汽车牌定位是一个公认的较难解决的图象侵害问题。目前已经实现的分割主要局限于灰度图象，且定位效果仍易受阴影和光照等条件的影响。为解决彩色图象牌照定位问题，提出了彩色图象边缘检测算子ColoPrewitt和彩色边缘检测与区域生长相结合的牌照定位算法ColorLP，其充分利用了颜色信息和牌照特点。ColoPrewitt算法简单，全面作用在颜色空间的3个分量上，在彩色牌照定位的边缘检测中具有传统算子无法比拟的优势，实验表明，检测出的牌照区域完整，且与背景易于进一步剥离，由此可见，ColorLP定位牌照区域准确率高，适用于任意背景、位置和光照下的牌照定位，且通过性较好。

It is well known that locating vehicle license plate is a very difficult problem in the fields of image segmentation and ITS(Intelligent Transprotation System).At the present time,the study of vehicle license plate locating mainly focuses on gray images so that the result is affected easily by the presence of shadows and illumination.In this paper,a new color edge detector ColorPrewitt and a new approach of vehicle license plate locating ColorLP are presented,which fully exploit color information and other features of vehicle license plate.ColorPrewitt not only is simple,but also has superiority over traditional color edge detectors in dealing with color vehicle license plate images because it doesn't just simply operate on the individual three channels of color space.It shows that the license plate edges detected using ColorPrewitt are clear,integrated and easy to be separated form the background.ColorLP combines ColorPrewitt and region growing image segmentation technology with high locating ratio and good generality,which is applicable to locate license plates in cases of various backgrounds,positions and illumination.