一种改进的车牌识别预处理方法

对车牌识别的预处理算法进行了研究,提出一种新的预处理流程.首先对车牌进行光照空域校正,然后进行同态滤波、直方图均衡、对比度拉伸,在求局部阈值时,利用Robert边缘检测算法缩小了需要确定局部阈值的图像范围,且利用中值滤波使二值车牌得到了增强.该算法原理简单,容易实现,处理速度快,实时性好,为图像处理提供了一种新方法.

An Improved Preprocessing Algorithm of Vehicle License Plate

The preprocessing of vehicle license plates under nonuniform illumination is a difficult task, this paper studies the preprocessing algorithm and proposes a new method. Firstly, image illumination is corrected in spatial domain, then homomorphic filter, histogram equalizer are applied, at last the image is enhanced by contrast stretching. The algorithm uses Robert edge detecting to limit the scope local threshold is required, and median filter is applied to enhance the binary image. Experiment results show that the algorithm has advantages of simple principles, easily realization, high speed, and it also provides a new method for image processing.