Based on the rational approximation of the FFD operator, we extend the two coefficients to be optimized to four coefficients, then we optimize them globally using simulated annealing algorithm.

• 本文在有理近似的基础上，将FFD算子展开式中的常系数由两个拓展为四个，然后采用模拟退火算法对这四个参数进行全局优化。