Awesome

ROS wrapper for ORB-SLAM3

A ROS wrapper for ORB-SLAM3. The main idea is to use the ORB-SLAM3 as a standalone library and interface with it instead of putting everything in one package.

• Pros:
  • Easy to update the ORB-SLAM3 library (currently in V0.3 Beta).
  • Easy to plug in different variants (and there are many) that are not built for ROS (hopefully).
• Cons:
  • Might be more difficult to spot bugs.
  • Development involves more steps (1. Make changes in ORB-SLAM3 library -> 2. Build ORB-SLAM3 -> 3. Change the ROS-wrapper if necessary -> 4. Test).
  • Might break when dependencies or upstream changes.

Current known limitations

Only works for RGBD node.

Installation

First install ORB-SLAM3 normally with all of its dependencies (any location is fine) then install this package in a catkin build environment.

1. ORB-SLAM3 (original or other variants)

• Install the prerequisites.
• Build and install ORB-SLAM3. Any location is fine (default directory that I use later on is the home folder ~):

cd ~
git clone https://github.com/UZ-SLAMLab/ORB_SLAM3.git ORB_SLAM3
cd ORB_SLAM3
chmod +x build.sh
./build.sh

• Make sure that libORB_SLAM3.so is created in the ORB_SLAM3/lib folder. If not, check the issue list from the original repo and rebuild the package.

2. ORB_SLAM3_ros (this package)

• Clone the package. Note that it should be a catkin build workspace.

cd ~/catkin_ws/src/ # Or the name of your workspace
git clone https://github.com/joeaortiz/ORB_SLAM3_ros.git

• Open CMakeLists.txt and change the directory that leads to ORB-SLAM3 library at the beginning of the file (default is home folder).

cd ~/catkin_ws/src/ORB_SLAM3_ros/
nano CMakeLists.txt

# Change this to your installation of ORB-SLAM3. Default is ~/
set(ORB_SLAM3_DIR
   $ENV{HOME}/ORB_SLAM3
)

• Build the package normally.

cd ~/catkin_ws/
catkin_make

• Unzip the ORBvoc.txt file in the config folder in this package. Alternatively, you can change the voc_file param in the launch file to point to the right folder.

cd ~/catkin_ws/src/ORB_SLAM3_ros/config
tar -xf ORBvoc.txt.tar.gz

• If everything works fine, you can now try the different launch files in the launch folder.

3. How to run

Example with the realsense camera. By default the ORB-SLAM3 is run in RGBD mode. First install the realsense ros wrapper with sudo apt-get install ros-$ROS_DISTRO-realsense2-camera, then you can launch ORB-SLAM3 with:

roslaunch orb_slam3_ros_wrapper run_realsense.launch

Published topic

When running in RGBD mode, the topic /frames is published which is a custom message containing synchronised:

• rgb of type sensor_msg/Image
• depth of type sensor_msg/Image
• pose of type geometry_msgs/Pose