heart rate variability

[prasadadiga]

hi everyone
i'm new to matlab , i've my project on the hear rate variability analysis(only linear)! so can any give algorithm as how to do it ! please forgive my dumbness!
i've done the following code !
%% Start and Clear Variables
close all
clear all
clc

disp(' WELCOME ')
disp(' %%%%%%%')
disp('Program to calculate ECG beats')
disp('-------------------------------')

%% User Inputs
file_name=input('Enter the name of the file with extention:','s');
sample_freq=input('Enter the sampling frequency of the signal:');

%% Load file
data=csvread(file_name);

dr=length(data);
%disp(dr);
%for i=1:dr

%end
%mx=max(data);
%disp(mx);
for i=2:dr
b(1)=data(1);
b(i)=data(i)-data(i-1); %first differentiation
if(b(i)<0)
b(i)=-1*b(i); %rectification
end
end
for i=3:dr
c(1)=b(1);
c(2)=b(2);
c(i)=(b(i)+2*b(i-1)+b(i-2)/4); %smoothening
end
for i=2:dr
d(1)=c(1);
d(i)=c(i)-c(i-1); %second differntiation
if d(i)<0
d(i)=-1*d(i); %rectification !!
end
end
for i=3:dr
e(1)=d(1);
e(2)=d(2);
e(i)=(d(i)+2*d(i-1)+d(i-2)/4); %smoothening
end

for i=1:dr
f(i)=(c(i)+e(i))/2;

end
maximval=0;
for i=1:dr
if f(i)>maximval
maximval=f(i);
end
end
for i=1:dr
if f(i)>=(0.4*maximval)
g(i)=200;
else
g(i)=0;
end
end
k=1;
for i=2:dr
if g(i-1)==0 && g(i)==200
h(k)=i;
k=k+1;
end
end
subplot(2,1,1),plot(e);
subplot(2,1,2),plot(g);
lt=length(h);
disp(lt);
for i=1lt-1)
rrnt(i)=h(i+1)-h(i);

end
%for i=1lt-1)
%disp(rrnt(i));
%end

nnmean=mean(rrnt);
disp(nnmean);
stdnn=std(rrnt);
disp(stdnn);
rmsssd=sqrt(mean(diff(rrnt))^2);
disp(rmsssd);


prasad

 

[vinodini]

Am getting error by implementing the above code. Wat to do?:???:

- - - Updated - - -

AS

??? Error using ==> mtimes
Inner matrix dimensions must agree.

Error in ==> ecg at 23
d = round(d0 * L / d0(15)); % Scale them to fit in length L




How to rectify this error...???
Please reply to vinodini_1992@yahoo.com

 

[cherryman]

Probably it should be the indexing multiplication and division. Try to change '*' to '.*' and '/' to './'
i.e.
d = round(d0 * L / d0(15));
to
d = round(d0 .* L ./ d0(15));