What is ALPR system?
ALPR is an acronym for Automatic License Plate Recognition. It is a system consisting of cameras with ANPR software that are capable to detect and read license plates, convert the information on the license plate into a digital format and send the result to processing systems, like an access control system, a tolling system or a parking management system.
ALPR is sometimes also referred to as ANPR (Automatic Number Plate Recognition) or just LPR (License Plate Recognition).
How does ANPR camera work?
ANPR camera constantly monitors an area, like a road or a vehicle entrance. It usually sends out infrared (IR) light that reflects on the license plate and that enables the traffic monitoring camera to find it and isolate it from the rest of the image.
ANPR cameras employ a technology called Optical Character Recognition (OCR) to read the license plates under almost all-weather conditions, without the need for human intervention.
Most ANPR cameras usually collect several frames (images) and automatically select the best ones to read the license plate.
Tattile ALPR cameras also collect and provide additional data, like the estimated speed of the vehicle, the vehicle direction and the country of origin. Some of the cameras are even capable to classify the vehicle and recognize the brand, colour, class and model.
The event of a passing vehicle is usually referred to as a transit. Transit-related output of cameras often consist of images (greyscale OCR image and colour contextual image) and METADATA such as the license plate, the date/time, GPS coordinates, etc. Images and METADATA are then sent out in various formats to multiple hosts: FTP Server, TCP Message, HTTP Post, etc.
Range of applications
ANPR system supports all kinds of applications. ANPR is mostly used for:
- Free Flow tolling
- Axle Counting
- Stop & Go tolling
- Low Emission Zone
- Speed Enforcement
- Red light enforcement
- Bus lanes enforcement
3. Vehicle tracking
- Homeland security
- Access control
- ANPR mobile
ANPR technology enables authorities to grant security, reduce & prevent crime.
Which are the main components of an ALPR system?
- ANPR cameras
- Optional external illuminators
- Optional triggering systems (Laser, Loops, etc.)
- Lane Controller
- Optional reviewing software