Fast O(1)双边滤波算法,由三角函数逼近方法实现非迭代算法，计算量不再受滤波窗口大小影响，只与图像大小有关，适合改进为GPU执行的并行算法（此函数还包含一个递归高斯算法）-Fast O (1) bilateral filtering algorithm, approximation by a trigonometric method to achieve non-iterative algorithm to calculate the amount of the filter window

函数逼近,通过拟合进行数值分析运算,拟合函数图像,(Through fitting, function approximation, numerical calculations, the fitting function image,)