High-quality photoplethysmography signals using a new non-contact method

Remote photoplethysmography (rPPG) is a non-contact method that uses a camera to capture images of the skin and measures pixel intensity variations, which correspond to changes in blood volume during the systolic and diastolic phases of the cardiac cycle. However, significant challenges in rPPG arise because the signal obtained is often immersed in substantial noise, and commonly used filters can distort the information in the signal. We propose a novel method to extract high-quality signals using remote photoplethysmography. Our approach combines correlation and decorrelation and the application of linear-phase filters. Despite the initial high noise levels, our method successfully yields high-quality signals, from which various physiological parameters of the cardiac cycle can be obtained. The key advantages of our approach are a) non-contact, b) preservation of important signal information, c) applicability in uncontrolled (non-laboratory) environments, and d) reliance on only a conventional camera. These features make rPPG particularly valuable in scenarios involving contagious diseases, helping reduce the risk of transmission.