  In this work, we present an approach for monocular hand-eye calibration from
per-sensor ego-motion based on dual quaternions. Due to non-metrically scaled
translations of monocular odometry, a scaling factor has to be estimated in
addition to the rotation and translation calibration. For this, we derive a
quadratically constrained quadratic program that allows a combined estimation
of all extrinsic calibration parameters. Using dual quaternions leads to low
run-times due to their compact representation. Our problem formulation further
allows to estimate multiple scalings simultaneously for different sequences of
the same sensor setup. Based on our problem formulation, we derive both, a fast
local and a globally optimal solving approach. Finally, our algorithms are
evaluated and compared to state-of-the-art approaches on simulated and
real-world data, e.g., the EuRoC MAV dataset.
