Your number's up! A simpler solution to ANPR complexity
View all articles 21st August 2013
Clever cameras can give you a picture of a readable number plate from a moving car at night. Even cleverer cameras can photograph and automatically read the number plate of the car. This is using a technology called ANPR.
Automatic Number Plate Recognition (ANPR) is the technology that allows computer processing of digital images using character recognition techniques to extract vehicle number plates.
To enable automatic tracking and recording of vehicle movements over a wide area, ANPR technology is employed (other methods include GPS tracking etc). Although the technology was first invented around 19761, one of the first widespread ANPR networks setup in the UK, was by Trafficmaster in 1998. This system eventually comprised of around 4000 cameras covering the UK road network. Each time a vehicle passes a Trafficmaster camera, the system generates a unique tag for the vehicle and the details are sent back to a central computer system. When another camera records the same vehicle then a simple calculation is made regarding the journey time for that particular route2.
When the Trafficmaster system was first introduced there was much controversy over capturing vehicle number plates, even though the company clarified that only the four central characters of the number plate were used to track a vehicle. Controversy has remained in the years following the introduction of the Trafficmaster system and there is still concern over tracking an individual's movement and potential misreadings. However, as our exposure to ANPR has increased, we are now both more familiar and generally more comfortable with the technology. For example, we accept that our number plate has been recorded by the petrol station when we fill up our cars. Other common everyday encounters with the technology range from the London congestion charging scheme, SPECS average speed cameras3 on roadworks, some police vehicles and the national police ANPR network, to full "ring of steel" monitoring systems around towns e.g. Royston4. There are even high-end hotels that greet your approach using the technology.
Interestingly, as our acceptance of this technology has increased, our awareness of protecting our identity has also increased and we are now familiar with seeing a vehicle on a news clip with an obscured number plate. This may be due to increased use of ANPR exacerbating problems like car cloning. Car cloning is where the real identity of a vehicle is masked by obtaining the details from a similar vehicle. Commonly, this used to be by manufacturing the false number plates, which in turn led to the process for obtaining new number plates being changed to require the purchaser of new number plates to present identification and vehicle details. It is now more common for the actual plates to be stolen from a similar vehicle. To counteract this theft issue there are initiatives to fit anti-tamper fixing screws, increasing the difficulty in stealing the number plate, and an increase in general car security.
Whilst, some situations require a number plate to be automatically read (i.e. use ANPR), in several situations, simply obtaining an image with a human-readable number plate is sufficient and can exclude this complexity. For example, congestion zone charge requires the automatic aspect of ANPR, but monitoring fly-tipping locations would not. In this situation, the image itself is the proof of the event. Other examples include simple car park monitoring, event parking, farm and forest track monitoring and traffic surveys. If an issue has arisen, captured data can be reviewed and details recorded manually or via further computer processing to yield a list.
The Blackeye Camera from Novetic has a specialised number plate capture mode. This has been specifically designed to increase the successful capture of vehicle number plates and address a common problem with other cameras - even head-on images of a moving vehicle with its headlights on are legible! See the example images below, taken from the same camera with and without the number plate mode. The Blackeye camera can record both types of images to give the best chance of capture. Take a closer look at the Blackeye Camera or contact us for further details.
References
- ᛏ Wikipedia, 2013 Automatic number plate recognition
- ᛏ trafficmaster, 2013 Company History
- ᛏ Vysionics, 2013 SPECS Average Speed Check Cameras
- ᛏ Tom Espiner, 24 July 2013 Police number plate camera scheme broke law in Royston
