This ROS package provides URDF models of thin cards with Apriltag textures, plus some example objects with attached Apriltag markers. Adding a few markers to your robots or enviroments allows you to test full vision pipelines based on the Apriltags detector.
All markers of the 16h5 and 36h11 tag families are included; markers of the other families can be generated quickly if needed. The implementation uses a set of 3D collada meshes, each one with the corresponding marker image as its texture. This should work in all recent versions of Gazebo and in rviz, using ROS Kinetic or newer.
A Pioneer and some AprilCubes in Gazebo:
Pioneer robot and AprilCubes in Gazebo
The AprilCubes in rviz:
Clone this repository into your workspace and run catkin_make.
There are no nodes to build.
For a first selftest using Gazebo and rviz for visualization:
roslaunch tams_apriltags apriltag_demo.launch
See the provided april_cube.xacro file for an example on how
to attach (multiple) apriltags to an URDF robot model:
roslaunch tams_apriltags april_cube_demo.launch
See apriltag_marker.xacro for the actual Xacro macro and its parameters.
You can specify marker name, tag family, tag ID, and the marker size by using parameters
"size" and "apriltag_size". In case of specifying both size parameters, the "size" parameter
will be recalculated. At the moment, the macro requires a parent object and generates
the corresponding fixed joint.
Note the use of Python expressions (introduced in ROS Jade) to rewrite the tag family string and to ensure leading zeros for the tag ID. The slightly weird scaling is needed because the master Collada mesh has size (100 x 100 x 0.1) millimeters.
At the moment, only the 16h5 and 36h11 tag families are provided. Don't hesitate to edit and run the provided generation scripts to create additional markers.