Multi-Channel Facial Photoplethysmography Sensing.

Motivated by the need for continuous cardiovascular monitoring, we present a system for performing photoplethysmography sensing at multiple facial locations. As a proof-of-concept, our system incorporates an optical sensor array into a wearable face mask form factor for application in a surgical hemodynamic monitoring use case. Here we demonstrate that our design can accurately detect pulse timing by validating estimated heart rate against ground truth electrocardiogram recordings. In an experiment across 10 experimental subjects, our system achieves an error standard deviation of 2.84 beats per minute. This system shows promise for performing non-invasive, continuous pulse waveform recording from multiple locations on the face.