Fig. 1. Structure of binocular structured light system

Fig. 2. Vertical and horizontal Gray-coded patterns

Fig. 3. 3D reconstruction results obtained by using single Gray code. (a) Using 10 Gray-code pictures; (b) using 9 Gray-code pictures; (c) using 8 Gray-code pictures

Fig. 4. Gray code assisted phase unwrapping

Fig. 5. Disparity maps of periodic jump correction. (a) Image before correction; (b) corrected image by traditional method; (c) corrected image by maximum probability method

Fig. 6. Linear interpolation diagram of right view pixels

Fig. 7. Point cloud effect comparison. (a) Pixel-level matching; (b) sub-pixel-level matching

Fig. 8. Comparison of palm surface reconstruction effects. (a) Using pixel-level matching; (b) using sub-pixel-level matching

Fig. 9. 3D palmprint acquisition system

Fig. 10. Calibration error of stereo camera

Fig. 11. Projected patterns

Fig. 12. Images obtained by left and right cameras before correction. (a) Left camera; (b) right camera

Fig. 13. Images obtained by left and right cameras after correction. (a) Left camera; (b) right camera

Fig. 14. Gray code phase shift decoding results of image taken by left camera. (a) Shadow area; (b) relative phase; (c) period; (d) absolute phase

Fig. 15. Disparity map

Fig. 16. Three-dimensional point cloud

Fig. 17. Point cloud filtering results. (a) Before point cloud filtering; (b) after point cloud filtering

Fig. 18. Reconstruction result of palm surface

Fig. 19. Images collected by 3D palmprint system based on stereo binocular camera. (a) Left view; (b) right view

Fig. 20. Comparison of experimental disparity maps. (a) Disparity map generated by traditional binocular stereo vision palmprint acquisition system; (b) disparity map generated by palmprint acquisition system proposed in this article