UW-3DGS: Underwater 3D Reconstruction with Physics-Aware Gaussian Splatting

TL;DR

This paper introduces UW-3DGS, a physics-aware Gaussian splatting framework for underwater 3D reconstruction that effectively handles light absorption, scattering, and turbidity, outperforming previous neural radiance field methods.

Contribution

The paper presents a novel plug-and-play physics-aware Gaussian splatting method with a learnable image formation module and uncertainty pruning for robust underwater 3D reconstruction.

Findings

Achieves higher PSNR, SSIM, and lower LPIPS compared to prior methods.

Reduces floating artifacts by approximately 65%.

Produces artifact-free geometry and realistic underwater images.

Abstract

Underwater 3D scene reconstruction faces severe challenges from light absorption, scattering, and turbidity, which degrade geometry and color fidelity in traditional methods like Neural Radiance Fields (NeRF). While NeRF extensions such as SeaThru-NeRF incorporate physics-based models, their MLP reliance limits efficiency and spatial resolution in hazy environments. We introduce UW-3DGS, a novel framework adapting 3D Gaussian Splatting (3DGS) for robust underwater reconstruction. Key innovations include: (1) a plug-and-play learnable underwater image formation module using voxel-based regression for spatially varying attenuation and backscatter; and (2) a Physics-Aware Uncertainty Pruning (PAUP) branch that adaptively removes noisy floating Gaussians via uncertainty scoring, ensuring artifact-free geometry. The pipeline operates in training and rendering stages. During training, noisy Gaussians are optimized end-to-end with underwater parameters, guided by PAUP pruning and scattering modeling. In rendering, refined Gaussians produce clean Unattenuated Radiance Images (URIs) free from media effects, while learned physics enable realistic Underwater Images (UWIs) with accurate light transport. Experiments on SeaThru-NeRF and UWBundle datasets show superior performance, achieving PSNR of 27.604, SSIM of 0.868, and LPIPS of 0.104 on SeaThru-NeRF, with ~65% reduction in floating artifacts.