filtering and combining signals

I have heart rate (HR) and respiration rate (RR) vectors. I assign scores for both heart rate and respiratory rate (to what extend these signals are worriesome). Then I add these scores to obtain a final score about the status of a patient.

These signals (HR and RR) need some filtering. I decided to use median filtering. Do you think it is appropriate to filter the HR and RR first, and then assign scores, or first assign scores and then take the median of the scores?

Answer 1

[Jan]

You need a scientific decision for a filter, not an opinion from the forum. Is there any evidence that a median filter does not delete the most important information? Maybe a high frequency change in HR or RR is hint for a specific problem. Then the filtering destroys the measurement.

Analyse the signal you want to obtain and the noise. If you have scientific reasons to identify noise securely, a matching filter can be created and applied to the measured signals, the HR and RR. Afterwards you can calculate the score.