(专业论文)车牌图像分割与识别算法研究.docVIP

. . . . . . 摘 要 随着科学技术的发展，人们的生活越来越智能化和自动化，车辆也越来越多，这给高速公路收费，小区管理等增加了压力，而智能交通管理系统能改变这一现状，提高交通管理的效率，使之科学化、规范化。车牌自动识别系统是智能交通管理系统的核心部分。基于图像的车辆牌照自动识别系统一般包括车牌定位、字符分割和字符识别三大块。车牌自动识别技术是计算机视觉与模式识别技术在智能交通领域应用的重要 研究课题之一。其目的就是给交通系统的自动管理提供方便，因此车牌自动识别系统是实现交通管理智能化的一个关键技术。 本文主要是针对车牌识别系统中的后两个部分即字符分割与字符识别的算法进行了研究，并通过实验得到了识别结果。 首先，在字符分割前对车辆牌照图像进行图像预处理，此阶段主要是研究图像灰度化处理、倾斜校正及图像二值化操作。倾斜校正主要是用基于直线旋转投影的算法检 测由于拍摄角度等问题造成的车牌牌照图像的倾斜角度，再对牌照图像进行矫正处理。 二值化采用的是全局阈值的最大类间方差法，该方法能很好的达到二值化的效果，采 用黑白跳变的算法去除车牌图像的上下左右边框及分割点。其次，釆用改进的垂直投 影的方法对图像进行分割，再对分割完的字符图像进行归一化处理，统一大小。最后，采用三层BP神经网络对字符进行识别，将网络分成汉字，字母，数字及字母三个分类 器，提取样本的细网格特征对BP网络进行训练，之后提取识别字符图像的细网格特征 送入BP神经网络中进行识别。 关键词：倾斜校正；二值化；字符分割；字符识别；BP神经网络 Abstract With the development of science and technology, Peoples lives are more and more intelligent and automated. There are more and more vehicles, which increase the pressure on the highway charges and district management. While the intelligent traffic surveillance (ITS) can change this situation, improve the efficiency of traffic surveillance, make it scientific and standardized. License plate recognition (LPR) technique is the kernel part of ITS. License plate recognition consists of three modules in general: plate location, character segmentation and character recognition. License plate recognition is one of the research subjects in which the technology of computer vision and recognition applied. The purpose of transporting systems is to facilitate the automatic management. Therefore, LPR is the key technology to achieve the demand of ITS. The thesis studies mainly the latter two modules of the license plate recognition system-character segmentation and character recognition, and the recognition results are obtained by experiments. First, there must be pre-processing for the vehicle license images before segmentation of the characters. In this phase, it has studied the gray image conversion, tilt correction, image binarization and so on. Tilt correction is mainly used an algorithm based on linear-rotation-project