Recovering and Visualizing Deformation in 3D Aegean Sealings

Archaeological research into Aegean sealings and sigils reveals valuable insights into the Aegean socio-political organization and administration. An important question arising is the determination of authorship and origin of seals. The similarity of sealings is a key factor as it can indicate different seals with the same depiction or the same seal imprinted by different persons. Analyses of authorship and workmanship require the comparison of shared patterns and detection of differences between these artifacts. These are typically performed qualitatively by manually discovering and observing shared visual traits. In our work, we quantify and highlight visual differences, by exposing and directly matching shared features. Further, we visualize and measure the deformation of shape necessary to match sigils. The sealings used in our dataset are 3D structured light scans of plasticine and latex molds of originals. We compute four different feature descriptors on the projected surfaces and its curvature. Then, these features are matched with a rigid RANSAC estimation before a non-rigid thin-plate spline (TPS) matching is performed to fine-tune the deformation. We evaluate our approach by synthesizing artificial deformations on real world data and measuring the distance to the re-constructed deformation.