A brave new digital world

This summer, SHARP will bring the digital age to Boneyard!

Our new Introduction to Photogrammetry course, to be run by Paul Docherty, will use the very latest imaging and rendering technology to bring to life our investigations into Sedgeford's ancient past, and teach interested participants how to do the same.

Paul is currently studying a BA in Archaeology by full-time distance education at Leicester University. Prior to that he was Head of Games Art and Design at Teesside University, bringing his background in engineering, physics, video game design and 3D graphic art to teach others in this ever-developing field. You can read a bit more about Paul here.

Here he is last summer on Boneyard doing the weekly wash (even digital pioneers need to have clean smalls).

So what is "photogrammetry", and why does it sound so complicated?

"Photogrammetry allows you to construct a digital 3D representation of a real-world object or environment for use in research or virtual reality environments where you can interact with the objects on your home PC," says Paul.

"The term ‘photogrammetry’ actually means measurements from photographs and one of its early archaeological uses was in recording old buildings and monuments in Germany during the nineteenth century. Its origins go much further back though to a process called projective geometry which was something Leonardo da Vinci experimented with.

"By placing an object of known measurement in the scene and then taking a photo you can later derive other measurements using the object as a scale. Modern photogrammetry is actually a process known as ‘multi-view stereophotogrammetry’, quite a mouthful which is why everyone shortens it to photogrammetry, or 3D. Although the maths can be quite complex that doesn’t matter because its all handled by the computer and the user doesn’t have to worry about it. The main thing is to ensure your photographs are correct!"

And it appears that photogrammetry has a wide range of applications in archaeology.

Paul continues: "Photogrammetry is used in more places than you would think! The technology behind it is actually used in such diverse areas as medical imaging and cartography (mapping), but on an archaeological level we tend to use it for aerial surveying, building surveying, and artefact digitising. We will work through these three areas during the course and I will also touch on some of the other types of digitising such as laser scanning and LIDAR throughout the week, but from an introductory point of view only so no one needs to worry about things getting too heavy!

"The main benefit from photogrammetry is that it is a non-intrusive and non-destructive technology and as such is safe to use in delicate situations.

"Because excavation is, by its very nature, a destructive process archaeologists can use photogrammetry to record an excavation at particular stages and as such keep a snapshot of those stages for later reference. In effect it is an evolution of the traditional site photography, except with many more photographs!

"Back in the lab or museum we can use photogrammetry to create a digital ‘copy’ of an artefact and make that available to a much wider audience for study.

"We can also create replicas of artefacts from the data using 3D printing technology, something I have experience in and will touch on during the course as well."

Here are a few images of a very famous archaeological artefact, showing how photogrammetry can be used to scan an object and digitise an image which can then be moved around digitally and studied in three dimensions - saving wear and tear on the original, as well as making that experience available to almost anyone, globally.

Can anyone learn and use these amazing skills, or is it limited to those with extensive computing and programming experience?

"Anyone who has used their computer for browsing the internet, working with office documents, or played games can grasp the technicalities of photogrammetry," says Paul, reassuringly.

"It's pretty safe to assume that most people know how to use a camera, what with mobile phones having them by default, and you do not need to be a professional photographer in order to succeed; in fact being a professional photographer could make you worse, and I will explain why on the course...!

"So anyone can get to grips with the processes involved fairly quickly, although some of the more specialised areas of photogrammetry do have a higher learning curve and I will touch on these during the course. I have heard some archaeologists say that photogrammetry is all done by the computer and so there is no skill involved. The message here is that anyone can learn basic photogrammetry but there are many uses for photogrammetry and these plus different levels of accuracy all depend on the skill of the ‘photogrammetrist’."

So is it possible that photogrammetry can ever replace excavation archaeology? Paul's answer to this question is instant and unambiguous.

"No!" he says. "Certainly not in the short term and not in cases of rescue archaeology. Excavation allows us to ‘selectively’ extract the past from its surroundings in order to study it using various observational and scientific techniques. This is something photogrammetry cannot do. But as technology improves we may see it being used more to record the actual excavation process in a way which allows us to compile a complete volumetric snapshot of the site as it was before excavation. This could then be used for much more detailed examinations regarding the stratigraphic positioning and orientation of site features and artefacts.

"It may even be used for developing new excavation techniques. Photogrammetry uses trigonometry to determine the position of points in space and for that to happen we need to be able to see those points. But by using photogrammetric techniques with other sensor types we can begin to reconstruct previously inaccessible areas. For example we can use thermal imaging to reconstruct heat signatures as 3D models by looking at the target from different angles. We have also seen the use of particle physics in discovering hidden chambers such as that recently found in the Great Pyramid.

"The field of photogrammetry is very exciting and I am sure that anyone who attends the course will come away with their own ideas as to how they can use it in their workplace. Oh, and did I mention it’s fun…!"

It certainly sounds like fun! And it's super-exciting to be using futuristic technology to explore the distant past, on the Boneyard and beyond.

To read more about Paul's course and join us in this brave new world of the old, head to the course page on the SHARP website.