Where does 31 come from in optical_flow_warp?

[NielsFuglsang]

Hello,

Nice work and code!

I have a question regarding the optical_flow_warp method. I understand that we want grid to have values in the range of [-1,1], but the multiplication with 31 seems arbitrary to me.

    flow_0 = torch.unsqueeze(image_optical_flow[:, 0, :, :] * 31 / (w - 1), dim=1)
    flow_1 = torch.unsqueeze(image_optical_flow[:, 1, :, :] * 31 / (h - 1), dim=1)

Can somebody further explain where this comes from?

[ToanLyHoa]

I have the same question