Blickfeld ROS2 package

This package provides a ROS2 node for publishing PointCloud2 messages from Blickfeld LiDAR devices. The driver is available under https://www.blickfeld.com/resources

Supported devices

The Blickfeld ROS2 driver supports all currently available Blickfeld LiDARs such as Cube 1 and Cube Range 1.

Supported ROS2 Distributions

The Blickfeld ROS2 driver supports the following ROS2 Distribution

  • Foxy Fitzroy

obtain

git clone --recursive <URL>

This will clone ros_blickfeld_driver.

Dependencies

As submodule ros_blickfeld_driver depends on:

  • ros_blickfeld_driver_core v0.2.3 (resides in modules directory)

To install the Blickfeld ROS2 driver, please make sure the following dependencies are installed on your system.

  • blickfeld-scanner-library (BSL) with system-wide protobuf installation. This package has been tested using BSL Version 2.18.2

  • ROS Foxy Installation with Ubuntu 20.04

  • diagnostic_updater can be acquired via your distribution’s package manager, ${ROS_DISTRO} should be your ROS 2 version. (foxy)

    $ sudo apt install ros-${ROS_DISTRO}-diagnostic-updater
$ sudo apt install ros-${ROS_DISTRO}-diagnostic-msgs

    or via

    $ rosdep update
$ rosdep install --from-paths src --ignore-src -r -y --skip-keys "blickfeld-scanner"

    The -skip-keys will instruct rosdep to not check blickfeld-scanner, which is not a ros package.

  • colcon installation: required for building the workspace

The default DDS of ROS2 Foxy FastRTPS is not compatible with BSL. Hence for ROS2 Foxy, we need to install DDS from other vendors. (e.g. Eclipse Cyclone or RTI Connext)

Build

Before building ensure that your ROS DISTRO is sourced. You will need to run this command on every new shell you open to have access to the ROS 2 commands. ${ROS_DISTRO} should be your ROS 2 version. (e.g. foxy)

$ source /opt/ros/${ROS_DISTRO}/setup.bash

To build the ROS2 driver, request the ROS2 driver from the Blickfeld Sales department and decompress the archive into your ROS2 workspace and run.

$ colcon build --symlink-install --cmake-clean-first

Switching to desired DDS

For ROS2 Foxy, we need to switch from the default DDS to a compatible one. This can be done using either of the two approaches.

  1. Exporting the RMW_IMPLEMENTATION for the present terminal session

   $ export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp

  1. Switching to the desired RMW_IMPLEMENTATION while running by adding a prefix before the ros2 run

   $ RMW_IMPLEMENTATION=rmw_cyclonedds_cpp ros2 run PKG_NAME NODE_NAME ARGUMENTS

NOTE

Before starting a communication with blickfeld driver, the default DDS should be changed to cyclone DDS or other vendors. Therefore it is suggested to set a system global variable for RMW_IMPLEMENTATION=rmw_cyclonedds_cpp.

Running the Blickfeld ROS node

Before running, ensure that your colcon workspace is sourced. This is achieved by sourcing the setup script in your colcon workspace.

$ source install/setup.bash

You can launch the ROS driver in a DHCP controlled Network by providing the Hostname of the LiDAR device (you can check and set the Hostname in the WebGUI of the device) e.g:

$ ros2 run blickfeld_driver blickfeld_driver_node --ros-args -p host:=cube-0175 --remap __node:=bf_lidar

If you connect the LiDAR directly to your PC or don’t have a DHCP Server you can launch the driver by using the IP configured in the WebGUI of the Device or the Fallback-IP of the Device (make sure to adjust your network-settings accordingly) e.g:

$ ros2 run blickfeld_driver blickfeld_driver_node --ros-args -p host:=cube-0175 --remap __node:=bf_lidar

You can also start it with more parameters, e.g.:

$ ros2 run blickfeld_driver blickfeld_driver_node --ros-args -p host:=cube-0175 -p publish_ambient_light:=true -p publish_intensities:=false

To visualize the published data, run rviz2

$ ros2 run rviz2 rviz2

If you prefer a similar way to launch, like you would in ROS(1) (beware of the new “.xml”), you can start the driver like this:

$ ros2 launch -a blickfeld_driver live_scanner.launch.xml host:=cube-0175

Or if you prefer to put the parameters into a yaml, run the python launch file. It reads the two yaml file containing the configurations.

$ ros2 launch blickfeld_driver live_scanner_yaml.launch.py

The yaml files are located in the ros2_blickfeld_driver/config folder of the blickfeld_driver package. There are two yaml files:

  1. driver_config.yaml

    Configures host id, output point cloud topic etc.

  2. blickfeld_scanner.rviz

    Configures the parameters for Rviz visualization, e.g. topic of point cloud, configuration of opened viewers etc.

Parameters

All the following parameters are available in launch and run:

Argument Default Note
host (required) The host name or the IP of the device you want to publish the point clouds from, e.g., cube-0175.
lidar_frame_id lidar The ROS TF where the point cloud should be in.
node_name bf_lidar Name of this ROS node.
remap true Remap this node’s input/output topics to commonly used ones.
If false, canonical names in the form of $(arg node_name)/foo*(in/out)are used, depending on whether a topic is an input or and output topic.
rviz false Start rviz if this argument is true.
publish_ambient_light false Set to true if the PointCloud2 message should contain the ambient light level.
publish_explicit_range false Set to true if the PointCloud2 message should contain therange field.
publish_intensities true Set to true if the PointCloud2 message should contain intensities.
publish_no_return_points false Set to true if the PointCloud2 message should contain points in a given range for pulses without a return.
publish_point_id false Add the scanline_id field, the scanline_point_index field (= the point’s number in the scan line), and the point_id (= frame-global point ID) to PointCloud2 message.
If the device is configured to return multiple return points (multiple reflections), all these three IDs will be identical; only the return_id will differ.
publish_point_time_offset false If true, the PointCloud2 message will contain the timestamp field per point to represent the time offset from the start of the frame.
no_return_point_range 1.0 Dummy range for points of pulses without a return.
returns_publishing_options strongest different options to publish multiple returns, possible values are: strongest closest farthest and all, in case of all, the field return_id (ID for each returned point) is added to the point cloud.
projection_type angle_preserving different options to project the data onto a 2D image, possible values are: angle_preserving or scanline_preserving. These indicate if a correct spehrical projection is desired, or each row of the image should correspond to one scanline.
publish_ambient_image false Enables publishing of am ambient light image.
publish_intensity_image false Enables publishing of an intensity image.
publish_range_image false Enables publishing of a range image.
publish_imu false Enables publishing of IMU data in burst mode.
publish_imu_static_tf_at_start false Call "Publish IMU tf transform" service once at the beginning.
use_lidar_timestamp true Set to true if the timestamp in the ROS point cloud message should be generated from the device timestamp; otherwise the timestamp will be the ROS time when the frame was received on ROS.
use_background_subtraction false Enables on-device background subtraction.
use_neighbor_filter false Enables on-device neighbor filter.
background_subtraction_exponential_decay_rate 0.005 Controls how fast objects switch between foreground and background. Exponential decay factor.
background_subtraction_num_initialization_frames 10 Number of frames to initialize the background with.
ambient_image_out $(arg node_name)/ambient_image_out Topic to publish the ambient image on.
diagnostic_out $(arg node_name)/diagnostic Topic to publish the diagnostic status.
imu_out $(arg node_name)/imu Topic to publish the IMU burst data.
intensity_image_out $(arg node_name)/intensity_image_out Topic to publish the intensity image on.
point_cloud_out $(arg node_name)/points_raw Topic to publish the PointCloud2 message to.
range_image_out $(arg node_name)/range_image_out Topic to publish the range image on.

Debugging

Add ‘__log_level:=debug’ to see details:

$ ros2 run blickfeld_driver blickfeld_driver_node --ros-args --remap __node:=bf_lidar -p host:=cube-0175 -p publish_ambient_light:=true -p publish_no_return_points:=true __log_level:=debug

ROS2 message content

To look at the ROS message sent by this ROS node, you can use

$ debugging_tools/ros2-topic-echoparsed.py

It shows all the fields present in the message.

Services

The Blickfeld ROS2 driver advertises different services. For service call change the default DDS from FastRTPS.

Set scan pattern

Before running, ensure that your colcon workspace is sourced. This service call will set scan pattern on a device.

e.g. ros2 service call /$(arg node_name)/set_scan_pattern blickfeld_driver/srv/SetScanPattern "{fov_horizontal: 72.0, fov_vertical: 30.0, angle_spacing: 0.4, scanlines_up: 28, scanlines_down: 28, frame_mode: 'COMBINE_UP_DOWN', pulse_type: 'INTERLEAVE'}"

Publish IMU tf transform

This service call will receive the static IMU data from device and creates a frame from the data with the frame_id $(arg lidar_frame_id)_imu.

ros2 service call /$(arg node_name)/publish_imu_static_tf_service blickfeld_driver/srv/ImuStaticTransformation

License

This package is released under a BSD 3-Clause License (see also https://opensource.org/licenses/BSD-3-Clause)