Non-Contact Vital Signs Monitoring Through Visible Light Sensing

Abstract

In this paper, we present a wireless system for monitoring human vital signs like breathing and heartbeat via visible light sensing (VLS). Typical techniques for tracking heathcondition require body contact and most of these techniques are intrusive in nature. Body contact might irritate the patient's skin and he/she might feel uncomfortable while sensors are touching their body. However, in this method, we can estimate the breathing and heartbeat rates without any body contact using a photo-detector. Vitals monitoring using VLS make use of the idea that reflected light signal off the human body received at the photo-detector will be affected by the chest motion during heartbeats and breathing. We implemented the system using off-the-shelf photo-detector and a signal acquisition system and obtained the results for different people and in different scenarios. We found out that the accuracy of our system compared to FDA approved equipment to measure heartbeats and breathing rate is 94%. This system can be used in various domains and applications in medical facilities and in residential homes.A provisional patent (US#62/639,524) has been obtained for this work.

MobiEye: turning your smartphones into a ubiquitous unobtrusive vital sign monitoring system

“…An RR and HR monitoring system based on visible light sensing (VLS) Abuella and Ekin (2018) included the photodetector sensor that measures the power spectrum of reflected signals from the subject's body. Compared with the standard pulse oximeter, the proposed system achieved 94% accuracy for RR and HR measurements.…”

Respiration Monitoring via Forcecardiography Sensors

“…Finally, referring to the methods based on modulation of other physiological signals, the well-known ECG-derived respiration (EDR) [57,58] measures ECG morphology changes due to sinus arrhythmia, relative movement of heart and electrodes and changes in lung volume, whereas the photoplethysmography (PPG)-derived respiration exploits the modulation in amplitude, baseline and frequency of the PPG signal caused by changes in blood stroke volume, heart rate and tissue blood volume and the variation of its pulse wave width under changes in artery stiffness during the respiratory activity [59,60]. On the other hand, contactless techniques comprise methods based on environmental respiratory sounds (e.g., microphones), air temperature (e.g., thermal cameras), chest wall movements (e.g., radar sensors, marker-based stereophotogrammetric systems, stereoscopic camera sensors) or modulation of other physiological signals (e.g., light intensity measurement, RGB cameras) [8,[61][62][63][64][65][66][67][68][69][70][71][72][73][74]. The great part of the instrumentation required by such methods is generally cumbersome and far from being wearable, or even portable, so its use has remained confined to research or clinical settings [1,2].…”

Machine Learning Assisted Visible Light Sensing of the Rotation of a Robotic Arm

“…To extend the potentials of VLS, these surfaces can be coated with codes, this means sequences of surface areas with different reflectivity values or different colors, which supports the identification of an object, its positon or a movement of the object [14] [15]. Applications of VLS range from presence detection [16], pose detection [17] occupancy estimation [18], and hand gesture recognition [19] [20] to vital sign monitoring [21]. Especially in scenarios in which human beings are involved, VLS has the advantage that it does not provide privacy concerns.…”