Improving Underwater Photogrammetric 3D Reconstruction Processing of Shipwreck Sites

Abstract. Applying image processing algorithms to enhance the clarity of underwater images can significantly assist in the visual interpretation of subsea environments. Taking advantage of techniques to maximise the information extracted from the captured input data to produce the highest quality output ensures a higher utilisation of the valuable recorded content which may have been collected at the high cost of a laborious diver survey or an expensive ROV (Remotely Operated Vehicle) expedition. Adopting photogrammetric 3D reconstruction processing in underwater imaging has enabled the creation of high-fidelity digital 3D models which have been used to map subsea infrastructure for maintenance and repair, coral reefs for ecological monitoring, and in the primary context of this article, shipwrecks sites for maritime archaeology and accident investigation. Alongside exploring algorithms to reduce the characteristic haze of underwater photography, this article illustrates the advantages of optimising the processes utilised at distinct stages of the photogrammetric 3D reconstruction workflow to improve the photorealism of the digital 3D models.