Personalized License Plate Recognition Technology Research

License plate is the unique legal symbol that is issued by the traffic administration department. License Plate Recognition (LPR) is the kernel resolution of Intelligent Transport System (ITS). LPR is widely used in the toll station, parking lot management, automatic payment highway fee, etc.With the development of transportation in our country, the amount of vehicle is rising rapidly and some new features of the license plate are required. First, the license plate coding system must ensure that the number of the license plate code is large enough for the rapid increase of the vehicles. Second, the license plate must be legible enough for easy recognition. Third, the license plate coding system must satisfy the demand for individuality. For the reasons above, The Ministry of Public Security. PR China announced on August 12th, 2002 that, in Beijing, Tianjin, Shenzhen and Hangzhou, a set of individualized license plate 2002 will be experimentally allied to instead of those used since 1992. With the popularization of the individualized license plate, more and more attention has been put to the recognition of the individualized license plate.This paper analyzes the specialties and difficulties of the recognition of individualized license plate, and discusses the resolve of these problems. First, we discuss noise suppress, image recovery and dot enhancement of gray level images. Second, we introduce the concept of plate segment and the adjustment of the slant plate image. Third, we discuss the binary of the plate image, including the recovery of uneven illuminated images. Fourth, we discuss the split of characters of the individualized license plate, including horizontal and vertical split.The individualized license plate is a new coding system of the vehicle, it is not so popular yet, and the recognition of individualized license plate is not widely used. With the wide use of individualized license plate, the technology of the recognition of the individualized license plate is sure to be used more and more widely. Some problems have not been discussed in the paper, waiting for further research.