边缘检测技术在汽车牌照自动识别监控系统中的应用毕业设计论文.doc

四川理工学院毕业设计(论文)



边缘检测技术在汽车牌照自动识别监控系统中的应用







摘要

车牌识别是智能交通中关键技术之一。车牌识别系统一般包括车辆图像采集、车牌定位、字符分割和字符识别四个模块。
本文在简单介绍车牌识别的四个模块的基础上,主要对车牌边缘检测进行了讨论,分析了Roberts算子、Sobel算子、canny算子、拉普拉斯(Laplacian)算子和Marr边缘检测算子。Roberts算子检测定位精度比较高,但对噪声敏感。Sobel算子可以产生较好的边缘效果,但是对噪声具有平滑作用,减小了对噪声的敏感性。但是,Sobel边缘检测算子也检测出了一些伪边缘,使得边缘比较粗,降低了检测定位精度。canny算子能在噪声抑制和边缘检测之间取得较好的平衡,并能产生较细的边缘效果。故本文采用canny算子对车牌的边缘进行了提取,仿真结果表明了该算子能较好的检测出图片的边缘信息。
关键词:车牌识别,车牌定位,字符分割,边缘检测
ABSTRACT

The car license recognition is one of key technologies in the intelligent transportation .The car license recognition system includes vehicles image gathering, the car license localization generally, the character division and the character recognition four modules.
This article in the simple introduction car license recognition four module foundations, mainly has carried on the discussion to the car license edge examination, has analyzed the Roberts operator, the Sobel operator, the canny operator, the Laplacian (Laplacian) operator and the Marr edge examination operator. The Roberts operator examination pointing accuracy quite is high, but is sensitive to the noise. The Sobel operator may produce the good edge results, but has the smoothing effect to the noise, reduced to the noise sensitivity. But, the Sobel edge examination operator also examined some false edges, caused the edge quite to be thick, reduced the examination pointing accuracy. The canny operator can obtains the good balance between the noise abatement and the edge examination, It can produce the thin edge results. Therefore this article used the canny operator to carry on the extraction to the car license edge, the simulation result has indicated this operator to be able the good examination picture edge information.
Key words: car license recognition, car license localization, character division, edge examination
目录
摘要 I
ABSTRACT II
第1章引言 1
课题背景及研究意义 1
国内外研究现状 2
汽车牌照识别国内外研究现状 2
边缘检测算法国内外研究现状 3
我国汽车牌照识别的难点