17.12.2004
Saab puts drivers in the picture for safer motoring

Saab is helping drivers stay focused on the road by developing a safety system that monitors eye and head movements and issues a warning signal if the attention of the driver strays long enough to risk causing an accident.

Two miniature cameras with infra-red lenses are installed in the car to monitor the driver's eye and head movement. As soon as the driver's gaze moves away from what Saab calls the "primary attention zone", the central part of the windshield in front of the driver, a timer starts counting. If the driver's eyes and head do not return to the "straight ahead" position within about two seconds, a buzzer will sound. And if there is still no response, a brake pulse will be delivered through the car's ESP system.

The measurement and processing of the infra-red image includes the relationship between eye-gaze direction and head movement. It is sufficiently accurate to detect when the driver retains some peripheral vision of the road ahead – for instance while looking in the rear-view mirror or turning a corner - and will consequently allow a slightly longer time to elapse before activating the warning buzzer.

The software is speed-sensitive. In this way, the system can distinguish between a busy city-driving environment and more open highway driving at faster speeds.

At low speed, as in city driving, there is a wide driver-attention zone, allowing for plenty of head movement but a shorter time "buffer" before the warning buzzer is triggered. High-speed mode will revert to a narrower attention zone and a longer time buffer due to reduced traffic density.

To further distinguish between prevailing traffic conditions, the warning system could also be linked to the satellite navigation system. The "buffer" time zone would then, for example, go to a short "zero tolerance" setting when the car is near a school or a hospital.

Infra-red imaging has been chosen as it gives a clear reproduction independent of light conditions. For maximum accuracy, two cameras are currently fitted to a 9-3 Sport Sedan test and development car, one at the base of the driver's A-pillar and the other in the center of the front fascia. In commercial production, these very small cameras would be completely hidden behind the main fascia paneling.