Automatic number plate recognition, or ANPR for short, is a system where number plates are remotely detected by number plate recognition cameras. These high definition cameras identify the alphanumeric characters on number plates using enhance optical character recognition technology. The plate numbers of multiple cars can be identified in a single frame by the cameras.
Once the number plates are scanned and identified, the data is stored in a central database managed by National ANPR Data Centre (NADC). The numbers are then compared against records of vehicles of interest, which includes vehicles reported stolen, used in criminal activities, etc. The real time analysis provides law enforcement agencies throughout the country with the ability to quickly locate and intercept vehicles.
ANPR is increasingly seen as a vital law enforcement tool to combat threats of terrorism and organised crimes. ANPR is also useful in resolving local crimes and civilian accidents. In addition, the presence of ANPR cameras in communities serve as a deterrent against crime – studies they have shown that the cameras actually helped in reducing crime simply by being there.
While a small number of cameras are mounted on police vehicles, the majority of them are installed at strategic locations around the country. These locations are determined using historical crime data to ensure maximum disruption against criminal activities. The locations of the ANPR camera are not disclosed to the public to prevent criminals from moving their operation or routes out of camera range.
However, to ensure that the cameras are not abused, a Privacy Impact Assessments are conducted by the police before installation. When deemed necessary, law enforcement agencies will liaise and solicit feedback from private and public organisations to protect the privacy of citizens.
ANPR constantly evokes the fear of tyrannical big brother oppression – and with good reason. Beyond privacy concerns, in the wrong hands, ANPR technology could be used to blackmail and intimidate the citizenry. This is the reason why data collected, stored and disseminated from ANPR cameras are strictly regulated under the Criminal Procedure and Investigations Act 1996 (CPIA) and other internal standards.
Access to the data is also limited to authorised members of the staff within a specific time frame, and only for relevant investigative purposes.
As a final precaution, all data in the NADC database are deleted after two years, expect for materials that are still relevant to ongoing investigations.
The accuracy and effectiveness of ANPR has seen the technology being used in the commercial sector at a smaller scale. Probably the most common use of ANPR outside of law enforcement is car park tracking and surveillance and security of gated communities.