A Real-Time Contactless Pulse Rate and Motion Status Monitoring System Based on Complexion Tracking

Area of Science:

• Biomedical Engineering
• Signal Processing
• Wearable Technology

Background:

• Contactless pulse rate detection using imaging is challenged by subject motion and low-light conditions.
• Existing methods often struggle with motion artifacts and environmental lighting variations, limiting accuracy.

Purpose of the Study:

• To develop a robust image-based contactless pulse rate detection system.
• To enhance accuracy in the presence of subject movement and dark environments.
• To enable real-time remote monitoring of vital signs.

Main Methods:

• Subject motion status detected via complexion tracking, with a motion index (MI) proposed for artifact filtering.
• Integration of near-infrared (NIR) LEDs for pulse rate measurement in dark conditions.
• Real-time data processing implemented on a Field Programmable Gate Array (FPGA) platform.

Main Results:

• Pulse rate detection error within -3.44 to +4.53 bpm under ambient light.
• Night mode detection error within -2.96 to +4.24 bpm at speeds > 14.45 cm/s.
• Successful transmission of instant pulse rate and motion status to a smartphone for remote monitoring.

Conclusions:

• The proposed method significantly improves the robustness of image-based contactless pulse rate detection.
• The system effectively mitigates challenges posed by subject movement and dark environments.
• The developed framework offers a reliable solution for remote, contactless vital sign monitoring.