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Archaeologists have long used digital photography to document ancient findings. But a group from the University of Kentucky Center for Visualization and Virtual Environments is using structured light illumination (SLI) to also gather 3-D data on such artifacts, allowing for scientific measurement and further study.

In September 2010, Blazie Professor Dr. Larry Hassebrook, Bill Gregory and graduate student Eli Crane joined cave specialists and Transylvania University professor Dr. Christopher Begley in exploring a Missouri cave to capture 3-D scans of cave art, human footprints and bear paw prints, all believed to be from the mid-1400s.

Carbon dating indicates that the Missouri cave was sealed off around 1435, perhaps by a cave-in. In 1985 the cave was reopened by a natural sink hole. In order to ensure the protection of the cave’s rare artifacts, the landowners granted generous access for scientific exploration and study on the condition that the cave’s location be kept secret.

The group entered the cave by rappelling in and then lowering equipment by rope. Dr. Hassebrook’s Vis Center team brought their custom-built, battery-operated SLI scanner, which allows for remote mixed resolution scanning without need for a generator. The team worked on two sites in the cave. One contained human and bear prints, and the other, known as the “art gallery,” contained the cave art.

The expedition was a complete success. The team collected more than a dozen 3-D scans of the prints and artwork. The scans produce a 3-D point cloud with more than 2 million 3-D points as well as an 18-million-pixel color image. Both the 3-D data and the color images are later combined into a single color 3-D scan. Adding the 3-D coordinates to the photographic images allows for scientific measurement and analysis of the data.

Dr. Hassebrook has already used the SLI scanning technology in Honduras, Spain and Kentucky, as well as various laboratory scans. The mobile mixed resolution SLI scanner shows great potential for further data acquisition of in situ archaeological artifacts in remote or sensitive areas.