A novel calibration method for uniaxial MEMS-based structured light system with linear transition function

In the field of structured light technique, it is a developing trend to use MEMS mirror instead of Digital Light Processing projector as an active light-emitting device with its advantages such as smaller size, reduced power consumption and faster scanning speeds. Given that MEMS mirrors operate as lens-free optical emitters and are limited to projecting uni-axial patterns, the classic pinhole model and projected-checkerboard-based calibration method are infeasible for the MEMS-based structured light system. Thus, the modeling and calibration of the MEMS-based structured light system present a formidable challenge. In this paper, we propose an improved pinhole model by introducing a linear transition function to model MEMS mirrors, along with a novel two-step calibration method to calibrate the system parameters. The proposed model, containing only 32 parameters, simplifies the calibration procedure without compromising accuracy. With no need of the projected checkerboard, the proposed two-step calibration method can acquire the system parameters accurately. In experimental parts, the ablation study on the proposed model and the convergence of the two-step calibration method are discussed firstly. The calibration and reconstruction accuracy based on the proposed model and calibration method are validated by 3D reconstruction of standard and free-from objects quantitatively and qualitatively.