Curved light surface model for calibration of a structured light 3D modeling system based on striped patterns.

Structured light is an optical 3D surface measurement technique with the merits of high speed and high robustness. However, the huge size of traditional digital light processing (DLP) projectors limits its convenience in numerous applications. In this paper, a one-axis MEMS mirror is used as the structured light projector in 3D modeling systems, and has the advantages of small volume and low cost. Limited by the inability to project orthogonal patterns and projection distortion, it is difficult for the one-axis MEMS mirror based 3D modeling system to obtain high accuracy through existing calibration methods. This paper proposed a calibration method for structured light 3D modeling systems that can only project stripes in one direction with projection distortion. A curved surface equation called curved light surface model was proposed to replace the ideal plane equation as the mathematic model of the projected structured light stripes. Experiment results verified that this method can significantly reduce the effect of projection distortion and an accuracy of 0.11 mm was achieved when measuring a standard dumbbell-shaped object with 201.10 mm center-to-center distance.