Merge pull request #6812 from aleksandaratanasov:master

samples/python/houghcircles.py

@@ -29,11 +29,14 @@ if __name__ == '__main__':
     cimg = src.copy() # numpy function
 
     circles = cv2.HoughCircles(img, cv2.HOUGH_GRADIENT, 1, 10, np.array([]), 100, 30, 1, 30)
+
+    if circles != None: # Check if circles have been found and only then iterate over these and add them to the image
         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.LINE_AA)
             cv2.circle(cimg, (circles[0][i][0], circles[0][i][1]), 2, (0, 255, 0), 3, cv2.LINE_AA)  # draw center of circle
 
-    cv2.imshow("source", src)
         cv2.imshow("detected circles", cimg)
+
+    cv2.imshow("source", src)
     cv2.waitKey(0)

samples/python/houghlines.py

@@ -36,6 +36,7 @@ if __name__ == '__main__':
 
     else:    # HoughLines
         lines = cv2.HoughLines(dst, 1, math.pi/180.0, 50, np.array([]), 0, 0)
+        if lines != None:
             a,b,c = lines.shape
             for i in range(a):
                 rho = lines[i][0][0]
@@ -47,6 +48,7 @@ if __name__ == '__main__':
                 pt2 = ( int(x0-1000*(-b)), int(y0-1000*(a)) )
                 cv2.line(cdst, pt1, pt2, (0, 0, 255), 3, cv2.LINE_AA)
 
-    cv2.imshow("source", src)
             cv2.imshow("detected lines", cdst)
+
+    cv2.imshow("source", src)
     cv2.waitKey(0)