OpenCV and aruco version

[abaybek]

Hello. Can your share your requirements.txt (pip freeze) file?

Because as I try to run your calibrate.py file, I get this type of errors.

1. OpenCV 3.1, Python 2.7
   AttributeError: 'module' object has no attribute 'getPredefinedDictionary'

2. OpenCV 4.0.0-pre
   AttributeError: 'cv2.aruco_DetectorParameters' object has no attribute 'doCornerRefinement'