Fig. 1. Schematic diagram of subsets before and after deformation

Fig. 2. Flow chart of DIC based on feature matching

Fig. 3. Blurring effects of Gaussian blurring and nonlinear blurring at different evolutionary times at different evolutionary time. (a) t_i=5.12 s; (b) t_i=20.48 s; (c) t_i=81.92 s; (d) t_i=130.04 s; (e) t_i=206.42 s

Fig. 4. Main directions of feature points

Fig. 5. Matching principle of IC-GN algorithm

Fig. 6. Simulated speckle patterns. (a) Reference image and ROI; (b) target image

Fig. 7. Experimental results. (a) Sampling data points at grid center; (b) feature points of reference image; (c) feature points of target image

Fig. 8. Feature matching points

Fig. 9. Calculation results under different displacements. (a) Computation time; (b) comparison of displacement