Fig. 1. Monte Carlo simulation flow chart of photon underwater transmission

Fig. 2. Simulated results of pulse echo signals under different scattering coefficients

Fig. 3. Signals separated by FastICA algorithm. (a) Target echo signal; (b) backscattering noise signal

Fig. 4. Schematic of experimental setup

Fig. 5. Schematic of scanning control and data acquisition

Fig. 6. Point cloud distance distribution of underwater target. (a)(b) Point cloud distribution before and after processing by FastICA algorithm when turbidity is 4.2 NTU; (c)(d) point cloud distribution before and after processing by FastICA algorithm when turbidity is 12.2 NTU; (e)(f) point cloud distribution before and after processing by FastICA algorithm when turbidity is 20.5 NTU

Fig. 7. Three-dimensional point cloud images of underwater target. (a)(b) Three-dimensional point cloud images before and after processing by FastICA algorithm when turbidity is 4.2 NTU; (c)(d) three-dimensional point cloud images before and after processing by FastICA algorithm when turbidity is 12.2 NTU; (e)(f) three-dimensional point cloud images before and after processing by FastICA algorithm when turbidity is 20.5 NTU

Fig. 8. RMSE of three-dimensional point cloud ranging under different turbidities

Fig. 9. Three-dimensional point cloud images of underwater target when the attenuation coefficient is 2.7 m^-1. (a) Unprocessed by FastICA algorithm; (b) processed by FastICA algorithm