LimHyungTae / patchwork

SOTA fast and robust ground segmentation using 3D point cloud (accepted in RA-L'21 w/ IROS'21)
MIT License
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Why is elevation_threshold different for each zone? #13

Closed natashasoon closed 2 years ago

natashasoon commented 2 years ago

Hi,

I read through your paper explaining the patchwork algorithm, but need a little more clarification on why different elevation thresholds are needed for each zone.

If I am understanding the parameter correctly, the elevation thresholds represent the adaptive midpoint function κ(r). Would I be correct to say that this parameter is simply the maximum height that the ground plane can be? In this case, why would the maximum ground height change depending on the distance of each zone?

Thanks!

LimHyungTae commented 2 years ago

Hello there, sorry for the late reply due to my paper works.

Because as the distance goes farther, we cannot sure that the z values of the ground have lower height. The elevation threshold is based on the fact that the z values of the ground are likely to be similar to the -h, where h is the sensor height. But there are some exceptional cases, such as steep slopes. It might have some higher z values. Therefore, it should become larger as the ring index is getting bigger.