Fig. 1. Underwater binocular vision imaging system based on active speckle projection

Fig. 2. Speckle patterns generated by the computer. (a) Speckle density is 1%, speckle size is 4 pixel, and size of each speckle is 2 pixel×2 pixel; (b) speckle density is 2%, speckle size is 9 pixel, and size of each speckle is 3 pixel×3 pixel

Fig. 3. Underwater active speckle projection and camera imaging

Fig. 4. Schematic of active projection speckle binocular stereo imaging

Fig. 5. Underwater binocular stereo camera imaging model with active speckle projection

Fig. 6. Influence of the speckle size on matching accuracy

Fig. 7. Influence of speckle density on matching accuracy

Fig. 8. Matching error of corresponding points at different distances. (a) Z=2400 mm; (b) Z=2800 mm; (c) Z=3200 mm; (d) Z=3600 mm

Fig. 9. Experimental equipment. (a) Underwater binocular stereo vision device; (b) projector

Fig. 10. Experiment scene

Fig. 11. Motion diagram of underwater target

Fig. 12. Underwater images acquired by left camera. (a) Image of frame 1; (b) image of frame 2; (c) image of frame 3; (d) image of frame 4

Fig. 13. 3D point cloud and fitting sphere at different motion positions. (a) 3D point cloud at frame 1; (b) 3D point cloud at frame 2; (c) 3D point cloud at frame 3; (d) 3D point cloud at frame 4