@ljaniec I'm not directly using the turtlebot3_remote.launch , I am trying to make a launch file that runs the laser_filter package to clean up my LiDAR data, I got the idea for the launch file here, as it is specific for the turtlebot3. When I look at the script(scan_to_scan_filter) in said launch file: type="scan_to_scan_filter_chain"., which you can see here. I don't see any node of the name robot_state_publisher here. I always ssh my TB3 and use the command roslaunch turtlebot3_bringup turtlebot3_robot.launch. Im not using ROS2, I use ROS1. Not sure why you say I should ros2 topic list -t .

I wrote the commands too fast and made a mistake, I mainly work with ROS2 now, sorry. I edited the commands - the info will still be useful to pinpoint the problematic node. ROBOTIS launchfile seems fine. Maybe it is a problem with ROS packages? Did you try to do clean & rebuild?

This project has an example launcher with laser_filters, maybe it could help you analyze your case

@ljaniec So I launch my turtlebot3_robot.launch first and then rostopic list and rosnode list. Then I note what info that gives me. In another terminal i launch the file I wanna use for my filter and then rostopic list and rosnode list again?

Yeah, sort of. You want to see where second robot_state_publisher come from.

@ljaniec You were right, launching my_laser_filter launch file activated a node robot_state_publisher, launcing my Rviz also activated a node of same name. This is because of this part of my launch file here:

 <include file="$(find turtlebot3_bringup)/launch/turtlebot3_remote.launch">
    <arg name="model" value="$(arg model)" />
  </include>

When I remove that part it's fine, however, the filter seems to not do anything though. This is my .yaml file. I was informed that the speckle filter was what would help me.

scan_filter_chain:
- name: speckle_filter
  type: laser_filters/LaserScanSpeckleFilter
  params:
    filter_type: 0
    max_range: 4.0
    max_range_difference: 0.1
    filter_window: 2

@ljaniec Do I change the scan topic in Rviz to scan_filtered?

By the example project I linked above you can see that there is a remap indeed:

<node pkg="laser_filters" type="scan_to_scan_filter_chain" name="laser_filter"> <rosparam command="load" file="$(find laser_filters)/turtlebot3_range_filter.yaml"/> <remap from="scan_filtered" to="/laserscan_filtered" /> </node>

I assume with RViz it should be something similar, just check every scan related topic in RViz.

@ljaniec Maybe the parameters I have set in my .yaml file are what the problem is now. I don't even know how to set them. The wiki for this package have a poor explanation for what the parameters are, I don't know what max_range or any of the other parameters are really responsible for.

It was hard to find but not impossible. I edited it in the answer.

@ljaniec the link you gave gives the same explanaition as whats in the wiki. for instance what does "minimum number of neighbors"?

Then you should read it more carefully and try more to understand it??? LaserScanSpeckleFilter - this is a filter that removes speckle points in a laser scan by looking at neighbor points. Read the code with the filter mechanism in mind: this filter removes laser data points which satisfies the following: for all points P1, if there exists a point P2 in (P1 - window, P1 + window) so that (angle(P1, O, P2)) < min_angle or (angle(P1, O, P2)) > max_angle, then remove all datapoint in (P1 - neighbor, P1 + neighbor), where O means the origin of the laser. By computing the angle differences between successive readings and discarding those that don't fit within a user-specified range you should get filtered scan. Parameters tuning is a must there - "Err and err and err again but less and less".

@ljaniec oh thanks! it seems to be working a bit now, but yeah, I think at this point my turtlebot3 might have a hardware issue as well.