13. April Tags

13.1. Learning Objectives

In this example, we show how to detect April Tags in a scene.

Prerequisites

13.2. Detect April Tags

  • Open the April Tag example by going to Isaac Examples -> ROS -> April Tag. Three April Tags will show up in the viewport.

  • Open up the Stage Tree, and then open the ActionGraph by right-clicking on the prim and selecting Open Graph. The ROS Clock publisher, TF publisher and Camera Helper nodes (for initiating the camera_info and rgb image publishers) should already be setup.

  • Press Play to start publishing data to ROS

../_images/isaac_ros_apriltag.png
  • In a new terminal with your ROS environment sourced, run roslaunch isaac_tutorials apriltag_continuous_detection.launch to run the april_tag detection node.

  • In a new terminal with your ROS environment sourced, run rviz -d ros_workspace/src/isaac_tutorials/rviz/apriltag_config.rviz to start rviz and show the detections from the camera image

  • To see the raw data for the detected tags run rostopic echo tag_detections

../_images/isaac_ros_apriltag_rviz.png

13.3. Summary

This tutorial shows the basics of detecting April Tags in Omniverse Isaac Sim.

13.3.1. Next Steps

Continue on to the next tutorial in our ROS Tutorials series, Docker April Tags Detection to learn how to run a ROS docker container with Omniverse Isaac Sim.

13.3.2. Further Learning