This project is a ROS wrapper for the EPFL's chilitags library.

The chilitags C++ library is a robust and lightweight library for detection of fiducial markers.

Main features:

• recognizes up to 1024 markers simultaneously in a scene,
• has a focus on robustness to bad light conditions,
• provides (filtered) 6D localization of the markers,
• supports objects with multiple markers (with increased robustness),
• OpenCV (>=2.3) is the only dependency.

This ROS node wraps the chilitags library to use the standard ROS mechanisms: images and camera calibration are read from a standard ROS camera, and 6D position of markers are published as TF transforms.

The most basic usage is:

$ rosrun ros_markers detect image:=/camera/image_raw

This will start to look for markers in the image stream, and publish the TF transformation of the detected ones.

The provided launch file list all the available parameters. The most important one is the markers configuration. This (YAML) file describes where are the markers on your objects, and let you publish the position of an object with multiple markers attached. See the sample configuration for a complete example.

• This project is very similar to ROS ALVAR. ALVAR has a broader scope (like support for integration with depth maps), but it is also heavier. Benchmarks have yet to be conducted.
• The standard (but much older) tool is ARToolkit. It also has ROS bindings.