Design On Vehicle License Plate Recognition System

Vehicle'license plate recognition system(LPRS) is the main part of the Intelligent Transportion System,and it plays great part in the contem- porary transportation management,Its realization can accelerate modern construction of speedway,city road and parking lots management. As the development of economy,vehicle will take more and more important role in human lifes. Increasing numbers of vehicle will promote the impr- ovement of vehicle management .Therefore, it will have comprehensive application prospect. The main important technology of LPRS consists of three modules in general, those are license plate locating,character segmentation and cha- racter recognition .License plate locating is the basic and premiss of the last two steps,and directly affects the process of the last two steps. Char- acter segmentation determines the validity of character recognition. This dissertation firstly introduces the research background and act- uality,the principle of recognition system and the demand of original image.In license plate locating,firstly process the pretreatment of ori- ginal image,this step consists of image gray image,filtering and image binary. In the part of gray image ,it presents a method of unequal R G B combination,the formula:Y= R×0. 299 + G×0. 587 +B×0. 114. In the process of image filtering,it uses three multiply three LaplacianThe Laplacian is ,The threshold value of gray image bina- ry T equal tom plusσ.The gray average numeralcharacter of standard vehicle license plate and its projection,this disserta- tion put forward the careless location of vehicle license plate.After the horizontal and vertical projection ,it combines the character of standard vehicle license plate to take careful location and find out the true license plate area. This dissertation gives sketch maps of license plate locating in the second chapter: picture 2.1 (a) (b),picture 2.2 (a) (b),picture 2.3 (a) (b) (c) .In the character segmentation,it uses a all-around threshold value ari- thmetic based on dimensional distributing of character to binary.(this ar- ithmetic is based on all-around threshold value,the threshold value is rea- sonable ,the effect of binary is better,and it can judge the types of license plate).Secondly it unifys the color of license plate'background and wipes off the interfere of horizontal frame .In the end it adopts vertical projecti- ve analyze combined with the character of license plate for vertical seg- mentation and it can confirm the left,right boundary of characters.After that ,this dissertation process the horizontal segmentation to confirm the up and down boundary of characters.This dissertation gives sketch maps of license segmentaion in the third chapter: picture 3.1 (a) (b) (c), picture 3.2, picture 3.3.In the character recognition , this dissertation firstly introduces the character of license plates'character. Secondly it analyzes arithmetics some character recognition arithmetics used much at present, those are template matching arithmetics and recognition arithmetic based on struc- ture of characters .Due to chinese character is more complicated than sy- mbols including alphabetic and digital character ,this dissertation prese- nts one recognition arithmetic based on structure of chinese characters solely .Experiment indicates that this dissertation gets good effect by meth- ods used in license plate locating,character segmentation and character recognition.