+#!/usr/bin/env python
+
+"""Go image recognition lines-finding module"""
+
+import sys
+import math
+
+try:
+ import Image, ImageDraw
+except ImportError, msg:
+ print >> sys.stderr, msg
+ sys.exit(1)
+
+import filters
+from hough import Hough
+
+def find_lines(image, show_all, do_something, verbose):
+
+ if verbose:
+ print >> sys.stderr, "preprocessing"
+
+ if show_all:
+ do_something(image, "original image")
+
+ im_l = image.convert('L')
+ if show_all:
+ do_something(im_l, "ITU-R 601-2 luma transform")
+
+ if verbose:
+ print >> sys.stderr, "edge detection"
+
+ im_edges = filters.edge_detection(im_l)
+ if show_all:
+ do_something(im_edges, "edge detection")
+
+ im_h = filters.high_pass(im_edges, 100)
+ if show_all:
+ do_something(im_h, "high pass filters")
+
+ if verbose:
+ print >> sys.stderr, "hough transform"
+
+ hough1 = Hough(im_h.size)
+ im_hough = hough1.transform(im_h)
+ if show_all:
+ do_something(im_hough, "hough transform")
+
+ im_hough = filters.peaks(im_hough)
+ if show_all:
+ do_something(im_hough, "peak extraction")
+
+ im_h2 = filters.high_pass(im_hough, 120)
+ if show_all:
+ do_something(im_h2, "second high pass filters")
+
+ im_h2 = filters.components2(im_h2)
+ if show_all:
+ do_something(im_h2, "components centers")
+
+ if verbose:
+ print >> sys.stderr, "second hough transform"
+
+ hough2 = Hough(im_h2.size)
+ # im_hough might be used instead im_h2, but at the moment it brings a lot of
+ # noise to the second transform, which later confuses the center-finding
+ # mechanism (which is not very robust yet)
+ im_hough2 = hough2.transform(im_h2)
+ if show_all:
+ do_something(im_hough2, "second hough transform")
+
+ im_h3 = filters.high_pass(im_hough2, 120)
+ if show_all:
+ do_something(im_h3, "third high pass filter")
+
+ im_h3 = filters.components(im_h3)
+ if show_all:
+ do_something(im_h3, "half centers")
+
+ if verbose:
+ print >> sys.stderr, "finding the grid"
+
+ lines_m = hough2.all_lines_h(im_h3)
+ lines = []
+ im_c = im_h2.convert('RGB').convert('RGB', (1, 0.5, 0.5, 0))
+ draw_c = ImageDraw.Draw(im_c)
+
+ for line_l in lines_m:
+ im_line = Image.new('L', im_h2.size)
+ draw = ImageDraw.Draw(im_line)
+ line_points = set()
+ for line in line_l:
+ draw.line(line_from_angl_dist(line, im_h2.size), fill=255, width=7)
+ draw_c.line(line_from_angl_dist(line, im_c.size), fill=(70, 70, 70), width=7)
+ for p in combine(im_h2, im_line):
+ line_points.add(p)
+ for point in line_points:
+ draw_c.point(point, fill=(120, 255, 120))
+ lines.append(hough1.lines_from_list(line_points))
+
+ if show_all:
+ do_something(im_c, "hough x lines")
+
+ image_g = image.copy()
+ draw = ImageDraw.Draw(image_g)
+ for line in [l for s in lines for l in s]:
+ draw.line(line_from_angl_dist(line, image.size), fill=(120, 255, 120))
+ if show_all:
+ do_something(image_g, "the grid")
+
+ return lines
+
+def combine(image1, image2):
+ im_l1 = image1.load()
+ im_l2 = image2.load()
+
+ on_both = []
+
+ for x in xrange(image1.size[0]):
+ for y in xrange(image1.size[1]):
+ if im_l1[x, y] and im_l2[x, y]:
+ on_both.append((x, y))
+ return on_both
+
+def line_from_angl_dist((angle, distance), size):
+ x1 = - size[0] / 2
+ y1 = int(round((x1 * math.sin(angle) - distance) / math.cos(angle))) + size[1] / 2
+ x2 = size[0] / 2
+ y2 = int(round((x2 * math.sin(angle) - distance) / math.cos(angle))) + size[1] / 2
+ return [(0, y1), (size[0] - 1, y2)]