When archaeologists swap tales from the field, they tend to use hand-drawn images of relics. But hand drawings can be time-consuming, expensive, and rife with error. Three-dimensional laser scans are beginning to gain traction, but without additional analysis, a 3-D scan can miss meaningful details, especially after it’s reduced to a 2-D image. Automatically tracing an object’s curves helps. The question is how to identify the best curves to trace.
One technique traces the ridges and valleys defining each bump on a surface [third from left]; another finds features by analyzing how a silhouette changes with small shifts in perspective [third from right]. A group of computer scientists at the Technion-Israel Institute of Technology and the University of Haifa, in Israel, has found a new set of curves to make 3-D scans really pop [far right]. Known as demarcating curves, these lines capture the strongest points of transition between a ridge and a valley. Here, a fragment of a Hellenistic lamp from between 150 and 50 B.C.E. becomes clear.