For simplifying the calculation of ray path changes caused by the optical wedge which is bound by the separating surface and the exit face of a prism, the paper provides a specific coordinate system and a regression approximative method.

• 文中给出选取分离面的一般原则，以及由分离面和棱镜出射面构成的光楔产生的光路变化计算，同时也给出能使其简化的坐标系和回归近似方法；