tabletop_segment

Simple ROS package to segment point clouds from tabletop surfaces. Uses a simple RANSAC routine to identify planes in a point cloud and removes them. Depends on PCL. Tested on ROS Melodic + PCL 1.8/1.9.

Usage

Launch the node with

roslaunch tabletop_segment tabletop_segment.launch <optional parameters>

Optional parameters include whether you wish to also launch a RealSense node or not, and which node should be used as a source of point clouds (default will be tabletop_segment/input_cloud. Parameters can be set at startup using the config file, or at runtime using rosparam. Subscribe or remap tabletop_segment/objects_cloud to use the segmented output.

The node crops the input point cloud before detecting planes. This happens according to the workspace parameters applied around the origin of the point cloud. If your scene features more planes, the largest plane in the workspace will get removed, the others will stay in the output point cloud. If your scene includes more than one object, the output point cloud will include all of them. The output point cloud preserves the input header reference frame.

Expected output

Input PC	Segmented PC

Topics and parameters

Subscribes to

Topic	Type	Description
tabletop_segment/input_cloud	sensor_msgs/PointCloud2	Point cloud to be segmented

Publishes

Topic	Type	Description
tabletop_segment/objects_cloud	sensor_msgs/PointCloud2	Segmented point cloud including everything that is not a planar surface
tabletop_segment/plane_cloud	sensor_msgs/PointCloud2	Segmented point cloud including the points belonging to the planar surface
tabletop_segment/plane_coefficients	pcl_msgs/ModelCoefficients	Coefficients of the detected plane

Rosparam

Parameters	Type	Description
tabletop_segment/crop_max_x	double	Workspace X upper bound
tabletop_segment/crop_max_y	double	Workspace Y upper bound
tabletop_segment/crop_max_z	double	Workspace Z upper bound
tabletop_segment/crop_min_x	double	Workspace X lower bound
tabletop_segment/crop_min_y	double	Workspace Y lower bound
tabletop_segment/crop_min_z	double	Workspace Z lower bound
tabletop_segment/plane_distance_threshold	double	Maximum distance from the plane of a point belonging to the plane itself
tabletop_segment/remove_outliers	double	Whether to remove outliers or not (not implemented yet)

TODO

• Implement rejection of small outlier clusters after segmentation
• Implement basic object-wise segmentation (e.g. euclidean)