Effect of Defocus Blur on the Signal Distribution of Camera-based Remote Photoplethysmography

摘要

Heart rate can be extracted from facial videos by camera-based remote photoplethysmography (rPPG). For a defocusblurred facial image, the edge of the face is blurred and the pixels near this region will be contaminated by thebackground light. In this paper, we map rPPG signal quality (rPPGSQ) on faces in videos with different degrees ofdefocus and propose a method to evaluate the effect of defocus blur on the signal distribution of rPPG. Our results showthat the degradation factor (DF) introduced in this paper can evaluate the effect of defocus blur on rPPGSQ effectively,and provide a clear region of high-rPPGSQ that can be selected as the optimized region of interest (ROI) in rPPGapplications.