questions about transformations

[MaicsCYB]

0. I cannot understand the details about transformations, I think the formulation wants to get E_g2c. so, why not use 'R_gv@E' instead of 'inv(R_vg)@ E @R_vg@R_gc'?

1. which is the correct coordinate system for 3d lane points?
   
   

thanks!

[ChonghaoSima]

0. the transformation is largely following GenLaneNet. You can have a try on R_gv@E method and see if there's any improvement.
1. sorry, that was a typo in OpenLane repo. We'll fix it. The correct coordinate system is vehicle coordinates.

[Mollylulu]

for this step

 cam_extrinsics[:3, :3] = np.matmul(np.matmul(np.matmul(np.linalg.inv(R_vg),cam_extrinsic[:3, :3]),R_vg), R_gc)

could you help me figure out, what is this inv(R_vg) @ E @ R_vg @ R_gc doing? To my mind, E_g2c is final target here, am I right? But I still can not understand each step transformation in above line. Could you give some interpretation that would be very appreciated :) thanks !

[nikhil-nakhate]

same question as above

[presmann]

@ChonghaoSima it seems quite strange that the annotations are in the vehicle_coordinate system. Specifically, the z part of the annotations tends to be negative most of the times. it seems to in the camera coordinates after all.
For example, in lane3d_1000/training/segment-15832924468527961_1564_160_1584_160_with_camera_labels/150767882737686600.json the first lane is (labels_dict is dictionary of the loaded json)

min(lanes_visualization_obj.labels_dict['lane_lines'][0]['xyz'][2])
Out[15]: -3.8558186921526554
max(lanes_visualization_obj.labels_dict['lane_lines'][0]['xyz'][2])
Out[16]: -2.2029994863655915

And the 2nd one is:

 min(lanes_visualization_obj.labels_dict['lane_lines'][1]['xyz'][2])
Out[18]: -2.4630904216158926
max(lanes_visualization_obj.labels_dict['lane_lines'][0]['xyz'][2])
Out[19]: -2.2029994863655915

and the third one is:

min(lanes_visualization_obj.labels_dict['lane_lines'][2]['xyz'][2])
Out[20]: -3.8966073247935045
max(lanes_visualization_obj.labels_dict['lane_lines'][2]['xyz'][2])
Out[21]: -2.4456845933203346

[RicardLee]

Please refer to https://github.com/OpenPerceptionX/OpenLane/issues/24. It should solve your questions. The annotations are under the Waymo camera coordinate (The typo has been updated in https://github.com/OpenPerceptionX/OpenLane/blob/main/anno_criterion/Lane/README.md).

[RicardLee]

We will close this issue, if you still have the same questions, please reopen this.

[usherbob]

It should solve your questions. The annotations are under the Waymo camera coordinate (The typo has been updat

Seems the link is invalid, may you update the explanation of this issue?

[ilnehc]

@usherbob Just change OpenPerceptionX to OpenDriveLab: https://github.com/OpenDriveLab/OpenLane/blob/main/anno_criterion/Lane/README.md