Only released in EOL distros:  

april: april_msgs | april_tags_node | april_test | april_tk | lcm

Package Summary

Wrapper for downloading and installing the April toolkit

ROS package that downloads and build the April Toolkit (

Running standalone tools

There is a convenience wrapper for running standalone tools with the environment variables correctly setup. These instructions mirror the instructions at

Camera Viewer

Since the april_tags_node package subscribes to a ROS image topic for the camera stream, it is not essential for this node to work. However, if you intend to run the standalone tools in the april_tk package, you'll need this viewer to work.

rosrun april_tk execute april.jcam.JCamView

Tag Generation

You can generate families of tags using the Tag Generator. This is necessary if you wish to print out copies of the tags.

mkdir ~/my_tags
rosrun april_tk execute april.tag.TagFamily april.tag.Tag36h11 ~/my_tags/tag36h11

Tag Test

You can run the default Tag Test application to make sure your tag is working. Note that the focal length of the camera as well as the tag size is hard-coded into Tag Test, so the detection might be projected incorrectly.

rosrun april_tk execute april.tag.TagTest --url <cam-url> [--tagfamily <tag-family>]

You can determine cam-url through the Cam Viewer utility. Run Tag Test without any arguments to see the help menu.

Updating the April Toolkit version

This package wrapper downloads a specific revision of the April toolkit for stability reasons (revision eafdf0739 from the april git repository). If you find an upgraded version of the repository to work better, feel free to submit a bug report.

Report a Bug

This package just serves as a wrapper for the APRIL toolkit. If you detect a bug in the wrapper, please report it on the repository page( If you find a bug in the APRIL toolkit, please contact the original developers.

Wiki: april_tk (last edited 2012-08-16 18:52:26 by PiyushKhandelwal)