Dependable coding of fiducial tags

Abstract

Fiducial tags can be recognised successfully and decoded by computer vision systems in order to produce location information. We term a system dependable if its observable results are predictable and repeatable. The dependability of such a vision system is fundamentally dependent on the scheme used to encode data on the tag. We show that the rotational symmetry common to many tag designs requires particular consideration in order to understand the performance of the coding schemes when errors occur. We develop an abstract representation of tags carrying symbolic data which allows existing information coding techniques to achieve robust codes. An error-correcting coding scheme is presented for carrying arbitrary symbolic data in a dependable vision system. © Springer-Verlag Berlin Heidelberg 2005.