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RGB-D Handheld Mapping

Description: This tutorial shows how to use rtabmap_ros out-of-the-box with a Kinect-like sensor in mapping mode or localization mode.

Tutorial Level: BEGINNER

Next Tutorial: Stereo Handheld Mapping

RGB and depth sensors

The RGB-D sensors which are OpenNI and OpenNI2 compliant would work out-of-the-box using openni_launch, openni2_launch, freenect_launch, iai_kinect2 or Zed packages. Sensors tested:

Mapping mode

There are two choices for online visualization: rtabmapviz or rviz. With the RVIZ plugin rtabmap/MapCloud, the clouds can be incrementally added to RVIZ. However using rtabmapviz, the interface should look like the tutorials of the standalone version. With the launch file rtabmap.launch below, set rviz:=true to open rviz and rtabmapviz:=true to open rtabmapviz (default true) for visualization.

The rtabmap argument "--delete_db_on_start" is used to start mapping from a clean database. You can also reset the memory from rtabmapviz using the action "Edit->Delete memory", or by using this service :

You should see something like this:

RGB-D Mapping

Use external odometry

If you want to use external odometry (e.g., you want to use odometry from your robot), you can set these arguments: "visual_odometry:=false odom_topic:=/my_odometry".

Where is the map saved?

~/.ros/rtabmap.db

RTAB-Map provides a tool to browse data in the database:

$ rtabmap-databaseViewer ~/.ros/rtabmap.db

Localization mode

In localization mode, a map large enough (>30 locations) must be already created (using rgbd_mapping.launch above).

In rtabmapviz (GUI), click on "Localization" in the "Detection" menu. By looking over locations in the map, RTAB-Map would localize itself in it by finding a loop closure. Once a loop closure is found, the odometry is corrected and the current cloud will be aligned to the map.

You can play with the relocation behaviour by resetting the odometry. You can use form the GUI the Detection->"Reset odometry" action or call the service on the terminal like:

Advanced

You can also start the launch file above directly in Localization mode with a previously built database. Set the parameter "Mem/IncrementalMemory" to "false". Also, when starting the rtabmap node, the argument "--delete_db_on_start" must not be set!

Since recent versions, rtabmap.launch has "localization" argument for convenience:

In the GUI, do Edit->"Download map" to download the map from the rtabmap node. At the start, you should see that the current displayed cloud is not aligned to the map, it is normal because the odometry is reset on each start. By looking over locations in the map, RTAB-Map would localize itself in it by finding a loop closure. Once a loop closure is found, the odometry is corrected and the map will appear with the current cloud aligned to it.


2019-07-20 13:12