Some useful weights of recursive weighted median filters

It is pointed out that the weights of weighted median and recursive weighted median filters have a close relationship to the root signal characteristics of these filters. The authors find a set of conditions on weights under which a recursive weighted median filter preserves a monotone or locally monotone sequence. They also find a set of conditions on weights under which the output of a recursive weighted median filter is the same as that of a recursive median filter. Finally, they present several examples to show the derived weight conditions more explicitly