Add HoughTransform examples python2

houghlines.py for HoughLinesP() and HoughLines()
houghcircles.py for HoughCircles()

samples/python2/houghcircles.py

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+#!/usr/bin/python
+
+'''
+This example illustrates how to use cv2.HoughCircles() function.
+Usage: ./houghcircles.py [<image_name>] 
+image argument defaults to ../cpp/board.jpg
+'''
+
+import cv2
+import numpy as np
+import sys
+
+
+print __doc__
+try:
+	fn = sys.argv[1]
+except:
+	fn = "../cpp/board.jpg"
+
+src = cv2.imread(fn, 1)
+img = cv2.cvtColor(src, cv2.COLOR_BGR2GRAY)
+img = cv2.medianBlur(img, 5)
+cimg = src.copy() # numpy function
+
+circles = cv2.HoughCircles(img, cv2.cv.CV_HOUGH_GRADIENT, 1, 10, np.array([]), 100, 30, 1, 30)
+a, b, c = circles.shape
+for i in range(b):
+	cv2.circle(cimg, (circles[0][i][0], circles[0][i][1]), circles[0][i][2], (0, 0, 255), 3, cv2.cv.CV_AA)
+	cv2.circle(cimg, (circles[0][i][0], circles[0][i][1]), 2, (0, 255, 0), 3, cv2.cv.CV_AA) # draw center of circle
+
+cv2.imshow("source", src)
+cv2.imshow("detected circles", cimg)
+cv2.waitKey(0)

samples/python2/houghlines.py

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+#!/usr/bin/python
+'''
+This example illustrates how to use Hough Transform to find lines
+Usage: ./houghlines.py [<image_name>]
+image argument defaults to ../cpp/pic1.png
+'''
+import cv2
+import numpy as np
+import sys
+import math
+
+try:
+	fn = sys.argv[1]
+except:
+	fn = "../cpp/pic1.png"
+print __doc__
+src = cv2.imread(fn)
+dst = cv2.Canny(src, 50, 200)
+cdst = cv2.cvtColor(dst, cv2.COLOR_GRAY2BGR)
+
+# HoughLines()
+# lines = cv2.HoughLines(dst, 1, cv2.cv.CV_PI/180.0, 50, np.array([]), 0, 0)
+# a,b,c = lines.shape
+# for i in range(b):
+# 	rho = lines[0][i][0]
+# 	theta = lines[0][i][1]
+# 	a = math.cos(theta)
+# 	b = math.sin(theta)
+# 	x0, y0 = a*rho, b*rho
+# 	pt1 = ( int(x0+1000*(-b)), int(y0+1000*(a)) )
+# 	pt2 = ( int(x0-1000*(-b)), int(y0-1000*(a)) )
+# 	cv2.line(cdst, pt1, pt2, (0, 0, 255), 3, cv2.cv.CV_AA)
+
+lines = cv2.HoughLinesP(dst, 1, cv2.cv.CV_PI/180.0, 50, np.array([]), 50, 10)
+a,b,c = lines.shape
+for i in range(b):
+	cv2.line(cdst, (lines[0][i][0], lines[0][i][1]), (lines[0][i][2], lines[0][i][3]), (0, 0, 255), 3, cv2.cv.CV_AA)
+
+cv2.imshow("source", src)
+cv2.imshow("detected lines", cdst)
+cv2.waitKey(0)