What is a License Plate Reader and where is it actually used?

License Plate Readers (LPR) are specially formulated cameras which are embedded with image processing technology used to identify vehicles by their license plates. These cameras when supported with a license plate database can help in recognizing the number plates of vehicles moving even at speeds of 50 ~100 MPH.

Thus, with the help of LPR cameras and supportive software database identifying or tracking down the offenders of traffic rules, drunken driving cases, vehicle thefts and those involved in criminal acts becomes easy. On a positive note, these cameras can also be used in parking lots for easy space management, toll-booth operations and in areas used for access control.

The working of such cameras goes as follows- The cameras are equipped with special form of Optical Camera Recognition feature, where algorithms are employed to transform the pixels of the digital image into the text of the number plate systems commonly used for infrared lighting to allow the cameras to take the picture at any time of day.

For tracking down vehicles, LPR Cameras also called as ALPR cameras are mounted on to police vehicles or stationary structures such as gates, bridges, electric poles and usually high vantage points to take photos of license plates at the rate of hundreds per minute.

The characters in the photo of the plate are then translated into letters and numbers which are compared with the database of law enforcement forces of registered vehicles known to be or suspected of being involved with crimes or infractions.

If in case, a license plate that was read matched with an entry on a database, then the license plate reader system will alert the officer (if the camera was mounted on vehicles) or command centers (if the camera was mounted on highways or at vantages points in city) that the suspected vehicle was in the radius of the LPR cameras.

Note- In order to utilize LPR algorithms, the image capturing camera must take the picture in a clear way, translate its characters, and identify the state that issued the plate. The better the algorithm, the more accurate the information will be.

These days, apart from specially formulated LPR cameras, installers are also recommending the usage of High Definition or 5MP cameras for LPR applications. So, when the LPR software is loaded onto the server and when the said cameras are integrated, the above stated results are obtained. In reality, such camera systems work pretty well for parking lot applications like parking space management and efficiency. But to identify fast moving vehicles in towns and highways, these cameras are not recommendable.

Generally speaking, License Plate Readers (LPRs) can record plates at about one per second at speeds of up to 100 MPH and they often utilize infrared cameras for clarity and to facilitate reading at any time of day or night. The data collected can either be processed in real-time, at the site of the read, or it can be transmitted to remote center and processed at a later time. This entire process can take place within 45 seconds and depends on the ability of the camera and the supportive database.

An automatic license plate reader is also known by the following terms-

  • ALPR
  • LPR Technology
  • License Plate Recognition
  • License Plate Camera
  • Automatic Vehicle Identification
  • Car Plate Reader
  • OCR (Optical Character Recognition)

And those offering such cameras and software are in the below link of DNF Security


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