Noncontact Monitoring Breathing Pattern, Exhalation Flow Rate and Pulse Transit Time

Abstract

We present optical imaging-based methods to measure vital physiological signals, including breathing frequency (BF), exhalation flow rate, heart rate (HR), and pulse transit time (PTT). The breathing pattern tracking was based on the detection of body movement associated with breathing using a differential signal processing approach. A motion-tracking algorithm was implemented to correct random body movements that were unrelated to breathing. The heartbeat pattern was obtained from the color change in selected region of interest (ROI) near the subject's mouth, and the PTT was determined by analyzing pulse patterns at different body parts of the subject. The measured BF, exhaled volume flow rate and HR are consistent with those measured simultaneously with reference technologies (r = 0.98, for HR; r = 0.93, for breathing rate), and the measured PTT difference (30-40 ms between mouth and palm) is comparable to the results obtained with other techniques in the literature. The imaging-based methods are suitable for tracking vital physiological parameters under free-living condition and this is the first demonstration of using noncontact method to obtain PTT difference and exhalation flow rate.

Robust heart rate from fitness videos

“…The fundamental use of rPPG leads to various applications for video health monitoring, enabling non-contact measurement of physiological parameters from a human body, such as heart-rate (Li et al 2014, Tarassenko et al 2014, Kumar et al 2015, Wang et al 2015a, Tulyakov et al 2016, heart-rate variability (Blackford et al 2016), respiration (Tarassenko et al 2014), SpO 2 (Guazzi et al 2015), pulse transit time (Shao et al 2014), blood pressure (Jeong et al 2016), atrial fibrillation (Couderc et al 2015), mental stress (McDuff et al 2014a), monitoring of neonates (Mestha et al 2014, Fernando et al 2015, living-skin detection for face anti-spoofing (Gibert et al 2013, Wang et al 2015b, Liu et al 2016, etc. In addition to the clinical and home-based applications, the rPPG technique would also be attractive in the gym.…”

\Accurate measurement of the pulse wave delay with imaging photoplethysmography

“…Uneven distribution of PTT at the facial area and stochastic variations of the notches amplitude in the PPG waveform may lead to incorrect estimation of the heart rate and other cardiovascular parameters in currently popular IPPG systems, if the algorithm is based on averaging over large area of subject's skin as it is frequently done in recent papers [13,15,16,19,20]. Our algorithm takes into account heterogeneous character of the PPG signals thus providing accurate physiological measurements of cardiovascular parameters in face of subjects.…”

“…However, all these techniques (including ECG) require contacts to the body, which is often inconvenient thus motivating the researchers to seek simpler techniques of blood pulsations monitoring. Recently, video based or imaging photoplethysmography (IPPG) was introduced as a technique for distant measurement and monitoring of cardiovascular functions [13][14][15][16]. This method became very popular among researchers because of its ease of use and potentially low cost.…”

Pulse and vital sign measurement in mixed reality using a HoloLens

“…Finally, holograms are anchored to display the magni ed blood volume pulse and heart rate information. et al 2010, 2011Shao et al 2014;Zhang et al 2017]. ese methods have been shown to be robust in the presence of head motions and to be able to detect subtle aspects of the pulse waveform morphology [McDu et al 2014].…”