Automated Reconstruction of Cuneiform Tablets

An important ambition of the Virtual Cuneiform Project has been the automated reconstruction of cuneiform tablets from virtual fragments. The first successful automatic joins of virtual fragments of cuneiform (from both Uruk and Ur) were achieved using a novel matching method. The matching method works by iteratively finding the best orientation of the two candidate fragments in three-dimensional space. A “cost function” assesses the fit of fragments using the distances between pairs of points evenly distributed across the joining surfaces. These distances are calculated using hardware acceleration provided by the computer’s Graphical Processing Unit (GPU). This speeds up what would otherwise be a long series of computations and enables possible matches to be evaluated in milliseconds for fragment pairs consisting of tens of thousands of vertices and a complete optimisation achieved within a matter of seconds. The matching algorithm is described in detail in our project publications.

Virtual tablet fragments and their accompanying depth-maps.
This figure shows virtual fragments under reconstruction by the automated matching algorithm. The “depth map” calculation performed by the Graphical Processing Unit (GPU) is illustrated by the colour map below. The lighter the shading the greater the distance between corresponding points and the darker the shading the closer they are. Left - depth map of the top face of the first fragment. Centre - depth map of the bottom face of the second fragment. Right - joined fragments and their summed depth map (i.e. the distance between the joined surfaces). The uniform, near zero, depth values of the summed depth map indicates a good quality join.
Virtually reconstructed cuneiform tablet.
This figure shows the first fragmented cuneiform pieces to be automatically joined. The fragments, W 18349 and Wy 777, are part of a letter written in the Neo-Babylonian empire (626-539 BC, around the time of King Nebuchadnezzar) and were found in the ancient city of Uruk (near modern-day Basra, Iraq). The fragments were scanned at the Heidelberg Graduate School of Mathematical and Computational Methods for the Sciences at the Interdisciplinary Center for Scientific Computing, Heidelberg University and are published with the kind permission of the German Archaeological Institute, Berlin.