The observance in the United States this week of Veterans Day, a federal holiday honoring those who have served in the American military, holds special meaning for those who lost loved ones when Japan bombed Pearl Harbor in Hawaii during World War II. An underwater 3D imaging project is using modern technology to bring greater insights to this tragic historical event.

The project surveying such sunken ships as the USS Arizona involves a combination of man power and unmanned surface vessels. It was prompted by the fact that recent underwater studies have shown that marine life in the decades since the 1980s had begun to inhabit the corroded and twisted passage-ways and bulkheads of some of these submerged vessels. The National Park Service (NPS), concerned about how these historic sites were changing over time, brought in advanced technology to help keep track of things and monitor for potential structural integrity issues.

The extensive surveying project is aimed at developing high-resolution data and 3D models though the use of, among other things, photogrammetry (making measurements from photographs), underwater acoustic mapping and Light Detection and Ranging (LiDAR). None of these uses of technology are taken lightly, especially when the scope of rendering an entire 3D model of a former battleship is considered. This is why the NPS turned to a team of select professionals and subject matter experts to help out with the endeavor.

During one dive to study the Arizona, for example, a technologist from software company Autodesk made his way underwater around a ship’s exterior using a waterproof map for navigation. While he was photographing elements to create the eventual 3D models, technicians from R2Sonic, an underwater equipment manufacturing company, trolled a 17-foot dinghy above the surface to collect acoustic data in real time from the Arizona’s still form to further enhance the final modeling.

Aside from these direct human efforts, less hands on technology also came into play. An unmanned surface vessel (USV), USV H-1750, was wirelessly controlled and navigated into tight nooks and crannies of the exposed wreckage of the Arizona. It spent time collecting multi-beam survey data to help paint a better picture of the inner goings-on of the vessels being monitored.

All of the data being collected for this ongoing project, which is said to cost over US$400,000, will be complied by Autodesk to construct the final 3D renderings and models of the historic sites. It will, in addition to offering a way point to track the status of the ships, offer a doorway for people of all generations to further connect with the human side of this location.

“I think the thing that has surprised us the most about this project so far is the visceral personal experience that working on such a place has on every member of the team,' said Pete Kelsey, Autodesk strategic projects executive. "Whether it's putting a [reconstructed] artifact in the hands of a 92-year old survivor who was here on Dec. 7th 1941, or showing it to kids in grade schools, [we're] basically using this 3-dimensional data to ensure that what happened here, that story, this history...will not end."

Source: U.S. Navy