Ultra-High Resolution Mapping

During the vertical reef of the Galapagos Expedition (expedition Fkt230928), we collected ultra-high resolution data of cold-water corals using a Voyis Insight Micro laser scanner with an integrated stills camera mounted on the porch of the ROV SuBastian. A custom mount was built so that we could adjust the angle of the system to make sure we could also map fully vertical walls in addition to other complex terrains. The system works by displaying a laser line (Figure 1) which is captured by a camera and transformed into over 2000 points with associated depth. Fifty lines per seconds were done as we slowly flew the vehicle. At the same time, two still frames per second were acquired, allowing us to also build coloured structure-from-motion reconstructions.

Figure 1: The laser scanner line visible on the seafloor while scanning a Madrepora coral colony. Over 2,000 depth measurements are taking along this line and 50 lines per seconds are captured and reconstructed into detailed 3D point clouds.

Amazing underwater scenes were imaged throughout the expedition. Although only preliminary datasets could be processed onboard, we were able to recognize imaged crabs to genus, see individual polyps on certain coral colonies and observe different intensity returns on the white and red bands of a rock fish or various sponges (Figure 2). With this dataset, we will now investigate fine-scale relationships between habitat complexity and the organisms that inhabit these areas. We are now able to image their habitat at the scale at which individual organisms experience it, allowing us to start also looking at biological interactions and how corals may help enhance biodiversity.

 Figure 2: Laser-scanner 3D point cloud of an anemone on rocks.