Automatic Number Plate Recognition (ANPR)Automatic Number Plate Recognition or ANPR is a technology that uses pattern recognition to 'read' vehicle number plates.
In simple terms ANPR cameras 'photograph' the number plates of the vehicles that pass them. This 'photograph' is then fed in a computer system to find out details about the driver and owner of the vehicle and details about the vehicle itself.
How does ANPR work?
ANPR 'reads' Vehicle Registration Marks - more commonly known as number plates - from digital images, captured through cameras located either in a mobile unit, in-built in traffic vehicles or via Closed Circuit Television (CCTV).
The digital image is converted into data, which is processed through the ANPR system. This system is able to cross reference the data against a variety of databases including the Police National Computer (PNC), Local Force Intelligence Systems and other related databases, for example DVLA
Once the data has been cross checked against these databases - a process that takes around 1.5 seconds to complete - information about the vehicle, its registered owner and driver appears on a computer where it is evaluated by ANPR officers. If the information supplied via the ANPR system alerts officers to an offence or relevant intelligence on a vehicle, the vehicle will be stopped to allow officers to investigate further. ANPR officers acting as 'interceptors' also use their observation to stop other offenders not highlighted by the system. ANPR systems are able to check up to 3,000 number plates per hour, per lane, even at speeds of up to 100mph.
Cambridgeshire Constabulary has a mobile ANPR unit as well as an in-car ANPR devices in dedicated vehicles. The mobile unit is most often seen in lay-bys, or safe locations along the county's roads. The ANPR mobile unit (pictured right) is a white Vauxhall van with a livery of the Constabulary Crest and 'Police Cameras In Operation' along each side. The cameras are stationed at the rear of the vehicle.
The ANPR mobile unit should be easily distinguishable from the safety camera mobile units that are liveried in highly visible blue and yellow checks. (The two mobile units are pictured below). The words 'Crime Cameras' have recently been added to the ANPR mobile unit to further distinguish it from the safety camera mobile units.
cameras are NOT safety cameras - i.e. they are not in place to
catch speeding motorists.
Safety camera mobile unit
ANPR mobile unit