基于先验知识的车牌垂直倾斜校正方法

摘要

This paper proposes a method of license plate vertical tilt correction .First ,roughly locate the character area and mark the region's largest connected domain by Vertical-Projection Principle ,and then find the Wide-Minimum bounding rectangle of original binary image connected domain part marked .Finally ,calculate the character vertical tilt angle based on the priori knowledge and affine transformation principle ,thus we can get the vertical tilt angle of the license plate . Compared with the classical correction methods ,this paper presents a more simple and practical way to meet the engineer-ing requirements .%提出了一种车牌垂直倾斜校正方法，首先通过垂直投影法粗定位字符区域，标记区域内最大连通域，然后寻找出原二值图中被标记的连通域部分的宽最短外接矩形，最后根据先验知识和仿射变换原理求出字符垂直倾斜角度，从而得到车牌的垂直倾斜角度。与已知的一些经典校正方法相比，该方法更加简单实用，能很好地满足工程需求。