Photogrammetry: Documenting WW2 Wrecks in 3D

WW2, WW2 Pacific treasures, WW2 Wrecks

By Pierre Kosmidis

Images: NOAA

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.

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Photogrammetry is visually a great representation of the object on the seafloor.

Top view of a model of a Corsair, compared with model showing camera locations.
Model of a Corsair, compared with model showing camera locations.

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.

Model of a Corsair from a 45 degree angle, compared with model showing camera locations.
Model of a Corsair from a 45 degree angle, compared with model showing camera locations.

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.

An example of photogrammetry work conducted by NPS photographer Brett Seymour of an upside down F4U Corsair at Midway Atoll.
An example of photogrammetry work conducted by NPS photographer Brett Seymour of an upside down F4U Corsair at Midway Atoll.

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. 

SOURCE: NOAA