摘要： 提出一种利用字符投影距离进行车牌校正的方法。根据伴生与互补颜色特征提取车牌中的字符区域，将车牌旋转计算字符区域在垂直坐标轴上的投影，利用投影的最小距离获取垂直倾斜角度。将车牌水平错切计算字符区域在水平方向投影，利用投影最小距离获得水平错切角度，采用双线性插值对图像进行校正。该方法不依赖车牌边框特征，抗干扰性强。实测车牌图像试验证明，该方法具有较高的鲁棒性和工程实用性。

关键词: 车牌校正, 伴生与互补, 投影最小距离, 错切

Abstract: This paper presents a method of VLP correction based on characters projection distance. It shows that the VLP characters can be extracted by concomitant and complement feature. The character is projected to vertical axis by rotating the VLP area and the tilt angle is captured by vertical projection minimum distance. The character is projected to horizontal axis by sheering the VLP area and the sheer angle is captured by horizontal projection minimum distance. Corrected image can be executed by bilinear interpolation. The method with good anti-interference does not depend on the VLP frame feature. Experiments on actual images taken under various conditions from traffic stations show good robustness and practicality.

Key words: VLP correction, concomitant and complement, projection minimum distance, sheering

中图分类号: 

• TP391.41