Research On Vehicle License Plate Location And Character Segmentation Under Natural Environment

With the rapid development of our country's road transportation, the intelligent traffic management system becomes a hotspot problem which is being paid attention. As a part of the intelligent traffic management system, License Plate Recognition System plays an important role in automatic charging system at entrance, automatic parking lot monitor system and automatic record of peccancy system.Being a special computer vision system in the real-time case, the LPR (License Plate Recognition) system mainly includes the subsystem of license plate detection and character recognition. The LPR system involves numerous discipline domains, such as Pattern Recognition and Artificial Intelligence, Computer Vision, Digital Image Processing etc. The detection of license plates is the key of LPR system. Because of the complex of image background, the uncertainty of plate position and image quality, the location of plates is not satisfied. Therefore, the study on the algorithm of license plate location is always the hotspot problem.This paper is mostly studying on license plate localization and character segmentation in LPR system. Based on discussing popular methods, the following three works have mainly been done in this paper, include:1. Proposes an effective preprocessing method of car image. The method firstly uses color edge detector to get the horizontal edge image, secondly it makes use of the global threshold method binary quantifying the grad image, and finally dilates the binary grad image from horizontal direction. After preprocessing, the area of license plate becomes outstanding.2. At the license plate location phase, we propose a new rough localization method which based on connected area horizontal clustering. The method sufficiently considers the horizon related feature of characters in grad image, which gets a better recall ratio in the experiment. Moreover, this paper uses the grad shape and color feature of license plate to carry out precise locating, which gets an approving localization result.3. At the character segmentation phase, a new approach for license plate character segmentation based on multiscale template matching is presented. The method takes into account of the structure feature of our country's...