Research Of License Plate Recognition Based On Digital Image Processing

The Vehicle License Plate Recognition (VLPR) is an important technique within the Intelligent Transportation System (ITS) which is the study topic in the front of the current transportation realm of world. And the VLPR is widely used on account of the combination of image processing, pattern recognition and automatization.Because of the exclusive, the clearest and exactest sign of the vehicle license plate, the Vehicle License Plate Recognition, a special vision system, can automatically record the dynamic data of the vehicle traveling, judge and extract the image data of vehicle license plate effectively, and recognize the character of vehicle license plate precisely.This paper deals with a complete VLPR system, overviewing the development history of the VLPR's technique and introducing the every component of VLPR system as well as domestic and international method of recognition. In this paper, a rough classification method of vehicle license plate that is based on the search of the connected area is presented after an image binarization method is discussed on the basis of the gray image translation. Then the accurate classification of vehicle license plate is made after the features of the plate area are extracted in the line with the inherent features of the vehicle license plate. This paper also purposes a license plate oriented image binarization that is based on color model and the combination of the method of connected area and perpendicular shadow to segment the character of the plate to solve characters stuck and over-segmentation. Therefore, the character of the plate will be recognized with the application of the method of model matching and the character recognition using combination features after the segment of the character in the plate.The dynamic vehicle license plate recognition discussed in this paper is the improvement of the existing technique of the VLPR, the increase in the speed and accuracy of the recognition and the expansion of its application. Thus, the VLPR system in this paper will satisfy the requirement of real-time ITS.