【作者】 赵咏梅；

【导师】 吕淑萍；

【作者基本信息】 哈尔滨工程大学 ， 模式识别与智能系统， 2005， 硕士

【摘要】 随着机动车辆规模及流量的不断增加,路政部门对交通管理智能化的要求越来越高。而实现智能化的关键技术之一——牌照定位技术尚未成熟,有待于进一步研究。 本文首先介绍了汽车牌照自动定位系统开发应用的技术路线、关键问题的解决方法及系统实现的措施,涉及了图像处理与识别等技术。其次深入研究了车牌定位方法的总体结构:首先对汽车图像进行灰度转换、平滑去噪、二值化预处理,再根据车牌上文字变化特点,快速、准确地从复杂背景中分割车牌。其中,本文对图像预处理、牌照的边缘检测、车牌定位分割等模块涉及到的新算法、新技术,进行了详细研究。 为了解决车牌识别中的首要问题——车牌自动定位技术,根据车牌区域灰度变化和车牌纹理特征,本文采用了“阈值自适应变步长动态分析”的定位算法,加快了定位处理的速度;根据车牌目标在图象中的成像特点,本文提出了基于投影不变性的车牌自动定位方法,该方法在车牌歪斜角度不大的情况下,成功地从复杂背景中检测定位出了车牌;当车牌歪斜角度大的情况时,本文提出了“改进的Hough变换提取车牌边线”的定位方法,该方法取得了较好的定位效果,可满足课题研究要求。论文的最后对车牌定位技术中存在的问题及发展的方向进行了总结和论述。更多还原

【Abstract】 With the sharp increase of the motor vehicle amounts, the intelligent traffic management is highly demanded more and more. However, the critical technology that can implement the intelligent traffic control, the technology of car license plate targets orientation, is at elementary phase and needs further research.First of all, the technical route applied in the license plate orientation system, and the methods to solve the key problem are discussed in this dissertation, which involves technology about image processing and identification. In the second place, the whole structure of license plate orientation is studied in this dissertation: at first, the car photograph should be processed by smooth filtering, gray stretching, binarization, then the location of the car target can be segmentated from the complex background based on the changes characteristic of the word. And some new algorithms and methods are presented in the dissertation such as: pre-processing of image, edge detection, license plate orientation and segmentation.In order to improve the efficient of the license plate location system, the mothod named "Adaptive threshold and dynamic analysis with a variable step" based on the characteristic of the gray and the texture of the car target is presented in the dissertation which can improve the orientation speed; The method named "Automatic orientation of car license plate targets based on the unvariable characteristic of the projection" is proposed in the dissertation in the terms of the imaging characteristics of the car license plate target. It can succeed in locating the car target from the complex background when the angle of inclination is relatively small. " A new way based on Hough transform to locate the edge of the car target" was proposed and was also applied which can get good location result and can meet the aim of the study of the project. Finally, the problems and the future directions of the car target orientation are discussed.更多还原