Non-contact photoplethysmogram and instantaneous heart rate estimation from infrared face video
This work provides a solution for non-contact heart rate monitoring in low-light environments, but it is incremental as it adapts existing principles to infrared video.
The authors tackled the problem of estimating instantaneous heart rate from face videos under low light conditions by using infrared cameras instead of conventional ones, and they demonstrated that their method matched ground truth electrocardiogram data in tests on 7 participants.
Extracting the instantaneous heart rate (iHR) from face videos has been well studied in recent years. It is well known that changes in skin color due to blood flow can be captured using conventional cameras. One of the main limitations of methods that rely on this principle is the need of an illumination source. Moreover, they have to be able to operate under different light conditions. One way to avoid these constraints is using infrared cameras, allowing the monitoring of iHR under low light conditions. In this work, we present a simple, principled signal extraction method that recovers the iHR from infrared face videos. We tested the procedure on 7 participants, for whom we recorded an electrocardiogram simultaneously with their infrared face video. We checked that the recovered signal matched the ground truth iHR, showing that infrared is a promising alternative to conventional video imaging for heart rate monitoring, especially in low light conditions. Code is available at https://github.com/natalialmg/IR_iHR