The Research Of Key Technology In Electronic Toll Collection System Based On UHF RFID

With the development of Chinese national economy, vehicles running on the road have increased year by year,and the network of highway gradually has been established. But,the method of the highway toll collection is almost manual,the process of collection takes long time,and causes the inefficiency. In order to adapt to the development of modern road demand,this paper presents a framework of Electronic Toll Collection System of highway which is based on the technology of UHF RFID,and has a research on the related techniques of this system.Firstly, makes a survey on the current status of Chinese road toll system, then have a study of the system which is based on RFID technology. Through the analysis of the functionality, composition, application of the system, present the key techniques of ETC.Secondly, introduce the structure and the principle of Ultrahigh Frequency Radio Frequency Identification(UHF RFID)technology, and then will introduce three anti-collision algorithm of three standard communication of UHF RFID.This paper introducing a classical algorithm-ALOHA algorithm and its extension of some of the algorithms of standard algorithm of TypeA.And mathematical methods and simulation methods from both of these algorithms are described. Through the demonstration shows that there are some shortcomings in existing anticollision algorithm,which is the recognition efficiency is generally low, and this kind of algorithm can only applies to some special occasions.An improved algorithm proposed ISR algorithm, which based on TypeB standard algorithm, are introduced. This algorithm is started from the collision, experiments show that IRBS algorithm can effectively reduce the total number of search and reduce the length of each command to send the data to be able to quickly and effectively identify the tag. This paper also analysis the SR slot random anti-collision algorithm of the ISO18000-6C, improved ISR algorithm based on the SR algorithm, according to the estimated number of tags of the first collision of the label, and then set a reasonable Q value. ISR algorithm and simulation results show that the ISR algorithm and tag identification number in the communication efficiency is superior to SR algorithm, effectively improving the performance of tag identification.Then, in the practical application of the toll collection, in order to prevent vehicle owners cheating by changing the vehicle tag, the technology of recognizing vehicles style is very important. In this paper, a technique of pattern recognition based on image processing is introduced, and also discussed the gray-scale transformation, binarization processing, edge detection and other methods to achieve the image of the contour extraction..In this paper, we investigate the two key technology of the Electronic Toll Collection System. One is the anti-collision technology of UHF RFID, and the other is technology of pattern recognition on vehicle. Based on the two standard algorithms of anti-collision technology, respectively, introduced an improved algorithm,both of theoretical analysis and experimental results show the excellent characteristics of the algorithm; and through experiment simulation achieved automatic identification of models in toll collection system.