Denso Corp exhibited a prototype of a system that measures the drowsiness level of the driver at the 42nd Tokyo Motor Show 2011.
The show will open for the public from Dec 3 to 11, 2011, in Tokyo.
A camera set on the steering column is used to take a picture of the driver's face, and a drowsiness level is determined based on the facial expression of the driver. Denso has not yet decided when to commercialize the system.
The system determines a drowsiness level by observing the activities of three kinds of muscles (frontal belly, orbicularis oculi muscle and greater zygomatic muscle) in nine areas on the driver's face. Denso found that there is a correlation between drowsiness and the amounts of those muscles' activities, it said.
Specifically, the system extracts 17 feature points from the facial image and determines the amounts of muscular activities to calculate a drowsiness level on a scale of one to six.
Existing systems determine a drowsiness level by, for example, observing how much the eyes are open. Therefore, they can determine it only after the driver's drowsiness level increases to a certain extent. On the other hand, the new system can detect the driver's drowsiness even when the drowsiness level is small, Denso said.
The company aims to commercialize the system by removing the influence of ambient light such as strong sunlight and combining a near-infrared camera with the system for nighttime use.