A Phys info.... (PPG extraction)

Question 1

Experiment Framework

Answer 1

In this study, participants wore 2 identical PPG sensors, one for the left and right pointer fingers. To induce movement artifacts, participates were asked to wave side to side for one task, and to move there hand up ad down for another task (right hand only for both tasks). They also collected clean while the participants sitting still for one minute.

Question 2

PPG signal processing based on DWT

Answer 2

DWT is used to remove noise as well as separate the AC/DC components of the. PPG signals

Question 3

AC component

Answer 3

The AC component (alternating current) represents the pulsatile part of the signal and is directly related to the blood volume changes with each heartbeat, and is often used to derive heart rate.

Question 4

DC Component

Answer 4

The DC (direct current) represents the non-pulsatile part of the signal and is caused by the static tissue and blood volume in the measurement site.

Question 5

Why do the AC/DC components need to be separated?

Answer 5

The need to be separated for accurate SpO2 and HR measurement.

Question 6

SpO2 and HR

Answer 6

Spod is. measure of oxygyn saturation. its calculated using the ratio of AC and DC parts of the red ad infared signalls. Heaart rate is deerived from the AC componennts peak to peak intervals

Question 7

Motion artifact detection

Answer 7

In the motion artifact detection step they first extract relevant features of PPG signals then use the results to train the SVM model.

Question 8

Motion artifact Removal

Answer 8

Motion artifacts primarily distort the PPG signals AC component which is used to derive both spO2 and HR measures, thus removing artifacts ad ensuring the accuracy of these measures is crucial. So they decided to se the kalman filter technique to rectify this issue, a method that excels in making accurate estimates from noisy data.