Data collection
Prerequisite
- The intrinsic parameters of the camera (i.e., camera matrix and distortion coefficients) need to be calibrated beforehand.
- The camera and LiDAR must be rigidly fixed.
Data collection steps
- Keep the sensor at rest and start recording
Image
andPointCloud2
messages. We recommend recordingCameraInfo
as well if it is available. - [For a non-repetitive scan LiDAR (Livox)] Wait for 10 ~ 15 sec without moving the sensor.
- [For a spinning LiDAR (Ouster)] Move the sensor up and down slowly for 10 sec. If your LiDAR has fewer scan lines (e.g., 16 or 32 lines), keep moving it a bit longer (e.g., 20 ~ 30 sec).
- Stop recording.
Note
While the calibration can be performed with only one rosbag at a minimum, we recommend taking several (5 ~ 10) rosbags for better calibration results.
Data acquisition example for an Ouster OS1-128:
Keep in mind
- The sensor must be kept at rest at the beginning of each rosbag to ensure that the first point cloud and image are taken at the same pose.
- LiDAR intensity data must exhibit some texture and geometry information. Be aware of that some LiDARs (e.g., Livox Avia) returns invalid intensity values for too close points.