基于计算机视觉检测的车牌自动识别系统.doc

基于计算机视觉检测的车牌自动识别系统

摘要
随着我国经济的高速发展，汽车的数量在急剧增加，国内高速公路、城市道路、停车场等设施的建设也越来越多，因此对交通控制、安全管理的要求也日益提高 。智能交通系统已成为当前交通管理发展的重要方向，而车牌自动识别就是是智能交通系统的重要组成部分。
本文论述了计算机视觉技术的检测原理、系统组成，研究了在车牌识别系统中的几项关键技术——图像预处理，定位及字符分割技术。
首先，本文对我国汽车牌照的特点进行了分析，在进行图像预处理时采用了适合字符纹理特征的垂直边缘检测算法，基于形态学的车牌区域检测，使用连通域分析的思想提取车牌区域。
而后，在进行车牌定位时采用了垂直边缘检测与形态学运算相结合的方法，这种方法定位准确，且对有一定角度倾斜的车牌有较好的适应性。
最后，在进行字符分割时采用字符纵向切割的方法，能够很好地去除车牌边框，分割出各个字符，再运用模板匹配法进行字符识别。
本文的算法以车牌区域的纹理分析、数学形态学为基础，有效提高了定位的准确性。实验结果表明该算法能够比较快速、准确、定位分割出车辆牌照。
关键词：计算机视觉技术；图像处理；车牌定位；字符分割；字符识别。

ABSTRACT
With the rapid development of China’s economy,the number of cars is growing sharply, domestic highway, urban roads and parking lot are becoming more and more too. So the requirements to the traffic control, safety management are also improving day by day. Intelligent transportation system has become the important direction of the current traffic management development, and automatic license plate recognition is an important part of it.
This article has discussesde the detection principle of Automated Visual Inspection and its system composition, studied several key technologies domain in the automatic license plate recognition ： car license image pretreatment, the car license localization and the character division technology .
First, this article carefully analyzed our country license plate characteristic, the image pretreatment part has used has suited the character texture characteristic the vertical edge examination algorithm, based on the morphology car license region examination, the thought extraction car license region which the use connected domain analyzed .
 Next , has used the method in the car license localization part which the vertical edge examination and the morphology operation unifies, this method localization is accurate, also to has certain angle incline car license to have the good compatibility .
 Finally, after the character division part uses first the crosswise longitudinal cutting method, can remove the car license frame well, divides each character .
 This article algorithm take the car license region texture analysis as a foundation, enhanced the localization accuracy effectively .The experimental result indicated this algorithm can quite fast, accurate, the localization divide the vehicles license plate.
 Key word: Automated Visual Inspection, Imagery processing, automatic license plate localization, Character division，Character recognition.

目录
基于计算机视觉检测的车牌自动识别系统 1
摘要 1
ABSTRACT 2
目录 3
第一章 绪 论 4
1.1 选题研究意义 4
1.2 车牌识别系统的研究现状 4
1.3 本文的框架结构 5
第二章 车牌自动识别系统简介 6
2.1 车牌识别系统基本工作原理 6
2.2 车牌自动识别系统中的问题与难点 7
第三章 图像预处理 9
3.1图像滤波 9
3.2 图像增强 9
第四章 车牌定位 12
4.1边缘检测 12
4.2 基于形态学的车牌区域检测 15
4.3 连通域标记与车牌区域提取 17
第五章 字符分割 20
5.1 车牌区域二值化 20
5.2 车牌水平边框去除 22
5.3 字符纵向分割 23
第六章 字符识别 25
实 验 结 果 27
总 结 30
1.本文主要研究的内容 30
2.主要创新点 30
3.存在的不足 30
参考文献 31