Features Extraction for Cuffless Blood Pressure Estimation by Autoencoder from Photoplethysmography.

Several studies have been proposed to estimate blood pressure (BP) with cuffless devices using only a Photoplethysmograph (PPG) sensor on the basis of the physiological knowledge that the PPG changes depend on the state of the cardiovascular system. In these studies, machine learning algorithms were used to extract various features from the wave height and the elapsed time from the rising point of the pulse wave to feature points have been used to estimate the BP. However, the accuracy is still not adequate to be used as medical equipment because their features cannot express fully information of the pulse waveform which changes according to the BP.

Measuring cognition delay caused by gaze movement toward the direction of depth.

It is difficult to judge from face images and/or from biological signal (such as brain waves) what the driver's state of cognition is. This paper reports experiments measuring the state of cognition accompanied with gaze movement in the direction of depth. While measuring the cognition time, the experimental setup was able to measure the effect of gaze movement in the direction of depth.