Fig. 1. Architecture of multi-point virtual-real registration technology system

Fig. 2. Structure of QR code target probe

Fig. 3. Typical characteristics of hydraulic pipeline assembly scenarios for Su-57 aircraft

Fig. 4. Different types of probe and a probe calibration base. (a) Universal needle probe; (b) through-hole probe; (c) chamfered probe; (d) probe calibration base

Fig. 5. Probe calibration principle. (a) Probe calibration principle for needle probe; (b) probe calibration principle for chamfered probe

Fig. 6. Schematic of QR code pose calculation

Fig. 7. Coordinate system transformation relations in the space of virtual-real mappings

Fig. 8. Flowchart for multi-point based virtual to real registration

Fig. 9. Probe calibration experiment

Fig. 10. Image captured by the camera

Fig. 11. HoloLens2-based single-point repeatability experiments

Fig. 12. An image seen in HoloLens2

Fig. 13. Setting up virtual test points

Fig. 14. Selecting real test points

Fig. 15. Registration points set in unity

Fig. 16. Real points selection and effectiveness of virtual-real registration

Fig. 17. Spatial distribution of virtual and real test points

Fig. 18. Virtual-real registration errors corresponding to different number of registration points

Fig. 19. RMSE corresponding to different number of registration points

Fig. 20. Schematic of coverage rate of the distribution of registration points

Fig. 21. Virtual-real registration errors corresponding to different coverage rates

Fig. 22. RMSE corresponding to different coverage rates