Changes between Version 4 and Version 5 of libpipi/research/filters Tweet

Timestamp:

08/21/2008 12:25:47 PM (16 years ago)

Author:

Sam Hocevar

Comment:

more stuff

libpipi/research/filters

@@ -1 +1 @@
 [wiki:libpipi << back to libpipi]
 
-== Gaussian kernels ==
+= Gaussian filtering =
+
+Current code:
+ * [/browser/libpipi/trunk/pipi/filter/blur.c]
+ * [/browser/libpipi/trunk/pipi/filter/convolution_template.h]
+ * [/browser/libpipi/trunk/pipi/filter/convolution.c]
 
 The usual way to create a Gaussian kernel is to evaluate a Gaussian function at the center of each cell:
@@ -11 +16 @@
  k[i][j] = exp(-((i×cosθ-j×sinθ-dx)²+(j×cosθ+i×sinθ-dy)²)/2σ)
 
-== Median filter ==
+{{{
+#!html
+<p><span style="background: red; color: yellow; padding: 0 3px; font-weight: bold;">TODO</span> interpolate the Gaussian integral on more points, eg. 5×5 (currently libpipi does it at the central point and at 8 additional points in the neighbourhood).
+}}}
+
+= Median filtering =
+
+Current code:
+ * [/browser/libpipi/trunk/pipi/filter/median.c]
 
 There are several ways to optimise a median filter.
@@ -18 +31 @@
  * [http://coding.derkeiler.com/Archive/General/comp.programming/2004-10/0289.html Sliding median filter]
  * [http://iris.usc.edu/Vision-Notes/bibliography/twod268.html A shitload of papers about median filtering and its derivatives]
+
+= Dilate / erode =
+
+Current code:
+ * [/browser/libpipi/trunk/pipi/filter/dilate.c]
+
+Erosion and dilation already work, but only for nearest pixels.
+
+{{{
+#!html
+<p><span style="background: red; color: yellow; padding: 0 3px; font-weight: bold;">TODO</span> each pixel couple test is done twice. There seems to be an opportunity for improvement there.
+}}}
+
+{{{
+#!html
+<p><span style="background: red; color: yellow; padding: 0 3px; font-weight: bold;">TODO</span> implement "dilate by X" (Manhattan distance).
+}}}
+
+{{{
+#!html
+<p><span style="background: red; color: yellow; padding: 0 3px; font-weight: bold;">TODO</span> implement "dilate by X" (Euclidian distance).
+}}}
+
+=== References ===
+
+ * [http://ostermiller.org/dilate_and_erode.html Efficiently Implementing Dilate and Erode Image Functions]