Two technologies for automatic vehicle identification systems: RFID vs ANPR

安全是重要的功能之一utomatic vehicle identification system, especially in the charging business of toll stations and parking lots.

Today, the Automatic Number Plate Recognition System (ANPR) is also often used to identify vehicles. However, people pay more attention to two aspects of ANPR: one is the high error rate of automatic vehicle recognition; the other is the financial provided by the government in ANPR technology. expenditure.

The application of radio frequency identification technology to the vehicle identification system will solve the technical and economic problems faced by the vehicle automatic identification system in a safer and more economical way.

The National Highway Administration uses infrared cameras with Optical Character Recognition (OCR) to read vehicle license plates for road toll collection, law enforcement, and monitoring of traffic near gates or parking lots.

The RFID technology mainly installs electronic tags on the windshield or other places of vehicles, and uses RFID infrastructures fixedly placed at entrances and exits and parking lots to identify passing vehicles.

The following mainly compares the two vehicle automatic identification technologies, RFID and ANPR, from the six aspects of resource allocation, detection rate, data accuracy, environmental immunity, multi-channel processing and security.

01 Resource deployment

User provisioning is the process of creating, maintaining, and deactivating access rights and privacy while ensuring the security of corporate resources.

Today, ANPR technology is mainly presented in the form of license plates. The RFID technology requires electronic tags to be attached to the windshield of the vehicle. Both of these vehicle identification technologies are used in conjunction with the back-end system. The latter mainly associates the identifier (license plate or RFID tag) with the users account. The data obtained through the RFID reader is stored locally and sent to the The cloud or server provides relevant data.

ANPR is often used as a technical choice for vehicle access systems, mainly because this technology provides lower supply costs at toll gates and parking lots on expressways, because ANPR is a government-registered license plate recognition system, and it is also A kind of pass that can be used at any time.

At present, many states and countries are adopting RFID transponders issued by the federal government. Therefore, drivers must attach RFID electronic tags to the windshield of the vehicle. Among them, drivers in Florida attach the Sun Pass tag to the vehicle to pay. Tolls for roads and parking fees for parking lots.

02 Detection rate

Comparing the detection rates of the two technologies, ANPR and RFID, requires consistent measurement methods. To this end, the total number of vehicles detected by ANPR technology through external triggers such as loop detectors is compared with the total number of tags or license plates captured by RFID technology.

ANPR technology based on visual recognition requires powerful optics, computing and digitization capabilities, but this will reduce the speed of license plate recognition per second. Due to environmental differences and different shutter speeds, the ANPR system can detect license plates at a speed of up to 160 kilometers per hour (100 miles per hour) on cars.

Long-range, UHF RFID technology actually better meets the challenge of high-speed vehicle identification. Nowadays, RFID systems are being applied to the license plate recognition of high-speed cars. Even if the car passes through toll booths at a very high speed, it does not slow downvehicle recognition and authentication are tested at more than 150 miles per hour. The Massachusetts Department of Transportation (MassDOT) demonstrated the accuracy of the RFID system. Compared with the paid battery panel system used in the past, its E-ZPass system has increased the charge based on RFID transponder power by more than 99% in six months.

03 Data accuracy

Data accuracy is a measure of correctly capturing vehicles and transmitting data.

RFID uses the Air protocol and combines Cyclic Redundancy Check (CRC) as a method to prevent erroneous data transmission between the electronic tag and the reader. ANPR relies on software algorithms and voting logic to determine the possibility of identifying characters. Since RFID can self-check the relevant data read, it provides more accurate data than ANPR.

The data accuracy rate of ANPR technology is not as high as that of RFID technology. The main problem is that ANPR has 4 incorrect data for every 100 readings. The IT West report shows that in the UK, the ANPR system uses 9,000 cameras and stores up to 30 million vehicle records every year. It also shows that this system carries up to 1.2 million wrong license plate readings every day! More than 400 million false readings.

04 Environmental immunity

As an optical technology, ANPR technology is susceptible to environmental factors. For example, some snow or dirt may conceal the license plate number, and the glare or white flashback of the sun's headlights on the vehicle will also make it difficult for the camera to distinguish and cover the license plate number. In addition, the license plate with red numbers and letters and the infrared camera form a very low contrast, which will also cause the ANPR to significantly reduce the detection rate of the license plate.

RFID technology is protected from external factors such as the environment. In the absence of light, a tag can also identify vehicle license plates at amazing driving speeds or from fog, snow, paint, and other harsh environmental conditions. However, RFID equipment has a longer life span than optical identification equipment and requires minimal maintenance to improve the flexibility of system configuration.

05 Multi-channel processing

A single RFID reader can manage two lanes. Each RFID reader will be uniquely identified based on the vehicle's identity information to distinguish its lane allocation.

A single RFID reader can manage two channels. The Wiegand switch transmits the data on the reader according to a specific antenna and transmits the Wiegand signal to the control panel of the access system. Whether the RFID reader reads the tags on the car along the same direction or in different directions, the license plate can be recognized. Each antenna has a unique identifier that matches the lane, so it can distinguish the direction of the vehicle read by the RFID reader, which helps to individually control the access gates. The "RFID+Weigand switch" solution can reduce the number of card readers and is easy to install and adjust signals, thereby saving time and costs.

ANPR technology requires multiple card readers to work together to recognize license plates in multiple lanes. Then, the cost of ANPR will be higher, because it needs to buy more hardware for maintenance. However, RFID technology helps reduce these costs. This is because rfid has multiple antennas to output data and can provide data support for different reading points. Because RFID technology is only a small part of the hardware cost in the vehicle identification system, it can potentially save a lot of hardware cost compared with purchasing multiple hardware components to obtain the same result.

06 Security

Security is one of the most important features in vehicle identification, especially when the vehicle conducts financial transactions, such as charging in a parking lot. However, ANPR (Automatic Number Plate Recognition System) does not have a built-in safety mechanism. For example, a high-quality fake license plate image affixed to the original license plate can actually deceive ANPR's camera system.

尽管一些形式的RFID enoug都不高h security, such as RFID tags used for inventory control or asset management. However, the RFID technology used in the vehicle license plate recognition system has the ability to embed a password into the transponder. Therefore, access to system data is not allowed without a password, which undoubtedly improves the security of the access system. In addition, RFID technology also has encryption functions. When the password itself is encrypted by the key, it is convenient to safely access the control system. With encryption, the control system cannot be accessed without a key. Currently, the highest form of security is the UCODEDNA chip from NXP Semiconductors, which combines anti-tampering features, such as cryptographic algorithms, to deter thieves and counterfeiters, while providing high-performance access control systems at high speeds.

RFID technology has been proven to save millions of dollars in reducing a large number of false readings and provides a modern, reliable and highly secure solution. At the same time, RFID reduces the inaccuracy between readings caused by external factors, thereby improving configuration flexibility. Another solution is a hybrid approach. A solution using ANPR and RFID technology can also prevent unauthorized vehicles and overcome the inaccuracy of ANPR in identifying vehicles, so that the vehicle access system can achieve good operating results. .

In fact, many countries are loading RFID technology into vehicle access systems, and RFID chips are properly installed or embedded in the license plates of vehicles.