Detecting pulse from head motions in video

We extract heart rate and beat lengths from videos by measuring subtle head motion caused by the Newtonian reaction to the influx of blood at each beat. Our method tracks features on the head and performs principal compo-nent analysis (PCA) to decompose their trajectories into a set of component motions. It then chooses the component that best corresponds to heartbeats based on its temporal frequency spectrum. Finally, we analyze the motion pro-jected to this component and identify peaks of the trajecto-ries, which correspond to heartbeats. When evaluated on 18 subjects, our approach reported heart rates nearly iden-tical to an electrocardiogram device. Additionally we were able to capture clinically relevant information about heart rate variability. 1