Lissajous MEMS laser scanning with visual-feedback calibration for miniaturized structured-light 3D imaging

Compact 3D vision for robotic and embedded platforms requires structured-light projectors that combine small size, variable pattern generation, and reliable calibration. This paper presents a miniaturized 3D imaging architecture based on Lissajous scanning of a biaxial MEMS mirror, integrating FPGA-controlled laser modulation, image-based visual-feedback calibration, and phase-shifting reconstruction. Unlike approaches requiring an angle sensor integrated with the MEMS mirror, the proposed method extracts projection-position and envelope deviations from images of a predefined reference pattern and compensates accumulated command-phase offsets through temporary drive-frequency perturbations. The resulting system supports focus-free arbitrary-pattern projection and calibration-assisted structured-light imaging within a compact optical architecture. The prototype generates structured-light patterns at 20 frames per second. Experiments on reference standard blocks and plaster models demonstrate calibrated pattern projection and the reconstruction of both planar and complex surface features. For the measured plaster-model dimensions, the relative errors with respect to a commercial laser-line profiler range from 0.89% to 1.50%. By jointly addressing MEMS scan control, projection calibration, and 3D reconstruction, this work provides a practical system-design framework for compact, hardware-efficient MEMS structured-light sensors toward robotic and industrial applications.