Changes between Version 10 and Version 11 of libpipi/research/filters Tweet

Timestamp:

08/22/2008 09:52:07 PM (16 years ago)

Author:

Sam Hocevar

Comment:

more stuff about the median

libpipi/research/filters

@@ -31 +31 @@
 The third way to optimise a median filter is by accounting for the size of neighbourhood changes in raster scan order: usually only a few values are removed from and added to the list of neighbours. This becomes promising with large kernel sizes, and efficient algorithms exist that handle this case in 1D at least ![2].
 
-Methods for O(r) or O(log(r)) median filters have been commonly used so far. Even an O(1) method has recently been discovered [3]. However, they all seem to rely on histograms, which only works well when the input data consists of 8-bit integers. Since libpipi does most of its computations using 32-bit floats, such techniques are of limited usefulness.
+Today, median filtering methods use O(r) techniques, but O(log(r)) ones exist, too [4].
+
+There is even a method in O(1) [3]. However, like many others, it relies on histograms, which only works well when the input data consists of 8-bit integers. Since libpipi does most of its computations using 32-bit floats, such techniques are of limited usefulness (but should be proposed anyway, because we have ways to tell whether an image has fewer than 8 bits per component).
+
+{{{
+#!html
+<p><span style="background: red; color: yellow; padding: 0 3px; font-weight: bold;">TODO</span> use ANYTHING but what we currently have... bubble sort, what the fuck!
+}}}
 
 === References ===
@@ -38 +45 @@
  * ![2] Juhola, M.   Katajainen, J.   Raita, T., [http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=80784  Comparison of algorithms for standard median filtering], IEEE Transactions on Signal Processing, Volume 39, Issue 1, Jan 1991 pp. 204-208
  * ![3] Perreault, S. Hebert, P., [http://nomis80.org/ctmf.html Median Filtering in Constant Time], in the September 2007 issue of IEEE Transactions on Image Processing
+ * ![4]  Gil, J.   Werman, M., [http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=211471  Computing 2-D min, median, and max filters], IEEE Transactions on Pattern Analysis and Machine Intelligence, 15, 504-507, 1993
 
 === Code ===