how to implement improved multisatge median filter??

The algorithm of multistage median filter is shown below. • Take four 1-D sub-windows along the horizontal, vertical, angle of 0 45 and 0 135 from the horizontal direction separately. • Get their median values respectively and then put the four median values in ascending order and obtain the maximum and minimum values. • Sort the maximum and minimum values and the value of pixel that need filtering, and get the median value of the three, and it is the output value of target pixel.