order of differentiation), 100 to amplify the signal
%%finding peak of the notch on the differentiated signal
np=1; % notch peak
m=length(p);
for i=2:m-1
if p(i)> p(i-1) && p(i)>= p(i+1)
val(np)= p(i);
pos(np)=i;
np=np+1;
end
end
u=1;
for j=1:2:length(pos)
notch_pos(u)=pos(j);
notch_val(u)=val(j);
u=u+1;
end
n_val=z(notch_pos);
%% reflection index = b/a *100
%b=diff between notch and peak in y axis
%a=ppg peak value in y axis
nv=n_val(2,:)';
ri=((ppg_val-nv)./ppg_val)*100;
ref_index=mean(ri)
%% stiffness index = h/ptt;
h=0.60;%h is the length from subject's finger tip to heart
si=(h./ptt);
stif_index=mean(si)

3 仿真结果

4 参考文献

[1]林金朝, 李必禄, 李国权,等. 基于EWT和结构特征提取的心电信号R波识别算法[J]. 电子学报, 2021, 49(6):7.

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部分理论引用网络文献，若有侵权联系博主删除。