Computer Aided Discrimination System On Vehicle Identification Number

Vehicle identification number(VlN) will be put on engine and frame as a seal when vehicles leave factory. A new vehicle's numbers must be stamped and the rubbings, which is called original label, must be perserved in the Traffic Department. The numbers will be stamped again and compared with the original label in the operations for Annual vehicle check-up, refit or transfer etc., and it will protect against that the numbers have been illegal changed. VIN is one and only ID of vehicles. Discriminating the numbers which have been factitious changed is important and it is the key to identify the validity of vehicles.With the rapid development of economy in our country, the quantity of vehicle become more and more. There are more than 500 thousand vehicles in the medium and large cities of our country on average. It's hard to discriminate such a large number of rubbings by human work. And with the increasing of criminal activities, it becomes more difficult to identify the validity of vehicles for Traffic Department, so it's necessary to improve efficiency and precision by using computers.In this thesis, a technique of image processing and its application in VIN is demonstrated. The two important parts of the technique are the image preprocessing algorithm and the image comparison algorithm. The image preprocessing algorithm is used in the register of vehicles, which includes Image Digitization, edge detection, de-noising, characters segmentation. This will set up data of the image, which includes the coordinate information of all the characters in the image.Image de-noising will greatly influence the latter compared results, so it is one of the emphases of study; On Character segmentation, template matching method is improved to overcome characters' conglutination and rupture effectively; The image comparison algorithm is used in image registration and to test the validity of vehicle through the similarity degree between the relevant characters.The use of comparison system will minimize the time of affair transaction and increase the efficiency for the traffic apartment; It will provided direct basis for the validity of vehicle, and has a great value of practicality.