中文说明：用来计算十字交叉点的中心位置，可以达到亚像素精度，在三维重建中经常会在物体表面做标志，本算法用于计算十字标记中心
English Description：
It can be used to calculate the center position of cross points, which can achieve sub-pixel accuracy. In 3D reconstruction, marks are often made on the surface of objects. This algorithm is used to calculate the center of cross marks