imago_pack/filters.py

   1 """Image filters module.
   2
   3 All filters return a filtered copy of the image, the original image is
   4 preserved.
   5 """
   6
   7 from PIL import Image, ImageFilter
   8
   9 import pcf
  10
  11 def color_enhance(image):
  12     """Stretch all color channels to their full range."""
  13     image_l = image.load()
  14     min_r, min_g, min_b = 999, 999, 999
  15     max_r, max_g, max_b = -1, -1, -1
  16
  17     for x in xrange(image.size[0]):
  18         for y in xrange(image.size[1]):
  19             min_r = min(min_r, image_l[x, y][0])
  20             max_r = max(max_r, image_l[x, y][0])
  21             min_g = min(min_g, image_l[x, y][1])
  22             max_g = max(max_g, image_l[x, y][1])
  23             min_b = min(min_b, image_l[x, y][2])
  24             max_b = max(max_b, image_l[x, y][2])
  25
  26     new_image = Image.new('RGB', image.size)
  27     new_image_l = new_image.load()
  28     for x in xrange(image.size[0]):
  29         for y in xrange(image.size[1]):
  30             r, g, b = image_l[x, y]
  31             r = (r - min_r) * 255 / (max_r - min_r)
  32             g = (g - min_g) * 255 / (max_g - min_g)
  33             b = (b - min_b) * 255 / (max_b - min_b)
  34             new_image_l[x, y] = (r, g, b)
  35            # print min_r, max_r, r, g, b
  36
  37     return new_image
  38
  39 def edge_detection(image):
  40     """Edge detection (on BW images)."""
  41     new_image = image.filter(ImageFilter.GaussianBlur())
  42     # GaussianBlur is undocumented class, it might not work in future versions
  43     # of PIL
  44     new_image = Image.fromstring('L', image.size,
  45                              pcf.edge(image.size, image.tostring()))
  46     return new_image
  47
  48 def peaks(image):
  49     """Peak filter (on BW images)."""
  50     image_l = image.load()
  51     new_image = Image.new('L', image.size)
  52     new_image_l = new_image.load()
  53
  54     for x in range(2, image.size[0] - 2):
  55         for y in range(2, image.size[1] - 2):
  56             pix = (sum([sum([
  57                 - image_l[a, b]
  58                     for b in range(y - 2, y + 3)])
  59                     for a in range(x - 2, x + 3)])
  60                 + (17 * image_l[x, y]))
  61             if pix > 255:
  62                 pix = 255
  63             if pix < 0:
  64                 pix = 0
  65             new_image_l[x, y] = pix
  66     return new_image
  67
  68 def high_pass(image, height):
  69     """High pass filter (on BW images)."""
  70     image_l = image.load()
  71     new_image = Image.new('L', image.size)
  72     new_image_l = new_image.load()
  73
  74     for x in xrange(image.size[0]):
  75         for y in xrange(image.size[1]):
  76             if image_l[x, y] < height:
  77                 new_image_l[x, y] = 0
  78             else:
  79                 new_image_l[x, y] = image_l[x, y]
  80
  81     return new_image
  82
  83 # TODO factor these into one method
  84 # TODO comment it
  85 def components(image):
  86     image_l = image.load()
  87     new_image = Image.new('L', image.size)
  88     new_image_l = new_image.load()
  89
  90     components = [None]
  91     comp_counter = 1
  92
  93     for y in xrange(1, image.size[1] - 1):
  94         for x in xrange(1, image.size[0] - 1):
  95             if image_l[x, y]:
  96                 s = {0}
  97                 s.add(new_image_l[x - 1, y - 1])
  98                 s.add(new_image_l[x, y - 1])
  99                 s.add(new_image_l[x + 1, y - 1])
 100                 s.add(new_image_l[x - 1, y])
 101                 if len(s) == 1:
 102                     components.append(set())
 103                     new_image_l[x, y] = comp_counter
 104                     components[comp_counter].add((x, y))
 105                     comp_counter += 1
 106                 elif len(s) == 2:
 107                     s.remove(0)
 108                     c = s.pop()
 109                     new_image_l[x, y] = c
 110                     components[c].add((x,y))
 111                 else:
 112                     s.remove(0)
 113                     c1, c2 = s.pop(), s.pop()
 114                     components[c2].add((x, y))
 115                     for (x1, y1) in components[c2]:
 116                         new_image_l[x1, y1] = c1
 117                     components[c1] = components[c1] | components[c2]
 118                     components[c2] = None
 119
 120     new_image = Image.new('L', image.size)
 121     new_image_l = new_image.load()
 122
 123     for component in components:
 124         if component:
 125             x_c = 0
 126             y_c = 0
 127             c = 0
 128             for (x, y) in component:
 129                 x_c += x
 130                 y_c += y
 131                 c += 1
 132             new_image_l[int(round(float(x_c)/c)), int(round(float(y_c)/c))] = 255
 133
 134     return new_image
 135
 136 def components2(image):
 137     image_l = image.load()
 138     new_image = Image.new('L', image.size)
 139     new_image_l = new_image.load()
 140
 141     components = [None]
 142     comp_counter = 1
 143
 144     for y in xrange(2, image.size[1] - 2):
 145         for x in xrange(2, image.size[0] - 2):
 146             if image_l[x, y]:
 147
 148                 s = {0}
 149                 for (a, b) in [(a,b) for a in range(x - 2, x + 3)
 150                           for b in range(y - 2, y + 1)]:
 151                     if not (b == y and a >= x):
 152                         s.add(new_image_l[a, b])
 153
 154                 if len(s) == 1:
 155                     components.append(set())
 156                     new_image_l[x, y] = comp_counter
 157                     components[comp_counter].add((x, y))
 158                     comp_counter += 1
 159                 elif len(s) == 2:
 160                     s.remove(0)
 161                     c = s.pop()
 162                     new_image_l[x, y] = c
 163                     components[c].add((x,y))
 164                 else:
 165                     s.remove(0)
 166                     c1 = s.pop()
 167                     components[c1].add((x, y))
 168                     new_image_l[x, y] = c1
 169                     for c2 in s:
 170                         for (x1, y1) in components[c2]:
 171                             new_image_l[x1, y1] = c1
 172                         components[c1] = components[c1] | components[c2]
 173                         components[c2] = None
 174
 175     new_image = Image.new('L', image.size)
 176     new_image_l = new_image.load()
 177
 178     for component in components:
 179         if component:
 180             x_c = 0
 181             y_c = 0
 182             c = 0
 183             for (x, y) in component:
 184                 x_c += x
 185                 y_c += y
 186                 c += 1
 187             new_image_l[int(round(float(x_c)/c)), int(round(float(y_c)/c))] = 255
 188
 189     return new_image