Research of underwater 3D imaging based on single-slit streak tube imaging lidar

Compared to traditional underwater cameras, lidar can capture more dimensional information about targets, thereby offering substantial advantages in underwater target detection. The Single-Slit Streak Tube Imaging Lidar (SS-STIL) is a high temporal resolution device designed for 3D precision measurement. It operates on the principle of time-of-flight, recording the 3D information of target as multiple high-precision 2D streak images. These images are then used to reconstruct the target's 3D information through advanced reconstruction algorithms. Existing researches on the imaging quality of Streak Tube Imaging Lidar (STIL) often fall short in thoroughly investigating the impact of water turbidity on imaging quality and particularly lack quantitative measurements of underwater imaging environments. To address the aforementioned issues, we first performed theoretical calculations and simulations of the SS-STIL for imaging targets in both air and underwater environments. Based on these simulation results, we determined the parameters for the main modules of the actual imaging system. We measured the water's attenuation coefficient in the experimental setting using a photometer, quantified five levels of underwater turbidity, and conducted experiments with our SS-STIL under these five different conditions. At an imaging distance of 4.5m and a water attenuation coefficient of 0.51m^-1 , our SS-STIL system achieved an imaging resolution of 1cm and a spatial resolution of 3cm, which is superior to other existing STIL systems.