Fig. 1. Flow chart of the underwater measurement system

Fig. 2. Principle of the binocular measurement system. (a) Internal structure of the system; (b) internal physical map

Fig. 3. Sealing condition of the equipment

Fig. 4. Underwater standard ball picture taken by the system

Fig. 5. Schematic diagram of the binocular vision model

Fig. 6. Schematic diagram of the line-structured light system

Fig. 7. Model of the underwater epipolar line dispersion curve

Fig. 8. Principle of the feature point matching method

Fig. 9. Target in the experiment. (a) Standard cylinder; (b) standard ball

Fig. 10. Actual situation of the static water environment. (a) Standard cylinder; (b) standard ball

Fig. 11. Processing result of the original image. (a) Original image; (b) region of interest; (c) feature information of structured light in the region of interest; (d) feature points extracted by our method

Fig. 12. Measurement results of underwater epipolar line matching method. (a) Standard cylinder; (b) standard ball

Fig. 13. Standard sphere model