Question about test_laser_assembler.launch

[kolohe113]

Hi! I am trying to make a 3d pointcloud from a spinning 2D LiDAR and feed it to Rtabmap by using laser_assembler. I notice there is a test_laser_assembler which has what I wanted. However, I do not understand why add in this:

 
  <node type="depthimage_to_laserscan" pkg="depthimage_to_laserscan" name="depthimage_to_laserscan">
    <remap from="image"       to="$(arg depth_topic)"/>
    <remap from="camera_info" to="$(arg camera_info_topic)"/>
  </node>

From my understanding, Rtabmap cannot subscribe to both scan and scan_cloud at the same time. Why do we need to add a laserscan in tis case?

Thank you

[matlabbe]

In this case, we simulated a laser scan from the camera just for convenience (so we can test the code with only a camera). You don't need it if you have a lidar.