better edge detection

diff --git a/filters.py b/filters.py
index ce955a4..825834f 100644 (file)
--- a/filters.py
+++ b/filters.py
@@ -1,17 +1,20 @@
-from PIL import Image
+from PIL import Image, ImageFilter

 
 

-def edge_detection(image, size):
+def edge_detection(image):
+    image = image.filter(ImageFilter.GaussianBlur())
+    # GaussianBlur is undocumented class, it might not work in future versions
+    # of PIL

     image_l = image.load()
     new_image = Image.new('L', image.size)
     new_image_l = new_image.load()
     
     image_l = image.load()
     new_image = Image.new('L', image.size)
     new_image_l = new_image.load()
     

-    for x in xrange(size, image.size[0] - size):
-        for y in xrange(size, image.size[1] - size):
+    for x in xrange(2, image.size[0] - 2):
+        for y in xrange(2, image.size[1] - 2):

             pix = (sum([sum([
                 image_l[a, b] 
             pix = (sum([sum([
                 image_l[a, b] 

-                    for b in range(y - size, y + size + 1)]) 
-                    for a in range(x - size, x + size + 1)])
-                - (((2 * size + 1) ** 2)  * image_l[x, y]))
+                    for b in range(y - 2, y + 3)]) 
+                    for a in range(x - 2, x + 3)])
+                - (25  * image_l[x, y]))

             if pix > 255:
                 pix = 255
             if pix < 0:
             if pix > 255:
                 pix = 255
             if pix < 0:

diff --git a/imago.py b/imago.py
index ff49826..87eaecf 100755 (executable)
--- a/imago.py
+++ b/imago.py
@@ -69,7 +69,7 @@ def main():
     if verbose:
         print >> sys.stderr, "edge detection"
 
     if verbose:
         print >> sys.stderr, "edge detection"
 

-    im_edges = filters.edge_detection(im_l, 2)
+    im_edges = filters.edge_detection(im_l)

     if show_all:    
         do_something(im_edges, "edge detection")
 
     if show_all:    
         do_something(im_edges, "edge detection")