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Hello, I have an rtabmap setup with:

  • Stereo camera for mapping with rtab
  • Wheel odometry only

In simulation and also real life I am getting incorrect loop closure that seem to mess up a good map. Is there any obvious stuff I'm doing wrong here?

Here is my rtabmap launch file:

    <node name="rtabmap" pkg="rtabmap_ros" type="rtabmap" output="screen" 
        args="--delete_db_on_start">


    <remap from="left/image_rect"   to="/stereo1/left/image_rect_color"/>
    <remap from="right/image_rect"  to="/stereo1/right/image_rect"/>
    <remap from="left/camera_info"  to="/stereo1/left/camera_info"/>
    <remap from="right/camera_info" to="/stereo1/right/camera_info"/>

    <param name="subscribe_stereo"      type="bool"     value="true"/>
    <param name="subscribe_depth"       type="bool"     value="false"/>
    <param name="approx_sync"           type="bool"     value="true"/>
    <param name="frame_id"              type="string"   value="base_link"/>
    <param name="grid_size"             type="double"   value="100"/>

    <param name="queue_size"            type="int"      value="30"/>

    <!-- all points below 20 cm are ground -->
    <param name="Grid/MaxGroundHeight"  type="string"   value="0.5"/>       

    <!-- all points above 20 cm and below 2 m are obstacles -->
    <!-- <param name="Grid/MaxObstacleHeight" type="string" value="3"/>        -->

    <!-- Use simple passthrough to filter the ground instead of normals segmentation -->
    <!-- <param name="Grid/NormalsSegmentation" type="string" value="false"/>  -->

    <!-- RTAB-Map's parameters -->
    <param name="Rtabmap/TimeThr"                   type="string"   value="700"/>
    <param name="Rtabmap/DetectionRate"             type="string"   value="1"/>
    <param name="Kp/MaxFeatures"                    type="string"   value="200"/>
    <param name="Kp/RoiRatios"                      type="string"   value="0.03 0.03 0.04 0.04"/>
    <param name="Kp/DetectorStrategy"               type="string"   value="0"/>
    <!-- use SURF -->
    <param name="Kp/NNStrategy"                     type="string"   value="1"/>
    <!-- kdTree -->
    <param name="SURF/HessianThreshold"             type="string"   value="1000"/>
    <!-- 3D->2D (PnP) -->
    <param name="RGBD/OptimizeFromGraphEnd"         type="string"   value="true"/>
    <param name="RGBD/LoopClosureReextractFeatures" type="string"   value="true"/>
    <param name="Grid/MaxGroundHeight"              type="double"    value="0.18"/>

    <param name="Vis/MinInliers"                    type="string"   value="10"/>
    <param name="Vis/InlierDistance"                type="string"   value="0.1"/>
    <param name="Viz/EstimationType"                type="int"      value="1"/>
    <param name="Vis/MaxFeatures"                   type="int"      value="1000"/>

    <!-- http://bit.ly/2wdXVtj -->

    <!-- Adding a despeckler -->
    <param name="Stereo/WinWidth"                   type="int"      value="15"   />
    <param name="Stereo/WinHeight"                  type="int"      value="3"    />
    <param name="Stereo/Iterations"                 type="int"      value="30"   />
    <param name="Stereo/MaxLevel"                   type="int"      value="3"    />
    <param name="Stereo/MinDisparity"               type="int"      value="1"    />
    <param name="Stereo/MaxDisparity"               type="int"      value="128"   />
    <param name="Stereo/OpticalFlow"                type="bool"     value="False" />
    <param name="Stereo/SSD"                        type="bool"     value="true" />
    <param name="Stereo/Eps"                        type="double"   value="0.01" />

    <param name="StereoBM/BlockSize"                type="int"      value="15"  /> 
    <param name="StereoBM/MinDisparity"             type="int"      value="0"   />
    <param name="StereoBM/NumDisparities"           type="int"      value="128"  />
    <param name="StereoBM/PreFilterSize"            type="int"      value="9"   />
    <param name="StereoBM/PreFilterCap"             type="int"      value="31"  />
    <param name="StereoBM/UniquenessRatio"          type="int"      value="15"  />
    <param name="StereoBM/TextureThreshold"         type="int"      value="2500"  />
    <param name="StereoBM/SpeckleWindowSize"        type="int"      value="1000" />
    <param name="StereoBM/SpeckleRange"             type="int"      value="4"   />

A video of the problem: https://youtu.be/tjO-dYugKbw

PS: This might be a simple issue having to do with my simulation cause the ground is very similar everywhere.

Thanks!


Originally posted by psammut on ROS Answers with karma: 258 on 2017-09-25

Post score: 0

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1 Answer 1

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Visually, the loop closure is good, but it is not the same location. This is a common problem with simulated environments with repetitive textures. Try decreasing RGBD/OptimizeMaxError parameter (default 1 meter) to something like 0.1 meter or less. This will make rtabmap rejecting loop closures that screw up too much the map.

<param name="RGBD/OptimizeMaxError"                type="double"      value="0.1"  /> 

Originally posted by matlabbe with karma: 6409 on 2017-09-26

This answer was ACCEPTED on the original site

Post score: 2


Original comments

Comment by psammut on 2017-09-26:
Mathieu with prompt and correct answers saves the day! I owe you so many beers man.

Thanks!

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