RPN_BBOX_STD_DEV and BBOX_STD_DEV in config.py

[ccnankai]

Hi @parap1uie-s
parameters：
RPN_BBOX_STD_DEV = np.array([0.1, 0.1, 0.2, 0.2])
BBOX_STD_DEV = np.array([0.1, 0.1, 0.2, 0.2])
in config.py
How do the values of these two parameters get? Is it based on experience?
thank you!