Missing sweeps virtual points

[zw615]

Hi, I just found there are about 2000 sweeps of virtual points missing.

Here are the number of files in sweeps/LIDAR_TOP/

ls sweeps/LIDAR_TOP/ | wc -l
297737

Here are the number of files in sweeps/LIDAR_TOP_VIRTUAL/

ls data/nuscenes/sweeps/LIDAR_TOP_VIRTUAL/ | wc -l
295489

I directly download and extract the data from the official link here. I am pretty sure I didn't mess with the data. I wonder is this normal?

Thanks!

[tianweiy]

hi zeyu, I also noticed this. I think the reason is that some of the sweeps are not used at all in our model. Basically, in nuscenes, we have key frames at 2FPS, and non keyframes (sweeps) at 20FPS. Our model uses key frames + last 9 non key frames so some non key frames may not be used at all in the training / inference.

The training / testing should work out of the box if you use the centerpoint repo.

Let me know if you have further questions

[zw615]

Thanks for your prompt reply!

As you may have noticed, I am not using the centerpoint repo. I have managed to migrate the virtual points related code to the mmdet3d repo and am using it. I find simply discarding the sweep when it is missing or repeating other sweeps is able to work.

Thanks!