A CDE Definition
license plate recognition
(Automatic License Plate Recognition) Also called "automatic number plate recognition" (ANPR), it is a law enforcement system that optically scans vehicle license plates. Using fixed-position cameras on highways or mobile cameras in patrol cars, the system identifies the plate and matches it against a database of stolen and uninsured vehicles, as well as vehicles registered to drivers with suspended licenses. Equipped with an ALPR, a police official can drive through a parking lot and process the plate number of every parked car. Some systems even photograph the driver.
From Fixed to Mobile
Developed in Europe in the late 1970s, the first systems used fixed cameras at highway intersections. Subsequent systems migrated to mobile use with faster cameras and better recognition algorithms. In addition, laptop computers became more powerful over the years, enabling more economical and effective mobile use.
Toll Collection and Speeding
ALPR is also used with toll collection systems such as E-ZPass to identify vehicles that go through a toll booth without paying and without an RFID tag. It is also used in combination with highway speed detection systems to identify violators and send them speeding tickets.
People Are Always Creative
Drivers have tried to circumvent these systems by obscuring the letters and digits in some manner or by making their plates more reflective with a plastic cover or spray. However, some countries that have used ALPRs have made modifications to the fonts on the next version of their plates to make them easier to identify at high speeds.
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