Could someone explain alpha_to_8 functions to me?

[yeyangfang]

In rc/lib/datasets/sample/ddd.py, there is a function def _alpha_to_8(self, alpha) I am a little confused about this function. Could someone explain this to me? What's the range for input alpha? Furthermore, how to model orientation in ddd detection?

[kshashankrao]

It is the conversion of alpha (in radians) to 8 scalars across 2 bins.