Camera tracking using concentric circle markers: Paradigms and algorithms

A C²Tag refers to a set of concentric circles of different radii. C²Tags have been recently introduced in computer vision, in particular for camera calibration, as they offer highly interesting photometric and geometric properties, compared to the classical “checkerboard” tags. In this work, we propose the general paradigm of camera tracking based on a planar marker consisting of at least two C²Tags. All the involved steps are described: detection, identification, 2D reconstruction, calibration and 3D reconstruction. Our contribution is to introduce the following missing steps required to deal with long video sequences under time constraints: key-frame selection, bundle adjustment and intermediate pose refinement.