Research on Future Road Supervision Front-end System Form Based on Electronic License Plates

1. Overview of current road surveillance front-end systems

Currently, the road monitoring front-end system has several types of overspeed recording system, bayonet recording system, interval speed recording system, and red light recording system. They have different functions and fulfill different requirements, and each has a corresponding national (recommended) standard. .

The above-mentioned systems are based on the cooperation of software and hardware, and focus on recording and storing road vehicles through pictures. Because the hardware and software components are basically the same, the overspeed recording system will be gradually integrated by the bayonet recording system, while the interval speed recording system is composed of 2 sets of bayonet recording systems. Therefore, the bayonet recording system is the most basic road monitoring front-end system.

The current bayonet recording system includes a coil bayonet recording system, a video bayonet recording system, a video+radar bayonet recording system, and a radar bayonet recording system.

1.1 coil bayonet recording system

The coil bayonet recording system uses a sense coil detection method at the front end. Two wired or wireless inductive coils are embedded in each lane. The principle of electromagnetic induction is used to detect passing vehicles in real time. And control the camera capture high-definition pictures of passing vehicles, while controlling the strobe light to fill light. The vehicle detection unit detects the running speed of the passing vehicle in real time. Due to the disadvantages such as the need for cutting, drilling and other destructive operations, construction, and post-maintenance costs, the video bayonet recording system was gradually replaced.

1.2 video bayonet recording system

The video bayonet recording system triggers the capture of passing vehicles by detecting the amount of change in pixels within the preset video area. From the coil bayonet recording system to the video bayonet recording system, it is a major advancement in technology, which is fundamental from hardware to software. The difference, but the video bayonet recording system has certain requirements on the brightness of the environment, in the early morning, evening, mist, cloudy days and other dark light or body color and background color similar, the vehicle capture rate will be significantly reduced, while the video card The mouth recording system uses a randomly generated speed value method and cannot provide an accurate speed measurement value, so a video + radar bayonet recording system appears.

1.3 Video + Radar Mount Recording System

In the video + radar bayonet recording system, a narrow-wave radar dedicated for bayonet is used, but the radar is in a subordinate position. After the radar detects the vehicle, it continuously provides the speed value to the camera to obtain an accurate speed measurement value, but the camera cannot be guaranteed. Radar data can be received every time. At the same time, the system's requirements for ambient brightness still cannot guarantee the vehicle capture rate. With the localization of flat-plate narrow-wave radars, the radar bayonet recording system has rapidly emerged.

1.4 Radar Mount Recording System

In the radar bayonet recording system, the bayonet-specific flat narrow-wave radar is still used, and the radar is in a dominant position. After the radar detects the vehicle, the captured signal and the vehicle speed value are sent to the camera at the same time, and the camera receives the capture signal and captures it. The speed value matches the picture and a complete record of the vehicle is generated. The radar bayonet recording system has become the current mainstream bayonet recording system with its advantages of accurate vehicle positioning, high capture rate, strong anti-interference ability, and ability to work in all-weather conditions.

With the rise and promotion of domestic electronic license plates and the formulation of related standards, the future bayonet recording system will be based on electronic license plate technology.

2. Introduction of electronic license plate

"Electronic license plate" is called "digital identity source of automobile identity information and management basic information" and is an electronic identity card of the automobile. In 2007, it was certified by the Ministry of Science and Technology and was affiliated with the "National Science and Technology Support Plan". The system is based on RFID technology and consists of electronic tags, readers, antennas, and base stations. It is an important part of the car networking system and is the basic data source for the work of other related systems.

The electronic tag stores vehicle information (vehicle number, vehicle type, frame number, maximum vehicle quality, age, tax payment, vehicle owner information, vehicle owner social credit code, and the ID number of the electronic tag, etc.) ), with tamper, anti-magnetic, waterproof, encryption, large capacity and so on. The basic working principle of the system is as follows: The vehicle with the electronic tag correctly installed enters the RF signal coverage area of ​​the antenna, receives a special RF signal from the reader, generates an inductive current, the internal circuit enters the working state, and automatically sends out the vehicle information. After the reader receives the vehicle information and decodes it, it sends it to the base station for further processing through the back-end software system. The system judges the validity of the card according to the relevant procedures, performs corresponding processing for different settings, and issues instructions to control the actuator.

The accuracy of currently used traffic flow detection equipment is not high, especially when it is impossible to accurately determine the type of vehicle. However, the electronic vehicle license plate system based on RFID technology has higher vehicle capture rate and license plate acquisition accuracy than other types of systems and can be used in all weather and all weather conditions. The work is not affected by the natural environment and the collected vehicle information data is accurate, comprehensive, real-time, etc., and the information is uploaded and integrated, updated, and feedbacked by the public security traffic unified management platform, and other departments (such as finance, insurance, social security, and civil aviation). The unified management platform such as ) communicates with each other to share data, realize cross-industry, cross-department, and cross-domain integrated application and jointly construct a safe city system.

3, the main technical indicators of the current electronic license plate system

3.1 Reading time:

<1 second.

3.2 Read success rate:

99.95% or more.

3.3 Reading distance:

0 to 30 meters.

3.4 positioning accuracy:

Low.

3.5 Allowed vehicle speed:

180 km/h.

3.6 All-weather, full-weather work:

The system is based on RFID technology and can work in all weather conditions and in all weather conditions without being disturbed by the natural environment.

4, the current status of the use of electronic license plate system

4.1 Main cities in China

The application of domestic electronic license plates is in its infancy. There is no unified model and mature experience in vehicle management based on electronic license plates.

Chongqing began to use it in 2012. The Chongqing electronic license plate is the first urban intelligent traffic management project in the province that is used on a large scale within the province. It solves the problem of “inability to accurately identify vehicle identities and qualifications” and at the same time builds a city-centered “ “Regional Electronic Traffic Charging System for Road Traffic” has gradually realized the functions of precise vehicle management, dynamic monitoring of road network, statistics and analysis of traffic flow, and dynamic taxation of various transportation taxes, travel services, and public traffic information release. "Chongqing" excellent project.

Beijing will launch an electronic license plate standard next year. Cities such as Tangshan, Nanjing, Shenzhen, Xiamen, Lanzhou and Yibin are also ready to use electronic license plates.

4.2 Major international use countries

The United Kingdom began using it in 2004 and is mainly used to collect congestion fees. Malaysia is mainly used for theft prevention of vehicles. Mexico

Used since 2004, it is mainly used to track and record vehicles entering and leaving the US-Mexico border. The United States began to use it in 1991. It is mainly used to improve the efficiency of the US-Canada border transport and the safety and visibility of goods on the way. All vehicles in Singapore are equipped with electronic identification cards similar to electronic license plates, which solve the problems of traffic control and traffic charges.

5. Several forms of road supervision front-end systems based on electronic license plates

We know that the road supervision system has different solutions according to different needs. According to the characteristics that each lane of each road can be finely managed, the road monitoring front-end system based on the electronic license plate can have the following Kind of form:

5.1 "Electronic License Plate" Bayonet Recording System

5.1.1 System Features:

No need to record pictures or measure speed values, the system cost is low.

5.1.2 System Introduction:

Through the single technology of electronic license plates, statistics on traffic flow and vehicle type flow are made available to ITS systems. As traffic in the old cities of major cities becomes increasingly congested, congestion fees for vehicles entering the congested areas can be collected in the future based on statistical results that meet the conditions, thus restricting irrelevant vehicles from entering congested areas and encouraging the use of public transport.

5.2 "Electronic license plate + camera" bayonet recording system

5.2.1 System Features:

No need to measure speed values, statistics vehicle traffic, record vehicles not driving in lane.

5.2.2 System Introduction:

In road sections that do not require speed measurement or speed measurement, the road conditions and traffic flow are monitored in real time to understand whether the road surface is abnormal. In stations, roads in front of plazas or other public areas, it is possible to investigate and punish illegally operated vehicles, vehicles that do not follow lanes, and cooperate with discipline inspection and supervision departments to strengthen the supervision of buses.

5.3 "Electronic License Plate + Radar" Bayonet Recording System

5.3.1 System Features:

No need to record pictures, need to measure speed values, statistics vehicle traffic, speed distribution.

5.3.2 System Overview:

In the road section that does not need to capture pictures, it is mainly through real-time monitoring of vehicle speed and traffic flow to understand whether the road surface has abnormal conditions. This form of system will be the main form of the future bayonet, and will be widely distributed in urban areas, provincial highways and highway sections. It is an information source for intelligent transportation networks and provides a large amount of detailed basic information for ITS systems and other systems. Make real-time traffic broadcast, real-time navigation, traffic guidance, traffic intervention possible, so as to better serve the majority of passengers.

5.4 "Electronic license plate + camera + radar" bayonet recording system

5.4.1 System Features:

The need to record pictures and speed values, statistical vehicle traffic, the number plate identification function in the software only play an auxiliary role in detecting whether the vehicle deck.

5.4.2 System Overview:

Meet the general technical conditions of GA/T 497-2009 road vehicle intelligent monitoring and recording system. Can realize all of the technical requirements, in addition to the current radar bayonet can not have two new features: First, according to the speed limit of the car, making the blue card truck and yellow truck the same speed limit, the blue card truck and yellow card electronic tag Special information is added to the camera and provided to the camera. The speed limit of the two vehicles is no longer based on the color of the license plate but on the basis of the model in order to limit the speeding of the blue brand truck. The second is to capture the number of shots according to the model settings. The camera automatically captures 2 shots according to the special information in the blue label truck and yellow label truck electronic labels. The first capture front shows the front features of the vehicle, and the second captures the back of the vehicle. The loading conditions of vehicles are to regulate the phenomenon of ultra-wide, ultra-high, and long-duty, etc., and carry out off-site punishment according to relevant regulations.

5.5 "Electronic License Plate + Camera + Radar" Interval Velocity Recording System

5.5.1 System Features:

Need to record pictures, average speed values, statistics car traffic.

5.5.2 System Overview:

Satisfy GA/T 959-2011 motor vehicle interval speed technical conditions. All of the technical requirements can be realized. In addition, as described above, there are two new functions that are not available in the current interval speed recording system: First, the speed limit is based on the model, and second, the number of shots is set according to the model setting.

5.6 "Electronic License Plate + Video Recording" Bayonet Recording System

5.6.1 System Features:

In the future of the popularity of electronic license plates, there is no need for radar, and only video capture and speed measurement are used.

5.6.2 System Introduction:

With the improvement of video software, technicians continue to invent new algorithms. In the near future, their functions will undergo a qualitative transformation. Video speeds will be achieved and the speed accuracy of national standards will be met, and national laws will be permitted. At the same time, a new video compression technology and video retrieval software have been invented. Under the support of higher-performance hardware, valid pictures are extracted from video and have the smallest repetition rate and are saved in a unified mode. The system also has new features based on the speed limits of the models.

5.7 "Electronic License Plate" Interval Velocity Recording System

5.7.1 System Features:

In the future of the popularization of electronic license plates, there is no need for cameras and radar, the system cost is low, installation and commissioning are simple and quick, and the system reliability is high.

5.7.2 System Overview:

When the vehicle passes through two sets of “electronic license plate” bayonet recording systems with fixed distances, the time is recorded separately, and the average speed value can be calculated by the software. It also has a new function based on the speed limit of the vehicle model.

6. Problems to be Solved in Road Supervision (Front End) System Based on Electronic License Plates

6.1 Response time:

Referring to GB/T 21255-2007 "vehicle speedometer", the response time should not exceed 0.5s. 0.5 s here refers to the time required for the system to enter the measurement area from the start of the vehicle until the record is formed. It can be considered that 0.5 s is the sum of the “detection time”, the “snapshot time”, and the “synthesis time”. Corresponds to the "electronic license plate subsystem," "camera subsystem," and "snapshot software subsystem." Therefore, the response time of the electronic license plate itself should be the "detection time", that is, its response time should be less than 0.5s.

6.2 Allowed vehicle speed:

Referring to current ITS industry radar and motor vehicle speedometer product specifications, the maximum allowable vehicle speed of the electronic license plate subsystem should be 250km/h. Vehicles traveling at high speeds should be able to capture and link with the camera in time.

6.3 Vehicle Positioning:

The vehicle positioning must be accurate. First, cameras in mainstream bayonet systems adopt fixed-focus lenses, taking into account the nighttime effect, the aperture is large, the depth of field is short, the depth of the image is clearly shorter, and the second is because of the nighttime. The depth range of the fill light range is short. If the positioning of the vehicle is inaccurate and the position of the vehicle is too different, it is likely that even the naked eye cannot see the number plate, causing the corresponding violation of the law to be forfeited.

6.4 Interference in adjacent lanes:

A standard lane width is 3.75 meters. When the vehicle is running normally, it should be on the center line of the current lane. If there are different levels of vehicle cross-line driving phenomenon, whether the electronic license plate subsystem can capture or omit repeated capture at 100%. . In addition, there are a large number of non-standard lanes, which are distributed in provincial highways, county roads, rural roads, and urban non-arterial roads, and are 3 to 5 meters in width. They should also ensure the capture rate of the lane and avoid the interference of adjacent lanes.

6.5 Data communication trigger protocol with camera and radar:

In the current radar bayonet system, data communication between the radar and the camera triggers three methods of RS232, RS485 and TTL levels. It is the choice of RS232, RS485, TTL level, or wireless communication. Consider the current mainstream approach and the direction of future technological development.

6.6 How to coordinate the primary and secondary triggering modes:

In the system, the linkage between the electronic license plate and the camera is the main triggering mode, and the radar and camera linkage capture is the auxiliary trigger mode. When the main trigger mode cannot be used (such as the damage, loss, installation, or vandalism of the electronic license plate) How to start the assist trigger mode in time, or adopt any other technical means to coordinate the two to avoid duplicate capture.

6.7 Video Speed:

Relevant companies and manufacturers actively research and develop new algorithms to make video speed measurement possible and more accurate, and they have obtained national legal approval through metrological verification. Create a new speed measurement method.

6.8 Formulate national standards:

The Ministry of Public Security took the lead and the Ministry of Industry and Information Technology and the Standardization Committee participated in the process of formulating, promulgating and implementing the national (recommended) standard of “General Technical Conditions for Electronic License Plate Road Supervision System” as soon as possible, clarifying related terms and definitions, unifying technical specifications of relevant products, and guiding The company regulates production and guides the various functional departments of provinces and cities to supervise law enforcement or carry out relevant work as required.

6.9 Sharing Information with Other System Platforms:

For example, the State Council issued the "Outline for the Construction of a Social Credit System (2014-2020)" on July 2nd, which explicitly proposed the establishment of a unified social credit code system for natural persons, legal persons, and other organizations. At the same time, in coordination with other related systems or regulations, it promotes the widespread use of a unified social credit code in social and economic activities. Citizens can know their own financial information, industrial and commercial registration, tax payment, social security contributions, traffic violations, and other types of credit information through the use of a search code.

6.10 How to prevent the license plate from being cloned:

Although each electronic license plate can have unique and non-modifiable ID numbers through chip curing technology and cannot be disassembled or disassembled and self-destructed, it still cannot prevent the electronic license plate from being cloned, thereby inconveniencing the next step.

6.11 Revise the relevant laws and regulations:

Revise relevant traffic laws and regulations, further increase penalties for all kinds of traffic violations, substantially increase the cost of traffic violations, and conduct technical and evidence collection and legal management. This will enable people to travel in a truly civilized way, truly experience driving pleasure, and create peace together. Road, harmonious traffic.

7. Concluding remarks

With the continuous construction of national roads and bridges and the continuous improvement of road traffic mileage, the road monitoring front-end system based on electronic license plates will become a necessary technical means for ensuring traffic safety and providing convenient travel, providing a variety of detailed systems for back-end systems. Basic data. At the same time, with the rapid development of software and hardware in the computer field and the ITS industry, the future of road monitoring front-end systems based on electronic license plates will become more and more complete, more scientific, more humane, and more forms will emerge. , To better serve our work and life, so that intelligent transportation can truly integrate into the construction of a safe city and become an indispensable sub-system for a safe city.