imago_pack/linef.py

   1 """Lines finding module."""
   2
   3 from functools import partial
   4 import sys
   5 from math import sin, cos, pi
   6
   7 try:
   8     import Image, ImageDraw
   9 except ImportError, msg:
  10     print >> sys.stderr, msg
  11     sys.exit(1)
  12
  13 import filters
  14 from hough import Hough
  15
  16 def prepare(image, show_image, logger):
  17     # TODO comment
  18     im_l = image.convert('L')
  19     show_image(im_l, "ITU-R 601-2 luma transform")
  20
  21     logger("edge detection")
  22     im_edges = filters.edge_detection(im_l)
  23     show_image(im_edges, "edge detection")
  24
  25     im_h = filters.high_pass(im_edges, 100)
  26     show_image(im_h, "high pass filters")
  27
  28     return im_h
  29
  30 def transform(image, hough, show_image):
  31     # TODO comment
  32     im_hough = hough.transform(image)
  33     show_image(im_hough, "hough transform")
  34
  35    # im_hough.image = filters.peaks(im_hough.image)
  36    # show_image(im_hough.image, "peak extraction")
  37
  38     im_h2 = filters.high_pass(im_hough, 96)
  39     show_image(im_h2, "second high pass filters")
  40
  41     im_h2 = filters.components(im_h2, 2)
  42     show_image(im_h2, "components centers")
  43
  44     return im_h2
  45
  46 def find_lines(image, show_image, logger):
  47     """Find lines in the *image*."""
  48     # TODO refactor into smaller functions
  49
  50     logger("preprocessing")
  51     show_image(image, "original image")
  52
  53     im_h = prepare(image, show_image, logger)
  54
  55     hough = Hough.default(im_h)
  56
  57     logger("hough transform")
  58
  59     im_h2 = transform(im_h, hough, show_image)
  60
  61     logger("second hough transform")
  62
  63     # im_hough might be used instead im_h2, but at the moment it brings a lot of
  64     # noise to the second transform, which later confuses the center-finding
  65     # mechanism (which is not very robust yet)
  66     hough2 = Hough.default(im_h2)
  67     im_hough2 = hough2.transform(im_h2)
  68     show_image(im_hough2, "second hough transform")
  69
  70     im_h3 = filters.high_pass(im_hough2, 120)
  71     show_image(im_h3, "third high pass filter")
  72
  73     im_h3 = filters.components(im_h3, 1)
  74     show_image(im_h3, "half centers")
  75
  76     logger("finding the lines")
  77
  78     lines_m = hough2.all_lines_h(im_h3)
  79     lines = []
  80     im_c = im_h2.convert('RGB').convert('RGB', (1, 0.5, 0.5, 0))
  81     draw_c = ImageDraw.Draw(im_c)
  82     bounds = []
  83
  84     for line_l in lines_m:
  85         im_line = Image.new('L', im_h2.size)
  86         draw = ImageDraw.Draw(im_line)
  87         line_points = set()
  88         for line in line_l:
  89             draw.line(line_from_angl_dist(line, im_h2.size), fill=255, width=7)
  90             draw_c.line(line_from_angl_dist(line, im_c.size),
  91                         fill=(70, 70, 70), width=7)
  92             for p in combine(im_h2, im_line):
  93                 line_points.add(p)
  94         for point in line_points:
  95             draw_c.point(point, fill=(120, 255, 120))
  96         lines.append(hough.lines_from_list(line_points))
  97         line_points = list(line_points)
  98         line_points.sort()
  99         bounds += [line_points[0], line_points[-1]]
 100
 101     show_image(im_c, "hough x lines")
 102
 103     image_g = image.copy()
 104     draw = ImageDraw.Draw(image_g)
 105     for line in [l for s in lines for l in s]:
 106         draw.line(line_from_angl_dist(line, image.size), fill=(120, 255, 120))
 107     show_image(image_g, "lines")
 108
 109     return lines, lines_m[0][0], lines_m[1][0], bounds, hough
 110
 111 def combine(image1, image2):
 112     """Return a list of points that are present in both images."""
 113     im_l1 = image1.load()
 114     im_l2 = image2.load()
 115
 116     on_both = []
 117
 118     for x in xrange(image1.size[0]):
 119         for y in xrange(image1.size[1]):
 120             if im_l1[x, y] and im_l2[x, y]:
 121                 on_both.append((x, y))
 122     return on_both
 123
 124 def line_from_angl_dist((angle, distance), size):
 125     """Take *angle* and *distance* (from the center of the image) of a line and
 126     size of the image. Return the line represented by two points."""
 127     if pi / 4 < angle < 3 * pi / 4:
 128         y1 = - size[1] / 2
 129         x1 = int(round((y1 * cos(angle) + distance) / sin(angle))) + size[0] / 2
 130         y2 = size[1] / 2
 131         x2 = int(round((y2 * cos(angle) + distance) / sin(angle))) + size[0] / 2
 132         return [(x1, 0), (x2, size[1])]
 133     else:
 134         x1 = - size[0] / 2
 135         y1 = int(round((x1 * sin(angle) - distance) / cos(angle))) + size[1] / 2
 136         x2 = size[0] / 2
 137         y2 = int(round((x2 * sin(angle) - distance) / cos(angle))) + size[1] / 2
 138         return [(0, y1), (size[0], y2)]