Overview

This package contains tools for Velodyne 3D laser scanner (tested with Velodyne HDL-32E). There are three main nodes:

• Laserscan Node - simulates conventional 2D scanner by using data from 3D LiDAR.

• Groundmap Node - estimates "safe ground" (i.e. not too rough, without high steps and other obstacles) around the robot.

• Cloud Assembler Node - combines several consecutive point clouds into a more dense cloud.

Each node has it's nodelet counterpart with same ROS API.

Use GitHub to report bugs or submit feature requests. [View active issues]

Installation

From source:

1. Clone the github repository.
2. Copy the cloned repository into the 'src' folder of your ROS workspace.
3. Recompile your ROS workspace: $ catkin_make.

Laserscan Node

Uses 3D data to simulate conventional 2D scanner. This way, Velodyne might be used with move_base.

Usage example:

   1 roslaunch but_velodyne_proc laserscan_node.launch

Topics

points_in (sensor_msgs/PointCloud2)

• input 3D cloud

• simulated 2D scanner output

Parameters

~frame_id (string, default: "")

• output frame_id (will be same as in input data if not specified)

• points under this height will be discarded

• points above this height will be discarded

• angular resolution (radians)

• points closer to the sensor than this will be discarded

Groundmap Node

Estimates frame-to-frame bumpiness of robot's surrounding and publishes it as an occupancy grid. This might be used by autonomous rovers supposed to navigate on a rough terrain.

Topics

points_in (sensor_msgs/PointCloud2)

• input 3D cloud

• 2D map of bumpiness

Parameters

~map2d_res (double, default: "0.001")

• resolution of output 2D map

• width of output 2D map

• height of output 2D map

• points further than max_range will be skipped

• angular resolution for internal processing

• radial resolution for internal processing

• tbd

• tbd

• simple filtering of isolated occupied cells

• tbd

• tbd

Cloud Assembler Node

When a robot is moving, this node combines few historic clouds and the current one to produce denser cloud.

Topics

/velodyne_points (sensor_msgs/PointCloud2)

• input 3D cloud

• dense cloud