Segmenting Computer-Tomographic Scans of Ancient Clay Artefacts for Visual Analysis of Cuneiform Inscriptions

Abstract

We address the automatic segmentation of computer tomographic scans of ancient clay tablets with cuneiform inscriptions enclosed inside a clay envelope. Such separation of parts of similar material properties in the scan enables domain scientists to virtually investigate the historically valuable artefacts by means of 3D visualization without physical destruction.We investigate two segmentation methods, the Priority-Flood algorithm and the Compact Watershed algorithm, the latter being modified by employing a distance metric that takes the ellipsoidal shape of the artefacts into account. Additionally, we propose a novel presegmentation method that suppresses the intensity values of the distance transform at contact points between clay envelope and tablet. We apply all methods to volumetric scans of a replicated clay tablet and analyze their performance under varying noise distributions. Evaluation by comparison to a manually segmented ground truth shows best results for the novel suppressionbased approach.