Research & Development Of License Plate Location System

Licence Plate Recognition System(LPRS)which is based on Digital Image Processing Technology mainly consists of four key technologies:Image preprocessing,License plate location,Character segmentation and Character recognition.It finds not only wide application in Intelligent Transportation System(ITS),but also is a hot point of research in Computer Vision,Image Processing and Pattern Recognition.So its related technology is attended prevalently.On the above background,the paper made a deep and systematic research for Licence plate recognition technology.The paper introduces the structure of the LPRS and presents a simple and practical algorithm of License Plate Location based on the quality of projection gray scale and the Prior knowledge of the license plate after the study of classic image segment and location algorithm.By transforming RGB image into gray image,binarying image,smoothing and sharpening image,edge detection operators and median filter and so on,its measure can deal with the inputed images,then the license plate is located precisely by Projection Technology.The results show that this algorithm bears good performance in the simulation of application.At the same time,the paper also propose a simpler theory of license plate location based on counting changing times of edge and method of vehiclelogo location.In the dissertation,the paper propose a method of vehiclelogo location from coarse to fine which is based on Human Visual Properties.The approximate scope of vehiclelogo is first confirmed by preexistent knowledge,then its finer position is found by edge detection and morphology operators,and finally it is located precisely by relation match operator in a very small scope.These researches have academic significance in Object Location System which is subject to illumination,noise,size,deformed,shape similarity and part occlusion.