An Automatic Number Plate Recognition System firstly locates a number plate on a vehicle and then reads and interprets the plate. Usually the system can create a log of vehicle movements with date, time and location.

Systems can not only read a plate, but having interpreted it, the software can usually look up the plate in a database and display information about the vehicle or driver on an operator's screen.

Instantaneous warnings can be given for vehicles of interest. e.g. a well known shoplifter arriving at a shopping mall.

ANPR is therefore suited to both security and access control applications. Police and Customs will use ANPR to check every vehicle passing a control point whilst a factory or car park operator might use the system for car park auditing, customer charging etc.

Often systems will be stand-alone i.e. one computer in a guard hut connected to one or two cameras. However, there is a often need to build expandable, fully integrated ANPR systems spanning a wide geographical area.

A modern example of this type of ANPR system is Congestion Charging where the systems need to run day and night collecting data in real time from hundreds of ANPR cameras. Every vehicle entering the centre of a city is checked against a list of exempt, pre-paid or non-paid drivers and the appropriate action taken.