Median filtering is especially useful in removing 'salt-and-pepper' noise. Its output at (x, y) is the median of those pixels contained in a window, centered in (x, y) in the original image. To use this function,

select Image: Spatial Filters: Median from the Origin menu.

For more specific information on this function, see documentation provided for the X-Function imgMedian in the Origin X-Function reference file. This can be accessed from the Command Window by typing

help imgMedian