Survey and photogrammetry in underwater archaeological contexts at low visibility in the Venice lagoon

Underwater archaeological research, survey, and documentation are influenced by environmental conditions, in particular for the photographic aspects. The last challenge of the underwater survey is the application of the photogrammetric technique in the low visibility of murky lagoon water with a strong current and constant tide. These conditioning factors have determined the employment of digital technologies to obtain a 3D model of archaeological sites in the Venice Lagoon. In these extreme conditions, typical of the Venice Lagoon, with water visibility around 0,5/1 m, digital techniques have permitted to obtain 3D models of submerged structures from the Roman period, thanks to a meticulous planning of the work, an extensive photogrammetric acquisition, and a strong topographic survey.