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Working principle and application scenario of license plate recognition system

Dec 24, 2019

by:Shenzhen TGW Technology Co.,Ltd

Working principle and application scenario of license plate recognition system

The license plate recognition system is an application of computer video image recognition technology in vehicle license plate recognition. License plate recognition is widely used in highway vehicle management and electronic toll collection systems. It is also the main means of identifying vehicle identity in combination with DSRC technology.


The license plate recognition technology requires that a license plate in motion can be extracted and recognized from a complex background, and vehicle license plate recognition, image pre-processing, feature extraction, license plate character recognition and other technologies should be used to identify vehicle license plate and color information.



 In parking lot management, license plate recognition technology is also the main method to identify the identity of a vehicle.

License plate recognition technology combined with electronic non-parking toll system (ETC) to identify vehicles, allowing vehicles to pass through the crossing without having to stop to realize automatic identification and charging of vehicles. In the management of the parking lot, in order to improve the efficiency of vehicle traffic at the entrance and exit, the license plate recognition aims at vehicles that do not charge parking fees (such as monthly trucks and free internal vehicles), and establish unmanned fast lanes to avoid the need for cards and parking. Change the management mode of access to parking lots.


Working principle of license plate recognition parking system

Nowadays, with the gradual expansion of urban vehicle crowds, many road junctions or parking lots have adopted intelligent license plate recognition technology, and the most prominent performance is that they are used in parking lots. Now many communities, commercial squares, shopping centers, airports, etc Each major parking lot has been transformed, from the traditional card parking system to the smart license plate recognition parking system. Then, what are the principles and applications of license plate recognition in the parking system? Let ’s take a look together.



First, the working principle of license plate recognition in the parking lot system

1. Vehicle viewing: Various methods such as buried coil viewing, infrared viewing, radar viewing technology, and barrier gate video viewing can be used to sense the passing of the vehicle and trigger image collection and capture.


2. Image collection: Real-time, uninterrupted recording, and collection of passing vehicles through high-definition camera capture host.


3. Preprocessing: Noise filtering, auto white balance, auto exposure and gamma correction, edge enhancement, contrast adjustment, etc.


4. License plate positioning: Force scanning is performed on the gray images in the future through image preprocessing to determine the license plate area.


5. Character cutting: After locating the license plate area in the image, through graying barriers, binarization, etc., the bit character area is accurately determined, and then character cutting is performed according to the character scale characteristics.


6. Character recognition: Scaling and feature extraction of the cut characters, matching with the standard character expression form in the character database template.


7. Effect output: Output the effect of license plate recognition in text format.


Detailed working principle of license plate recognition parking system


Two, four major applications of license plate recognition

1, Parking lot and community entrance

The application of parking plate and community entrance and exit license plate recognition technology is mainly used to record the vehicle license plate number, license plate color, and time of entry and exit, and to complete the automatic processing of the vehicle in order to save manpower and forward power; for example, it can be used to distinguish between entering vehicles in smart communities. Is it due to the community, the automatic timing of toll gates for the completion of non-internal vehicles? In some units, this application can also be linked with the vehicle dispatching system to automatically and objectively record the vehicle out of the unit.


It is very difficult to manually record the license plate number and parking time of the traveling vehicle by the parking lot and the entrance and exit of the community. Not only errors will occur, but also a lot of manpower needs to be invested. A small license plate recognition device can handle many questions at the entrance and exit of the parking lot. The license plate is blocked, the paint is cracked, and the blur can be analyzed and identified, which saves a lot of trouble for the staff at the parking lot and the entrance.


2, Expressway Toll Station

Nowadays, China's highways are being built for thousands of miles, and the highways are unobstructed. Each exit is provided with a toll station, which facilitates toll collection on the one hand and helps traffic police to standardize the traffic on the highway. The application of the license plate recognition technology at the entrances and exits of highway toll stations can greatly facilitate traffic police to identify the license plate information of illegally trekking vehicles and to effectively handle and arrest some illegal vehicles.


卡 The toll gate is generally located in an open-air environment, coupled with some vehicles traveling fast, so the requirements for license plate recognition technology are very high. Traditional license plate recognition is about 160P pixel license plate recognition. Useful image planning is small, the license plate miss rate is high, and it cannot meet the needs of the toll station bayonet. Now the application of high-definition license plate recognition has dealt with the question of the low license plate recognition rate, thus providing a reliable basis for the law of public security and traffic police.


The license plate recognition system is installed at the entrance and exit of the toll booth. When a vehicle enters, the system recognizes the license plate of the vehicle and sends the recognized license plate information to the designated base processing server. By comparing it with the theft of the suspected vehicle in the database, It can be judged whether the road gate vehicles entering or exiting the toll gate of the expressway are stealing suspicious vehicles, which can greatly avoid the occurrence of illegal and illegal incidents and see the information about the work supply that has occurred.


3. Application in highway bayonet

With the increase in the number of roads created by our country and the overall improvement of people's living standards, the number of people who buy cars now continues to increase, posing various illegal questions to the highway. As a necessary basis for illegal vehicle punishment, the license plate recognition technology can automatically check and identify the vehicle number plate in the video. The most typical one is the security checkpoint system. This system assumes that without the license plate recognition technology, there is no real intelligence Into.


完善 A complete security bayonet processing system should have three primary functions of automatic license plate recognition, bayonet application system and base processing channel. The license plate recognition is the most important part in the meantime. The quality of the license plate recognition directly affects the overall function of the bayonet system, and the recognition speed is its most important technical indicator. The recognition speed is fast, the system requirements occupy fewer system resources, the possibility of manual intervention is small, and the work burden of the system network is correspondingly reduced. The recognition of the license plate is fast and accurate. The license plate recognition system is intelligent and useful to complete the automatic comparison alarm to avoid many false alarms. It can provide powerful and reliable crack detection information for anti-theft vehicles, deck vehicles illegally grabbed vehicles and other illegal crime detection.


Detailed working principle of license plate recognition parking system


4. Application in urban transportation

In recent years, with the rapid development of society and the economy, the rapid increase in the number of motor vehicle barriers, road transportation has become more and busier. The hostility of traffic handling status and needs has further intensified, and criminal and public security cases related to traffic have also increased year by year. Under this circumstance, how to use preemptive technology to strengthen the police's investigation and control of motor vehicles and drivers in the city, and to provide technology for impacting various illegal and illegal acts is a question that the police's traffic processing department needs to deal with urgently.


Nowadays, the license plate recognition parking lot system is currently considered to be a set of parking lot management systems that are more convenient to manage and vehicles pass quickly. Because of its advantages such as high recognition rate and fast traffic, it has been favored by many users. However, in order to better manage the parking lot and the problem of parking difficulties, the parking lot system is constantly upgraded and the functions are constantly increasing. Of course, the license plate recognition technology must not fall behind. The license plate recognition system will definitely bring a lot of convenience to the management of the parking lot system.


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