The value of critical destruction: Evaluating multispectral image processing methods for the analysis of primary historical texts

Multispectral imaging—a method for acquiring image data over a series of wavelengths across the light spectrum—is becoming a valuable tool within the cultural Correspondence: Melissa Terras, Department of Information Studies, Foster Court, University College London, Gower Street, WC1E 6BT, London. E-mail: [email protected] Digital Scholarship in the Humanities The Author 2015. Published by Oxford University Press on behalf of EADH. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact [email protected] 1 of 22 doi:10.1093/llc/fqv036 Digital Scholarship in the Humanities Advance Access published October 7, 2015 by gest on Jauary 9, 2016 http://dshrdjournals.org/ D ow nladed from and heritage sector for the recovery and enhancement of information contained within primary historical texts. However, most applications of this technique, to date, have been bespoke: analysing particular documents of historic importance. There has been little prior work done on evaluating this technique in a structured fashion, to provide recommendations on how best to capture and process images when working with damaged and abraded textual material. This article introduces a new approach for evaluating the efficacy of image processing algorithms in recovering information from multispectral images of deteriorated primary historical texts. We present a series of experiments that deliberately degrade samples cut from a real historical document to provide a set of images acquired before and after damage. These images then allow us to compare, both objectively and quantitatively, the effectiveness of multispectral imaging and image processing for recovering information from damaged text. We develop a methodological framework for the continuing study of the techniques involved in the analysis and processing of multispectral images of primary historical texts, and a dataset which will be of use to others interested in advanced digitisation techniques within the cultural heritage sector. .................................................................................................................................................................................