Underwater galvanometer 3D scanning system based in turbid water: imaging model, adaptive exposure algorithm, and accuracy analysis

The inherent characteristics of lasers, including monochromaticity, coherence, and concentrated energy, provide significant advantages for achieving high-precision imaging in turbid water environments. This study presents the imaging characteristics of lasers in varying turbid water by utilizing a custom designed galvanometer-based underwater 3D laser scanner to establish a line laser imaging model. Based on this model, an adaptive laser image exposure algorithm was proposed to enhance the adaptability of underwater 3D laser scanning technology in turbid environments. The experimental results obtained from a series of scanning conducted on various targets, demonstrate that the scanner can achieve sub-millimeter-level 3D scanning accuracy within a turbidity range of 10 NTU and a working distance of 1000 mm.