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License Plate Recognition System Performance Judgment Key Indicators
From the technical point of view, there are three indicators for the performance of the license plate recognition system , namely, the recognition rate, the recognition speed, and the background management system. Of course, the premise is that the system must be able to operate stably and reliably. The following is a detailed description of the three indicators:
1, recognition rate
A license plate recognition system is practical, the most important indicator is the recognition rate. The international transportation technology has made a special discussion on the recognition rate indicators. The requirement is that the correct recognition rate for the whole card is 24% to 75%. Xinluotong’s license plate recognition system has achieved a full recognition rate of over 90% in practical applications.
In order to test the recognition rate of a license plate recognition system , it is necessary to install the system in a practical application environment, run it for more than 24 hours in all weather conditions, collect vehicle license plates when at least 1000 natural vehicles are in circulation, and need to identify and identify vehicle license plates. The results are stored for viewing. Then, you also need to get the actual passing vehicle image and correct human recognition results. After that, the following recognition rate can be calculated:
1) The recognition rate of the natural traffic flow = the total number of vehicles actually passing through the total number of correctly identified total cards;
2) Percentage of identifiable vehicle license plates = Total number of vehicles that actually passed the total number of vehicle license plates correctly read;
3) Fully-recognized correct recognition rate = Total number of car licenses correctly identified by the entire card The total number of manually-obtained license plates determines the recognition rate of the license plate recognition system, such as the credibility and misrecognition rate. The intermediate result in the recognition process.
2, recognition speed
The recognition speed determines whether a license plate recognition system can meet real-time application requirements. A system with a high recognition rate, if it takes a few seconds or even minutes to recognize the result, then this system will have no practical significance because it can not meet the real-time requirements in practical applications. For example, one of the functions of license plate recognition in highway toll collection is to reduce travel time, which is a powerful guarantee for reducing transit time and avoiding traffic jams in this type of application. The speed of recognition proposed by international transportation technology is within 1 second, the sooner the better.
3, background management system
A license plate recognition system background management system, determine the license plate recognition system is easy to use. It must be clearly understood that the important point is that the recognition rate of 100% is not possible because the vehicle license plate is dirty, obscure, blocked, or the weather may be bad (snow hail, fog, etc.).
The functions of the back-end management system should include:
1) The recognition results and the reliable storage of vehicle image data, when the multi-functional system operation makes the network go wrong, it can protect the image data from being lost, and at the same time, it is convenient for manual inspection afterwards;
2) Effective automatic comparison and inquiry techniques, the identified license plate number shall be automatically compared with the thousands of license plate numbers in the database and prompt alarms. If the license plate number is not correctly read, fuzzy query shall be used. Technology can produce relatively "best" comparisons;
3) A good license plate recognition system for network operation, but also need to provide real-time communication, network security, remote maintenance, dynamic data exchange, automatic database updates, hardware parameter settings, system fault diagnosis.
The license plate recognition system can not only be used in places such as parking lots, but also can be installed on roads. It can also identify stolen vehicles driving on the road. Of course, this requires the police to establish a stolen vehicle database, and then connect this database to the monitoring system. As soon as the vehicle is monitored, the stolen vehicle can be notified to the police at the first time to provide assistance for the police's detection work. This system also has broad application prospects in the field of vehicle security and anti-theft. Based on its role, as well as various problems existing in various parking lots and transportation areas, for example, as the urban population increases, the number of vehicles will inevitably increase, and the problems will increase, and these problems will increase. It is impossible to rely solely on manpower to solve the problem. Therefore, the automatic license plate recognition system is increasingly used, and it is closely related to the development of society and people's living needs.