Inscription/Impression Reading on Archaeological Artefacts and Manuscripts

(supervisor: Tony Cook)

Nature of project: experimental, software

Available to full-time physicists or joint students.

Project description and methodology

Old clay tablets containing ancient writings, can often be very difficult to decipher after many centuries underground. Likewise old letters, written in pencil/ball point pen may have hidden in them faint writing impressions, from an earlier draft version on the preceding sheet, and this may be of great interest to historians. This project is intended to develop a simple low cost demonstration kit that could, if taken through to fruition, help museums and archaeologists extract previously unreadable writings from ancient artefacts and sheets of paper. It could also be a useful low cost forensic tool for local, or community, police forces.

The proposed technique will rely upon obtaining multiple images of the same object (or paper), keeping the camera fixed, but moving the light source (LED) across the scene at different angle steps. Statistical imaging techniques will be employed, by stacking difference images (full frontal zero phase angle image minus a normalized image taken with the LED at a specific slant angle) into a image cube. The Z-axis in the image cube will correspond to illumination angle. Maximum differences in contrast (to be defined, e.g. standard deviation, or max-min, etc, at a given pixel location) will be investigated to find out the best technique for recovering the inscriptions.

The student will have to take into account likely optical scattering properties of the material, the inverse square law to compensate for the fact that the LED source is not at infinity, and the effects of image noise in poorly illuminated parts of an artefact.

Experimental inscriptions can be generated by the students for artificial clay tablets, or by writing impressions made through two or more layers of paper. Once the technique has been perfected on these, a few genuine museum artefacts, and sample paper documents, will be requested from the RCAHMW (Aberystwyth), the National Museum Wales (Cardiff), or the National Library (Aberystwyth), to see if your technique will discover any new information about the writings present on these. Or if your apparatus is portable enough it could be taken down to these sites.

A successful project will develop beyond the above in one/some of the following directions:
1) Apply the technique to very small samples e.g. texture on surfaces that have been worked by craftsmen such as potters or sculpters, using a USB microscope

2) Apply the technique to fossils

3) How well do impressions made on paper last, if the paper is squashed e.g. in a book?

4) Investigate the use of polarized light to see if this can bring out extra detail on specular surfaces

When considering where to take your project, please bear in mind the time available. It is preferable to do fewer things well than to try many and not get conclusive results on any of them. However, sometimes it is useful to have a couple of strands of investigation in parallel to work on in case delays occur.

This project is only available as a Y3 project.

Initial literature for students:

  1. Malzbender, T. Gelb, D., and Wolters, H. Polynomial Texture Maps, http://www.hpl.hp.com/research/ptm/papers/ptm.pdf
  2. Goskar, T. A. & Earl, G. P. 2010. Polynomial texture mapping for archaeologists. British Archaeology 111, 28-31.
  3. Hamiel, J.S. & Yoshida, J.S. Evaluation and Application of Polynomial Texture Mapping (PTM) in the area of Shoe/Tire Impression
  4. Fearnside, A. and Masding, P., (2012) The Polarisation of Moonlight, BAA Lunar Section, The Moon, December 2012, p55-75, available from your supervisor.

Novelty, degree of difficulty and amount of assistance required

About average level difficulty. This project will be suitable for students who have an interest in image processing and archeology/history.

Project milestones and deliverables (including timescale)

milestoneto be completed by
Decide what samples to investigate and make contact with museums who have collectionsChristmas
How deep an impression can you recover, and if made with a pen, through how many sheets of paperend of February
Experiment with polarized light on specular surfacesmid-March
Try a wide range of samples and fully evaluate the techniquesEaster

Students taking this project will have to submit a full risk assessment form