Converting beat-by-beat data into second average

3 views (last 30 days)
Jason on 26 Oct 2022
Commented: William Rose on 28 Oct 2022
Hi,
I have a 30-minute recording of heart rate measured beat-by-beat (2003 samples), however i would like to have this dataset as averages of each second (1800 samples). I believe an interpolation of the data may be required but unsure how to acheive this.
Any help would be greatly appreciated!
Thanks.

Mathieu NOE on 26 Oct 2022
hello
you can use smoothdata to smooth / average your curve then you do the interpolation to resample at dt = 1 second
nota that your original sample rate (0.8985 second) and the target one (1 second) are very close, so there are not many samples of data in a 1 second long buffer. I supposed that it was rather a matter of smoothing (but maybe I'm wrong)
t = TimeHR.Time;
y = TimeHR.HR;
dt = mean(diff(t)); % original rate
% smoothing using 'samples' length window
samples = 5;
ys = smoothdata(y,'gaussian',samples);
% interpolate to get 1 s time increment data
new_t = t(1):1:t(end);
new_ys = interp1(t,ys,new_t,'linear');
figure
plot(t,y,new_t,new_ys)
Mathieu NOE on 28 Oct 2022
My pleasure !

William Rose on 26 Oct 2022
I have done this in Labview before but not Matlab.
Make a time series of HR versus time, where HR is computed as 1/(R-R interval), and the time of each HR esitmate is the midpoint time between the two RR intervals. Now you have two vectors of equal length : t_raw (unevenly sampled) and HR. Then make a time vector with the values t=(0,1,2,...), and use interp1() to interpolate the HR to the 1-second time vector.
William Rose on 28 Oct 2022
Jason, you’re welcome. Good luck with your work.

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