Noncontact Measurement of the Autonomic Nervous System Using RGB Camera

Abstract

In this study, we focused on the color change in facial image, green and red value because the absorption efficiency of hemoglobin is different. With reference to these phenomena, the reaction of RG in the video is considered to indicate the contraction and expansion reaction of blood vessels, that is, the reaction of autonomic nerves. To prove it, we conducted a verification experiment. The subjects were 4 males (22.5 +- 0.5 years old). We measured the changes of the heart rate (HR) and the change in G / R value, which is the ratio of green and red values in facial image due to cold water load. As a result, HR increased sharply and G / R value decreased im-mediately after the cold water load. After that, it was confirmed that both of them recovered to the resting value at the end of the cold water load.