Scan Ground Filter#

Purpose#

The purpose of this node is that remove the ground points from the input pointcloud.

This algorithm works by following steps,

Divide whole pointclouds into groups by horizontal angle and sort by xy-distance.
Check the distance and vertical angle of the point one by one.
Set a center of the ground contact point of the rear or front wheels as the initial point.
Check vertical angle between the points. If the angle from the initial point is larger than "global_slope_max", the point is classified as "no ground".
If the angle from the previous point is larger than "local_max_slope", the point is classified as "no ground".
Otherwise the point is labeled as "ground point".
If the distance from the last checked point is close, ignore any vertical angle and set current point attribute to the same as the last point.

This implementation inherits pointcloud_preprocessor::Filter class, please refer README.

This implementation inherits pointcloud_preprocessor::Filter class, please refer README.

Name	Type	Default Value	Description
`base_frame`	string	"base_link"	base_link frame
`global_slope_max`	double	8.0	The global angle to classify as the ground or object [deg]
`local_max_slope`	double	6.0	The local angle to classify as the ground or object [deg]
`radial_divider_angle`	double	1.0	The angle which divide the whole pointcloud to sliced group [deg]
`split_points_distance_tolerance`	double	0.2	The xy-distance threshold to to distinguishing far and near [m]
`split_height_distance`	double	0.2	The height threshold to distinguishing far and near [m]
`use_virtual_ground_point`	bool	true	whether to use the ground center of front wheels as the virtual ground point.