Virtual Cuneiform Tablet Archiving and Reconstruction

This project will advance two key areas of acquisition and presentation of 3D virtual artefacts: the geometrical processing of 3D acquisition algorithms, and the online delivery and manipulation of virtual artefacts. The project ambitions support the digital preservation and virtualization of ancient Mesopotamian cuneiform tablets which are not otherwise accessible.

The aim of the project is to advance technology for the acquisition and online delivery of 3D archaeological artefacts.

Cuneiform script is one of mankind’s earliest systems of writing. It was developed in Mesopotamia around 3,300 BCE and remained in use until the first century CE. Cuneiform was written by making wedge-shaped impressions with a reed stylus on handheld clay “tablets”. These cuneiform tablets were the original mobile information technology - their writing was an intellectual breakthrough that made recording information possible.

Thousands of inscribed cuneiform tablet fragments have been excavated in the last 200 years; the largest collections are housed in the British Museum in London and the Penn Museum in Philadelphia. Other significant collections include those housed in the Iraq Museum in Baghdad and the Louvre in Paris. Only a small number of artefacts can be physically exhibited at any time and there is necessarily limited access to all stored collections. In addition, the loss and damage of cultural artefacts in the Middle East and elsewhere has underlined the considerable importance of recording and preservation efforts and has motivated new digital archiving initiatives.

The virtual archiving and reconstruction research proposed will have significant impact by supporting worldwide access to virtual 3D cuneiform archives which would otherwise be unavailable or at-risk. The project will extend the collaborative efforts of an international team of researchers, summarized at http://virtualcuneiform.org, that have an ambition to support virtual access to cuneiform artefacts and to reconstruct cuneiform tablets by joining virtual fragments together.

The project’s objectives are twofold:

1. Optimisation of Photogrammetric 3D Acquisition Processing
A low-cost 3D acquisition system using photogrammetric reconstruction has been developed. This prototype system works well for the purpose of matching fragments of broken cuneiform tablets. However, the third-party open-source photogrammetric reconstruction algorithms currently used are designed for general-purpose applications and do not take advantage of the characteristics of inscribed or engraved artefacts such as cuneiform tablets. As a consequence, the accuracy of the 3D models produced is not as precise as the visual perception created by the photographic texturing suggests. A closer estimate to the actual shape of a tablet fragment could be obtained by exploiting a-priori knowledge of the characteristics of the impressions and of the homogenous surface texture regions.

Two approaches to improve the 3D mesh accuracy will be investigated. The first will modify the point-cloud reconstruction and surface meshing algorithms by exploiting a-priori knowledge of the properties of clay cuneiform tablets to prevent smoothing in key areas where abrupt colouring change is apparent (indicating a likely sharp edge). The second approach is the introduction of a post-processing stage that modifies the mesh based on characteristic features in the texturing image, i.e. a texture-informed 3D sharpening filter. Both approaches will be explored and novel processing and reconstruction algorithms developed.

2. Enabling Online Delivery and Manipulation of Virtual Artefacts
Ideally, a data storage format for online applications should be efficient, minimising download times and bandwidth requirements, and progressively encoded allowing varying levels of detail from a single model. The file formats available for 3D virtual asset storage do not satisfy these requirements. As a consequence, existing online 3D archives either use low resolution 3D models or suffer excessive download times, are non-responsive and are not mobile-friendly. Some experimental methods exist, but none that are suitable for deployment online with high-definition 3D models. Using modern browser capabilities, there are no fundamental technological barriers to developing this technology. There are multiple component issues to be addressed, however, and this will form the main part of this section of the research.