Information Technology Reference
In-Depth Information
Fig. 3.1
The Lexus driver
monitoring system uses six
IR sensors (visible
immediately in front of the
instrument panel). Source:
Wikimedia Commons
the possibility to check for the current estimated level of alertness at any given
time. This system falls under the “vehicle-based” category
1
of driver drowsiness
detection methods.
Lexus and Toyota:
The Japanese automaker (part of the Toyota group) has
offered, in selected vehicles, a “Driver Monitoring System”, which first became
available in 2006 [
8
]. It uses a CCD (charge-coupled device) camera, mounted on
top of the steering column cover to monitor driver attentiveness using eye track-
ing and head motion detection techniques. Six built-in near-infrared LED sensors
enable the system to work accurately both day and night (Fig.
3.1
). During start
up, the system automatically estimates the position of the driver's facial features
and measures the width and center line of the face. This information is used as a
reference to monitor the movement of the driver's head when looking from side
to side (Fig.
3.2
).
The solution works in conjunction with Lexus' “Advanced Obstacle Detection
System” as follows. If the driver turns his head away from the road ahead while
the vehicle is moving and an obstacle is detected in front of the vehicle, the
system activates a pre-crash warning light and buzzer. If the situation persists,
the brakes are briefly applied to alert the driver. And if this still fails to elicit
action from the driver, the system engages emergency braking preparation and
front seatbelt pre-tensioning.
The combination of different monitoring devices places this system in the
“hybrid” category (according to the different categories listed in Chap.
2
).
The “Driver Monitoring System” has been modified in 2008 by Toyota
company to include eyelid detection which is used to determine the state of
driver's eyes [
9
]. This increases the overall robustness of the system. If the eyelids
1
Please refer to Chap.
2
for a description of all categories.
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