depth_image_to_laserscan not publishing to /kinect_scan topic in ROS2 Galactic

Question

Hello,

I am trying to convert a depth image to a laser scan using the depthimage_to_laserscan package in ROS2 Galactic, but I am having trouble getting the node to publish the converted LaserScan data. Despite being able to subscribe to the input depth image topic (/kinect_sensor/depth/image_raw), the node doesn't seem to be publishing the converted data to the /kinect_scan topic. Or the node is not properly doing its task: converting the data...

Here's the launch file snippet for the depthimage_to_laserscan node:

Kinect depthimage to laserscan conversion node

depthimage_to_laserscan_node = Node(
    package='depthimage_to_laserscan',
    executable='depthimage_to_laserscan_node',
    name='depthimage_to_laserscan',
    parameters=[kinect_params_file, {'use_sim_time': use_sim_time}],
    remappings=[('depth', '/kinect_sensor/depth/image_raw'),
                ('scan', '/kinect_scan')],
    output='screen')

And my kinect_params.yaml file:

depthimage_to_laserscan_node:
  ros__parameters:
    output_frame: kinect_depth_frame
    scan_height: 1
    range_min: 0.45
    range_max: 10.0
    scan_topic: /kinect_scan

When I inspect the /depthimage_to_laserscan node using ros2 node info, it shows that the node subscribes to /kinect_sensor/depth/image_raw and publishes to /kinect_scan. However, when I echo the /kinect_scan topic, it is empty and produces no output.

Here is a LINK to a video demonstrating the issue.

I have already tried changing the scan_topic to the original /scan topic in the parameter file and have also checked that the frame_id in the header of the depth image messages is consistent with the output_frame parameter, but these didn't solve the issue.

Could anyone please help me to understand what might be going wrong and how to get the depthimage_to_laserscan node to publish the LaserScan data correctly?

I am facing a similar issue and behavior using other packages image-proc, as related here: https://github.com/ros-perception/image_pipeline/issues/832

Thank you in advance for your help.

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Originally posted by Vini71 on ROS Answers with karma: 266 on 2023-07-25

Post score: 0

Answer 1

Solving QoS mismatch and compatibility issues when compiling depthimage_to_laserscan package for ROS2 Galactic

The depthimage_to_laserscan package on the ros2 branch is not directly compatible with ROS2 distributions Galactic or later due to dependency errors related to image_geometry and rclcpp_components. Changes in the ROS2 API cause these errors.

One solution is to compile the foxy-devel branch instead, which has been adapted to newer API changes and is confirmed to build successfully in Galactic. These modifications can be analyzed by comparing the ros2 and foxy-devel branches, as shown in this comparison link.

However, even with these modifications, an additional problem can arise when running the nodes: mismatched the Quality of Service (QoS) settings for the depth camera plugin and the depthimage_to_laserscan package.

The default Gazebo camera plugin publishes data with a "Best Effort" reliability policy, but the depthimage_to_laserscan package expects a "Reliable" QoS setting. This mismatch can be diagnosed by examining the QoS settings of the publishers and subscribers in the ROS system:

 ros2 topic info -v /camera/depth/image_raw or 

or

 ros2 topic info -v /depthimage_to_laserscan/scan

Type: sensor_msgs/msg/LaserScan

Publisher count: 1

Node name: depthimage_to_laserscan
Node namespace: /
Topic type: sensor_msgs/msg/LaserScan
Endpoint type: PUBLISHER
GID: 92.e2.10.01.7d.66.f8.f5.48.6d.4b.b3.00.00.17.03.00.00.00.00.00.00.00.00
QoS profile:
  Reliability: RELIABLE
  Durability: VOLATILE
  Lifespan: 9223372036854775807 nanoseconds
  Deadline: 9223372036854775807 nanoseconds
  Liveliness: AUTOMATIC
  Liveliness lease duration: 9223372036854775807 nanoseconds

Subscription count: 1

Node name: rviz
Node namespace: /
Topic type: sensor_msgs/msg/LaserScan
Endpoint type: SUBSCRIPTION
GID: e7.0b.10.01.a6.72.90.06.d0.aa.e8.d8.00.00.62.04.00.00.00.00.00.00.00.00
QoS profile:
  Reliability: BEST_EFFORT
  Durability: VOLATILE
  Lifespan: 9223372036854775807 nanoseconds
  Deadline: 9223372036854775807 nanoseconds
  Liveliness: AUTOMATIC
  Liveliness lease duration: 9223372036854775807 nanoseconds

After modifying the source code "DepthImageToLaserScanROS.cpp:

DepthImageToLaserScanROS::DepthImageToLaserScanROS(const rclcpp::NodeOptions & options): rclcpp::Node("depthimage_to_laserscan", options){
  // auto qos = rclcpp:: SystemDefaultsQoS(); // Changed because depth camera publisher does not use RELIABLE (default) QoS but BestEffort
  auto qos = rclcpp::QoS(rclcpp::QoSInitialization::from_rmw(rmw_qos_profile_default));
qos.reliability(rclcpp::ReliabilityPolicy::BestEffort);

, the workspace must be rebuilt using colcon build. The change should resolve the QoS mismatch and allow the depthimage_to_laserscan node to successfully subscribe to the depth camera images.

A video displaying this fix working Depth to Scan

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Originally posted by Vini71 with karma: 266 on 2023-07-28

This answer was ACCEPTED on the original site

Post score: 0