Multiple switching light sources based motion artifacts reduction in reflectance photoplethysmography.

Area of Science:

• Biomedical Engineering
• Signal Processing

Background:

• Photoplethysmography (PPG) signals are susceptible to motion artifacts, limiting their clinical utility.
• Existing methods for artifact reduction can be complex or require specialized hardware.

Purpose of the Study:

• To develop and validate a simple, effective technique for eliminating motion artifacts in PPG signals.
• To demonstrate the efficacy of the proposed method using a single green LED light source.

Main Methods:

• Utilized a single green LED light source and a photodetector to acquire PPG signals from the wrist.
• Implemented a signal subtraction technique using two green signals with differing light intensities.
• Evaluated performance across five distinct conditions: stationary, finger movement, gripping, vertical bending, and horizontal swinging.

Main Results:

• The proposed signal subtraction method effectively reduced motion artifacts.
• Clean and reliable PPG signals were consistently obtained across all tested movement scenarios.
• The technique proved robust even under challenging conditions involving significant physical motion.

Conclusions:

• The developed technique offers a practical solution for motion artifact removal in PPG.
• This method enhances the reliability of PPG signal acquisition, particularly in ambulatory or dynamic settings.
• The use of a single green LED with intensity modulation presents a cost-effective approach to artifact-free PPG.