Questions : preprocess

[CHIH-CHIA]

Hi,
I have some doubts about the pre-processing part.
Why does it want to multiply by two and then reduce one ( *2 - 1 ) at "frame_preprocess"?
What is the relationship between this and normalization?

data[:, 3] = (
(data[:, 3] - min_position_x) / (max_position_x - min_position_x)
) * 2 - 1
data[:, 4] = (
(data[:, 4] - min_position_y) / (max_position_y - min_position_y)
) * 2 - 1

[huang-xx]

@CHIH-CHIA
This step normalizes the date to the range of [-1,1]. You can also normalizes to the range of [0,1] if you want, there will be no significant difference in results.