laser_filters LaserScanRangeFilter not publishing

edit

I'm trying to use the LaserScanRangeFilter to remove points that are far away. However, nothing is published on the topics it should be mapping to.

Here is my laser_filter_config.yaml:

scan_filter_chain:
  - name: range
    type: laser_filters/LaserScanRangeFilter
    params:
      use_message_range_limits: false
      lower_threshold: 0.0
      upper_threshold: 2.0
      lower_replacement_value: -.inf
      upper_replacement_value: .inf

Here is my launch file (I am using the Autonomous Research Kit provided by Clearpath for the Husky robot):

<launch>
  <!-- We want to wait for the ARK to start up, so we don't run right away -->
  <arg name="node_start_delay" default="4.0" />  
  <arg name="route" default="$(dirname)/../config/route.json"/>

  <!-- Start the ARK navigation server -->
  <include file="$(find husky_cpr_ark_navigation)/launch/husky_ark_navigation.launch">
      <arg name="front_laser" value="/front/scan_processed"/>
      <arg name="rear_laser" value="/rear/scan_processed"/>
  </include>

  <node pkg="laser_filters" type="scan_to_scan_filter_chain" output="screen"
      name="laser_filter">
    <rosparam command="load" file="$(dirname)/../config/laser_filter_config.yaml" />
    <remap from="/front/scan" to="/front/scan_processed" />
    <remap from="/rear/scan" to="/rear/scan_processed" />
  </node>
</launch>

I can do rostopic echo /front/scan and rostopic echo /rear/scan and I see the lidars are generating data, but nothing appears when I do rostopoic echo /front/scan_processed or rostopoic echo /rear/scan_processed.

I also looked at rqt_graph and there is nothing going in or out of the laser_filter node.

I would really appreciate any advice.