Abstract
Many studies have investigated the relationship between mental load and biological signals such as heart rate and blood pressure. In such studies, the experiments involved attaching sensors on the bodies of test subjects to measure biological signals. However, there are concerns regarding the additional psychological stress on the subjects caused by these sensors. To solve this problem, we propose a new non-contact method to measure not only heart rate but also blood pressure variability. In this method, the time delay is calculated between two pulse waves obtained from different parts of a subject's body captured by a video camera. This index is considered to have a negative correlation with blood pressure variability because it approximates the pulse transit time obtained from a photoplethysmograph. The proposed index was calculated from video images of 20 healthy subjects performing the Valsalva maneuver. The results showed that the correlation coefficient between blood pressure and the proposed index was approximately 0.6.
