Samenvatting
In this study it was found that the finger blood pulse shows various fluctuations in different driving conditions. The nature of the finger blood pulse fluctuations was used for estimating a driver's internal state. Indexes suitable for expressing the fluctuations were moment and density. These indexes were calculated by using a return map. However, these results were measured by an off-line system, and were calculated after the experiment. So, an on-line (real-time) system was needed in order to construct a driver's internal state monitoring system. As a first step, an on-line system for estimating the human internal state was developed. This system is available for estimating the human internal state every 30 seconds. (A)