J4 ›› 2012, Vol. 25 ›› Issue (3): 1-6.doi: 10.3976/j.issn.1002-4026.2012.03.001

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基于明暗度分类和改进二分法的车牌字符分割

徐雷1, 张小宁2   

  1. 1.上海同济城市规划设计研究院,上海 200092; 2. 同济大学经济与管理学院,上海 200092
  • 收稿日期:2012-03-08 出版日期:2012-06-20 发布日期:2012-06-20
  • 通信作者: 张小宁(1975-),国家杰出青年基金获得者,教授,博导,研究方向为交通与物流系统优化与管理。Email:cexzhang@tongji.edu.cn。 E-mail:cexzhang@tongji.edu.cn
  • 作者简介:徐雷(1987-),男,硕士,研究方向为交通图像处理与分析。Email: devics@163.com
  • 基金资助:

    国家自然科学基金(71125004)

A brightness classification and improved dichotomy based license

 XU Lei1, ZHANG Xiao-Ning2   

  1. 1.Shanghai Tongji Urban Planning and Design Institute, Shanghai 200092, China;
    2.School of Economics and Management, Tongji University, Shanghai 200092, China
  • Received:2012-03-08 Online:2012-06-20 Published:2012-06-20

摘要:

      车牌字符分割易受到车牌倾斜及边界、杂点的干扰,致使复杂条件下的车牌图像分割准确率不高,针对该缺点提出一种鲁棒性强的分割算法。在车牌预处理阶段进行图像明暗度分类及灰度图增强,以此为基础进行倾斜校正及上下边界定位;在字符切分阶段采用改进二分法进行分割,之后对1,2,6,7四个字符实现了边界精确定位。实验表明,该算法实时性较好,能够有效克服车牌对比度不高、模糊、粘连和倾斜的缺点。

关键词: 明暗度分类, 字符分割, 改进二分法, 分裂与合并, 边界精确定位

Abstract:

      License plate (LP) segmentation can easily be affected by rim, noise and LP rotation, which causes low segmentation accuracy. We presented a goodrobustness segmentation algorithm for the issue. The algorithm performed brightness classification and grayscale enhancement in the preprocessing stage before tilt correction and localization of the upper and lower boundaries. An improved dichotomy algorithm was then applied to segment LP characters. We implemented precise border localization for characters 1, 2, 6 and 7. Experiment shows that the algorithm has low computational burden and can effectively overcome such negative influences as low contrast, blurness, character adhesion and LP tilt.

Key words: brightness classification, character segmentation, improved dichotomy, split and merger, border precise localization

中图分类号: 

  • TP391.4