By Pierre Kosmidis
Bert Ho from the National Park Service Submerged Resources Center explains a new approach to documenting WW2 Wrecks:
“Photogrammetry is a method of taking measurements or distances between objects from photographs. Usually, these measurements and distances can produce underwater 3D models of WW2 aircraft wrecks.
Photogrammetry is visually a great representation of the object on the seafloor.
In order to create a photogrammetric model, the photographer needs to shoot still imagery spaced at an interval, in sequence, and generally spiraling upward and around the entire object.
If shot correctly, these images can be stitched together via a modeling software to generate a 3D point cloud and model that has the potential to provide scientific information such as size, surface area, or distance between objects.
Since these 3D models are using individual photographic pixels that are cross-referenced and visible in multiple images, the color value, or look, for each pixel is retained. This results in a photorealistic point cloud capable of an accurate representation of underwater objects—in this case World War II airplanes.
Depending on the size of the object or scene, this could result in hundreds, if not thousands of images, with the dive being anywhere from 15 minutes to well over an hour.