ArUco Fractal Tracker

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

Features

• Detects ArUco fractal marker in images.
• Estimates the pose of detected marker with respect to a camera optical frame.
• Publishes the marker pose as a geometry_msgs::msg::PoseStamped.
• Broadcasts the transform from the camera optical frame to the marker frame using TF.
• Retrieves camera calibration parameters dynamically from a sensor_msgs::msg::CameraInfo topic

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> \
  --remap image_input_topic:=<your_camera_image_topic> \
  --remap image_output_topic:=<output_processed_image_topic> \
  --remap poses_output_topic:=<marker_pose_topic> \
  --remap camera_info_topic:=<your_camera_info_topic>

Note: Replace <path_to_marker_config>, <marker_size>, <your_camera_image_topic>, <output_processed_image_topic>, <marker_pose_topic>, and <your_camera_info_topic> with your actual file path, marker size, and topic names.

Parameters

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

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.

To generate your own marker, see this article: Fractal Markers: a new approach for long-range camera pose estimation under occlusion.

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.