Question about absolute velo

[iMbaGong]

Thanks for open-source great work!
I have a question about absolute velo computation

SparseBEV/models/sparsebev_transformer.py

Lines 178 to 183 in 4d028e9

	# calculate absolute velocity according to time difference
	time_diff = img_metas[0]['time_diff'] # [B, F]
	if time_diff.shape[1] > 1:
	time_diff = time_diff.clone()
	time_diff[time_diff < 1e-5] = 1.0
	bbox_pred[..., 8:] = bbox_pred[..., 8:] / time_diff[:, 1:2, None]

Why I have to div the velo with time here? Thanks a lot!

[afterthat97]

velocity = distance / time

The model predicts distance, so we need to divide it by time.

[iMbaGong]

I just didn‘t see it already a new prediction, i thought it was same as used in sampling then. Thanks a lot!