Fig. 1. Structure and reflection principle of quasi-distributed FBG

Fig. 2. Flow chart of four reconstruction algorithms

Fig. 3. Strain field reconstruction system based on FBG sensor^[17]. (a) Physical system diagram; (b) strain mode

Fig. 4. Shape reconstruction results in the case of circular arcs with different curvature radii^[20]. (a) Curvature radius is 180 mm; (b) curvature radius is 160 mm

Fig. 5. Comparison of test surface and 3D reconstruction graphics effect^[31]. (a) Constant curvature surface; (b) wave-shape surface; (c) mouse-shape surface; (d) constant curvature reconstructed surface; (e) wave-shape reconstructed surface; (f) mouse-shape reconstructed surface

Fig. 6. Simulation result^[41]. (a) Comparison of iFEM reconstruction displacement and FEM simulation displacement; (b) relationship between measuring point density and reconstruction error

Fig. 7. POS six-dimensional deformation measurement method^[51].(a) Measurement results and errors of displacement; (b) measurement results and errors of angle

Fig. 8. Comparison of wing box shape reconstruction by different methods^[52]. (a) Ko displacement theory; (b) modal transformation method; (c) iFEM