11:30–11:45 | ABSTRACT 1390
HIGH-RESOLUTION SPAD FLASH LIDAR FOR 3D IMAGING IN TURBID AQUATIC ENVIRONMENTS
Direct time-of-flight (dToF) flash lidar is a promising approach for 3D imaging in turbid aquatic environments, where optical attenuation and backscattering limit imaging range and contrast. Here, we demonstrate a high-resolution dToF flash lidar detector, originally developed for space applications with support from the European Space Agency in collaboration with Fondazione Bruno Kessler, for underwater 3D imaging. The system operates at 532 nm and is based on a 256 × 256 pixel Single-Photon Avalanche Diode (SPAD) array, with an integrated time-to-digital converter (TDC) in each pixel and a 20° field of view. In air, it achieves a depth precision of 1.37 cm at a 6 m range on a target with 50% albedo. Its time-gating capability enables selective rejection of early-arriving backscattered photons, reducing the impact of scattering in turbid water on the reconstructed 3D image. Performance was evaluated in a controlled turbidity experiment using a 1 m water tank in which turbidity was controlled and attenuation measured, with the target positioned 3 m from the sensor. Structured targets were used to assess identifiability under increasing turbidity. Without time-gating, target identification was limited to 1.2 attenuation lengths. With time-gating, the target remained clearly identifiable up to 5.4 attenuation lengths, while range measurements were still possible beyond 7.0 attenuation lengths despite significant image degradation. These results demonstrate the potential of time-gated dToF flash lidar to extend 3D imaging capability in highly scattering aquatic environments.
Jannis Holzer, Swiss Center for Electronics and Microtechnology (CSEM), [email protected], https://orcid.org/0009-0005-7091-1859
David Nguyen, Swiss Center for Electronics and Microtechnology (CSEM), [email protected]
Eleonoor Bosch, Swiss Center for Electronics and Microtechnology (CSEM), [email protected]
Enrico Manuzzato, Fondazione Bruno Kessler, [email protected]
Leonardo Gasparini, Fondazione Bruno Kessler, [email protected]
Christophe Pache, Swiss Center for Electronics and Microtechnology (CSEM), [email protected]
