simple detect line using hough transform

mahotas/tests/LineDetectorByHough.py

@@ -0,0 +1,54 @@
+# -*- coding: utf-8 -*-
+# Copyright (C) 2008-2014, Jasson <[email protected]>
+# License: MIT (see COPYING file)
+
+import math
+import numpy as np
+
+class Line():
+    def __init__(self,r,angle):
+        self.r = r
+        self.angle = angle
+    def __eq__(self, other):
+        if self.r == other.r and self.angle == other.angle:
+            return True
+        else:
+            return False
+    def __hash__(self):
+        result = 31 + int(self.r)
+        result = 31 * result + int(self.angle * 100)
+        #print result
+        return result
+
+class Counter(dict):
+    def __missing__(self, key):
+        return 0
+
+class LineDetectorByHough:
+    countersDICT = Counter(dict())
+    def __init__(self):
+        pass
+
+    def find(self,img):
+        rows, cols = img.shape
+
+        points = 0
+        for x in range(0, rows):
+            for y in range(0, cols):
+                if (img[x, y] == 1):
+                    points = points + 1
+                    for angle in np.arange(0, 2 * np.pi, 2 * np.pi / 40):
+                        # print 'angel=',x, y, angel
+                        angle = round(angle, 2)
+                        angle = angle % round(np.pi, 2)
+                        r = round(self.calcR(x, y, angle),1)
+                        #print 'r,angel=', r, angle
+                        self.countersDICT[Line(r, angle)] += 1
+        #print "points=", points
+        #print "line (r ,angle) count"
+
+        for (k, v) in self.countersDICT.items():
+            if(v > rows/2):
+                return k.r, k.angle
+    def calcR(self,x,y,angle):
+        return x* math.cos(angle) + y * math.sin(angle)

mahotas/tests/test_hough_transform_line.py

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+# -*- coding: utf-8 -*-
+# Copyright (C) 2008-2014, Jasson <[email protected]>
+# License: MIT (see COPYING file)
+import unittest
+import numpy as np
+import math
+
+from LineDetectorByHough import LineDetectorByHough
+from LineDetectorByHough import Line
+
+
+class test_hough_transform_line(unittest.TestCase):
+
+    def test_simpleImg_hough_detect(self):
+        img = np.zeros((80, 80), bool)
+        img[6,:] = 1
+
+        c = LineDetectorByHough()
+        lines = c.find(img)
+
+        self.assertEquals(lines,Line(6,0))
+
+    def test_counter(self):
+        c = LineDetectorByHough
+
+        line = Line(10,np.pi/4)
+        c.countersDICT[line] += 1
+
+        line = Line(10,np.pi/4)
+        c.countersDICT[line] += 2
+
+        self.assertEquals(c.countersDICT[line], 3)
+
+    def test_line_r_calc(self):
+        c = LineDetectorByHough()
+        self.assertEquals(c.calcR(10,10,np.pi/4), math.sqrt(10*10 + 10*10))
+
+
+
+