note: the “tutroals” (!) site has been deprecated since 2014. please use official docs:
https://docs.opencv.org/master/dc/dbb/tutorial_py_calibration.html
intrinsic calibration doesn’t concern itself with coordinate frames. it’s all about the lens and “sensor” properties.
if you want to establish your camera’s coordinate frame relative to some other coordinate frame (or vice versa), that’s “extrinsic” calibration.