ArUco Fractal Tracker

This ROS2 package is designed to detect and estimate the pose of ArUco fractal markers.

Features

• Detects ArUco fractal markers in images.
• Estimates the pose of detected markers with respect to a camera frame.
• Publishes the marker pose as a geometry_msgs::msg::PoseStamped.
• Broadcasts the transform from the camera frame to the marker frame using TF.

Installation

Prerequisites

• ROS2: Make sure you have ROS2 installed on your system. This package has been tested with ROS2 Foxy, but it should work with other ROS2 distributions as well.
• OpenCV: For image processing.
• ArUco Library: Required for marker detection.

Building

1. Clone this repository into your ROS2 workspace:

   cd <your_workspace>/src
   git clone https://github.com/dimianx/aruco_fractal_tracker.git

2. Navigate to the workspace root and build the package:

   cd <your_workspace>
   colcon build

3. Source your workspace:

   source <your_workspace>/install/setup.bash

Usage

Running the Node

To run the ArUco Fractal Tracker node, use the following command:

ros2 run aruco_fractal_tracker aruco_fractal_tracker_node --ros-args -p marker_configuration:=<path_to_marker_config> -p marker_size:=<marker_size> -p cam_params_file:=<path_to_cam_params> --remap image_input_topic:=<your_camera_image_topic> --remap image_output_topic:=<where_to_output_processed_image> --remap poses_output_topic:=<where_to_publish_marker_pose>

Parameters

• marker_configuration (string): The configuration file for the ArUco fractal markers.
• marker_size (double): The size of the marker in meters.
• cam_params_file (string): The camera parameters file (in YAML format).

Topics

The node uses the following topics:

• image_input_topic (input): The topic from which the node subscribes to images for processing.
• image_output_topic (output): The topic on which the node publishes images with detected markers and pose information.
• poses_output_topic (output): The topic on which the node publishes the pose of the detected marker as a geometry_msgs::msg::PoseStamped.

Example Marker

An example ArUco fractal marker configuration is provided in the example_marker folder. This folder contains both the marker image and configuration file necessary for testing the node. To use this example marker:

1. Navigate to the example_marker folder.
2. Print out the marker image (marker.png) and place it in the camera's field of view.
3. Use the provided configuration file (marker_configuration.yaml) to run the node.

References

• Romero-Ramire, Francisco J., Rafael Munoz-Salinas, and Rafael Medina-Carnicer. "Fractal markers: A new approach for long-range marker pose estimation under occlusion." IEEE Access 7 (2019): 169908-169919.