Fig. 1. 3D shape and deformation measurement system based on DIC-assisted-FPP

Fig. 2. Generalized tripartite phase unwrapping method. (a) Encoding and decoding process for 8-period fringes; (b) schematic of tripartite phase unwrapping method^[21]

Fig. 3. Schematic of three-dimensional displacement calculation method

Fig. 4. Calculation process of conversion coefficients

Fig. 5. Calculation method of conversion coefficient based on intensity model and chromatic difference model. (a) Object's color information and constraints; (b) RGB color model; (c) five typical color backgrounds and their best corresponding speckle colors

Fig. 6. Schematic of information separation method for coefficient conversion in RGB color model

Fig. 7. Conversion factor optimization. (a) Bayer filter matrix; (b) a set of hiding coefficient and extracting coefficient optimization results

Fig. 8. Comparison of three FPP combined DIC methods. (a) Filtering method^[33]; (b) color channel separation method^[32]; (c) speckle hiding method

Fig. 9. Measurement of the shape accuracy of table tennis using hiding coefficient. (a) Primordial diameter; (b) reconstructed 3D results and diameter difference

Fig. 10. Evaluation of deformation accuracy of proposed measuring system using the extraction coefficient. (a) Measuring positions of standard flat; (b) speckle extraction results; (c) Z-direction displacement accuracy; (d) displacement error and RMSE along X,Y, and Z directions

Fig. 11. Insole shape and deformation measurement results. (a) Hidden and extracted of speckles; (b)-(e) 3D shape at four moments; (f)-(h) 3D displacement of three processes