About mhairimaxwell

Researcher on the ACCORD project

How to build 3D models using aerial videos: the Access Archaeology group pass on their experience

Although the Uist group helped the ACCORD team produce a brilliant set of 3D images of the best preserved wheelhouse on Uist during their stay, after they left we felt rather overwhelmed by the computing power required to deliver 3D imaging of any scale when working offline.  However the potential of this technique for recording some of the thousands of archaeological sites on Uist would not go away and we were keen to work out how at least to test the software with a basic laptop or PC of the kind that most community members have at home.  We also felt that aerial photography was a good way of getting a good general overview of some of the bigger sites – we had been testing a basic kite rig over the summer and using it to mesh 2D photographic views that could also be used to generate plan drawings.
As the kite rig took pictures using video it was suddenly realised that rather than dealing with digital still images of between 2-10mB each, extracted stills from video film are only around 150kB in size and the 50 or so of these required to generate a half decent 3D image would only be a 7.5MB file rather than up to 0.5GB for full size stills.  Using these small images, rather than waiting hours for a result, you will see something in a few minutes.
This enigmatic and unrecorded site was only recently discovered by a local resident in a remote peninsula on the island of Grimsay.  It comprises a long natural rock outcrop jutting out into a marshy area, which has at one end a curious V shaped plan structure with corbelled rubble walls and a water basin at its node point.  The image is made up of around 30 no 150kB digital stills taken off a video recorded by a Canon Ixus 220 camera suspended from a Cody kite.

This enigmatic and unrecorded site was only recently discovered by a local resident in a remote peninsula on the island of Grimsay. It comprises a long natural rock outcrop jutting out into a marshy area, which has at one end a curious V shaped plan structure with corbelled rubble walls and a water basin at its node point. The image is made up of around 30 no 150kB digital stills taken off a video recorded by a Canon Ixus 220 camera suspended from a Cody kite. Copyright: David Newman.

The remote moorland on the east side of Uist has hundreds of shieling mounds scattered across its hills, some alone, some in groups of up to 15, where families used to spend summers grazing their cattle away from the machair townships.  Many of these sites are unrecorded and some of the larger mounds show clear signs of earlier settlement lying under 18th/19thC shieling structures.  This remote example is one of the largest so far discovered and includes the remains of four separate stone buildings on its summit and west facing slope.  A smaller partner mound on the other side of the adjoining burn has been partly eroded revealing some of its sectional structure.  The image is made up of around 80 no 150kB digital stills taken off a video recorded by a Canon Ixus 220 camera suspended from a Cody kite.

The remote moorland on the east side of Uist has hundreds of shieling mounds scattered across its hills, some alone, some in groups of up to 15, where families used to spend summers grazing their cattle away from the machair townships. Many of these sites are unrecorded and some of the larger mounds show clear signs of earlier settlement lying under 18th/19thC shieling structures. This remote example is one of the largest so far discovered and includes the remains of four separate stone buildings on its summit and west facing slope. A smaller partner mound on the other side of the adjoining burn has been partly eroded revealing some of its sectional structure. The image is made up of around 80 no 150kB digital stills taken off a video recorded by a Canon Ixus 220 camera suspended from a Cody kite. Copyright: David Newman

So the Uist ACCORD group recommends the following procedure as a start up 3D imaging idea:

1. take a video rather than stills of your site remembering to cover all angles (no kite needed!),
2. abstract around 50 still shots,
3. download the freeware version of Agisoft PhotoScan and the very useful pdf instructions, load up your photos and run the software (the ‘workflow’ tab is key!) be amazed at the results of your work.
Clearly the detailed quality of imaging isn’t nearly as good as it would be with high resolution stills, but it will get you used to both the techniques, the software and the abilities of your own computer.  When you are reassured you have mastered the technology, you can be more confident about setting your PC up to run overnight.
Good imaging!
David Newman, October 2014.

The Uist ACCORD group included:  Simon Davies, Ian and Felicity Bramwell, Catherine Macleod, Calum Fraser, Austen Dancey and David Newman

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An Icon of the Uists: the Grimsay Wheelhouse in 3D

Back in August ACCORD was in the Uists with the Access Archaeology group. Together we decided to record in 3D a Late Prehistoric wheelhouse, using a visualisation technique called photogrammetry. Check-out a fly-through here, the Grimsay wheelhouse brought to life!

The Grimsay wheelhouse was excavated and partially reconstructed by local retired engineer Roy Ashworth in the early ’90s and is iconic of archaeology in the Uists.

 

Useful tip on how to sharpen a 3D still in Photoshop!

On the 4th and 5th of October we were in Kirkcudbright, Dumfries and Galloway, working together with the local History Society. Using photogrammetry we recorded selected tombstones in Kirkcudbright Kirkyard in 3D- and the results were fantastic! One of these was the headstone dedicated to ‘Billy’ Marshall, a traveler and ‘King of the Gypsies’ who apparently married at least 17 times and lived to the ‘advanced age of 120 years!’ Find out more about him on his Wikipedia entry here.

One of the group members, George Wishart has passed on this very helpful tip for sharpening stills from 3D PDFs, so you can get an image like this:

3D model of Billy Marshall's headstone

3D model of Billy Marshall’s headstone, made by the Kirkcudbright History Society and ACCORD.


“3D PDFs do not open in Photoshop. However if I rotate the image to the desired position, I can then capture it using “Print Screen”. Ctrl v opens it in Photoshop. I can then crop the desired part to A4. That can then be sharpened. I like to use a duplicate layer with high pass filter in the duplicate layer which I then blend in overlay mode. The image can then be flattened and saved as a jpeg. Worked well on William Marshall.” George Wishart, October 2014.

Thanks George! Please do keep passing on tips and hints, either by using the reply tabs on the blog here, or email them to M.Maxwell@gsa.ac.uk and I will post them for you.

Falstaff in 3D!

“All’s one for that.”
[He drinks]History of Henry IV, Part I Act 2, Scene 4.

Work in progress of a 3D model of the Shakespearean character Falstaff, currently in Calderglen Country Park, East Kilbride. Made by the How Old Are Yew group, based in Castlemilk, Glasgow.

3D model of Falstaff

unfinished 3D Photogrammetric model of the Falstaff sculpture in Calderglen Country Park, made by the How Old Are Yew group.

The Craw Stane in 3D!

CrawStane (Adobe PDF file, make sure you have the latest version. Will not currently work in your browser- you must left click to download & save on your desktop/ in your documents and then open. Be patient, it is a 44.8MB file- and then bingo! Be amazed.)

Check this out! A model made out of only 130 photographs and then processed using Agisoft photoscan, by the Rhynie Woman group in Rhynie, Aberdeenshire. We think there is some more detail revealed… what do you see?

CrawStane

Recording the Stones at Camas nan Geall and St Comghan’s Churchyard, Ardnamurchan

Jon Haylett, member of the Ardnamurchan Community Archaeology group writes…

Members of Ardnamurchan Community Archaeology spent the weekend (8th to 10th of August) working with the ACCORD Project, which works together with local groups in the digital recording of heritage places or objects. Organised by Archaeology Scotland‘s Project Manager Cara Jones (at left in picture), it involved two of ACCORD’s researchers, Dr Mhairi Maxwell (standing next to Cara) and Dr Stuart Jeffrey who are based at the Digital Design Studio at the Glasgow School of Art.

Camas Nan Geall, Ardnamurchan. Photos taken by Jon Haylett of the ACA group.

The team at Camas Nan Geall, Ardnamurchan. Photo taken by Jon Haylett of the ACA group.

ACCORD were very keen that we should drive the training days, so we chose the graveyard at Camas nan Geall and St Comghan’s churchyard in Kilchoan as containing monuments which we felt were of considerable significance but which were also in need of recording since they are exposed to continuous weathering.

Camas Nan Geall, Ardnamurchan. Photos taken by Jon Haylett of the ACA group.

The team at work at Camas Nan Geall, Ardnamurchan. Photo taken by Jon Haylett of the ACA group.

Camas Nan Geall, Ardnamurchan. Photos taken by Jon Haylett of the ACA group.

Recording the multiperiod standing stone/ Early Medieval cross-slab using photogrammetry at Camas Nan Geall, Ardnamurchan. Photo taken by Jon Haylett of the ACA group.

At Camas nan Geall we used the standing stone as a model for photogrammetry, which turns digital photographs into 3D digital models.  Since the process improves with the number of pictures taken, we took as many pictures as possible, guided by Stuart (centre), ACCORD’s lead investigator.

Taking pictures round the sides was easy enough, but to complete the model Stuart demonstrated a telescopic holder which, using a camera which is controlled by wi-fi, enabled us to take pictures of the top of the stone.  Andrew Perkins, right, is operating the camera from a tablet.

With the graveyard recently cleared by ACA members, it was an ideal time to record the 18th century gravestones.  

Camas Nan Geall, Ardnamurchan. Photos taken by Jon Haylett of the ACA group.

17th Century graveslabs, possibly belonging to the Campbells, at Camas Nan Geall, Ardnamurchan. Photo taken by Jon Haylett of the ACA group.

To do this, we were taught a second technique, Reflectance Transformation Imaging, which is designed to bring up features which, to the eye and in on ordinary photographs, are lost.  This process is great fun in that….

Camas Nan Geall, Ardnamurchan. Photos taken by Jon Haylett of the ACA group.

Our RTI tent (!) at Camas Nan Geall, Ardnamurchan. Photo taken by Jon Haylett of the ACA group.

….it has to be done in darkness so, to the amusement of passers-by, tarpaulins were carefully stretched across the stones and most of the group squeezed under them.

 With a camera held securely on a tripod, and a torch which is angled low across the face of the stone and moved into several positions, twenty or so pictures were taken of each stone which, when processed by the software, brought out many hidden features.

On Sunday we spent time in St Comghan’s churchyard.  It contains a number of grave slabs which are dated to the 14th or 15th century and according to local folklore may have been brought here from Iona.  The stone in this picture is much smaller than the grave slabs but has an interesting design on it.

Camas Nan Geall, Ardnamurchan. Photos taken by Jon Haylett of the ACA group.

Intricate 14th/15th Century graveslab in Kilchoan Parish Churchyard, Ardnamurchan. Photo taken by Jon Haylett of the ACA group.

Sadly, Sunday saw some very heavy rain. This we could cope with, particularly those under the tarpaulin (there are five under it!), but the midges were out in force and were no respecters of archaeological research, so the day’s outside work was somewhat curtailed.

Camas Nan Geall, Ardnamurchan. Photos taken by Jon Haylett of the ACA group.

Kilchoan Parish Church, Ardnamurchan. Using RTI to record the 14th/15th century graveslabs in the rain & vicious midges. Photo taken by Jon Haylett of the ACA group.

As part of the course, we had an initial, brief look at the pictures the software can produce, and the results were spectacular, but huge amount of data remain which ACA members are now beginning to process.  We hope to be able to publish this soon in the hope that these digital pictures will help to put Ardnamurchan even more firmly on the archaeological map, but we also hope that they will be enjoyed by those who are unable to visit the sites.

Many thanks to Cara, Mhairi and Stuart for a super weekend.

Jon Haylett, member of the Ardnamurchan Community Archaeology group.

Read Jon’s blogs at Mingary CastleA Kilchoan Diary and West Ardnamurchan News

Canmore entries for the sites can be found here: Camas Nan Geall and Kilchoan Old Parish Church

From Gallipoli to Colintraive – Todd Ferguson of the ColGlen Archaeology Group reflects on the digital recording of a WW1 memorial…

On a rather fine Saturday morning in June, the ColGlen Archaeology Group came together to take part in the final session with Dr. Stuart Jeffrey, Dr. Mhairi Maxwell from ACCORD – they also brought along a friend of theirs’, Alistair Rawlinson from DDS, the world’s leading expert on laser scanning historical monuments. We all felt very privileged to have Al doing the scans, especially on learning he traveled all over the globe using the same technique and equipment on sites such as Mount Rushmore.

Stuart prepared the agenda for the weekend and did his best to scare us with words like LIDR and Photogrammetry which we all now know is the science of making measurements from photographs, especially for recovering the exact positions of surface points or in the ColGlen Archeology Group vernacular direct from our very own Cathy Grant “It’s like magic”.

This brings me to a site in Colintraive that is very dear to my own heart, having spent almost 20 years living in Australia and New Zealand. Gallipoli, during World War One, is an event etched in the stone memorials and hearts of every ANZAC. The 25th April celebrations are a national holiday where we are reminded ‘Lest We Forget’ – not to mention the only time of the year we can partake in a gambling game of ‘Two Up’ between 12 and 5pm, a popular game amongst the ANZAC’s.

Having fun under the tarp! The ColGlen group taking photographs using the Magic Pole to create a photogrammetric model of the WW1 memorial.

Having fun under the tarp! The ColGlen group taking photographs using the Magic Pole to create a photogrammetric model of the WW1 memorial.

We decided that this mystery memorial on the beach, that few had seen, should be the first site that we tried out our new skills of photogrammetry. Cameras in hand we began to cover every angle and surface that we could, made a lot easier thanks to Gordon hacking through most of the undergrowth at the back of the monument. Stuart brought out his secret weapons – the ‘Magic’ pole and iPad for ensuring that we captured the top parts of the monument, and much fun under the tarpaulin had begun.

The rain had started to drizzle as we finished up and headed back to the hall for soup and sandwiches provided as always by Danuta (thanks again). Stuart loaded the photographs and we sat back to let the software do its thing. Slowly but surely the monument began to appear before our eyes on the screen. It truly was like magic.

We then began to uncover more about the MacKirdy names on the plaques.

It turns out that Peter and Robert were twin brothers who like many young men before them headed off across the water to fight in the Great War. Peter, was a Lieutenant-Commander with ANSON Battalion of the Royal Naval Reserve, was wounded on April 25th 1915. He subsequently died of his wounds on May 29th 1915, aged 26.

His brother Robert, who was a Captain in the Argyll and Sutherland Highlanders, left for Gallipoli on the 3rd June 1915. Robert was subsequently killed in fighting at Achi Baba, Gallipoli on 12th July 1915 aged 26, a mere 44 days after his brother Peter.

newspaper clipping commemorating the deaths of the MacKirdy brothers. Posted by @InverclydeWW1 on Twitter 11th June 2014.

Newspaper clipping commemorating the deaths of the MacKirdy brothers. Posted by @InverclydeWW1 on Twitter 11th June 2014.

Screenshot of the photogrammetric model created by the ColGlen Archaeology Group (generated using Agisoft Photoscan) of the WW1 memorial. Dedicated to the MacKirdy borthers who fell at Gallipoli in 1915.

Screenshot of the photogrammetric model created by the ColGlen Archaeology Group (generated using Agisoft Photoscan) of the WW1 memorial. Dedicated to the MacKirdy borthers who fell at Gallipoli in 1915.

 

 

 

They shall grow not old,
As we that are left grow old,
Age shall not weary them,
Nor the years condemn.
At the going down of the sun,
And in the morning
We will remember them.

Lest We Forget.

 

 

 

 

Peter and Robert MacKirdy are not forgotten and their memory lives on within the Helles Memorial, Gallipoli for Robert (http://www.twgpp.org/information.php?id=3495679) and the Portsmouth Naval Memorial for Peter (http://www.twgpp.org/information.php?id=3318647). It was, however a small glen in the North West of Scotland, Colintraive, Argyll where we became friends with them.

Next year is the 100th Anniversary of their deaths and it would be wonderful if we could have a dawn service on 25th April 2015 and remember all of the young men from the area who perished in the Great War and all others.

I’d like to thank Stuart, Mhairi, Al for their patience and experience. I’d also like to thank all the members of the ColGlen Archeology Group.

MACKIRDY, PETER MACKAY, Lieutenant.-Commander. R.N.Y.R Anson Battalion Royal Naval Division, twin son of Robert MacKirdv of Greenock and Glasgow, Sugar Broker, by his wife, Elizabeth, daughter of Peter Mackay born Greenock 1 Sept. 1888; educated Collegiate School, Greenock ; was an Engineer ; Sub-Lieutenant., R.N.V.R.. 17 Julv. 1910; Lieutenant. 10 April. 1913, and Lieutenant-Commander, 10 April. 1913; died of wounds received in action at the Dardanelles, 29 May 1915.

MACKIRDY, ROBERT FINGLAND, Captain, 5th Battalion. Argyll and ’Sutherland Highlanders (T.F.). twin son of Robert MacKirdv, of Greenock and Glasgow, Sugar Broker, by his wife, Elizabeth, daughter of Peter Mackay of Greenock: born Greenock. 1 Sept. 1888; educated Collegiate School. Greenock, and was a Commission Agent; joined the 5th Argyll and Sutherland Highlander (T.F ) 22 March, 1907; became 2nd Lieutenant. 23 March. 1908; Lieutenant 20 Jan 1912 and Captain 1 Nov. 1914; volunteered for Imperial service on the outbreak of war; left for Southampton ; went to the Dardanelles, 3 June. 1915, and was killed in action there while fighting at Achi Baba, 12 July, 1915.

Todd Ferguson, resident of Colintraive and member of the ColGlen Archaeology Group.