Confusion about "filter_out_range" function

[where2go947]

Hi, thanks for your implementation about LiDAR ground removal. However, I'm confused about function filter_out_range

• function project_5D return the point5D with shapes [N,3+2], while 5 represent x, y, z, seg_index, bin_index axis in order: https://github.com/SilvesterHsu/LiDAR_ground_removal/blob/745d4c1a2a3174b9936a535de93994e597f26d97/module/ground_removal.py#L118-L138

• But in function filter_out_range, the point5D[:,4] seems to be regarded as radius? https://github.com/SilvesterHsu/LiDAR_ground_removal/blob/745d4c1a2a3174b9936a535de93994e597f26d97/module/ground_removal.py#L140-L151

Is there anything wrong with my understanding? Thanks in advance!