WHEN the Taliban blew up two 6th-century statues of Buddha in Afghanistan’s Bamiyan valley in 2001, an ancient wonder was lost to the world. Modern technology can’t bring those artefacts back, but 3D laser scanning and high-resolution photography can help preserve other parts of our cultural heritage before they succumb to natural disasters, vandalism, or the ravages of age.
Since the fall of the Buddhas CyArk, a non-profit firm based in Oakland, California, has been busy creating exact digital copies of more than 70 famous sites including the Rapa Nui statues on Easter Island and the ruined city of Nineveh in Iraq. Most sites lie in the paths of .
CyArk’s latest project is to scan each of the 21 Spanish churches that stretch up the California coast between Sonoma and San Diego. The 18th-century missionaries who built them could not have realised that they were building El Camino Real almost . Some, such as Mission San Miguel Arcángel in southern California, have already been cracked by earthquakes.
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If the firm can digitise all the missions before the next earthquake hits, at least there will be a record, said CyArk director Tom Greaves, speaking at an October event at the Mission Dolores, a 236-year-old church in San Francisco (see picture).
There, CyArk demonstrated how the technology works. A statue of St Francis seemed to watch with wooden eyes as a vertical line of green dots swept slowly across his contours, noting everything from his tonsured head to his sandals. As each beam bounced off a surface, it returned to the 3D laser scanner at the centre of the church, which was measuring the time it took each of the thousands of beams to return. The closer the surface, the faster the beams return, allowing the scanner to construct a finely textured 3D map. The full scan was complete in 6 minutes, and less than half an hour later, a CyArk technician had assembled it into a and everyone in it.
Impressive as this was, however, Cyark’s equipment can capture much bigger bounty. In 2010, along with the , a laser-scanning team from Glasgow, UK, the group set out to record Mount Rushmore. To capture every angle of the monument, they had to build a special sling for the laser scanner and suspend it from ropes in front of the presidents’ faces (see “The world in your pocket“).
The resulting digital image allows visitors to virtually stand More practically, Lee says, it could also be used by the monument’s caretakers to determine which areas of the granite are shifting and cracking so that they can better maintain it.
“The resulting digital image allows visitors to virtually stand on George Washington’s nose”
But damage is far from the most interesting secret that has been revealed by digital reconstruction. After CyArk’s recent scan of the giant heads of the Moai statues on Easter Island, for example, researchers noticed for the first time that the eyes on the statues were not looking out to sea, as had been commonly thought. Instead, they appear to be looking down.
The Easter Island heads are famously mysterious, but even as thoroughly examined a statue as Michelangelo’s David held secrets for a team from Stanford University in California who laser-scanned it in 2001. The eyes of David, they discovered, are looking in different directions. Michelangelo had likely done this deliberately, to optimise the statue’s appearance from multiple angles.
3D scanning is not just for buildings or statues. The technology can reconstruct entire natural environments that no longer exist. Digital reconstruction, for example, could put fallen rocks back into place, says of Queens University in Belfast, UK, recreating what our ancestors would have seen from their cave doors 300,000 years ago.
This is also where the technology will offer benefits to people other than historians and archivists: eventually, it could lead to digital museums of exact replicas. Mission Dolores is one of 500 historic sites that CyArk hopes to scan as a sort of virtual reality space for visitors, long after the structures are gone. The church’s image is already available online, complete with high-definition photographs that add a layer of realism. Visitors can fly around the outside of the church and zoom in to its ornate altar. Think of it as a museum in The Matrix.
It’s too late for the Buddhas, but digital preservation is already bearing fruit elsewhere. In 2010, the tombs of the Bugandan kings at Kasubi, Uganda, were burned down by arsonists. In this case CyArk had already scanned them. When the caretakers phoned the organisation to ask if the tombs could be reconstructed, founder Ben Kacyra “was delighted to say yes.”
The world in your pocket
Three-dimensional laser scanners can produce perfect replicas of delicate archaeological structures (see main story). However, many of them are expensive, time-consuming to use and are limited to easily accessible environments that don’t have nooks and crannies the scanner can’t reach.
Soon all that could change thanks to a portable device, developed by Robert Zlot and colleagues from the CSIRO Autonomous Systems Laboratory in Brisbane, Australia, that lets you scan almost any environment you can walk around.
The handheld device, called Zebedee, wobbles on a spring, sweeping up information about its environment on the fly. Between each sweep, the proprietary software compares successive maps, identifies previously observed surfaces and figures out the user’s movements.
“It’s groundbreaking,” says Shane Rolton of , a scanning company in Sydney, Australia. The Zebedee, he says, can be squeezed into any area you can reach with your hand or with an extension pole and has even been used while abseiling down a cliff.
This extreme portability has allowed Zebedee to map the Jenolan Caves in the Blue Mountains of Australia. Later this year the team will use Zebedee to map more Australian caves in the Nullarbor Plain to help study ancient art in one of the world’s oldest mines. Michael Slezak
