不利用IDL自带函数的情况下，实现自定义窗口半径的中值滤波算法，窗口边缘值的问题采用重复边缘和补0两种方法。(If we don't use IDL's own function, we can realize the median filter algorithm of the custom window radius. The problem of window edge value adopts two ways: repeated edge and complement 0.)