Clever Cars Can Read Road Signs

The plaintive plea to the traffic cop is the same the world over: "Sorry
officer, I didn't know I was speeding." But drivers may soon have to come
up with a better excuse. A new electronic driver's assistant will detect road
signs and warn drivers not to ignore them.

The Australian invention is part of a global effort to make drivers more
aware of road signs, especially those concerned with safety. Eventually,
GPS-based systems could entirely replace road signs, but until then, ideas like
the new driver assistance system (DAS) developed at the National Information and
Communications Technology Australia (NICTA) lab in Canberra may help.

DAS uses three cameras: one to scan the road ahead and a pair to monitor
where the driver is looking. The road camera is mounted on the rear view mirror
and a "gaze monitoring" pair are set on either side of the instrument
panel on the dashboard.

Images
from the cameras are fed to a computer system fitted behind the dash. Software
on the PC detects road signs and works out where the driver is looking. The
speedometer is also connected to the computer, so the system always knows how
fast the car is traveling. The software scans the video pictures and detects
road signs by recognizing their symmetrical shapes: rectangles, diamonds,
octagons or circles. Once a sign is detected, the image is compared to a list of
signs stored in the computer's memory. If it recognizes a stop sign, the
computer checks if the car is slowing down.

The computer uses a commercial package called FaceLab to analyze images from
the stereoscopic cameras and work out where the driver is looking. If the driver
appears not to have seen a sign, and the car's speed does not change, an alert
is issued, says Nick Barnes, one of the developers at NICTA.

NICTA's team will tell the International Conference on Intelligent Robotic
Systems in Sendai, Japan, this week that in preliminary tests DAS performed
"pretty well" even at high speeds. Soon, full-scale road trials with
more signals will test the system.

Newscientist