Automatic License Plate Recognition

Do you remember the television dramas where police officers would call in to the station to have someone check a license number for “wants and warrants?” Those days are behind us. New technology has significantly improved the efficiency and accuracy of that process.

Automatic (or Automated) License Plate Recognition (ALPR) programs are one of law enforcement officers’ newest weapons against criminals. Using car-mounted infrared cameras linked to optical character recognition (OCR) software, these systems scan the license plates of cars that pass on the street. The software will automatically check license numbers against databases of stolen vehicles, outstanding warrants, etc.

When there is a hit, an audible alarm sounds, alerting the officers. Otherwise, the system continues to work silently, and the officers can go on with the rest of their routine duties. Since the system works automatically, it can process as many as 3,000 plates in an hour, an efficiency level that would be impossible for a human checking manually, even with a good computer and software.

When officers receive a warning signal for a license match, they can approach the suspect vehicle already aware of prior criminal activities. In the words of the old adage, forewarned is forearmed.

According to Motorola, one of the manufacturers of ALPR systems, the software can also map all instances of a single license plate number tracked by the system and cross-reference other identifications like driver’s licenses against the license plate database. This kind of data mining can aid in the investigation of a variety of criminal activities.

In the website for PIPS Technology, another manufacturer, additional uses are identified, such as automated toll processing, which reduces manpower requirements and congestion and improves traffic flow. ALPR provides scanning of license plates without requiring vehicles to stop. Another option, currently more utilized in Europe, is congestion charging, where vehicles are identified and billed for entry into high traffic areas during certain times of the day. The intention of these programs is to encourage drivers to avoid congested areas at peak traffic times.

Automated parking control is another option for the system. Utilizing license numbers to permit access or assess charges eliminates the need for paper tickets and the possibilities for ticket fraud. Photo capture of license plates with time stamp can resolve disputes.

ALPR systems can be placed in fixed locations like toll booths or parking lot entry gates, or can be mounted on vehicles for mobile surveillance. The sophisticated camera systems are designed to be used in all light and weather conditions.

If it seems like science fiction come to fruition, it’s like much of our current technology. Fifty years ago it was only the science fiction buffs who believed these kinds of gadgets would become reality.


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