Motion Artifact Removal of Photoplethysmogram (PPG) Signal.

Photoplethysmogram (PPG) has been used with great effect for predicting human vitals such as heart rate variability or blood oxygen saturation (SpO2), etc. The quality of PPG signal is affected mainly by noise, drift and motion artifacts. Although noise and drift are relatively easy to remove, motion artifacts pose a challenge. Classical techniques for motion artifact removal are time-frequency based. However, this affects the signal as the PPG signal and motion artifacts distortion lie in the same frequency band, making it difficult to remove the motion artifacts without affecting the signal. In this work, we propose a motion artifact removal technique in time domain, which is based on correcting individual pulses in the PPG signal, considering a global pulse average and a windowed local pulse average. We show the effectiveness of our approach both qualitatively as well as quantitatively.