Fluctuation of capillary pulse as an index for driver's internal states

In this paper, fluctuations of capillary pulses are discussed under different internal state conditions, especially different emotional states. Capillary pulses of finger were measured under various situations such as watching video movies, answering quizzes and so on. It is found that fluctuations of finger capillary pulses can be used for estimating the driver's internal states. Suitable indices for the fluctuation are moment and density of its return-map.<>