Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/IWORKS|Filter">Filter</a><hr>
<H4>Median Filter</H4>
The median filter smooths image data.  The median filter computes the
median values within a rectangular filter window surrounding each pixel.
This has the effect of smoothing the image and preserving edges. <p>
Example:
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<PRE>
   5 3 11 
  12 4  9     3x3 filter window
   8 6 14
</PRE>
The median filter finds the median pixel value (the &quot;middle&quot;
value in an ordered set of values, below and above which there
are an equal number of values). For example, 8 is the median
value for the above given set of grey level 
values (3,4,5,6,(8),9,11,12,14).<p>
NOTE: In order to filter pixels located near the edges of the image,
edge pixel values are replicated to give sufficient data.
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