Optimizing Camera Exposure Control Settings for Remote Vital Sign Measurements in Low-Light Environments

Ismoil Odinaev, Jing Wei Chin, Kin Ho Luo, Zhang Ke, Richard H.Y. So, Kwan Long Wong; Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) Workshops, 2023, pp. 6086-6093

Remote photoplethysmography (rPPG) is an optical technique that enables both non-invasive and efficient measurement of vital signs from facial videos. However, the quality of rPPG measurements can be adversely affected by improper camera exposure control and bad lighting conditions. In this paper, we present a systematic study of camera exposure control settings, specifically gain and exposure time, in low-light environments. Our results indicate that manual adjustment of gain and exposure time can significantly improve the quality of rPPG measurements, enabling accurate vital sign measurement even in environments with illuminance levels as low as 25 lux. Furthermore, we demonstrate that the optimal brightness range for rPPG-based vital sign measurement depends on the sensitivity of the vital sign to the shape and peaks of the rPPG signal. These findings have important practical implications for the use of rPPG in healthcare and remote monitoring applications.