LPR: From Law Enforcement to Everyday Applications

Many technologies earned their stripes in law enforcement first before moving on to other applications for the general public. One of those is License Plate Recognition (LPR), also called Automatic License Plate Recognition (ALPR) technology.

LPR: From Law Enforcement to Everyday Applications

What Is ALPR, and How Does It Work?

ALPR is a combination of cameras and software, linked together to automatically read the license plate of a vehicle and check it against a database of information. It achieves this through the use of Optical Character Recognition technology that transforms the characters on the plate into usable data. Law enforcement is automatically alerted if the license plate is registered to someone who is wanted, missing, involved in a crime, or even if their registration is expired.

From the Precinct to the Public: Everyday Applications of ALPR

Car Repossessions and Parking Violators

Like it or not, repossessing cars is a necessary business, and watching the tow trucks just slowly drive through parking lots looking for vehicles on the repo list, or even those parked illegally, is just one impressive ALPR technology example. As soon as they hear an audible "Beep!", they lay down their forks and drive away with the car. ALPR's can scan thousands of plates simultaneously.

Registration Cheaters (i.e. Switched Plates)

The sensitive license plate recognition algorithm is what really drives the ALPR technology. One company's algorithm, SentiVeillance, can look at a live traffic camera and pinpoint whether a car's license plate matches the registration data from the registration sticker on the windshield of the same car in that image. Impressive!

SentiVeillence conducted two groundbreaking experiments with their ALPR algorithm. They used 5 datasets containing a total of 9,239 images of different sizes. They set the camera's ability to interpret the number 1 as the letter I, and the letter O as zero for the first experiment, and no rules for the second one. They achieved an overall accuracy rating of 97.48 percent.

Gated Communities

Some residential communities have delegated secure access to ALPR technology. The idea is pretty straightforward: all resident's vehicle license plates are registered into a database and that database is maintained by the security company. Even if someone switches the license plates to gain entry, it
probably wouldn't work due to cheat detection.


From its origins in law enforcement, ALPR technology has expanded into various industries, transforming operations and improving efficiency. As the technology continues to evolve, we can expect to see even more innovative applications of ALPR in the future.