Ocean water is opaque to electromagnetic waves. This complicates remote mapping and research of the seafloor. A new ROV imaging and modeling approach was demonstrated by Dr. Tom Kwasnitschka from GEOMAR Helmholtz Centre for Ocean Research Kiel to create a three-dimensional (3D) high definition digital photorealistic model of a complete deep sea hydrothermal vent system. This approach makes deep sea ecosystems amenable to analytical research, for example, by visualizing seafloor models in 3D virtual reality and applying appropriate numeric analyses.

The researchers applied high definition panoramic imaging technology to survey a hydrothermal vent site at Niua South volcano in the Northeastern Lau Basin off Tonga and create a digital model of an entire hydrothermal vent field that can be explored using virtual reality simulators. Amid concerns over the impact of deep sea mining upon marine ecosystems, such 3D models and visualizations can provide granular information about these habitats and their susceptibility to perturbations.

The study created the first data set of its kind, with a multi-perspective 3D terrain reconstruction of the vent field at sub-centimeter scale across 25 acres. The previously unparalleled resolution will allow researchers to define the attributes of venting, fluid temperature/chemistry, and animal clusters, and has already revised scientists understanding of the hydrothermal structure. “The biological, chemical and geological relationships in these areas are complicated and intricate, in ways that are not completely understood. Being able to view the whole system has evaded most scientists as they are unable to experience this deep sea environment, until now,” said Dr. Kwasnitchka.

219,000 digital single lens reflex camera images were made over five days. Combining these photographs with photogrammetric and acoustic data has allowed for the creation of extremely detailed 3D images, such as these.
In Falkor's dry lab, researcher Rachel Boschen tries out the Virtual Reality simulation of the hydrothermal vents by wearing goggles to immerse herself in the experience.

Remotely Operated Vehicle (ROV) ROPOS, supported by Schmidt Ocean Institute, was fitted with a quiver of survey cameras. A high-resolution camera with a LED strobe flash was used to survey the site while two machine vision cameras gathered stereo still images as part of the real-time 3D scanning workflow. A workstation outfitted with specialized software modified the wide-angle distorted images in real-time so that the vents could be experienced using a virtual reality head-mounted display. Falkor’s high-performance computing system helped to process the data and create a first version of the terrain model. To identify expected gaps around the chimney walls, a laser based light system on the ROV registered the vents from all sides, delivering a near real-time 3D preview of the structures. Imaging sonar was also integrated into this task, delivering additional information that will be fused with the stereo camera data.

The ROV video was streamed live to Schmidt Ocean Institute’s YouTube page to be viewed worldwide, and several live connections with museums, college classrooms, and planetariums were made. A 74-hour marathon dive set a new dive time record for ROV ROPOS. With the data collected, the team is working on creating the first ever open-access, virtual model representing an entire vent field.

A photogrammetric model of the central part of the Niua South hydrothermal field with better than 5 cm resolution. Individual chimneys are shown on mounds of talus, broken-off pieces of their precessors.