[Zurück]

T. Pintaric:
"An Adaptive Thresholding Algorithm for the Augmented Reality Toolkit";
in: "Proceedings of the Second IEEE International Augmented Reality Toolkit Workshop", IEEE Computer Society Press, Tokyo, Japan, 2003.

It is well known that fixed global thresholds have adverse effects on the reliability of marker-based optical trackers under non-uniform lighting conditions. Mobile Augmented Reality applications, by their very nature, demand a certain level of robustness against varying external illumination from visual tracking algorithms. Currently, ARToolKit depends on fixed-threshold image-binarization in order to detect candidate fiducials for further processing. In an effort to minimize tracking failure due to uniform shadows and reflections off a marker surface, we propose a fast algorithm for selecting adaptive threshold values, based on the arithmetic mean of pixel intensities over a region-of-interest around candidate fiducials.

ARToolKit, Adaptive Thresholding