C2Tag, a robust and accurate fiducial marker system for image-based localization from challenging images
Our papers on C2Tags has been accepted for publication in CVPR 2016.
C2Tags are a new approach to visual marker tracking that has been designed for localization in challenging environments, such as the film sets in our H2020 project POPART.
Like a few earlier papers, C2Tags consist of concentric rings, whose position in space has been reconstructed before tracking occurs. The new contribution of C2Tags lies in the detection algorithms, which enable it to tolerate considerable partial occlusion and intense motion blur, and still locate and subsequently identify the marker.
For POPART, where we use the C2Tags to track film camera movement on film sets where natural feature detectors fail or faster processing is required, this ability to handle fast motion and occlusion is a major game changer.
Fiducials offer a reliable detection and identification of images of known
planar figures in a view. They are used in a wide range of applications, especially when a reliable reference is needed to, e.g., estimate the camera movement in cluttered or textureless environments.
A fiducial designed for such applications must be robust to partial occlusions, varying
distances and angles of view, and fast camera movements.
In this paper, we present a new fiducial system, whose markers consist of concentric
circles: relying on the their geometric properties, the proposed system
allows to accurately detect the position of the image of the circles’ common center.
Moreover, the different thickness of its rings can be used to encode the information
associated to the marker, thus allowing the univocal identification of the marker.
We demonstrate that the proposed fiducial system can be detected in very
challenging conditions and the experimental results show that it outperforms other recent fiducial systems.