Ray ground filter is not actually removing ground points

[jfqureshi]

Checklist

• [X] I've read the contribution guidelines.
• [X] I've searched other issues and no duplicate issues were found.
• [X] I'm convinced that this is not my fault but a bug.

Description

Hello, I am using Autoware.ai + Carla Simulator. The issue I have is that my ray_ground_filter is actually not removing the ground points. So, my vehicle is unable to move because it detects the ground points. Any help would be appreciated.

Expected behavior

The output points topic points_no_ground should be without ground points.

Actual behavior

The ground points are not removed from the output points topic points_no_ground .

Steps to reproduce

Use ray_ground_filter node with points_rawas input topic.

Versions

Ubuntu 18.04 ROS Melodic Autoware.ai 1.14

Possible causes

Bug in the code

Additional context

Please find the visualization of the no ground topic. i,e points_no_ground https://drive.google.com/drive/u/0/my-drive

[mitsudome-r]

@jfqureshi We cannot determine if this is a bug or parameter issue just from your information. I think your shared link to google drive isn't valid. If you want to share the file, you have to right click your file and get the link through "Share" option.

Have you tried playing around with the parameters in ray_ground_filter node? Relevant code Here are some of the parameters that you might want to checkout.

• min_height_threshold: points lower than this value will be removed
• local_max_slope: angle of slope that the node use to determine if the point is ground or not. Roughly speaking, if the angle between two points has larger than this value, it will be considered as an obstacle.
• min_point_distance: Minimum valid distance, points closer than this will be removed.

Also, you might want to make sure that you have tf published between your sensor frame and base_link frame.

[jfqureshi]

@mitsudome-r Thanks for the answer and sorry for the wrong link. Here is the correct link https://drive.google.com/file/d/1X26bm_zTzDOzGxVh6XLew3RIIbcYLUAy/view?usp=sharing I think the issue is with the parameters(quite convinced). I tried to play with them but I still couldn't get to a point where all the ground points are removed. I have my Lidar at (x,y,z = 0,0,2 m) from the base_link.

Also I wanted to ask the height parameters are with respect to base_link frame, right? Here are my ray_ground parameters:

• clipping_height = 2.0
• min_height_threshold = 0.05
• local_max_slope = 5.0
• min_point_distance = 1.85

These are here default values. I tried to tune them but when I didn't succeed I restored to default values.

And here is my ray_ground_filter node: https://drive.google.com/file/d/1kLOet7fyAEYQu0qU-Ik2vPzIoBYl0a-x/view?usp=sharing

This picture is with 0.2 m min_height_threshold https://drive.google.com/file/d/1xXdZhIg4KDGD0emRiCaEGxx7hNx5Yu_w/view?usp=sharing

And finally, if you notice in this picture: https://drive.google.com/file/d/1Wfj4a3q4g_Iedwpi7WEVSSjUVPchdd-I/view?usp=sharing It removes the ground points correctly at some instances. For example the bushes on the left are detected correctly and the ground points near them are removed(if you look at the camera picture and the point_cloud). But on the left lane ahead of the vehicle, the ground points are not removed.