In order to solve the problem that the relative orientation between depth camera and inertial measurement unit is difficult to measure directly

a non-contact calibration method based on the construction of displacement vectors by sensing the same hand motion is proposed to compute the relative orientation. Firstly

the relative orientation calibration problem of a depth camera and an inertial measurement unit with time-varying pose relationship is described and analyzed. Then the depth camera and the inertial measurement unit are used to simultaneously capture the movement of a hand swinging in arbitrary direction in the space

to construct displacement vectors. Finally

leveraging these displacement vectors

a model is built up based on the rotation invariance principle of a rigid body

and then solved with the least square method to obtain the calibration result. To verify the accuracy and effectiveness of the proposed method

in the one hand

a comparison between the measured data and the white noise simulation data is conducted. The simulation result shows that the relative orientation deviation after calibration is less than ±4°. On the other hand

an experiment to capture the human arm motion with a depth camera and an inertial measurement unit is also conducted. The experimental result shows that parameters of the human arm could be only correctly reflected after calibration. The calibration method presented in this paper is simple in principle

easy to operate

and without requirement of contact measurement or other auxiliary equipment

which is applicable to sensor calibration in scenarios such as robot remote control and motion sensing games.