Re: Issue Getting Map from Rtabmap

Posted by matlabbe on
URL: http://official-rtab-map-forum.206.s1.nabble.com/Issue-Getting-Map-from-Rtabmap-tp6068p6072.html

Hi,

For rgbd_odometry, I would choose between the nodelet version or not, to avoid confusion between both (they even have different parameters). As you are doing fusion of odometry, make sure to disable publish_tf from rgbd_odometry node to avoid conflict with tf published by robot_localization for example.

<!-- under rgbd_odometry node -->
<param name="publish_tf" value="false"/>

I don't recommend synchronizing all those topics together:

<remap from="odom"      	  to="/odom1"/>
<remap from="scan_cloud"        to="/velodyne_points"/>
<remap from="depth/image"       to="/camera/aligned_depth_to_color/image_raw"/>
<remap from="rgb/camera_info"   to="/camera/color/camera_info"/>
<remap from="rgb/image"         to="/camera/color/image_raw"/>

Like in the examples on this page, use rgbd_sync nodelet if you are synchronizing images with a lidar or external odometry (not synced with images). In your case, it would look like this:

    <!-- Use RGBD synchronization -->
    <!-- Here is a general example using a standalone nodelet, 
         but it is recommended to attach this nodelet to nodelet 
         manager of the camera to avoid topic serialization -->
    <node pkg="nodelet" type="nodelet" name="rgbd_sync" args="standalone rtabmap_ros/rgbd_sync" output="screen">
      <remap from="rgb/image"       to="/camera/color/image_raw"/>
      <remap from="depth/image"     to="/camera/aligned_depth_to_color/image_raw"/>
      <remap from="rgb/camera_info" to="/camera/color/camera_info"/>
      <remap from="rgbd_image"      to="rgbd_image"/> <!-- output -->

      <!-- Should be true for not synchronized camera topics 
           (e.g., false for kinectv2, zed, realsense, true for xtion, kinect360)-->
      <param name="approx_sync"       value="false"/> 
    </node>

    <node name="rtabmap" pkg="rtabmap_ros" type="rtabmap" output="screen" args="--delete_db_on_start">
          <param name="frame_id" type="string" value="base_link"/>

          <param name="subscribe_depth" type="bool" value="false"/>
          <param name="subscribe_rgbd" type="bool" value="true"/>
          <param name="subscribe_scan_cloud" type="bool" value="true"/>

          <remap from="odom" to="/odom1"/>
          <remap from="scan_cloud" to="/velodyne_points"/>
          <remap from="rgbd_image" to="rgbd_image"/>

          <param name="queue_size" type="int" value="10"/>
          <param name="approx_sync" type="bool" value="true"/>

          <!-- RTAB-Map's parameters -->
          <param name="RGBD/NeighborLinkRefining" type="string" value="true"/>
          <param name="RGBD/ProximityBySpace"     type="string" value="true"/>
          <param name="RGBD/AngularUpdate"        type="string" value="0.01"/>
          <param name="RGBD/LinearUpdate"         type="string" value="0.01"/>
          <param name="RGBD/OptimizeFromGraphEnd" type="string" value="false"/>
          <param name="Grid/FromDepth"            type="string" value="false"/> <!-- occupancy grid from lidar -->
          <param name="Reg/Force3DoF"             type="string" value="true"/> <!-- 2D mapping? -->
          <param name="Reg/Strategy"              type="string" value="1"/> <!-- 1=ICP -->
          
          <!-- ICP parameters -->
          <param name="Icp/VoxelSize"                 type="string" value="0.2"/>
          <param name="Icp/MaxCorrespondenceDistance" type="string" value="0.2"/>
    </node>

Note that approx_sync should be true for rtabmap node, as velodyne and camera topics would not be exactly synchronized. This is probably the reason why the map was empty (though I am surprised you didn't have warnings about rtabmap not receiving topics...).

cheers,
Mathieu