Automatic license plate recognition is a technology that uses optical character recognition on images to read the license plate of the vehicle. You can use existing closed circuit television, road rules enforcement cameras or cameras designed specifically for the task. The ANPR is used by police forces around the world for law enforcement purposes, including to check if a vehicle is registered or licensed. It is also used for electronic toll collection on pay-per-use roads and as a method of cataloguing traffic movements, for example, by motorway agencies.
Automatic recognition of the number plate can be used to store the images captured by the cameras as well as the license plate text, with some configurable to store a photograph of the driver. The systems usually use infrared illumination to allow the camera to take the photograph at any time of the day. ANPR technology must take into account plate variations from one place to another.
Concerns about these systems have centered on fears of privacy that the government traces citizens' movements, misidentification, high error rates, and increased public spending. Critics have described it as a form of mass surveillance.
ANPR was invented in 1976 in the Division of Scientific Development of the Police in the United Kingdom. Prototype systems were in operation in 1979, and contracts were awarded to produce industrial systems, first at EMI Electronics, then Computer Recognition Systems (CRS) in Wokingham, UK. Early test systems were deployed on the A1 road and in the Dartford tunnel. The first detention through the detection of a stolen car was made in 1981. However, the ANPR did not become widely used until new developments in cheaper and easier to use software were pioneers during the 1990s. The collection of ANPR data for future use (ie, resolution of unidentified crimes) was documented in the early 2000s. The first documented case of ANPR used to help solve a murder occurred in November 2005 In Bradford, UK, where the ANPR played a vital role in the location and subsequent conviction of killers of Sharon Beshenivsky.
Automatic Number Plate Recognition (or what is often referred to as number plate recognition) is a special form of optical character recognition (OCR). License Plate Recognition (LPR) is a type of technology, mainly software, that allows computer systems to automatically read the registration number (license number) of vehicles from digital images. Automatically reading the registration number means transforming the pixels of the digital image into the ASCII text of the license plate. Although license plate recognition has a special type of OCR technology, Optical Character Recognition (OCR) technology is strictly considered a type of technology, mainly software, that allows you to scan paper documents and convert them into editable electronic files. From the LPR / ANPR point of view, the quality of the image is always a key factor. Capturing fast moving vehicles needs a special technique to avoid motion blur that can drastically decrease the accuracy of recognition. To ensure the correct image quality, a short shutter time is required with the combination of high power lighting. The best illumination is IR, because the retro-reflective plates reflect this type of light very well and it is undetectable for the human eye. This combination works well during day and night and provides good consistent image quality. Only dedicated ANPR cameras meet these requirements, such as AHR's ANPR cameras, which provide flexible shutter control with built-in IR flash capable of trapping vehicles up to 250 km / h, suitable for all types of license plate applications .