Integrating 3D Reconstruction and AR for Enhancing Visitor Experience in Submerged Heritage Sites

Abstract. Underwater Cultural Heritage (UCH) sites offer unique opportunities for archaeological exploration and cultural tourism but remain difficult to interpret due to the environmental constraints of the underwater setting. This paper introduces an integrated Underwater Augmented Reality (UWAR) system designed to support real-time, site-specific interpretation for recreational divers. The approach combines opto-acoustic 3D reconstruction with thematic annotation and portable AR delivery. A high-resolution, georeferenced 3D model of the site is generated by fusing multibeam sonar and underwater photogrammetry data. This model provides the spatial framework for distributing interpretive content through georeferenced Points of Interest (POIs), including descriptive texts, images, and 3D reconstructions. The system architecture includes a smart buoy equipped with USBL and GNSS positioning systems and an underwater mobile device for AR visualization. This setup enables real-time localization and contextual content delivery without the need for permanent infrastructure. The presented UWAR system aims to improve site readability, promote active learning and support sustainable cultural engagement, offering a scalable model for heritage interpretation in underwater environments.