Blood pressure estimation using video plethysmography
Remote sensing of vital physiological signs allows for unobtrusive, nonrestrictive and non-contact assessment of individual's health. By using video plethysmogram obtained by digital camera recordings of patient's face or hands, health parameters such as heart rate, respiratory rate and heart rate variability have already been investigated. In this paper, time-domain video plethysmogram from forehead was used for calculation of pulse transit time, which is related to blood pressure. Synchronous measurements of non-contact video plethysmogram, 12-channel electrocardiogram and invasive blood pressure were performed on three subjects. Our results demonstrate that pulse transit time method can be equally efficient with non-contact VPG signal, with error mean and standard deviation of 9.48 ± 7.13 mmHg and 4.48 ± 3.29 mmHg, for systolic and mean arterial pressure, respectively. Additionally our findings show that delay in pulse transit time, calculated from two different VPG signals from forehead and palm, could provide clinically useful measure of changes in systolic blood pressure.