ANPR Systems (Automatic Number Plate Recognition) use optical character recognition software to convert images of vehicle registration numbers into information for real time or retrospective matching with law enforcement and other databases. They have been hailed as mechanisms for "denying criminals the use of the road" and "intelligence-led policing". They have also been described as a foundation for Intelligent Transport Systems (ITS) and congestion management regimes. Promoters of private ANPR Systems (Automatic Number Plate Recognition) networks have marketed them as solutions to non-payment by customers at petrol stations and as a tool for cutting costs in the management of commercial car parks.
Selection might be manually determined by an operator or automatic, for example of every vehicle passing a particular point or every heavy vehicle (with size triggering the camera). Many ANPR Systems (Automatic Number Plate Recognition) feature dual cameras: an infra-red device that captures multiple images of the specific number plate and a conventional color device that records an image of the plate in context, ie takes a snap of the car.