tango_tracker

ROS package using opencv to track a wheeled robot using fiducial markers.

• tango_tracker
  • Nodes
    • tango_tracker.py
      • Subscribes:
      • Publishes:
      • Parameters:
      • Usage:
  • Setup
  • Launch Files
    • tracker_debug
      • Arguments

Nodes

tango_tracker.py

Detects ARUCO-5x5-50 markers in each message from the color image input and publishes their location.

All input images are scaled to height = 500px, keeping constant aspect ratio. Current camera images will end up with h=500px w=888px.

Subscribes:

• /camera/color/image_raw (sensor_msgs.Image): Color image input

Publishes:

• /orientation_2d (std_msgs.Int8): Angle of marker in degrees, where 0 is right on the x axis, increasing counter-clockwise
• /position_2d (geometry_msgs.Point): Image X and Y coordinates of the robot. Z is always zero
• /px_scale (std_msgs.Float32): Estimated image scale for this frame, in cm/px
• /debug/final_img (sensor_msgs.Image): Resultant debug image showing detected markers

Parameters:

• ~show_ui (boolean, Optional): If True, show the opencv tracking UI for debugging. Defaults to false
• ~robot_arucoID (int, Optional): ID of the Aruco marker on the robot. Defaults to selecting the lowest Aruco marker ID in the frame
• ~marker_size (float): Measurement in centimeters of aruco marker width/height
• ~debug_video (boolean, Optional): If true, output video file of annotated debug frames to ~video_location. Defaults to false
• ~video_location (str, Optional): directory and filename of debug file. Filetype should be '.avi'. Defaults to '~/DebugVideo.avi'

Usage:

To track the robot: rosrun tango_tracker tango_tracker.py

To track the robot and show the debug UI: rosrun tango_tracker tango_tracker.py _show_ui:=True

To track the robot with a specific marker ID: rosrun tango_tracker tango_tracker.py _robot_arucoID:=<marker_id>

Setup

Place contents of repository in the directory <ros_workspace_dir>/src/tango_tracker. Build and source your ROS workspace.

Launch Files

tracker_debug

Example usage:

roslaunch tango_tracker tracker_debug.launch marker_size:=5 rosbag_path:="/home/rose/Documents/TangoProject/2022-06-06-14-05-29.bag"

Arguments

• marker_size (float): Measuerment in centimeters of aruco marker width/height
• rosbag_path (str): Absolute path to a rosbag containing the /camera/color/raw_image topic