Sea-Undistort: A Dataset for Through-Water Image Restoration in High-Resolution Airborne Bathymetric Mapping

Abstract

Accurate image-based bathymetric mapping in shallow waters remains challenging due to the complex optical distortions, such as wave-induced patterns, scattering, and sunglint, introduced by the dynamic water surface, the water column properties, and solar illumination. In this work, we introduce Sea-Undistort, a comprehensive synthetic dataset of 1200 paired $512\times 512$ through-water scenes rendered in Blender. Each pair comprises a distortion-free and a distorted view, featuring realistic water effects, such as sun glint, waves, and scattering over diverse seabeds. Accompanied by per-image metadata, such as camera parameters, sun position, and average depth, Sea-Undistort enables supervised training that is otherwise infeasible in real environments. We use Sea-Undistort to benchmark two state-of-the-art image restoration methods alongside an enhanced lightweight diffusion-based framework with an early fusion sun-glint mask. When applied to real aerial data, the enhanced diffusion model delivers more complete digital surface models (DSMs) of the seabed, especially in deeper areas, reduces bathymetric errors, suppresses glint and scattering, and crisply restores fine seabed details. Dataset, weights, and code are publicly available at https://www.magicbathy.eu/Sea-Undistort.html.