In order to overcome the difficulties, a sequential quadratic approximate algorithm is proposed based on exact dual mapping.
为了克服这些困难，提出了一种基于序列二次近似算法精确的对偶映射。
2
The approach starts from an analysis of spherical harmonics and finds out a quadratic polynomial form of environment mapping.
该方法从分析球面调和函数入手，首先得出环境贴图的二次多项式表达形式；
3
But the quadratic curve can be used only in condition when each X-coordinate of the points sequence mapping to only one Y-coordinate, so it can't be used in fitting closing curve.