by Hiroki Nishino.

This new fiducial tracking method is based on the combination of topological region adjacency and angle information, whereas existing works by Johnston’s RAG target [3], Costanza’s D-Touch [2], and Kaltenbrunner’s reacTIVision [1] are all based on the uniqueness of the topological region adjacency structure.

Such a combination of the topological region adjacency and angle information enables a wider unique ID range, while maintaining the merit of fast and robust fiducial tracking in topology-based approach. Our method makes it possible to obtain the 6 degrees-of-freedom (6DoF). Such problems of a narrow unique ID range and lack of 6DoF information have been the main deficits in most systems based on topological region adjacency approach, when compared to other fiducial tracking methods.


  1. Bencina, R., Kaltenbrunner, M. and Jorda, S. (2005). Improved Topological Fiducial Tracking in the reacTIVision System. Proc of IEEE Procams’05
  2. Costanza, E .and Robinson, J.(2003). A region adjacency tree approach to the detection and design of fiducials, Proc of VVG 2003, pp.63-69
  3. Johnston,D.(2001).UntetheredVR.Ph.Dthesis, University of Essex

H. Nishino, A 6DoF Fiducial Tracking Method Based on Topological Region Adjacency and Angle Information for Tangible Interaction, The Fourth ACM International conference on Tangible Embedded and Embodied Interaction (ACM TEI 2010) , MA, USA, 2010 Jan. pp.253-256