说明：  自适应中值滤波-Chan R H, Ho C W, Nikolova M. Salt-and-pepper noise removal by median-type noise detectors and detail-preserving regularization[J]. IEEE Trans. Image Process, 2005, 14(10): 1479～1485. 该文献中自适应中值滤波算法代码
(matlab code of adpative median filter)