LeagTag: An Elongated High-Accuracy Fiducial Marker for Tight Spaces *

Fiducial markers enable reliable service robot control. In human-robot coexistence environments, efficient placement of square or circular markers can be challenging due to limited space. In this study, we developed a world-first, elongated fiducial marker, capable of high-accuracy 6-DoF measurements, designed to be installable in tight spaces. We introduced two types of lenticular angle gauges to enhance pose estimation and developed new marker patterns and measurement algorithms to maintain recognition distance and accuracy. The proposed marker achieved a measurement accuracy of 0.1% position error and 0.5° orientation error. This technology will enhance the practicality and applicability of fiducial markers, contributing to the creation of robot-friendly space for future service robots.