Underwater depth imaging using time-correlated single-photon counting

TLDR

Underwater depth imaging in highly scattering media is challenging, motivating the use of time‑of‑flight and time‑correlated single‑photon counting (TCSPC) techniques. This study investigates a TCSPC‑based depth imaging system for operation in such environments. The system employs a pulsed supercontinuum laser, a monostatic scanning transceiver, and a silicon SPAD detector, while a parallel LiDAR model is developed and validated against experimental data. Laboratory experiments achieved depth images up to eight attenuation lengths with per‑pixel acquisition times of 0.5–100 ms and optical powers from 0.8 nW to 950 µW, and the validated model can predict system performance across diverse scattering conditions and parameters.

Abstract

A depth imaging system, based on the time-of-flight approach and the time-correlated single-photon counting (TCSPC) technique, was investigated for use in highly scattering underwater environments. The system comprised a pulsed supercontinuum laser source, a monostatic scanning transceiver, with a silicon single-photon avalanche diode (SPAD) used for detection of the returned optical signal. Depth images were acquired in the laboratory at stand-off distances of up to 8 attenuation lengths, using per-pixel acquisition times in the range 0.5 to 100 ms, at average optical powers in the range 0.8 nW to 950 μW. In parallel, a LiDAR model was developed and validated using experimental data. The model can be used to estimate the performance of the system under a variety of scattering conditions and system parameters.