Fig. 1. Camera keyhole imaging model

Fig. 2. Principle of digital image correlation measurement

Fig. 3. Mirror measurement scheme

Fig. 4. Measurement process

Fig. 5. Experimental site of accuracy verification

Fig. 6. Calibration accuracy comparison of the two DIC units

Fig. 7. Morphology fitting of reconstructed surfaces

Fig. 8. Results of uniaxial tensile strain

Fig. 9. Scheme of casing test

Fig. 10. Testing site of casing

Fig. 11. Photogrammetry of measurement site of casing and subset division

Fig. 12. 3D reconstruction of ribbed plate in inner region of tested casing prototype

Fig. 13. Casing simulation calculation

Fig. 14. Measurement of casing deformation