Assessment of psychophysiological characteristics using heart rate from naturalistic face video data

Heart rate is a strong indicator of a person´s psychophysiological state. For this reason, many applications would benefit from noncontact measurement of heart rate. The paper describes a new procedure for estimating blood volume pulse from a video of a person´s face, with an emphasis on real-life scenarios. The approach builds on the algorithm known as Eulerian video magnification, which has shown promise under laboratory conditions, but exhibits problems when attempted in naturalistic situations. In particular, problems arise due to movement by the subject, changing illumination conditions, and low-frame-rate video. This paper describes the procedure that we have developed to address some of these problems, including video rates down to 10 frames per second. The procedure has been tested using videos of indoor subjects, as well as drivers of automobiles in naturalistic situations. The paper also shows analysis and comparison of different stress levels using the extracted heart rate information for a driver on the road.