Fig. 1. Triangulation principle of the point structured light

Fig. 2. Principle of the polynomial direct calibration model

Fig. 3. Diagram of the finite element region division

Fig. 4. Area division template. (a) X direction; (b) Y direction

Fig. 5. Division results of subarea calibration

Fig. 6. Physical image of the experimental device

Fig. 7. Residual scatter plot. (a) Plane fitted by the global direct method; (b) residual distribution of the global direct method fitting; (c) plane of the subarea calibration and fitting; (d) residual distribution of the subarea calibration and fitting

Fig. 8. Original image and its three-dimensional spatial distribution. (a) Projection of convex surface; (b) three-dimensional scatter plot of convex surface; (c) projection of concave surface; (d) three-dimensional scatter plot of concave surface