Fig. 1. Structure of underwater laser line scanning imaging system

Fig. 2. Schematic diagram of working mode of underwater laser line scanning imaging system

Fig. 3. Calibration method of line scanning system in air

Fig. 4. Flow chart of stripe center extraction algorithm

Fig. 5. Gray value distribution diagram of three channels on row pixels with noise

Fig. 6. Comparison of extraction results in complex seabed environment

Fig. 7. Flow chart of pose correction

Fig. 8. Scanning imaging experiment at the bottom of the laboratory water tank

Fig. 9. Experimental results of underwater precision test of standard ball

Fig. 10. Photo of laser line scanning system offshore site work， and the right figure is a partial enlarged view

Fig. 11. Typical laser line scanning seafloor image

Fig. 12. 3D point cloud images of the submarine slope area before and after pose correction with the triangular displacement method

Fig. 13. 3D point clouds and photo of seafloor raised stone

Fig. 14. 3D point cloud and local photo of the long and narrow tunnel

Fig. 15. Comparison of depth measured by line scanning and altimeter