Seamless Integration and Implementation of Distributed Contact and Contactless Vital Sign Monitoring

TL;DR

This paper presents a scalable, integrated system for simultaneous contact and contactless vital sign monitoring using fiber Bragg gratings and radar, achieving accurate respiration and heartbeat detection in real-time for multiple individuals.

Contribution

It introduces a novel, seamlessly integrated system combining optical and radar methods for scalable, real-time vital sign monitoring with high accuracy.

Findings

Successfully monitored three people simultaneously.

Maximum measurement errors: 1.6 respirations/min, 2.3 beats/min.

Effective even with short 5-second monitoring periods.

Abstract

Real-time vital sign monitoring is gaining immense significance not only in the medical field but also in personal health management. Facing the needs of different application scenarios of the smart and healthy city in the future, the low-cost, large-scale, scalable, and distributed vital sign monitoring system is of great significance. In this work, a seamlessly integrated contact and contactless vital sign monitoring system, which can simultaneously implement respiration and heartbeat monitoring, is proposed. In contact vital sign monitoring, the chest wall movement due to respiration and heartbeat is translated into changes in the optical output intensity of a fiber Bragg grating (FBG). The FBG is also an important part of radar signal generation for contactless vital sign monitoring, in which the chest wall movement is translated into phase changes of the radar de-chirped signal. By analyzing the intensity of the FBG output and phase of the radar de-chirped signal, real-time respiration and heartbeat monitoring are realized. In addition, due to the distributed structure of the system and its good integration with the wavelength-division multiplexing optical network, it can be massively scaled by employing more wavelengths. A proof-of-concept experiment is carried out. Contact and contactless respiration and heartbeat monitoring of three people are simultaneously realized. During a monitoring time of 60 s, the maximum absolute measurement errors of respiration and heartbeat rates are 1.6 respirations per minute and 2.3 beats per minute, respectively. The measurement error does not have an obvious change even when the monitoring time is decreased to 5 s.