Fig. 1. Algorithm architecture

Fig. 2. Pyramid optical flow method

Fig. 3. Ring matching with bidirectional optical flow method

Fig. 4. Extracting new feature point with masks

Fig. 5. 3D-2D point projection

Fig. 6. Relationship between camera coordinate system and image coordinate system

Fig. 7. Basic stereo matching results

Fig. 8. Proposed matching algorithm

Fig. 9. Feature points retained by ring matching

Fig. 10. Extracting new feature points without mask

Fig. 11. Extracting new feature points under masks

Fig. 12. Comparison of the number of feature points

Fig. 13. Algorithm trajectory. (a) Top view; (b) xyz axis coordinate decomposition value