This is a Robot Operating System (ROS) wrapper of the AprilTags 2 visual fiducial detector. For details and tutorials, please see the ROS wiki.

Authors: Danylo Malyuta
Maintainer: Danylo Malyuta, [email protected]
Affiliation: NASA Jet Propulsion Laboratory, California Institute of Technology

Pull requests are welcome! Especially for the following areas:

• Publishing of the AprilTag 2 algorithm intermediate images over a ROS image topic (that AprilTag 2 already generates when tag_debug==1)
• Conversion of the bundle calibration script from MATLAB to Python
• Extend calibration to support calibrating tags that cannot appear simultaneously with the master tag, but do appear simultaneously with other tags which themselves or via a similar relationship appear with the master tag (e.g. a bundle with the geometry of a cube - if the master is on one face, tags on the opposite face cannot currently be calibrated). This is basically "transform chaining" and potentially allows calibration of bundles with arbitrary geometry as long as a transform chain exists from any tag to the master tag
• Replacement of AprilTag 2 core algorithm's usage of custom linear algebra and image processing functions with Boost and OpenCV
• Supporting multiple tag family detection (currently all tags have to be of the same family). This means calling the detector once for each family. Because the core AprilTag 2 algorithm is the performance bottleneck, detection of n tag families will possibly decrease performance by 1/n

The source code in apriltags2/ is wholly the work of the APRIL Robotics Lab at The University of Michigan. This package simply rearranges the source code to be able to compile it with catkin.

The source code in apriltags2_ros/ is original code that is the ROS wrapper itself, see the LICENSE. It is inspired by apriltags_ros and provides a superset of its functionalities.

If you use this code, please kindly cite:

• D. Malyuta, “Navigation, Control and Mission Logic for Quadrotor Full-cycle Autonomy,” Master thesis, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109, USA, December 2017.
• J. Wang and E. Olson, "AprilTag 2: Efficient and robust fiducial detection," in ''Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)'', October 2016.

@mastersthesis{malyuta:2017mt,
  author = {Danylo Malyuta},
  title = {{Guidance, Navigation, Control and Mission Logic for Quadrotor Full-cycle Autonomy}},
  language = {english},
  type = {Master thesis},
  school = {Jet Propulsion Laboratory},
  address = {4800 Oak Grove Drive, Pasadena, CA 91109, USA},
  month = dec,
  year = {2017}
}
@inproceedings{Wang2016,
  author = {Wang, John and Olson, Edwin},
  booktitle = {2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
  doi = {10.1109/IROS.2016.7759617},
  isbn = {978-1-5090-3762-9},
  month = {oct},
  pages = {4193--4198},
  publisher = {IEEE},
  title = {{AprilTag 2: Efficient and robust fiducial detection}},
  year = {2016}
}