Imaging the Tintagel early medieval inscribed slate

English Heritage have just announced the important and rare discovery of an early medieval stone inscribed with writing, dating from the 7th century.  I was called in by Cornwall Archaeological Unit, who discovered the stone in the summer of 2017, to help enhance the inscriptions.

Some of the writing is very faint, and so rather than the usual technique of using 3D capture (close range laser scanning or photogrammetry), I opted to use Reflectance Transformation Imaging (RTI) to obtain our best chance of reading all of the letters.

The results were fantastic, and I was lucky enough to be perhaps the first to read some personal names from 1,300 years ago, as I processed the data from my home office.

There have been many calls via Twitter to see more of the enhanced images, so here they are (released under a Creative Commons attribution non-commercial license) with thanks to Professor Michelle Brown who conducted the interpretation and final transcription.

Enhanced image of the inscription
tito
vi.ri. duo
Æ(D A?) fili 
Enhanced version of the inscription
bue dic
tu Δ/D A

There’s a great article on the Guardian which describes the Tintagel excavations and the significance of the discovery in more detail.

3D capture of historic costumes at Helston Museum, Cornwall

Sign reading "3D scanning project. Thanks to Cornwall Museum Partnership with funding from Arts Council England we are learning how to 3D scan our collection"In December 2017 I was asked by Helston Museum to train staff and volunteers in how to use photogrammetry to record their historic costume collection in 3D. The costume gallery had closed and become a much-needed storage area. They decided that online 3D models, and possibly through screens in the museum, would be an interesting and engaging way to present the costumes now in the museum stores. They could record and display many more than there has ever been physical gallery space for.

The best way to capture the costumes is, of course, to use a mannequin. This would allow the costume to be viewed in the way it would have been worn, and rotated and viewed from any angle, an advantage over traditional static photographs. They would use Sketchfab to display the results.

Helston Museum decided to try the project in a very public way. Training was conducted in their temporary exhibition space, with panels explaining what was going on to the public. Projectors were used to display the results, as they happened. Staff and myself were on-hand to answer any questions from the public.

Over the course of a week, I trained both permanent staff, the Director and Assistant Curator, as well as a group of volunteers. They were shown how to light the mannequins, how to photograph them for 3D photogrammetry, and how to process and clean the 3D data on one of the museum’s existing PCs.

A volunteer photographs the dressed mannequin from every angle to ensure good coverage for photogrammetry
A volunteer photographs the dressed mannequin from every angle to ensure good coverage for photogrammetry

Some volunteers were more interested in photography, others in costume handling, and others in data processing and editing. I worked with their strengths, and the museum now have a great team to take the project on themselves. I remain available for questions from the team, and hope to teach some more advanced methods as they gain experience and confidence with 3D digitisation.

Helston Museum are Cornwall’s first museum to create a Sketchfab account, where they will share the results of this ongoing project. Visit Helston Museum on Sketchfab.

 

Hendraburnick ‘Quoit’ – the most decorated stone in southern Britain?

hendraburnick-featured-image

Last year (2016) I was asked by Dr Andy Jones from Cornwall Archaeological Unit to record and study the surface of Hendraburnick Quoit on Bodmin Moor in Cornwall. The work, funded by Cornwall Archaeological Society, involved detailed 3D recording of the surface of the two stones that comprise the monument (which isn’t actually a quoit, more a ‘propped stone’). It was a complex task for which I used photogrammetry as the 3D scanning method. It involved careful planning and then taking many hundreds of high resolution photographs to guarantee coverage at an even resolution across all sides of both stones to enable careful study with millimetric levels of accuracy.

Our research was covered in the Telegraph who used the curioisty-grabbing headline “Ancient stone monuments may have been used for mysterious moonlit ceremonies, say archaeologists“. A full account of the project and our interpretation of the site can be found in the article Hendraburnick ‘Quoit’: recording and dating rock art in the west of Britain in Time & Mind – the “Journal of Archaeology, Consciousness and Culture”.

Analysis

After processing the 3D data I began the lengthy task of analysing the surfaces in great detail. Each potential feature was subjected to four checks using alternative methods, including virtual RTI and cross sections. I burnt a lot of midnight oil ensuring finding ‘cup marks’ and tracing the grooved lines that connect many of them together. I found 105 cup marks and 47 possible grooved lines connected or radiating from them, following the slope of the stone. This suggests that the lines were made in-situ rather than before the stone was moved in prehistory to its current location. This makes Hendraburnick Quoit the most known decorated or deliberately marked stone in southern Britain – possibly topping even Stonehenge in number of human-made features (152) on its surface.

The result was this plan:

Plan of cup marks on Hendraburnick propped stone
Cup marks on Hendraburnick propped stone

A very reduced resolution model of Hendraburnick can be viewed on Sketchfab, to aid understanding of the monument.

2017 so far

Headphones, iMac, microphone

This year has been a strange one so far. The first months of this year saw me suffering from chronic back pain, and finding the road towards being pain free. I’m on that road, but not at the end of it yet. So, a bit of a setback.

I’m typing this on my new sit/stand electrically adjustable desk perched on an ‘active’ stool, standing on a soft rug. Some will view this as laughably hipster, others with back pain will know that anything is worth a try. It’s definitely helping.

Now that I’m easing back into work, I’ve got a number of projects underway. I’m working on another shipwreck project on the Isles of Scilly to create accessible tours of a group of wrecks, and I have a number of 3D archaeological recording contracts booked in. It’s always nice to do some gentle fieldwork. It might be a while before I’ll be able to dig again!

Computer with microphone and headphones
Recording a voiceover using a large diaphragm condenser microphone and Focusrite audio interface using a split-screen layout for video and script.

Yesterday saw me recording a voiceover for a shipwreck dive video. It was nice to dust off some old skills and try out some new software. I think the result sounds good. I don’t particularly like the sound of my own voice, but I am used to it after years of recording podcasts.

Along with a nearby colleague, I have undertaken another survey of the medieval Market Cross here in Penzance, where we have combined photogrammetry, Reflectance Transformation Imaging (RTI), traditional measured survey, and photography. We hope to produce the clearest possible images of the inscriptions and decorations and work with a specialist in medieval writing to see if we can provide an updated view of this important monument.

I’m also planning some meetings with museums in Cornwall to introduce the idea of 3D recording and public dissemination of their collections via Sketchfab. There are so many wonderful objects in the stores of Cornish museums, rarely if ever being displayed. As 3D scanning becomes easier, and the benefits are realised, I’m sure that this will become a rapidly growing area. I have my first meeting on Monday at a small museum that punches well above its weight.

Tehmina and I are planning a month-long trip to New Zealand this July/August, which is part of her work as Cornwall’s ACE supported Changer Makers programme. We will visit many of New Zealand’s museums for Tehmina’s research, and I hope to investigate how technology is being used to record and interpret the shared pasts of the diverse groups of people who live there.

We have also joined the Folklore Society to access their journals and become more widely involved in the field of folklore research. As practitioners of some traditional Cornish customs (mainly “guise dancing” – a kind of mumming using disguises during the Christmas period) we have begun to thoroughly research it with the aim of producing academic and popular articles to draw attention to this wonderful tradition. We have discovered some wonderful things and even talked to some very elderly people who took part in guise dancing in the 1920s-40s. But that is another blog post all of its own…

So, now we’re nearly half way through 2017, here’s to a productive and enjoyable, and hopefully more spinally flexible rest of the year. With any luck, and I say this each year, I’ll write a little more.

HMS Colossus Diver Interpretation

HMS Colossus

I have just completed a project creating an interactive diver interpretation for the wreck of HMS Colossus with marine archaeologist Kevin Camidge. Commissioned by Historic England, we have created a mobile-friendly website where divers and non-divers alike can explore the wreck. It is situated south of the island of Samson on the Isles of Scilly, and sank in 1798.

As the Colossus is in relatively shallow waters, it is a popular and accessible location for diving. A physical dive trail already exists; concrete stations around the site on the seabed with tethered and numbered buoys and an accompanying guide. To help divers plan a visit, and to provide non-divers with a sense of what the site is like, we have created an “interactive plan”. Utilising Sketchfab, visitors can explore a simplified model of the wreck via computers, tablets and smartphones, tapping the dive stations to explore different locations in more detail, as well as viewing “diver-eye” videos of the site itself.

We opted to create a simplified 3D plan based on the archaeological survey, clearly indicating in bold colours the different components of the wreck, rather than adopt a photorealistic approach. The wreck itself is a mass of seaweed and sand-covered dark wood which can be difficult for the layperson to interpret.

Explore the wreck of HMS Colossus – dive in literally or virtually!

Point Cloud Penzance – the town in 3D

Using 3D data (LiDAR) collected by the Environment Agency through the Government Open Data initiative I have created an interactive 3D model of the town centre of Penzance, Cornwall.

It’s a very detailed model, with a measurement point every 50cm or so across the entire town. There are 12.9 million vertices (points) in this model.

You may need a reasonably modern computer for the model to work correctly, but give it a try. Use your left mouse button to rotate the model, right-hand button to pan, and the scroll wheel (or equivalent gesture) to zoom.

View this model directly on Sketchfab, where you can try full-screen mode.

If you get too close to buildings you may notice that you can see the ‘points’ that the model is made from. In the future technology will allow agencies to collect much more accurate and dense data, and faster computers will allow us to view more detailed models. Until then – enjoy!

LiDAR data is extremely useful to archaeologists to identify features in the landscape. This is my primary use of such data. In the future data like this will be useful for understanding how our towns have changed. This model is presented here for a bit of fun, and to demonstrate the many uses that this kind of data can have.

Penzance LiDAR
Penzance LiDAR with Ambient Occlusion to show streets and features more clearly.

3D Printed Replica of the Mermaid of Zennor

In August 2015 I was commissioned by National Maritime Museum Cornwall to produce a 3D printed replica of the late medieval bench end in the church of St Senara in Zennor. It depicts a mermaid, which is famously known as the Mermaid of Zennor. This has, along with another medieval bench end, been incorporated into a seat called the “Mermaid Chair”. The replica was for an exhibition entitled “Mermaids: Women at Sea” highlighting the achievements of female sailors. Naturally, people would expect to also see a mermaid – a legendary woman of the sea – as part of the display.

The concept was to produce a half-size replica, which would be mounted upon a large photograph of the church interior. The 3D print would be positioned exactly over the portion of the photo occupied by the original – a collage of 2D and 3D. Visitors would be encouraged to touch the exhibit – something that should not be encouraged with the original medieval frieze.

Before any work was undertaken, we sought permission from the churchwardens. They were keen to hear about the capture methods and learn more about the exhibition, and kindly gave us the go-ahead.

I used photogrammetry – a form of 3D capture that uses photographs – to capture the entire bench-end. Using natural light only a tripod was necessary to compensate for the long exposure times. Before commencing the capture I planned my visit with advice from the churchwarden, when there would be no direct sunlight pouring in through the stained glass. This is essential for correct colour capture, pretty as that may have looked.

There were many challenges with the capture in-situ in the church. Aside from technical challenges, St Senara is a well-visited church, and everyone wanted to see the mermaid. And to find out what I was doing. So it took a little longer than I had hoped, as it is always good to explain what’s going on to curious visitors, but the results turned out very well indeed.

The resulting model consisted of tens of millions of measurement points which were used to create a highly accurate and ‘watertight’ 3D model. Given that the rear of the mermaid bench-end would be fixed to a display panel, the model was altered to create a smooth plane on the reverse to aid mounting. After preparing the model for 3D printing (checking the model for errors that could confuse a 3D printer) the data was sent to ThinkSee3D for printing. The resulting replica would be half actual size (182mm x 380mm x 20mm) – full size (370mm x 755mm x 40mm) would have been prohibitively expensive and would need to be printed in two parts then glued together. It would be printed in full colour using a solid gypsum-based resin.

After some small test prints and experiments with colour, and a coat of varnish to replicate the finish of the real medieval wood, the finished 3D replica of the Mermaid of Zennor was ready. Museum staff mounted the print carefully over one of my photos – the result was rather effective!

3D printed replica of the Mermaid of Zennor medieval bench end mounted over a photograph of the real bench in the church of St Senara.
3D printed replica of the Mermaid of Zennor medieval bench end mounted over a photograph of the real bench in the church of St Senara.

Since the Mermaids exhibition ended at NMMC, the 3D printed replica has gone on show in the “All Monsters Great and Small” exhibition at the Royal Cornwall Museum.

On Sketchfab and Cultural Heritage

Sketchfab screenshot

When I first started out with learning 3D visualisation techniques and software back in 2001 I longed for a way to share my models online. In the early days there was VRML and other, proprietary, methods (Superscape, Shockwave 3D, etc) but these required either big browser plugins with limited capabilities or in the case of VRML, very low polygon (simple) models. My 100,000 polygon reconstruction of the Tudor palace at Oatlands which I built from archaeological and contemporary visual evidence was never going to make it online back then.

Without providing a history of the technology used to present 3D models online – I’ve probably tried most methods through the years – we now have a splendid service called Sketchfab. I’m certain that someone has used the YouTube analogy here. Putting video online used to be hard until YouTube and the many similar services that came and went. Now you can open a Sketchfab account, upload your models, edit how you’d like them to initially appear, and share your links or embed them in your website or social media timeline. There are many sophisticated tools to change how your model appears, from its textures, to the environment and lighting, background photo, visual effects, and interactive annotations.

In the world of cultural heritage Sketchfab opens up a whole range of possibilities. Annotations allow numbered points to be attached to geometry and through the use of Markdown, those annotations can include embedded photos and hyperlinks.

Here we see a model of Hoa Hakananai’a from the British Museum’s Sketchfab account (3D capture by my colleagues at Archaeovision) with annotations to explain some of the carvings on the statue.

I’m currently working on an interactive plan of a shipwreck where annotations contain links and are used as the launch to pages with further information. It’s a really nice way to explore it without, or indeed before, any diving.

Sketchfab also contains a really good user community, including a dedicated cultural heritage group.

There’s always room for improvement. I’d love to see a point-to-point measuring tool, and I hope that the download facility one day allows for charging for models – that way people who can’t afford to give away their content can perhaps earn a bit of income, which could be good for freelancers and for Sketchfab via a commission model.

Other than that, Sketchfab is pretty amazing. Go and sign up – it’s free.

Here’s a lovely statue-menhir from the island of St Martins on the Isles of Scilly that I scanned in 2015. Sketchfab’s now ubiquity allows models to be embedded within WordPress by just pasting the link into a new line in the editor. Very handy.

 

Animal Headed Saints

Discovery News Homepage 9 December 2015

Today sees the release of the January/February 2016 edition of British Archaeology. It features an article by Prof Michelle Brown and I on the early medieval cross-base at Gulval Church and its unusual depictions of the Four Evangelists.

Whilst my copy of the magazine has yet to be delivered the story has been picked up by Discovery News in a piece entitled “Medieval Monument Depicts Animal-Headed Saints“. Use the arrow buttons or square page buttons to navigate through the story.

Findings also suggest that people from the U.K. at this time were traveling to the Middle East, and vice versa, negating a prior belief that contact between this region and the U.K. was interrupted from about the end of the Roman Empire in the West in 476 A.D. to the start of the Medieval Crusades in 1095 A.D.

Subscribe to British Archaeology and find out about the latest issue.

Read about my initial discovery in my post “A Medieval Discovery at Gulval Church, Cornwall“. The British Archaeology and Discovery stories cover subsequent research with Michelle.

Announcing cornishmemory.com – a new resource for Cornwall’s audio-visual heritage

cornishmemory.com logoSince November 2014 some of my time has been spent working with Azook CIC,  a “not-for-profit social enterprise dedicated to growing cultural confidence amongst Cornish communities by connecting people with their cultural heritage”. Initially working on the MemoryFish project looking at fishing heritage in Cornwall, I began to help them rebuild cornishmemory.com so that it would have capacity to display tens of thousands of historic photos, films and audio recordings from around Cornwall. Many of these items have been digitised from private and pubic collections with the support of the Heritage Lottery Fund as part of Azook’s Re:collect project.

The new version of cornishmemory.com is built using an open source platform called Omeka, which is designed for “scholars, museums, libraries, archives, and enthusiasts”.  I customised it for their needs and populated it with over 31,000 items, assisted by many open source tools along the way, such as LibreOffice and OpenRefine.

There are lots of improvements and additional functionality planned for 2016 (Creative Commons licensing, metadata enhancement, temporal searching, Google site search, more content, etc).

Visit cornishmemory.com if you are interested in any aspect of the the history of Cornwall.