Automatic licence-plate recognition (ALPR, sometimes also called ANPR - Automatic Number-Plate Recognition) is a specialized application that uses optical character recognition on images or live video feeds to automatically read vehicle registration plates. Major uses of ALPR include electronic toll collection on pay-per-use roads and law enforcement scans of vehicle registrations, e.g., for
- Recovery of stolen vehicles
- Motorway monitoring
- Border control
- Homeland security initiatives
- Disrupting major crime and terrorism
Major challenges with ALPR are
- Insufficient image resolution from low-quality cameras
- Blurry images, particularly motion blur
- Poor lighting and low contrast due to overexposure, reflection or shadows.
- A different font, popular for vanity plates
- Different license plate designs in different countries
While some of these challenges can be corrected in software, high-quality hardware aligned with the software algorithms used is still key to a high recognition rate.
Our solutions are available as fixed or mobile ALPR systems with over 900 reads per minute. Vehicles in excess of 250 km/h closing speeds may be captured correctly. Plates from all countries can be read, including difficult to read flat and vanity tags. Recognized license plates can be compared live against up to 4 million lines of hot-list files for vehicles of interest. A sophisticated analysis software provides an easy-to-use interface to data collected.
For the ALPR software platform, different cameras are available depending on the intended usage scenarios. All solutions provide a b/w close-up photo of plates and a color overview photo of car and surrounding scene. They include in-camera image processing and components to forward captured information to command centres or analysis software.