High accuracy algorithm for calculating best fitting sphere of high-order aspheric surface

A high accuracy algorithm based on one dimensional search which is used for calculating the BFS (best fitting sphere) of high-order optical aspheric surface is proposed, according to the geometric property between the aspheric surface and its BFS. This method can be used to calculate the radius and the center location of the BFS and the asphericity for conicoid and high-order aspheric surface (including concave and convex surfaces). The analysis of calculation examples shows that, this method can reduce the maximum asphericity from 500.8 m to 30 m for high-order aspheric surface, and it can get the same asphericity for conicoid compared to other methods. In addition, it can get better BFS than other methods when used for high-order aspheric surface, and its fast speed and hig