Stationary Automatic License Plate Recognition Systems (ALPR) are common throughout the industrialized world. However, a new mobileAutomatic License Plate Recognition System is now available in British Columbia, and may be cruising down a road near you soon.
This system can capture up to 3,000 license plates per hour. It has three cameras mounted outside the police vehicle.
Front left side
This camera is used to capture license plates of oncoming vehicles.
Front right side
This camera is used to capture license plates of cars in the right-hand lane (on a four or more lane road), as well as cars parked on the right side of the road.
Rear right-angle camera
This camera captures the license plates of parked cars in a parking lot.
This system seems to be an advance over previous systems, which were either stationary or were drive-by parking lot control systems.
(Update: 15-Feb-2017: Video of Automatic License Plate Recognition System )
At the outset of a shift, the on-board computer in the police vehicle downloads a list of all plates of stolen vehicles, plates of known uninsured vehicles and plates of known unlicensed drivers. As the police vehicle proceeds down the road, it compares the license plate of every car it sees to the database.
An audible alarm sounds whenever the system discovers a car on the "hot list." The system is installed in unmarked cars as well as standard police cruisers.
Automated systems to read license plate numbers were first used in the UK; prototypes in 1976 gave way to established systems by 1981 (when the first stolen car was detected with such a system).
However, science fiction writers have thought about such systems for a while longer. In his 1941 novel Methuselah's Children, Robert Heinlein wrote about traffic control cameras:
She signaled the traffic control ahead; it cut her out of the stream of vehicles and reduced the speed of her car, then rang the alarm which notified her to resume local control. Before doing so she fumbled in the storage compartment on the instrument board and fumbled, apparently purposelessly.
But the registration number which the traffic control automatically photographed as she left the controlway was not the number in which the car was registered.
It's interesting to note that exactly the same scheme was tried along Canada's 401 highway. It is reported that a driver used a wire leading from the interior of the car to the front plate to switch to an alternate plate while driving through camera zones. (Since it has been reported on, the system obviously needed more work!)
ALPR systems have obvious applications in and around airports and other secure zones. However, there are also a variety of legitimate concerns raised about such systems, and whether or not the extensive database searches intrude upon the privacy of individuals.
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