Apocalypto: Revealing the unreadable


Stored in various public archives and private collections around the world, there are untold numbers of documents whose content is lost to memory and history. They cannot be read by normal means, because the parchment and paper they are written on has degraded; any attempt to handle or process the document for reading will at the very least cause it permanent damage. One of the prime catalysts of document degradation is the iron gall ink used in their writing; this provides a contrast for X-Ray imaging. The low attenuation produced by the tiny quantities of iron and other metals in the inks requires a system with a very high contrast ratio and excellent immunity from artifacts to enable ink imaging. The new generation XMT TDI scanner being developed at Queen Mary fulfills these criteria. A 3D volumetric dataset produced by XMT scanning the document is modeled and digitally re-created, producing a readable image of the text. The post-processing is performed in six stages, noise removal, data segmentation, surface construction, flattening, data projection and image generation. The scanning process takes upwards of a day, so it is important that the documents are not damaged by long exposure to the X-Ray flux. Investigations ongoing and due to be be published have shown no detectable extra damage to either old or modern scanned parchment.

Proceedings of SPIE - The International Society for Optical Engineering 8506 ยท October 2012