Contactless Vital Sign Monitoring System for Heart and Respiratory Rate Measurements with Motion Compensation Using a Near-Infrared Time-of-Flight Camera

Abstract

This study describes a contactless vital sign monitoring (CVSM) system capable of measuring heart rate (HR) and respiration rate (RR) using a low-power, indirect time-of-flight (ToF) camera. The system takes advantage of both the active infrared illumination as well as the additional depth information from the ToF camera to compensate for the motion-induced artifacts during the HR measurements. The depth information captures how the user is moving with respect to the camera and, therefore, can be used to differentiate where the intensity change in the raw signal is from the underlying heartbeat or motion. Moreover, from the depth information, the system can acquire respiration rate by directly measuring the motion of the chest wall during breathing. We also conducted a pilot human study using this system with 29 participants of different demographics such as age, gender, and skin color. Our study shows that with depth-based motion compensation, the success rate (system measurement within 10% of reference) of HR measurements increases to 75%, as compared to 35% when motion compensation is not used. The mean HR deviation from the reference also drops from 21 BPM to −6.25 BPM when we apply the depth-based motion compensation. In terms of the RR measurement, our system shows a mean deviation of 1.7 BPM from the reference measurement. The pilot human study shows the system performance is independent of skin color but weakly dependent on gender and age.

Laser spectroscopic method for remote sensing of respiratory rate

“…More specifically, with spectral measurements carried out in this work, a submillimetre accuracy can be anticipated which is more than sufficient for remote real-life reparation rate measurements. Accurate measurement down to ~ 1 mm corresponding to human chest wall movement is still a big challenge for the state-of-the-art imaging sensor used for detecting respiratory rates in adults and neonates [ 25 , 26 ]. In other words, our proposed laser spectroscopic technique outperforms the exiting high-resolution time of flight camera-based system with which the depth resolution is around several millimetres for short range measurements.…”

Geriatric Care Management System Powered by the IoT and Computer Vision Techniques

“…Additionally, taking into account the problems associated with time-inefficient work in care homes, contactless monitoring of vital signs may be beneficial for healthcare [ 34 , 35 , 36 ]. In particular, contactless measurement techniques can be applied to measure the respiratory rate and monitor the heart rate variability, which is one of the fourth most important vital parameters [ 37 ]. Monitoring the respiratory rate is useful for the recognition of psychophysiological conditions, the treatment of chronic diseases of the respiratory system, and the recognition of dangerous conditions [ 38 , 39 ].…”

Light and Displacement Compensation-Based iPPG for Heart-Rate Measurement in Complex Detection Conditions

“…The temperature will also change with the same period. Paper [ 9 , 10 ] use a near-infrared camera to irradiate the human body and measure the human heart rate by measuring the temperature change period in a specific area. However, such sensors are not universal enough, which affects their popularization to some extent.…”