The Research Of License Plate Recognition And Tag Information Tamper Detection Of Taxi Inspection System

In recent years, because of the increase of illegal operations of cars, the numberof road traffic accidents and criminal events are rising. To regulate the order of thetaxi market, the intensity of the vehicle identity inspection has been increased by theTaxi Inspection System that combines radio frequency identification technology andimage recognition technology, positioning rate of license plate image and thesecurity of electronic tags stored data has been studied as focal point in this system.In this thesis, the research of algorithm including license plate location andtamper detection has been done. Firstly, analysis the shortcoming of the currentmethod of license plate image positioning is presented, and a license plate locationimproved algorithm is proposed. Secondly, analysis the security risks of the datastored in electronic tag, and do research about the method of information security.According to the above two problems, this paper takes the solution for theseproblems:In the process of License Plate location, the method based on gray image isused, the result of location is affected by the area which is similar to license platecharacteristic. And the method based on mathematical morphology is used, thelocation result is affected by the result of Image edge detection. In this paper, aimproved positioning method is proposed based on combining the advantage ofabove two methods. Firstly, the characteristics of Gray-scale image of license platecharacters and background is presented, Then after the process of image difference,the method of counting the numbers of grayscale jump is used in the stage ofhorizontal positioning. After that, to realize the precise positioning of the plateimage, the image located in horizontal direction has been processed by the techniqueof mathematical morphological and projected in vertical direction. Compared to theexisted location methods, the performance of the proposed method is quite good forstrong anti-interference ability and higher accuracyBecause of the privacy of the data, the correctness of information is verfied bythe method which is proposed in this paper after the tag information is read by reader.A tamper detection method based on chaotic theory and hamming code has beenproposed. After the label’s data to be protected is read by reader and processed, theresult will be as the input of chaotic system to generate feature information that will be encoded by hamming code, and the encoded information will be used as tamperdetection information. In the process of tamper detection, the information to betested will generate again according to chaotic system, then the feature informationstored in the tag is decoded after the process of hamming code check, the method canachieve the purpose of tamper detection by compareing with two kinds ofinformation. Experiments show that the security of data is strengthened and tamperdetection and localization is realized.Based on the precise location, the license plate recognition is realized. Thenafter getting the data by reader, the process of tamper detection is done. Finally, TaxiInspection System has been designed and implemented based on the result of twomethod of recognition.