Method for eliminating an impulse noise of video signal and apparatus therefor

A median filter adaptively increases a window size when there is a possibility that an impulse noise will be present in the median value. When it is determined that an impulse noise is not present in the median value obtained as a median-filtering result, the median filter checks whether or not an impulse noise is present in a target pixel value which is to be subjected to median filtering. When there is a possibility that an impulse noise is present in the target pixel value, the median filter outputs the median value. On the other hand, when an impulse noise is not present in the median value as a check result, the median filter outputs the input target pixel value. Accordingly, an impulse noise can be effectively eliminated from a video signal mixed with a positive impulse noise and a negative impulse noise, while the edge change of the video signal produced by the median filter itself can be minimized. An adaptive median filter is also described.