Brief introduction of license plate recognition system

VLPR(vehicle Plate Recognition) is a technology that can detect and monitor vehicles on the road, and automatically extract vehicle license plate information (including Chinese characters, English letters, Arabic numerals and license plate color) for processing. License plate recognition is one of the important parts of modern intelligent transportation system, and it is widely used. Based on digital image processing, pattern recognition, computer vision and other technologies, it analyzes the vehicle images or video sequences shot by the camera to get the unique license plate number of each vehicle, thus completing the recognition process. Through some subsequent processing means, the functions of parking lot charge management, traffic flow control index measurement, vehicle positioning, vehicle anti-theft, automatic supervision of expressway speeding, electronic police running red lights, expressway toll station and so on are realized. It is of practical significance for maintaining traffic safety and urban security, preventing traffic jams and realizing traffic automation management.

Vehicle license plate number is the only "identity" sign of a vehicle. Automatic license plate recognition technology can automatically register and verify the "identity" of vehicles without any changes. This technology has been applied to many occasions, such as road toll collection, parking management, weighing system, traffic guidance, traffic law enforcement, road inspection, vehicle scheduling, vehicle detection and so on.

Several applications are listed below:

-Monitoring and alarm

For vehicles listed in the "blacklist", for example, wanted or reported lost vehicles, unpaid vehicles, vehicles without annual inspection, hit-and-run vehicles and illegal vehicles, just input their license plate numbers into the application system, and license plate recognition equipment will be installed at designated intersections, bayonets or carried by law enforcement officers at any time as required. The system will read the license plates of all passing vehicles and compare them with the "blacklist" in the system. Once the designated vehicle is found, it will send out an alarm message. The system can work all day without fatigue and the error rate is extremely low; Can adapt to high-speed vehicles; Can complete the task in the process of vehicle driving, without affecting normal traffic; The whole monitoring process will not be noticed by the driver, and the confidentiality is high. The application of this system will greatly improve the efficiency of law enforcement.

-Penalties for speeding violations

License plate recognition technology combined with speed measuring equipment can be used to punish speeding vehicles, generally used in highways. The specific application is: set up speed monitoring points on the road, capture speeding vehicles and identify license plates, and send license plates and pictures of illegal vehicles to various exits; Set penalty points at each exit, use license plate recognition equipment to identify passing vehicles, and compare the number with the number of speeding vehicles received. Once the numbers are the same, start the early warning equipment and notify the law enforcement personnel to deal with it. Compared with the traditional overspeed monitoring method, this application can save police force, reduce the work intensity of law enforcement personnel, and is safe, efficient and hidden. Drivers need to remind themselves not to speed at all times, which greatly reduces the accidents caused by speeding.

—— Vehicle access management

Install license plate recognition equipment at the entrance and exit to record the license plate number and entry and exit time of the vehicle, and combine it with the control equipment of automatic doors and railings to realize the automatic management of the vehicle. When it is applied to the parking lot, it can realize automatic time charging, automatically calculate the number of available parking spaces and give tips, thus realizing the automatic management of parking charges, saving manpower and improving efficiency. When it is applied to intelligent community, it can automatically judge whether the driving vehicle belongs to the community or not, and realize automatic timing and charging for vehicles in non-community In some units, the application can also be combined with the vehicle dispatching system to automatically and objectively record the departure of vehicles in the unit. License plate recognition management system adopts license plate recognition technology to realize no parking and no swiping, which effectively improves the traffic efficiency of vehicles.

-Automatic release

Input the specified license plate information into the system, and the system will automatically read the license plates of passing vehicles and query the internal database. For vehicle systems that need automatic release, drive electronic doors or fences to let them pass, and warn other vehicle systems, which will be handled by the personnel on duty. Can be used in special units (such as military administrative areas, secret units, key protection units, etc.). ), road and bridge toll stations, senior residential areas, etc.

—— Expressway toll management

License plate recognition equipment is installed at every entrance and exit of the expressway. When the vehicle enters, it recognizes the vehicle license plate and stores the entry information into the toll collection system. When the vehicle arrives at the exit, it recognizes its license plate again and calls the entrance information according to the license plate information, and realizes the charge management by combining the entrance and exit information. This application can realize automatic billing, prevent cheating and avoid the loss of accounts receivable.

Expressway has begun to implement network toll collection. With the expansion of the network scope, the tariff difference of different models is getting higher and higher. In the existing toll collection system, the problem of drivers changing cards to evade fees will become more and more prominent. Using license plate recognition technology is the fundamental way to solve this kind of problem.

-Calculate the driving time of the vehicle.

In the traffic management system, the average travel time of vehicles on a certain road can be used as a parameter to judge the degree of road congestion. Install license plate recognition equipment at the beginning and end of the road, read all passing vehicles and send the license plate number back to the traffic command center. The management system of the command center can calculate the average driving time of the vehicle according to these results.

-Automatic registration of license plate numbers

Traffic supervision departments deal with a large number of pictures of illegal vehicles every day. Generally speaking, the license plate number is manually identified and then input into the management system. This method has a large workload and is easy to fatigue and misjudge. Using automatic identification can reduce the work intensity and greatly improve the processing speed and efficiency. This function can be used in electronic police system, road monitoring system and so on. License plate recognition parking lot management system automatically recognizes the vehicle license plate image taken by the camera at the entrance and converts it into a digital signal. To realize one card and one car, the advantage of license plate recognition is that it can correspond the card with the car, so that management can be improved to a higher level. The corresponding advantage of the card with the car is that the long-term rental card must be used with the car, eliminating the loopholes in the use of one card with more cars and improving the efficiency of property management. At the same time, it automatically compares the vehicles entering and leaving to prevent theft. The upgraded camera system can collect clearer pictures and save them as files, which can provide strong evidence for some disputes. It is convenient for managers to compare vehicles when they leave the scene, which greatly enhances the security of the system.

Automatic license plate recognition technology is a pattern recognition technology that uses dynamic video or static images of vehicles to automatically identify license plate numbers and license plate colors. Through the collection and processing of images, we can complete the function of automatic license plate recognition, automatically extract license plate images from images, automatically segment characters, and then recognize characters. Its hardware foundation generally includes trigger equipment (monitoring whether the vehicle enters the field of vision), camera equipment, lighting equipment, image acquisition equipment, and a processor (such as a computer) that recognizes the license plate number.

Schematic diagram of license plate recognition application