"It's very common," says Jess Hanham casually, when asked how often he finds suspected unexploded bombs. Mr Hanham is a co-founder of Spectrum Offshore, a marine survey firm that does a lot of work in the Thames Estuary. His firm undertakes all sorts of marine surveying, but working on sites for new offshore wind farms has become a big business for him. Work in the Thames Estuary, and other areas that were the targets of bombing in World War 2, are likely to involve picking up signals of unexploded munitions. "You can find a significant amount of contacts that need further investigation and for a wind farm that will be established in the initial pre-engineering survey," he says.

There's still no completely safe and surefire method for locating unexploded ordinance after a war is over, but researchers at Ohio State University have found a way to harness image processing algorithms, powered by machine learning, to study satellite imagery and locate hot spots where UXO are likely to be located. The researchers focused their efforts on a 100-square-kilometre area near Kampong Trabaek, Cambodia, which was the target of carpet-bombing missions carried out by the United States Air Force during the Vietnam War. The team was given access to declassified military data that revealed that 3,205 bombs had been dropped in the area between 1970 and 1973. Determining exactly how many of those bombs didn't explode has gotten harder and harder as, six decades later, nature has slowly reclaimed the country's heaviest hit areas, hiding and obscuring the craters that are counted and used to make accurate estimates. The OSU study used a two-step process to come up with a more accurate estimate of how many bombs were still left in the area.

Jennifer Griffin takes us back through the history of US-Vietnam relations. Researchers at Ohio State University are using satellite images and sophisticated artificial intelligence technology to search for unexploded bombs from the Vietnam War. The technology already has been used to survey Vietnam War-era bomb craters in Cambodia. "The new method increased true bomb crater detection by more than 160 percent over standard methods," researchers explain in a statement. "The model, combined with declassified U.S. military records, suggests that 44 to 50 percent of the bombs in the area studied may remain unexploded."

Researchers have used artificial intelligence to detect Vietnam War-era bomb craters in Cambodia from satellite images – with the hope that it can help find unexploded bombs. The new method increased true bomb crater detection by more than 160 percent over standard methods. The model, combined with declassified U.S. military records, suggests that 44 to 50 percent of the bombs in the area studied may remain unexploded. As of now, attempts to find and safely remove unexploded bombs and landmines – called demining – has not been as effective as needed in Cambodia, said Erin Lin, assistant professor of political science at The Ohio State University. She cites a recent UN-commissioned report that has criticized the Cambodian national clearance agency for presenting a picture of rapid progress by focusing on areas at minimal or no risk of having unexploded mines.