April Tags#

Learning Objectives#

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

Getting Started#

Prerequisites

Detect April Tags#

  • Open the April Tag example by going to Window > Examples > Robotics Examples, and then click on the Robotics Examples tab and expand the sections on the left hand side and open the example: 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 <noetic_ws>/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

Summary#

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

Next Steps#

Continue on to the next tutorial in our ROS Tutorials series.

Further Learning#

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