Jess

Enhancing worn inscriptions and the Day of Archaeology 2012

My name is Tom Goskar and I am one of the organisers of the Day of Archaeology, as well as being a freelance archaeologist who specialises in applying digital techniques to different aspects of the discipline. My day today has been rather mixed, but predictably involved being at the proverbial digital coalface of archaeology in two aspects.

At 8am I checked my email to catch up with the behind-the-scenes talk between the eight organisers of the Day of Archaeology, and log into this website to begin moderating the posts that were by then flowing thick and fast. By 11am I had been on a Google Hangout with Pat and Jess, and we had re-jigged the homepage to make it easier to explore, as well as temporarily excluding posts from last year to highlight the new contributions. It looked much better afterwards. I have been dipping into the website on and off all day, making sure that posts looked good, and expanding and linking the occasional acronym to help readers know what they are. The DoA moderators have been hard at work in the engine room!

In between, for a personal project I have been processing 3D data from a medieval cross close to where I live, here in Penzance, Cornwall, as well as helping to refurbish a soon-to-be-open digital arts space in the town centre.

The Penzance Market Cross, made in the 11th century, is decorated and has many inscriptions. These are very eroded and most people do not notice them. Unless you happen to see the stone in just the right glancing sunlight, the sides of the cross appear to just have some panels of dots and a few lines, not much else. Nothing could be farther from the truth. Using photogrammetric techniques, I have been examining the cross to see if how well 3D capture techniques can enhance the inscriptions and decorations, with the aim of comparing my results with drawings made using traditional techniques (rubbings, chalking, torchlit photos).

In the spirit of the Day of Archaeology, below is a working illustration showing the north east elevation of the Market Cross, which I produced for this blog post. In the centre of the image is the cross as the casual visitor may see it. To the left, the colour information has been removed (which can sometimes be distracting), leaving the shape of the stone artificially coloured grey, with a virtual light source moved to show some of the decoration. To the right, a Radiance Scaling shader has been applied, which colours concavities and convexities to help reveal details on the stone.

Penzance Market Cross

Penzance Market Cross, captured in 3D with photogrammetry, and enhanced using digital filters.

 

As you can see from the Radiance Scaling image to the right, there is definitely more going on than first meets the eye. The figure in the second panel from the top is clearly visible, as are the letters and glyphs in the lower two panels. As I type, I am processing a mesh with a much higher level of detail, and look forward to the results which will be ready in the early hours of tomorrow morning. Comparing the results to the accepted interpretations made by Professor Charles Thomas will be interesting, whether they differ or help to confirm what we already know.

So, my Day of Archaeology has been a busy and varying one, and it’s not over yet. Time to publish this post, and return to the list of posts to publish some more from around the globe, so that we can all show to the world what archaeologists really get up to in our own words. I hope that it helps people today and in the future to understand just how exciting and relevant archaeology is to us all.

You can follow my archaeology musings over at my blog Past Thinking.