How ANPR Can Add Value To Your Organization

Automatic Number-Plate Recognition technology has been around for decades, however it has only quite recently started seeing private use with significant advances in the underlying hardware capabilities. In the past, the infancy of the technology resulting in high deployment price, misidentification and high error rates made it infeasible for private use. So what exactly is ANPR, how does it work and what are the benefits it provides for a private organization? Let’s take an in-depth look below.

What is ANPR?

Automatic Number-Plate Recognition, or License-Plate Recognition as it’s known in some parts of the world, is a technology that utilizes optical character recognition on camera images to detect and read vehicle number-plates. The complexity of such a system can range from using standard security cameras to specialized equipment designed for working in difficult environments. Historically such systems have seen public usage for law enforcement using fixed position cameras but advancements have enabled mounting cameras in mobile positions, (such as on top of patrol vehicles) leading to mobile recognition systems to be used as well.

Vehicle mounted camera for mobile ANPR systems

Benefits of ANPR

1. Speed: Modern day ANPR systems are able to process high quality video streams at near real-time speeds providing immediate actionable intelligence.
2. Accuracy: Once trained with enough local plates and optimized, the OCR can provide readings for plates in different languages at a sufficiently high accuracy level.
3. Integration: While usage of a specialized camera is recommended to achieve best possible results, ANPR software can easily integrate with an organization’s existing surveillance systems.
4. IoT-Enabled: Where once the software part of the solution was housed in a separate computer system, now thanks to advancements in communications technologies and embedded systems this is no longer the case. Edge compute devices can process videos in real time and transmit the results to a private cloud using 5G/4G capabilities.

Use Cases

With all these advantages it’s no wonder that ANPR has taken a rise in all sorts of applications, a few of which are mentioned below:

1. Traffic Enforcement: Cities use ANPR to enforce traffic laws by detecting any traffic violations and automatically sending tickets to the involved parties.
2. Parking Management: Organizations with their own personal parking spaces can utilize these systems to manage those spaces — tracking traffic flow throughout the day and providing information in case security needs to find a certain vehicle’s owner.
3. Automated Entrance: By informing systems of vehicles owned by company employees, these vehicles can automatically be allowed entrance onto company premises. Conversely, if an organization would like to blacklist a vehicle from entering the premises they can easily do so.

The Underlying Technology

There are two main components of any ANPR system — the imaging hardware and the plate recognition software. The camera used for capture will vary depending on the usage environment. It may need to have IR illumination capabilities to perform at nighttime, a faster shutter speed to capture clear images of vehicles at high speeds, or even to function under harsh weather conditions.

The software part of an ANPR system ordinarily consists of two parts — the plate detection and the character recognition. The detection part dictates which frames in a stream are useful and detects license plates and passes them on to the character recognition system. The character recognition reads the plate characters and returns the vehicle plate in text format.

Condensed representation of ANPR workings

Current Limitations

So as we can see ANPR is clearly quite a powerful technology, however it is not without its limitations, the greatest of which include:

1. The biggest challenge to detecting and recognizing vehicle number plates are the various modifications vehicle owners can make (regardless of intent to evade such systems), most common being the usage of vanity plates. The best solution for a private organization when coming across such a plate is to raise a system flag for manual intervention. However on the government level, efforts can be taken to ensure vehicle owners do not deliberately attempt to hide their license plates from ANPR systems.
2. Another issue is found in the variation of number plate design between multiple states / provinces. These differences in text font can throw off OCR systems if they are untrained on any new designs. This can be solved by adding an image classification layer in the recognition software to help identify which state / province a plate belongs to as well as training regularly on any newly introduced fonts.

Conclusion

The use of ANPR for private surveillance purposes is on the rise. Being able to monitor vehicle flow and parking usage patterns has tremendous value for organizations and individuals alike. I hope this little primer was informative, if you want to know more sound off in the comments.