How to use License Plate Recognition Camera Systems

The latest numbers from the Bureau of Transportation Statistics reveal that at least 270 million registered automobiles and motorcycles travel on U.S. roads every year. Unfortunately, many of these registered vehicles are operated by would-be criminals in search of the perfect opportunity.

Any vehicle registered with their state’s Department of Motor Vehicles is mandated to have at least one license plate displayed prominently on the back and front of their car. However, because police mostly rely on checking back license plate information to pull a driver over, some states now allow drivers to have just one license plate on the back of their vehicle.

While an online license plate search can potentially provide generic information, such as the make and model of the vehicle and registration status, only law enforcement is allowed to access personal/protected information through license plate checks. Types of information police can view include the driver’s social security number, driver’s license number, and, more importantly, if the driver is legally licensed to drive or has active warrants.

So, how can a license plate recognition camera system benefit a parking lot, parking garage, business, and property managers?

What Does a License Plate Recognition (LPR) Camera System Do?

LPRs capture clear images of license plates that include the time and date of the capture. LPR cameras can be installed at entrances, exits, within parking areas, or wherever managers think they are needed. Each license plate capture can be stored for review later or sent through software that compares the plate number to a database containing other plate numbers.

For example, government institutions and military bases utilize license plate recognition systems to prevent unauthorized intrusions. Unless the LPR capture “recognizes” the employee’s license plate number, that employee won’t be allowed to go through a secured entranceway.

Another example of the advantages of LPRs involves parking garages or parking lots where drivers are limited to how long they can park. By providing license plate captures to parking enforcement personnel, an LPR alerts managers to drivers who are staying too long or attempting to evade paying to park.

When LPR database software detects something unusual about a license plate capture, the software alerts selected individuals’ cell phones, tablets, or laptops. That person can then decide whether or not to contact law enforcement.

What Equipment Does an LPR Camera System Need to Work Properly?

Components of a licensed plate recognition camera system include:

  • Video management software that incorporates optical character recognition and algorithms to convert license plate captures into readable text
  • High-resolution IP cameras to capture images as clearly as possible
  • Infrared LED cameras capable of taking captures day or night
  • The built-in or external infrared light that reduces glare and visibility interference caused by shadows and bright overhead lights in parking lots and underground parking garages
  • Speed limit signs of slowing down traffic approaching an LPR camera. Most cameras only need a few seconds to focus and capture an image of incoming license plates.
  • Accessories to ensure cameras are angled correctly and installed at specific heights necessary to record images of license plates. Although cameras are capable of zooming in on plates, it is highly recommended that the distance between vehicles and cameras is minimized.

As soon as an LPR system is up and running, managers can begin recording and storing license plate numbers in a database. Video footage of license plates can also be stored on a hard drive if desired.

The Technology Behind LPR Camera Systems

Pattern Recognition

Pattern recognition used by LRPs is called concrete item recognition. License plates and their alphanumeric characters are tangible objects involving temporal and spatial items. For example, spatial items represent all physical objects (in this case, the license plate), while temporal items represent light, temperature, and information delivered by waveforms.

Feature Recognition

LPR software extracts specific components of a license plate capture (shape, texture, gray shade, etc.) to process the image as accurately as possible. Feature extraction also filters out patterns that are recognized as “unrequested” or unnecessary to informational algorithms.

Character Recognition

Character recognition technology differentiates between segmented characters and background “noise.” When license plate recognition systems were initially offered, they relied on a formula-based type of recognition technology. That has since been replaced by neural network technology.

LPR software contains unique algorithms essential for analyzing and data-mining a license plate image:

  • Normalization (for adjusting contrast, brightness, and gray shadow)
  • Optical character recognition (character recognition)
  • License plate sizing, spacing, and orientation (optimizes dimensional adjustments)
  • Localization (detects, focuses on, and isolates license plates before capturing an image)
  • Segmentation of alphanumeric characters

Some software may contain additional or different sets of algorithms to accommodate customer specifications.

Popular Applications of License Plate Recognition Systems

  • Research facilities, military bases, and government buildings
  • Gas stations and convenience stores where pull-offs and petty thefts frequently occur
  • Entrances to gated communities
  • Parking lot and parking garage entrances
  • Entrances to toll booths on toll roads
  • Anyplace where a manager wants to monitor the flow of traffic (who is coming in, how long they stay, etc.)

Before considering implementing an LPR system, managers should be aware there are 16 states with laws designed to regulate the use of license plate recognition systems. For example, New Hampshire state, county, and local law enforcement agencies are the only entities permitted to use LPRs. Arkansas forbids the use of LPRs by companies, individuals, state agencies, and partnerships. But, Arkansas does allow parking and law enforcement personnel to have “limited use” of LPRs. The majority of states have no laws regarding the implementation of LPRs.

Benefits of Licensed Plate Recognition Camera Systems for Different Businesses

Retail Businesses (department stores, restaurants, shopping centers)

Suppose managers think a driver behaves suspiciously or just has a “hunch” something isn’t right about a returning customer. In that case, they can show license plate captures to their local police department. Law enforcement has access to more detailed, nationwide databases that provide more information about the driver behind the license plate.

Parking Lots Requiring Permits

An LPR system would detect vehicles that do not have a permit sticker needed to park in specific zones. It would also spot drivers parking in restricted spaces. Once unauthorized vehicles are detected, a manager or security guard could tell the driver to leave or have the car towed.

Gas Stations

Many gas stations require drivers to pay before they pump. However, there may be times when a clerk is extremely busy and inadvertently allows someone to pump gas before paying. Unfortunately, the worst-case scenario involves a driver speeding away without paying. LPRs would also benefit gas station owners who have employees they suspect are allowing friends to pump and pull off.

Extra Security for Gated Communities

People choose to live in gated communities for one reason–the peace of mind they feel by having security personnel or unmanned security systems protect their community. License plate recognition cameras add an extra layer of security by capturing images of license plates entering and leaving the community. For example, managers can scan LPR images to detect infrequent visitors if a series of burglaries occur in a gated community.

Learn more about how license plate recognition camera systems can significantly improve your company’s security by contacting Vision Detection Systems today.

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