HE ancient settlement of Amheida lies deep beneath windblown layers of sand in the Western Desert of Egypt. Dr. Lynn Meskell, an archaeologist at Columbia University, is keenly interested in the buried remains, but she doesn't plan on relying solely on trowels to reveal them.
Instead, she is going to combine digging with three-dimensional imaging. Drawing on a five-year, $2 million grant recently awarded by the National Science Foundation, Dr. Meskell and other Columbia scholars hope to bring digital archaeology to the desert, including a robot equipped with remote-sensing equipment. The robot will trundle through the sand, creating 3-D images of what lies beneath and pinpointing the most promising spots for excavation before the trowels begin their slow and laborious digging.
That's just one of the digital approaches the multidisciplinary team plans on developing. The grant program, which is led by Dr. Peter K. Allen, a professor of computer science at Columbia, is designed to bring the benefits of integrated circuits, laser scanning and sophisticated algorithms to the gritty world of an archaeological dig and the analysis of historical sites in general.
The participants hope to create a variety of computer-based aids, including image- processing software and easily searched databases, that archaeologists can use to visualize, model or analyze the structures or sites they are investigating.
Among the ruins of Amheida at the Dakhla oasis, a 13-hour drive from Cairo, the walls of some mud-brick structures still stand, and there are visible traces of streets. The site fascinates Dr. Meskell, an expert in Egyptian archaeology who is field director of the dig. Many of the remains on the surface date from Roman times, she said, but the settlement itself may be far older.
Dr. Meskell prefers to investigate not the tombs of pharaohs, but the settlements of ordinary people. "This is a living site, not a burial site," she said, "and that's what interests me."
To locate the best places to search for details of vanished lives - the wall paintings, the food residue, the many artifacts that will help her build a picture of life in the settlement - she will collaborate with a number of her Columbia colleagues, including Dr. Roelof Versteeg, a geophysicist who has previously visited Amheida to explore the possibility of making a geophysical map of the site.
Dr. Versteeg concentrates on imaging the top 20 meters of the earth, using sensors like ground-penetrating radar to create images of an area below the surface. As part of the grant, he will develop subsurface surveying tools that archaeologists, even those with little or no background in computer science, can use to zoom in on promising spots for investigation. "We want to give archaeologists glasses to look into the earth," he said.
One tool he is using is a magnetometer, which measures the earth's magnetic field. "Mud-brick structures have a different magnetization than the surrounding sand," he explained. The magnetometer can distinguish the signature or pattern of the buried mud-brick buildings from other underground objects like stones. "We're going to use these sensors like a medical technician uses ultrasound, so that we get a lot of information noninvasively," he said.
To automate the search for auspicious areas within the extensive site, Dr. Versteeg will work closely with Dr. Allen, who has created a robot outfitted with a laser scanner. Dr. Versteeg hopes to mount his sensors on this robot so that it can pace the desert, revealing what lies below.
"The robot won't get tired," Dr. Versteeg said. "It will work all night."
The group plans to investigate at least a 4,000-acre urban core at the center of the site, said James Conlon, assistant field director of the excavation, who has spent one preliminary season at Amheida.
The robot, which is equipped with a highly accurate global positioning satellite system, could make its way through this area, Dr. Versteeg said, measuring, for instance, the earth's magnetic field, then moving two inches and taking another data point, gradually building an image of the magnetic anomalies of the subsurface to find the most promising areas for digging.
The robot does a much better job of measuring than humans do, Dr. Versteeg said. "Normally we would do this manually," he said, "but students wear out, and they don't go in a straight line.`
Above-ground sensing at Amheida will be accomplished by the same robot, this time equipped with a laser scanner. Each scan consists of about a million range data points. (Range is the distance the laser beam travels to the surface it is illuminating.) Dr. Allen and his group have written algorithms that relate this dense scanning data to a set of photographs of the same object. These photographic images are overlaid on the geometric models. "We take 3-D models and automatically register photographs with them," he said, to produce images that have not just shape, but also intense color and highly realistic texture.
During the first year of the National Science Foundation project, the computer- based methods to be used in Amheida will be developed and tested at the Cathedral of St. John the Divine in New York, near the Columbia campus. By the spring of 2003, the group plans to be working in Egypt, Dr. Allen said.
By using a combination of below- and above-ground scanning, Dr. Allen said, he hopes to produce an integrated model of the site.
Also working on the project are two other Columbia University computer scientists: Dr. Steven Feiner, who will develop ways to view the streams of data that the systems will generate, and Dr. Kenneth Ross, who will be developing a query language so that people in the future will be able to ask questions of the gigabits of archaeological data that may arrive daily.
Dr. Feiner will be devising ways to display the data in real time, probably using a wireless radio-based system linked to laptops and palmtop computers. Dr. Ross's job will be to help future archaeologists search the databases.
"Archaeologists find artifacts everywhere," he said. "It's quite a challenge to keep track of all that information." Dr. Ross wants to set up the database so that people who are not experts in computer science can have access to the data and run queries. "My concern is to make the data accessible so that someone in the future can ask questions that might not have been thought of when the excavation was happening," he said.
