Data preprocess

[zhangpur2]

Hi, thanks for your great work:)
There's some problem with understanding the official code:
curr_dets, add_num = add_miss_dets(
prev_dets,
dets,
iou_threshold=iou_threshold,
fix_threshold=fix_threshold) # add missed dets
add_count += add_num
add_frame += int(add_num > 0)

Why do we need the function of add_miss_dets? Actually the program always end up at
if len(index) == 0:
return dets, 0

inside the function, when dealing with pp_train_dets.pkl and pp_val_dets.pkl.

[Wenwei Zhang]

This function adds detected objects from previous frames into current frames. However, during our experiment, we find this trick does not help, so we do not use it in this release code.

[zhangpur2]

Thanks.