filters.py

   1 from PIL import Image
   2
   3 def edge_detection(image):
   4     image_l = image.load()
   5     new_image = Image.new('L', image.size)
   6     new_image_l = new_image.load()
   7
   8     for x in xrange(2, image.size[0] - 2):
   9         for y in xrange(2, image.size[1] - 2):
  10             pix = (sum([sum([
  11                 image_l[a, b]
  12                     for b in range(y - 2, y + 3)])
  13                     for a in range(x - 2, x + 3)])
  14                 - (25 * image_l[x, y]))
  15             if pix > 255:
  16                 pix = 255
  17             if pix < 0:
  18                 pix = 0
  19             new_image_l[x, y] = pix
  20     return new_image
  21
  22 def peaks(image):
  23     image_l = image.load()
  24     new_image = Image.new('L', image.size)
  25     new_image_l = new_image.load()
  26
  27     for x in range(2, image.size[0] - 2):
  28         for y in range(2, image.size[1] - 2):
  29             pix = (sum([sum([
  30                 - image_l[a, b]
  31                     for b in range(y - 2, y + 3)])
  32                     for a in range(x - 2, x + 3)])
  33                 + (16 * image_l[x, y]))
  34             if pix > 255:
  35                 pix = 255
  36             if pix < 0:
  37                 pix = 0
  38             new_image_l[x, y] = pix
  39     return new_image
  40
  41 def high_pass(image, height):
  42     image_l = image.load()
  43     new_image = Image.new('L', image.size)
  44     new_image_l = new_image.load()
  45
  46     for x in xrange(image.size[0]):
  47         for y in xrange(image.size[1]):
  48             if image_l[x, y] < height:
  49                 new_image_l[x, y] = 0
  50             else:
  51                 new_image_l[x, y] = image_l[x, y]
  52
  53     return new_image
  54
  55 def components(image):
  56     image_l = image.load()
  57     new_image = Image.new('L', image.size)
  58     new_image_l = new_image.load()
  59
  60     components = []
  61     comp_counter = 0
  62
  63     for y in xrange(1, image.size[1] - 1):
  64         for x in xrange(1, image.size[0] - 1):
  65             if image_l[x, y]:
  66                 s = {0}
  67                 s.add(new_image_l[x - 1, y - 1])
  68                 s.add(new_image_l[x, y - 1])
  69                 s.add(new_image_l[x + 1, y - 1])
  70                 s.add(new_image_l[x - 1, y])
  71                 if len(s) == 1:
  72                     components.append(set())
  73                     new_image_l[x, y] = comp_counter
  74                     components[comp_counter].add((x, y))
  75                     comp_counter += 1
  76                 elif len(s) == 2:
  77                     s.remove(0)
  78                     c = s.pop()
  79                     new_image_l[x, y] = c
  80                     components[c].add((x,y))
  81                 else:
  82                     s.remove(0)
  83                     c1, c2 = s.pop(), s.pop()
  84                     components[c2].add((x, y))
  85                     for (x1, y1) in components[c2]:
  86                         new_image_l[x1, y1] = c1
  87                     components[c1] = components[c1] | components[c2]
  88                     components[c2] = None
  89
  90     new_image = Image.new('L', image.size)
  91     new_image_l = new_image.load()
  92
  93     for component in components:
  94         if component:
  95             x_c = 0
  96             y_c = 0
  97             c = 0
  98             for (x, y) in component:
  99                 x_c += x
 100                 y_c += y
 101                 c += 1
 102         new_image_l[int(round(float(x_c)/c)), int(round(float(y_c)/c))] = 255
 103
 104
 105     return new_image
 106
 107 def half_centers(image):
 108     image_l = image.load()
 109     new_image = Image.new('L', image.size)
 110     new_image_l = new_image.load()
 111
 112     x_s = 0
 113     y_s = 0
 114     n = 0
 115     for x in range(0, image.size[0] / 2):
 116         for y in range(0, image.size[1]):
 117             if image_l[x, y] > 127:
 118                 x_s += x
 119                 y_s += y
 120                 n += 1
 121     new_image_l[x_s / n, y_s / n] = 255
 122
 123     x_s = 0
 124     y_s = 0
 125     n = 0
 126     for x in range(image.size[0] / 2, image.size[0]):
 127         for y in range(0, image.size[1]):
 128             if image_l[x, y] > 127:
 129                 x_s += x
 130                 y_s += y
 131                 n += 1
 132     new_image_l[x_s / n, y_s / n] = 255
 133
 134     return new_image
 135