[Image-SIG] ImageFilter.MaxFilter and MedianFilter

[Dominik Royko]

I noticed that images filtered with ImageFilter.MedianFilter(3)
differed from those filtered with ImageFilter.RankFilter(3,4).
(Rank values seem to go from 0 to (size*2)-1).

Further inspection reveals:
>>> ImageFilter.MaxFilter(3).rank
2
>>> ImageFilter.MaxFilter(5).rank
4
>>> ImageFilter.MedianFilter(3).rank
1
>>> ImageFilter.MedianFilter(5).rank
2

Should these not be 4, 12, & 8, 24?  Am I missing something?
Suggested patch follows.

Dominik Royko.


--- PIL/ImageFilter.py  2002-11-17 13:55:42.000000000 -0500
+++ PIL-patch/ImageFilter.py    2004-01-23 15:27:16.000000000 -0500
@@ -92,7 +92,7 @@ class MedianFilter(RankFilter):

     def __init__(self, size=3):
         self.size = size
-        self.rank = size/2
+        self.rank = (size*size)/2

 ##
 # Min filter.  Picks the lowest pixel value in a window with the given
@@ -124,7 +124,7 @@ class MaxFilter(RankFilter):

     def __init__(self, size=3):
         self.size = size
-        self.rank = size-1
+        self.rank = (size*size)-1

 ##
 # Mode filter.  Picks the most frequent pixel value in a box with the