[3] Karakos D G,Trahanias P E.Combining vector median and vector directional filters [ C ].Image Processing.Proceedings.IEEE,International Conference Washington D C,USA,1995,1(23-26):171-174.
[4] Astola J,Haavisto P,Neuvo Y.Vector median filters [ J ].Proc.IEEE,1990,78(4):678-689.