说明：  以YCgCr和YCbCr颜色空间为基础，分别建立了平行四边形模型和椭圆模型，采用光照补偿法对图像进行预处理，从而避免了光照不均对检测结果所造成的误差。
(Based on the YCgCr and YCbCr color spaces, the parallelogram model and the ellipse model are established respectively. The image is pretreated by the light compensation method, so as to avoid the error caused by the uneven illumination.)