Research On Vehicle License Plate Automatic Location And Recognition

With the development of the road transportation, the traditional transportation management by hand can not meet the practical demands nowadays. More and more attention is being paid to the application of telecommunication and computer technologies in transportation and thus it is developing faster and faster. The transportation in China is going into an information and digital era. Automatic license plate identification plays an important role in Intelligent traffic control system, parking lot monitor system and automatic charging system. Vision-based approach is promising since it requires no pavement adjustments and is more flexible and economical.The license plate identification system has to implement license plate region identification, character segmentation and character recognition. We use edge features and mathematics morphology to locate the plate region. First edge information is used to get binary image. Second, the method of combining mathematical morphologic with binary image projection is use to determine the horizontal and vertical positions. In addition, there are two methods to recognized character. One is topology, which is single and quick. Other is NN, which is complex but robust.A Vision-based license plate identification system has to be robust, since the plate may be inclined or distorted and the characters may be blurred and the strokes become disconnected. The algorithms also have to be adaptable since the light condition and image capture position could vary.