分析图像，使用pixval函数来获得牌照的背景色的亮度值和坐标；通过统计的算法找出车牌的范围；通过修剪得到最终图像。-Analysis of images, a function to obtain a license to use pixval background color brightness values ​ ​ and coordinates　through statistical algorithms to identify the scope of the license plate　by trimming the final image.