Fig. 1. Schematic diagram of micro-element segment before and after deformation

Fig. 2. Schematic diagram of coordinate conversion

Fig. 3. Surface strain distributions of structure to be tested. (a) Load is 40 N; (b) load is 100 N

Fig. 4. Schematic diagram of overall system structure

Fig. 5. Physical distribution diagram of experimental device

Fig. 6. Schematic diagrams of fiber wavelength offsets at different pressure points. (a) Pressure point is at s1; (b) pressure point is at s2; (c) pressure point is at s3; (d) pressure point is at s4; (e) pressure point is at s5; (f) pressure point is at s6; (g) pressure point is at s7; (h) pressure point is at s8; (i) pressure point is at s9

Fig. 7. Comparison and analysis diagram of actually measured strain values and simulated values

Fig. 8. Three-dimensional surface reconstruction by MATLAB

Fig. 9. Three-dimensional surface map after Qualify point cloud processing

Table 1. Error analysis table when pressure point is at s2

Table 2. Error analysis table when pressure point is at s9

Table 3. Error analysis table when pressure point is at s7