Hi M Harikumar.
Good question! Here is what I have for you.
"The aruco module is based on the ArUco library, a popular library for detection of square fiducial markers developed by Rafael Muñoz and Sergio Garrido:"
Regarding the python, I am certain you may find tutorials on the process on the openCV site.
Fiducial Marker definition: "In computer vision, a fiducial marker is a known object which can be easily identified."