Many wearable devices include PPG (photoplethysmography) sensors for non-invasive heart rate monitoring.However, PPG signals are heavily corrupted by motion interference, and rely on simultaneous motion measurements to remove the Racquet Sports - Badminton interference.Accelerometers are used commonly, but cannot differentiate between acceleration due to movement and acceleration due to gravity.
This paper compares measurements of motion using accelerometers and gyroscopes to give a more complete estimate of wrist motion.Results show Face Cleansers the two sensor signals are very different, with low correlations present.When used in a wrist PPG heart rate algorithm gyroscope motion estimates obtain better performance in half of the cases.