Modeling and correction of intrinsic nonlinear distortion in polygon-mirror confocal microscopy

Polygon-mirror confocal microscopy (PMCM) enables high-speed optical sectioning imaging, but reflection-point migration on rotating facets introduces intrinsic nonlinear distortion. We establish a physical model that maps this displacement through relay optics to the object-plane sampling lattice. Parameter analysis identifies the relay-lens focal-length ratio as the dominant factor, followed by facet length and incident angle. Experiments at 20×, 50×, and 100× magnifications confirm the predicted approximately sector-shaped field deformation and position-dependent lateral scaling. After model-based coordinate remapping, the maximum absolute relative deviations were reduced to approximately 0.1% along both scanning directions, demonstrating effective correction of the intrinsic geometric distortion under the tested conditions.