Basic Information on immedian

Task: immedian
Purpose: Median filter over an image
Categories: map analysis

      IMMEDIAN is a MIRIAD task which performs a median filter over an image.
      No subregion can be selected, the whole image is processed.
      See also ELLINT for a median filter in elliptical rings.
      Masking information is properly processed: if any of the associated pixels has
      been masked out, they will not be used in the median filter.
      Edge pixels are not filtered and passed onto the output image unchanged.
 

Key: in
      The input image. No default.

Key: out
      The output image. No default.
      Note: Nasty things can happen to 4D+ datasets.

Key: size
      Half the box size. The filtering box will be square and have
      a size of 2*SIZE+1, and will thus always have an odd number of pixels
      centered on the pixel to be filtered. Edge pixels are left untouched.

Key: nsigma
      If set to a non-zero value, instead of a median, all outliers
      more than nsigma*sigma from the mean are removed in computing
      the filtered output value