4. IMPORTANT: Setting Parameters of Patchwork in Your Own Env.

WARNING: Parameters are important!!

I think this page is the main of wiki.

Please read this explanation carefully, otherwise, you can get some catastrophic failures as follows:

Above all things, we thank 薛银涛 who provides ouster-128 pcd files.

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Explanation of Parameters

The most important parameters in params.yaml for your scenes will be explained.

Transformation

Note that our Patchwork assumes that the point cloud is w.r.t. the LiDAR coordinate which is parallel to the X-Y plane of the ground. That is, if you use a tilted LiDAR setting, the point cloud should be transformed appropriately. In this repo, transformation is not supported. But you can utilize extrinsic_trans and extrinsic_rot.

Important Parameters that Must Be Changed in Your dataset

For using Patchwork in your dataset, the following two parameters must be revised:

• sensor_height: Indeed, it denotes the height from the ground to the coordinate. Thus, it is set to 1.723 m in the KITTI dataset. If your point cloud (or pcd) was already transformed to the ground frame, i.e. height difference btw ground and the coordinate is equal to zero, then sensor_height should be set to 0 like params_ouster128.yaml
  • **230925 Update: **In this repository, All-Terrain Auto-heighT (ATAT) estimator is included. So, the sensor_height is roughly auto-cablibrated.
• elevation_thresholds: (updated in 230502) Elevation filters are w.r.t. the sensor_height. This denotes that if the patches whose mean z values are larger than this sensor_height + elevation_threhsholds[#], the patches are rejected. Thus, the values of elevation_thresholds should always be positive.