CMU team's scanner unlocks secrets from the past

A 140-year-old block of sandstone in a Scott cemetery might help revolutionize how we protect our identity and health.

For now, though, Carnegie Mellon University professor Yang Cai is using his digital scanning technology to learn more about a woman buried beneath the towering oak tree at Old St. Luke's Episcopal Church.

"This is just kind of a fun project ... but I think it's very meaningful to have something where people feel excited," said Cai, director of Carnegie Mellon CyLab's ambient intelligence lab, as research assistants cloaked in black focused a beam of light and a digital camera on Isabelle Seville's weathered gravestone. "We take this as a combination of science, art, technology and culture."

The project's components are fairly simple -- a light projector, a tripod-mounted camera and a laptop computer, all powered by an oversized battery. It's the still-developing software, which builds crisp three-dimensional images and maps, that's jaw-dropping.

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The Rev. Richard Davies couldn't read the worn indentations in Seville's tombstone. Charcoal or crayon rubbings revealed little. But Cai's technology constructed a 3-D image, complete with Seville's name, and her place and date of birth -- London, 1781.

Davies talks about the technological breakthrough as a kind of blessing for historic preservationists.

"These stones have absorbed the spirit of many prayers," said Davies, 80, of Mt. Lebanon as he paced the cemetery filled with British settlers and Revolutionary War veterans. "It just blew my mind, what scientific things they're looking to do with this technology. Stuff that comes out of (this) is amazing."

Archaeologists and taphophiles -- lovers of tombstones and cemeteries -- seem to agree.

Darlene Applegate knows methods for studying cemeteries can be antiquated. The Western Kentucky University anthropology professor, who has taught graveyard archaeology since 2002, uses metal rods to search cemetery soil for buried grave markers.

To read weathered inscriptions, Applegate needs a sunny day to bounce light off a hand-held mirror.

"There's some limitations to that," she said. "This digital scanning thing? That would be revolutionary."

Cai's technology might prove even more useful for preservationists in the Rust Belt, where acid rain has attacked marble tombstones' vulnerable faces, said Michael Trinkley, director of the Chicora Foundation, a Columbia, S.C.-based heritage and preservation group focused on cemeteries.

It's tough to say how many tombstones in graveyards, which are abandoned burial grounds, or cemeteries, which are not abandoned, cannot be read through careful rubbings or digital photography.

"There are some that are so eroded, so damaged, that for all intents and purposes, we still categorize them as 'no longer legible,' " Trinkley said.

Cai, who jumped into the historic Scott cemetery after studying 3,000-year-old rock art this summer in Italy, wants to challenge the concept that stones are "no longer legible." But he also has his sights on bigger goals.

Cai thinks the technology, once refined, will produce detailed 3-D scans of a person's body for medical and security purposes. It could help satellites produce high-tech images of Earth's topography or large features such as a tsunami's waves.

But first, he and his crew will produce a digital map of Old St. Luke's, allowing users to navigate through a 3-D rendering instead of presenting them with a book of crude rubbings and ancient wills.

"Technically, it's pretty doable," Cai said. "I'm just surprised people never thought of this."