Introduction to License Plate Recognition

Remember the security cameras of yesteryear? It was often difficult to make out anything on the footage that was recorded at such a low resolution, it would make the first TVs seem like the HD TVs of today.

But times have moved on. There’s been massive advances in security technology in recent years. These cameras are now ultramodern tools that play a crucial role in any security application.

One of these advances is most certainly License Plate Recognition technology. It takes security around building and businesses to the next level. But what is it exactly and how does it work? This post delves into these questions in more detail.

License Plate Recognition Cameras vs. License Plate Capture Cameras

As the name implies, license plate capture cameras (LCC) capture license plates, much like a regular camera captures a scenic landscape at sunset. They function like regular security cameras but have the necessary higher resolution, shutter speed, and headlight compensation to consistently capture number plates.

There are several ways in which these cameras capture license plates. Some, for instance, use WDR or Wide Dynamic Range to balance out the levels of light in the photograph that makes the picture clearer and the number plate more visible.

Think of a portrait that is taken directly into the sun. The bright light from the rear will make the subject difficult to see. In the same way, the glare from headlights, streetlights, and other light sources will obscure the license plate in the picture.

The important thing to keep in mind with LCC cameras is that they only capture number plates, and they have no ability to read them and convert them to data. That’s where license plate recognition cameras (LPR) come in.

In contrast to LCC cameras, LPR cameras are more advanced and can read the number plate and store the number it reads. It does this with specialized software that rely on optical character recognition (OCR) to recognize each character in the number plate and translate it to digital data. Once it’s turned into data it can be written to a database that allows users to sort, search, and compare number plates.

Like their LCC counterparts, they also use high-definition cameras, fast shutter speeds and glare compensation to capture the number plates clear enough so that the software can read the number.

The Advantages of License Plate Recognition Cameras

Considering the above, it’s easy to see why LPR systems offer a distinct advantage over LCC systems. Because it stores the number plates as data, security staff can search for any license plate number, see the exact time, and date a vehicle has accessed the property. This makes it easy to see who was present at the business when a crime occurred or detect suspicious patterns around the building.

Also, when a crime is committed, and because the number plate is stored, security staff can trace the license plate number to the owner and facilitate the criminal’s arrest.

Some high-quality LPR cameras and software have innovative features and can:

• Read multiple number plates from one image.
• Distinguish license plate numbers from other text on cars.
• Read motorcycle and temporary number plates.
• Recognize the plate type, state, and country.
• Recognize different vehicle types and shapes that makes it possible to read number plates from unusual vehicles.
• Store video footage in the cloud for easier access and more convenience.

Ultimately, LPR cameras are an excellent crime deterrent. When they’re constantly present at a premises, it’s difficult to hide from them. Thus, criminals would be less likely to commit crimes because they know it will be harder to get away.

But their main benefit is not only confined to being reactive, they can also be used proactively to manage security. Businesses can, for example, use them with immense success for access control. Because the data is saved in a database, access to the premises can be given only to certain number plates. For example, when a business has a motorized gate, the system can read an approaching vehicle’s number plate, compare it to the database, and if the vehicle is authorized, open the gate. Conversely, if the vehicle is not authorized, the gate won’t open.

What Can License Plate Reader Software Do?

Before looking at what license plate reader software can do, it’s important to understand how it works. At its core, license plate reader software is a form of optical character recognition, which, in turn, is similar to image recognition.

These systems are trained on huge datasets to recognize specific numbers or letters. For example, by training the system with many pictures of number plates, it will recognize number plates in pictures. Likewise, if it’s trained with number and letters, it will recognize those in an image.

So, putting that into practice, the system recognizes the number plate from an image and then recognizes the separate numbers and letter on the number plate.

Once the number plate is recognized, it’s converted to data that is then written to a database. Using video management software, the system can store footage of each number plate and data about the number plate in and the database. This makes it possible to search for number or data relating to numbers, and even the specific make or model coupled to a specific number plate.

Why is License Plate Recognition Being Used?

License plate recognition is a crucial tool in security applications. For this reason, it’s extremely important when:

• An area must be secured.
• Gated entrances and parking lot traffic needs to be monitored.
• Gated entrances need access control.
• Tracking down criminals after the commission of the crime.
• Tracking down a stolen vehicle or a vehicle that was used in a crime.
• Enforce parking laws and regulations.

Apart from security applications, businesses can also use LPR systems to reduce liability by providing evidence against false claims. In simple terms, with the ability to search for number plates, dates, and times, a business can see exactly what happened.

Getting Started with License Plate Recognition

To get started with license plate readers, it’s not necessary to have any specialized equipment and a normal security camera will do, as long as it has the necessary resolution and glare protection to make the number plates easy to read.

Typically, the minimum resolution required is 1080p. Higher resolutions such as 1440p or 4k will deliver larger, cleared images. Apart from that, these cameras need to be strategically placed and optimally positioned to clearly capture license plates.

The big problem is that these cameras, although perfectly capable of showing number plates in enough detail to read from them, does not record the numbers. The simple reason for this is they don’t have the necessary software capabilities to read and record the numbers and write them to a database.

For that you need a LPR camera or the required OCR software to read and record the number plates from the footage. Pricing for these can range anywhere from $300 to $3000 depending on the features of the particular camera and the manufacturer you are considering. Also, keep in mind that there may be additional costs for the software and licensing costs.

Tips for Installation of License Plate Recognition Cameras

To be most effective, any LPR camera should be installed correctly, and preferably by a qualified technician.

The Right Location

The camera’s main goal is to capture number plates, so it’s of little use if it’s mounted somewhere where it won’t capture any. For this reason, it’s always best to mount it at potential choke points or where a lot of vehicles move in and out constantly. Some examples of these are:

• The entrances and exits to parking lots.
• Gates.
• Bridges.
• Street and alleys.
• Drive-throughs.

By mounting the camera to face these choke points, it will have the best opportunity to capture number plate data consistently and accurately.

Optimal Positioning

Once the position is set, the next thing to do is to position the camera optimally. In other words, it should be mounted at the correct height and distance from the choke point.

Ideally, the camera should be mounted between 2 to 6 meters or 6 to 18 feet from the ground. For the best results, the angle between the license plates should be about 30°, so the camera should be mounted with these numbers in mind. Logically then, the closer it is mounted to the choke point, the lower it will have to be.

Adjusting Settings

The final step is to adjust the camera’s settings to ensure the optimum results. For example, the zoom could be adjusted to narrow the field of view around the choke points. The tighter the field of view is around the choke point, the more detail it will capture.

Likewise, other settings should be adjusted to ensure optimal performance depending on the prevailing light conditions.

Summary

To ensure watertight security around buildings and businesses, LPR cameras are an indispensable tool that can not only protect the business but keep its customers safe.

So, for businesses that want to expand their surveillance and security capabilities, LPR cameras are the best solution.