Hideki Tomimori

Reduction of baseline fluctuation in Electrocardiogram measurement for a car driver

Baseline fluctuation in Electrocardiogram (ECG) measurement system for car drivers is analyzed. The goal of this research is to develop a system that detects changes in R-R interval fluctuation, which is related to drowsiness and stress of the driver, and alert the driver to prevent drowsy driving. This system measures ECG with a contact electrode on the steering wheel and a capacitively coupled electrode on the drivers seat. This configuration allows ECG measurement while the driver is holding the steering wheel with one hand. The major source of baseline fluctuation is the static electricity generated by body motion, especially the pedaling motions that involve contact and removal of foot on the pedal. Baseline fluctuation can be as large as hundred times of the R-wave amplitude. Analysis of equivalent circuit model and experiments have shown that the baseline fluctuation can be reduced to 0.05 V by introducing an additional electrode on the drivers floor and connect it to the electrode in the steering wheel.

Pupil detection in the presence of specular reflection

In this work we describe a method of pupil detection for subsequent gaze tracking, when specular reflection is present in the image. Gaze tracking commonly uses the spatial relationship between the pupil and corneal reflection, but is not robust when the user is wearing eyeglasses, since light reflected from the surroundings changes the appearance of the pupil. In this research we propose and evaluate a pupil detection method that can perform robustly even in the presence of such reflection.

Development of adaptive noise reduction technology for in-vehicle heartbeat sensor

We proposed a noise reduction method for in-vehicle heartbeat sensor systems. The system measures the drivers heartbeat using a steering wheel electrode and a seat electrode that has dual construction. This configuration allows measurement while driving with one hand and provides two signals for noise cancellation. However, the amplitude ratio of the common mode noise varies when driving at high speeds. We multiplied a coefficient that was derived from the Root Mean Square (RMS) ratio between the two signals. This method enabled us to obtain 80% or more of the heartbeat signal while driving at high speed with one hand.