No matter if you have ever heard of an automatic licence plate recognition cameras (LPR) or not, they have already been deployed around us for many use cases. The most common example is toll roads. Every time you get on or get off a toll highway, these LPR cameras will scan your vehicle’s license plate. Then, the software will process the images and create a digital record of your license plate. This is how you get billed every time when you use a toll road. Police have also been using this system to identify vehicles that were involved in crimes.

But the real questions are: how do these systems actually work? Are there any other uses outside of police and toll management? What role does an LPR system play for use cases like parking management, journey time analysis (JTA), access control, traffic control, and threat detection? Can businesses also gain commercial benefits from using this system? This article will address all these questions and is the only resource you will need before you place your LPR order.

What are automaticlicence plate recognition cameras (LPR)?

You do not need an advanced engineering degree to be able to know what LPR is. The name, automatic License Plate Recognition is straightforward enough to explain what this camera does. However, if you are a business owner who has a large property to protect, or if you are hoping to build a “bulletproof surveillance system ” to protect a school or a hospital, you may want to dig a little bit more on how this type of camera works. The system includes more than just some specialized cameras, it also requires a dedicated software system and a database to ensure this system is able to correctly recognize license plates at a high rate of speed and in a dark environment. This section will walk you through how an LPR hardware and software system works.


From a hardware standpoint, it's normally not possible nor ideal to use a regular security camera as licence plate recognition cameras. An LPR camera needs to have hardware components that support an optical character recognition (OCR). OCR technology with the proper software allows users to read letters and numbers from an image. The resolution requirement for an LPR camera is not as high as a regular security camera, since the purpose of these cameras are only needed for reading license plates. To learn more about the surveillance camera resolution, please check out Analog vs. Digital Image Resolution .

In addition, infrared illuminators are required for LPR cameras for several crucial reasons. First, infrared lighting is helpful in creating a clear image due to is unique reflective properties when it hits metal. Infrared light also reflects off the white space on a vehicle’s license plate. These characteristics of infrared lighting help LPR systems to create accurate readings when the lighting condition is poor, such as dark and overcast conditions. On top of all that, infrared light is not visible nor harmful to the human eyes. It would not disturb fast-flowing traffic at night.


The software aspect of the system can be more complicated than the hardware. You need a powerful software and database to quickly process all the images that LPR cameras take. We are talking about processing hundreds or thousands of license plate images per minute.

To have a better reading, the images from the cameras must have proper size, orientation, and brightness. At a higher level, LPR software will run an image enhancement algorithm to improve image quality. Usually, LPRs capture cars at different rates of speed, different angles, or in different weather conditions. This process makes sure that all these different factors can be removed through image sizing, orientation, and normalization. There are so many factors that could negatively affect the license plate recognition process, and these challenges will be addressed in the next section.

OCR Algorithm

The final step is to apply an OCR algorithmic process to extract numbers and letters from the images. Since we already created sufficient contrast to the images and between the license plates’ characters and their background from the previous image enhancement process, the software can breakdown the characters individually to isolate letters and numbers. Once we have individual letters and numbers, we can compare each character image to the actual character one at a time until we see a match. As soon as we identify all the individual characters, we can re-assemble them into a complete license plate.

Positioning of licence plate recognition cameras (LPR)

Before we move on to the next section, it is worth mentioning that these LPR cameras can be deployed in two ways. One way is fixed positioning, such as toll road highway entrance or on the side of a wall. The other way is these cameras can be mobile and can be mounted on top of police cars for officers to search for car thieves on the road. This is one example of the use for a mobile camera. When mobile solutions are involved, additional calibration and testing becomes even more challenging.

What are some challenges of licence plate recognition cameras (LPR) cameras?

When it comes to analysis the accuracy of an LPR system, there are so many challenges that need to be taken into consideration. All these challenges result in a less than 100% accuracy. Therefore, the better strategy is to deploy an LPR system with a highly experienced LPR professional. This ensures your system is efficient and properly optimized rather than constantly having to source for a more expensive camera that have only a slightly higher accuracy.

Viewing Distance of licence plate recognition cameras

The first question one may ask is how far can an LPR camera see? To answer this question, you need to understand that these cameras are usually mounted above the horizontal level of license plates They will either be mounted on top of a pole or on another vehicle. However, how far away the car will be measured at a horizontal distance.

With that being said, assume that the manufacturer recommends the height when installing an LPR camera to be 6 meters or 20 feet above ground. The ideal distance for the camera root to get the most accurate reading will be between 20 to 25 meters, or between 65 to 82 feet. However, a license plate recognition cameras can usually read anywhere between 8 meters to 30 meters with high accuracy. The figure below shows these numbers and how to better understand them. The distance values mentioned are referenced on the x-value in the figure. If needed, the assistance of a trained professional should be able to adjust the viewing distance by lifting or lowering the height of the camera mount.

As seen in the figure 1, it is not ideal to place your LPR cameras too high above the ground. There is no way the camera would be able to take and image of a vehicle’s license plate from that high up. The recommended viewing angle usually is at a 30-degree angle from the road. If your applications require the camera to placed at a higher angle placement, you will need to consult with a professional and source for more specialized cameras.

Figure 1. Licence plate recognition cameras visible distance

Licence plate recognition cameras in Low Light

The second most common challenging scenario for LPR cameras are low light. Can an LPR still take accurate readings at night? The short answer is yes. As we mentioned earlier, LPR cameras are equipped with infrared illuminators, which emit infrared lights to scan vehicles at night. It does not require complicated image processing or advanced camera lenses as conventional security cameras for low light situations. Once again, an LPR system only needs to read the license plate clearly. Therefore, the low light conditions can be easily removed through infrared lighting. If you need a further improved low light LPR system performance for a place such as an undergrad parking garage, you will need to choose cameras that come with stronger infrared LEDs or multiple infrared LEDs. If you are interested in infrared security cameras and want to learn more, please check out this article, How Do Infrared Security Cameras Work ?

Blurry Images

Another question to ask is what about blurry images? If the first-hand image is very blurry, it will definitely be a serious problem. The only thing you could count on is the image processing (OCR) software, and there is no guarantee that the final result will be 100% clear enough to read. To avoid motion blur, there are a few things you can do. The easiest one is to make sure that the mounting of the camera is strong, and it should not be swinging too much in the wind. You will need to consult with an experienced professional to make sure the mounting strength is secure and not causing blurring issues.

Another way for cameras to avoid motion blur is that they need to have a faster shutter speed, which would need to be faster than 1 millisecond. Of course, the faster the shutter speed the better, and the faster moving object it can capture. Today, the LPR cameras on the market should not have many issues capturing cars that are traveling up to 125 km per hour (or 75 mph). If the LPR system intended use is for catching speeding cars, a more advanced system will be more desirable.

It is worth mentioning that the OCR software are fairly powerful, and their blur-tolerance is getting better and better. Afterall, there are only 26 letters and 10 numbers the choose from that can be on a license plate in North America. If a car is not traveling over 200 km per hour, and the license plate is not covered in mud or snow, there is a very high chance for the LPR system to accurately process the image and get a satisfying result.

Resolution Necessary for LPR Cameras

As we mentioned a few times previously, licence plate recognition cameras do not need to have a high resolution compared to conventional security cameras since it is only used to capture license plates. But what is the actual resolutions required for LPR? In most use cases, a 4-million-pixel camera is adequate for license plate recognition. You do not want to spend much more money to source for ultra-HD cameras. The 4 MP cameras should be more than adequate to do the job. If you are curious about where HD surveillance cameras are useful, you can find your answer in Where to Use High-Definition Surveillance Cameras .

How to professionally install an licence plate recognition cameras?

As we mentioned earlier, the LPR system can get very complicated. Conventional security cameras capture everything in video format. Besides recording videos, there are no further actions for the security system to do any image processing or analysis other than storing video files securely somewhere. So, for conventional security cameras, all you need do is to pick a wide-angle camera to cover all the areas you want to cover. On the other hand, for an LPR camera, you need to make sure they are positioned properly to capture license plates. We previously mentioned its viewing distance and viewing angle in the previous section. You do not want to position the camera outside of its reading range.

Where to Install licence plate recognition cameras

Another thing you will notice is that you only need to install LPR cameras at places where you want to record license plates. For example, you may only be wanting to record a car’s license plate at the entrance or exit of a toll road. There will be no need to install several LPR cameras every 100 meters across a highway. The same thing can be said for parking garages. There is no need to install many LPR cameras through out the parking garage to cover every corner as if they were security cameras. They are only needed at the entrance and the exit.

Software Installation

The most challenging part is the software installation. We previously mentioned there are further image processing for licence plate recognition cameras. Users may want this part to be pre-programmed and automated so that all license plate information will be extracted and stored without too much human operation. This part cannot be done without an experienced professional who is familiar with different types of software and configurations.

Referring to a previous example, there is no need for the same software configuration for the highway entrance/exit as a parking garage. That is because cars are traveling at very different speeds in these two scenes. Assume we have the same cameras for the highway entrance and parking garage entrance. You would probably want to set the shutter speed at a faster value on the highway than you would at the parking garage.

In a parking garage, cars traveling at a much lower speed, this lower shutter speed will greatly improve the image quality and would have better license plate recognition results. There are many other parameters in LPR software, such as capture resolutions, analysis resolutions, queue time, reporting confidence, and analysis timeout. It can easily get overwhelming for people who are less experienced in this space. Therefore, some professional assistance is highly recommended when it comes to LPR hardware and software installation.

What are some key aspects during the operating phase of an LPR system?

licence plate recognition cameras are a complicated system from both installation and operation standpoints. Installation only counts as half of your effort to have a fully functioning LPR system. The first crucial aspect of an LPR system is cybersecurity. This factor applies to both hardware and software. You must make sure the camera you chose has impenetrable hardware housing, secure authentication, secure access control, trusted protection, strongly encrypted transmission, and encrypted storage. Throughout the life span of these cameras, users need to constantly check if their camera hardware has been tampered with or disabled. You do not want your LPR cameras to be compromised from the hardware level. Otherwise, all the results generated by the software would be false.

Importance of Protecting LPR Data

On the software or network layers, you want to ensure your software and network cannot be accessed by unauthorized programs. This requires a strong network control software, encrypted database, and multi-level authentical access. You can learn more about scalable data network from How to set up a scalable data network . Objectively speaking, a license plate number should be visible to the public. It is already public information. However, when you have a list of them for special purposes, you do not want that information to be leaked, accessed, or modified by unauthorized people. An example would be when the police are secretly tracking a dangerous criminal in his vehicle. If the police database system is compromised, the criminal could end up knowing that the police are after his car. Then the criminal could end up abandoning the car.

Another example of an LPR system security breach is if a warehouse has a list of contracted truck license plate records, and they are leaked to their competitors. The competitors might be able to figure out their cargo flows and patterns. Or the competitors could reach out to these truck drivers for their own business benefits. Another scenario would be what if one of the warehouses was able to hack into another warehouse’s LPR system database and make changes to their existing truck license plate data? It would easily paralyze the operations of the warehouse whose LPR system was hacked.

You would not want any of these scenarios to happen to you. All cybersecurity concerns need to be seriously considered and eliminated to the maximum level throughout the life cycle of the LPR system. It is recommended that you consult a professional team and source for trustworthy hardware and software to stop cyber breaches from happening.

Creating a Proper Result Log

The next major step is to make sure that you can properly create a result log and license plate database for better and faster future access. That requires users to make use of all the functions built into the system after all the cameras are installed and parameters configured. Of course, based on different companies and their different applications, the operation process will look quite different from case to case. Nevertheless, the main data managing concept is still valid for most use cases.

You need to know that all LPR software usually have a comprehensive log of past images or even videos. You should be able to easily sort and filter by factors like time, region, or camera. This will make your life a lot easier when you need to quickly find records from the past. You can also use the built-in search engine to find a particular license plate. On top of that, users can build customized license plate lists. Businesses can use this function to build a VIP list or a “banned” list. You can be highly creative when creating these lists that can be of benefit to your business. We will discuss more about this function for the different business sectors in the last section.

Inputting license plate data manually

Remember, you also can manually change the license plate number if the LPR system did not generate an accurate result. Or you can just manually add license plates through a registration process. For example, when guests check into a hotel, guests can manually submit their license plate instead of using LPR scanning to avoid the chance of inaccurate scanning. This process can be done in bulk through software. Any database should allow you to import, export, or make changes in batches, meaning processing a large amount of license plates all at once. This will help database maintenance operations become very efficient.

How to integrate an LPR system to your existing CCTV system?

From what we have discussed earlier in this article, it is not difficult to conclude that an LPR can be a standalone system. It does not require information sharing outside of its system. It usually works independently or operates alongside a CCTV system. However, there are advanced solutions that allow users to integrate an LPR system with a video management system (VMS). This only requires the LPR software to have an open API. For LPR cameras and recognition software, they can be flexible, which means this integration does not require changes to your cameras and only in the backend of your software.

What does this integration actually mean to the users? A VMS manages all the digital videos that were captured by a CCTV system. It has more advanced features and more user-friendly interfaces when it comes to managing footage or audio. However, an LPR system does not have all the advanced capability to manage its images or video files. It would be redundant to build all these advanced features into an LPR system. Why do not we just integrate the best of both worlds? If a business like a warehouse already has a CCTV system for security reasons, it will be a low-cost upgrade to add an LPR system while still using the existing VMS functions for both CCTV and LPR.

Benefits After Integration

What are some benefits users will see after the integration? A short answer would be a CCTV system and an LPR system that can share their database directly with each other and present only through VMS. A CCTV system can only recognize the make, model, and color of a vehicle. An integrated system will add license plate numbers and the unique identifier of a vehicle, to the mix. When police officers need to investigate a crime involving a car, users do not need to manually cross-reference data from a CCTV and an LPR system separately. It can all be done automatically through an integrated system. For operations like car parking management, traffic management, retail plaza parking, and toll routes records, the efficiencies can be greatly improved by using this integrated system.

Once again, this operation requires advanced knowledge of security camera systems. You need to consult with a professional who has knowledge in both CCTV and LPR systems before you buy and install any hardware or software. The reason being this integration requires openness in the LPR software since LPR system has lower security concerns than CCTV. You do not want to acquire the wrong software that does not allow you to interact with this type of integration. Or that the software integration was not done in a seamless way, which would result in a security vulnerability. This will expose your system to hackers.

What business could benefit from an LPR system?

For security reasons alone, an LPR system has already become a more attractive option for many private sectors such as hospitals, residential buildings, airports, museums, parking facilities, and resorts. The list goes on. It is a great solution when you do not want to deploy too many expensive security cameras that record high-quality videos and take up so much storage space and only end up capturing the rare occasional crime. Being able to provide accurate license plate numbers would be more helpful for the police when there is a crime.

However, an LPR system cannot be a replacement to conventional security camera systems in terms of catching illegal activities. It can be a good supporting system that only focuses on security issues that involve vehicles. A conventional security camera may have a hard time identifying the license plate. But when you cross-reference with an LPR system, you can capture the unique identifier of a vehicle, which can be extremely helpful evidence for the police. So, instead of over-deploying security cameras, you can deploy much cheaper LPR cameras at a few designated locations. It is also much cheaper to save license plate numbers than hours and hours of HD surveillance video footage.

Applications in Warehouses

For a warehouse facility, it is necessary for the warehouse owner to track trucks that are going in and out of the facility. This system does not only mitigate theft, but also helps the warehouse manager use an automatic truck check-in scheduling to improve work efficiency and avoid traffic congestion. Any license plates that are not in the database can be locked out or locked in.

Applications in Retail Parking

If we are speaking about managing traffic, a retail plaza can benefit from an LPR system for both security and business reasons. A major problem for retail parks is having to constantly deal with unauthorized parking. Having security guards staring at a stopwatch and having only watching a few cars at parking spots for hours is certainly not a solution. By having an LPR system record license plates and tracking their parking time and location, a central control room would be able to automatically identify unauthorized parking, and then issue tickets or report them to the proper authorities.

Of course, when it comes to crimes, retailers also constantly battle thieves and shoplifters as well. Retailers can create their own customized “shoplifter” license plate lists or even share these lists with other retailers. Once a license plate from the list is captured by an LPR, retailers can quickly react and work with law enforcement to stop more crimes from happening. If you wish to learn more about how to choose security system for your business, please read How security cameras help protect your business .

Other Applications

Besides the security use of the LPR system, you can also use it to create your own database for business purposes and make use of it daily. An example would be using them at a hotel, a casino, or a resort and creating a VIP list. When tracking and keeping records of these VIP customers, it is more efficient to use an LPR system that only records license plates. Another example is that when a condominium that wants to limit external vehicle parking. If the condominium has a database of all authorized license plates, any other vehicle with license plates that are outside of its database will be denied from entering their parking facility. The same idea can also be applied to places like medical facilities, storage facilities, and factories.

What have we learned?

An LPR is a complicated but very helpful system for businesses from both a security and business operation standpoint. It highly recommends special cameras and software, and the proper installation by a trained professional to generate the most accurate readings. If you think your business needs an LPR system and you would like to talk to an experienced professional, look no further. Please contact Panopticon Solutions today to book your consultation appointment: 416-613-8828.