Median filtering

[bijus7]

Does median filtering replace the origin value once? If is it so why that only value is replaced?

 

[slugg]

Does median filtering replace the origin value once?

Any filter replaces the originating value only once. If there are two replacements, then it is two filters. You can have multiple passes of a single filter, if you'd like, but each one modifies the sample only once. Internal, computational "replacements" do not count; this would be an implementation-specific detail not relevant to the actual filtering operation.

If is it so why that only value is replaced?

Can you please rephrase this question? I can't figure out what you're trying to ask...