Tag Archives: UCL CEGE

Exploring 3D technologies at the BPMA

The last 12 months have been exciting for the Digital team here at the BPMA. Our Share Academy/London Museums Group funded project, From Vault to View, which partnered us with Mona Hess from UCL’s Civil, Environmental and Geomatic Engineering Department, has given us both a lot to do and to think about. The project has now come to an end, but it has increased the knowledge we now have of 3D technologies, and encouraged us to do much more.

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George V Die for striking leads. 1½d postage British Empire Exhibition, 1925

The aim of the project was to test different methods of capturing objects in 3D. Working with our little-viewed objects, Mona tried a variety of techniques to see what would produce good 3D models and what wouldn’t. The objects chosen posed real challenges: many were made of bright metals, which makes them difficult to capture using laser scanning or photogrammetry techniques; some were complex shapes, such as a flintlock pistol; while others had such a lack of detail making them difficult to measure and recreate as 3D computer models.

So what did we get out of it? Before the project we knew very little about how 3D

imaging worked. We felt the buzz around these technologies, such as 3D printing, but had little idea of how these things were created or how they might be used. All we really knew was that we had a rich treasure of 3D objects that no-one could really access physically in a satisfactory way.

By the end of the project, the BPMA had purchased photogrammetry software which has enabled us to try 3D imaging for ourselves – and the results are extremely promising. These techniques can be learnt by our staff and employed to create 3D models of items in the museum collection for exploration by the public.

This new-found knowledge, though still fairly elementary, has given us confidence to explore other uses for 3D imaging. In December 3D experts, ScanLab Projects, spent a week scanning the work depot, platforms and tunnels of Mail Rail which we will be opening to the public in 2016 as part of our plans for The Postal Museum. The results are truly astounding and we hope to show them in the near future.

Scanner capturing Mount Pleasant platform

Scanner capturing Mount Pleasant platform

Beyond all this, the project has given us an opportunity to revisit the objects and see them afresh. Although we weren’t able to obtain good 3D models of objects such as the large printing plates and the rollers, we did get excellent images of a number of dies using a technique known as Reflectance Transformation Imaging [RTI]. We also obtained an excellent laser-scanned 3D model of the Machin cast of Queen Elizabeth II – a truly unique and iconic object. The fruits of these experiments will eventually be made available via our website and online catalogue as we integrate the technology.

Plaster head of HM the Queen made by Arnold Machin for new definitive issue of stamps, third version (POST 118/5373)

Plaster head of HM the Queen made by Arnold Machin for new definitive issue of stamps, third version (POST 118/5373)

-Martin Devereux, Head of Digital

After a break following the first trials of our 3D scanning project

After a break following the first trials of our 3D scanning project, work continued last week when Martin Devereux, Head of Digital, and Stuart, Philatelic, took three objects to UCL to be scanned by Mona Hess, our 3D specialist. 

These were no ordinary objects, however. Stuart, our philatelic archivist and I took a flintlock pistol used to guard mail coaches, a handstamp used to cancel mail carried by the first airmail trial in 1911, and an iconic plaster cast of Her Majesty the Queen, sculpted by Arnold Machin. The Machin cast is recognised around the world as it has appeared on UK stamps since 1967.

Handstamp getting scanned by the

Handstamp being scanned by the Arius 3D colour scanner.

Each of these items poses a serious challenge to current 3D digitisation techniques. Glossy surfaces and deep features mean that lasers do not work as effectively as with less shiny and less detailed subjects.

Mona spent over 3 hours scanning the plaster cast with the Arius 3D colour scanner, while Stuart and I, along with MSc student, Sarah Sifontes Duran, captured the geometry of the handstamp and flintlock pistol, using an infra-red scanner – a technique that Mona is pioneering. The aim of this work is to produce a set of techniques which can be combined quickly and at low-cost to produce accurate and detailed representations of objects in three dimensions.

Stuart carefully transporting the Machin cast.

Stuart carefully transporting the Machin cast.

Output of the Machin 3D scan.

Output of the Machin 3D scan.

Digitising the plaster cast of Her Majesty was the climax of the day and a highpoint for Mona. She has scanned many memorable objects over the years and the Machin cast is certainly a significant addition to her list.

Flintlock pistol being scanned.

Flintlock pistol being scanned.

Machin cast close-up.

Machin close-up.

Once the cast had been scanned, the remainder of the day saw the scanning of the flintlock pistol and handstamp using the Arius colour scanner.

Mona is working to refine the results of the trials and further work will be undertaken over the summer as the project moves forward.

-Martin Devereux, Head of Digital

From Vault to View: Scanning trials

It’s been an exciting month for those involved in our 3D digitisation project, as it moved into the trial stages. A while back we shared what objects we selected for the scanning. A couple of weeks ago, Mona Hess, the project’s 3D digitisation specialist, visited the BPMA to undertake trials of low-cost scanning and photogrammatery techniques. 

In conjunction with our Conservator, Krystyna Koscia, Mona tested the application of a cyclododecane spray – a substance which, when applied to objects, makes them easier to digitise with a laser–scanner.

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Cyclododecane spray applied to test objects.This substances evaporates shortly after application and makes the object easier to scan with a laser.

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Mona applies the Cyclododecane spray to test objects as Krysia looks on.

The main event of the day was the photographing of a large printing plate against a target background, from which photogrammetric measurement will be taken to create a 3D map of the plate. You can find out more about photogrammetry and other techniques we will be using in this post. The plate was also scanned using a low-cost laser scanner, to obtain a rough geometry of the plate itself. Other objects were also photographed and scanned, including a die, an embossing die, a slogan die and a roller.

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Martin examines the plate.

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Mona standing on a stool for photogrammetry imaging.

You can check out the preliminary 3D model of the plate online now, and manipulate the model. We promise that the final results will be more detailed!

Trials continue in May, when Mona will be using the laser-scanner at UCL to scan other key objects from the collection.

-Martin Devereux, Head of Digital

How will we record the printing plates, stamps and rollers? Brief introduction to 3D imaging technologies

A couple of weeks ago, we introduced our 3D scanning project, Stamp printing plates, dies and rollers: from vault to view, in partnership with UCL. Mona Hess, Research Associate and PhD candidate at UCL, is the 3D specialist for this project. Mona has been working with museums for the past 10 years, creating three-dimensional digital models and physical replicas through 3D printing (such as these busts of Darwin and James Watt). She is interested in opening up archives and collections, giving visitors access to hidden objects. In this post she will introduce the different techniques we will be using to capture some of our hard-to-photograph philatelic material.

The BPMA’s philatelic collection goes far beyond stamps. It also includes plates, stamps and rollers, all of which are difficult to photograph. Many of these objects, especially the plates, rollers and dies can’t be on display to the public. There are conservation and security issues that prevent them from coming outside of the vaults. Despite this we still want philatelists, researchers, enthusiasts and visitors to be able to see and interact with these objects digitally.

Mona Hess face to face with the 3D digital model of Mrs.Flaxman

Mona Hess face to face with the 3D digital model of Mrs.Flaxman by the British artist John Flaxman, who used to be a professor at the UCL Slade School of Art. Copyright Mona Hess, UCL CEGE.

The creation of these 3D digital objects can be produced by ‘3D imaging’. We will be using “non-contact optical surface imaging”. The surface of the object will be recorded from all angles, and the model can be turned, zoomed and panned, almost as if you would have the real object in your hand.

For creating three dimensional images of printing plates, dies and rollers we will apply and combine different technologies:

  • Photogrammetry and ‘structure from motion’ is based on photography. We will produce a set of images while walking around the object. Usually the camera settings, background and lighting does not change while we do that. A software programme is then able to compute the common points to create a three-dimensional surface of the object with the colour, called ‘texture’. To be able to apply a scale to the object we need to include some known lengths in the photographs. This method is versatile with regards to object type imaged the equipment is very mobile, and the equipment affordable.
Photogrammetry of an Egyptian Cartonnage Mask from the UCL Petrie Museum of Archaeology.

Photogrammetry of an Egyptian Cartonnage Mask from the UCL Petrie Museum of Archaeology. Copyright Mona Hess, UCL CEGE.

An Egyptian is placed under the PTM/ RTI dome at UCL with 64 different light positions.

An Egyptian artefact is placed under the PTM/ RTI dome at UCL with 64 different light positions. Copyright Mona Hess, UCL CEGE.

  • Low cost 3D laser scanning can use sensors usually intended for gaming, like the Xbox Kinect. These sensors have inbuilt range sensing with human gesture recognition (natural user interfaces) that allow for objects to be captured using infrared signals. From initial tests we know that this technique is able to record the shiny surfaces of the printing plates. The information will give an overall picture, but not enough detailed information of the surface.
A low cost 3D sensor is used to 3D scan a Sepik Yam mask from the UCL Ethnographic Collection.

A low cost 3D sensor is used to 3D scan a Sepik Yam mask from the UCL Ethnographic Collection. Copyright Mona Hess, UCL CEGE.

  • Therefore we will also use High resolution 3D colour laser scanning on selected objects. The Arius 3D colour laser scanner is installed fixed in an air-conditioned room and used for high-quality digitisation of museum objects.  While this will give us a very detailed surface geometry, all objects will need to come to UCL.
The high-resolution 3D colour laser scanner at UCL is set up by Mona for the scanning of a relief of Mrs Flaxman by the British artist John Flaxman, who used to be a professor at the UCL Slade School of Art.

The high-resolution 3D colour laser scanner at UCL is set up by Mona for the scanning of a relief of Mrs Flaxman. Copyright Mona Hess, UCL CEGE.

As you might have gathered, the printing plates, dies and rollers will be difficult objects, so multiple techniques may be enlisted for each object. We will have to combine recording methods to find out how we can represent the fine engraving used in the dies and the overall geometry of the plates.

We would like to invite you at the end of the project to get your hands on the digital 3D models and tell us what you think about them. It is important for us to know how detailed these objects should be and depending on how you want to use them (i.e. on your mobile phone) the resolution can be lower.

If you are interested to know more about the technology, please visit Science of 3D where we explain the science behind our optical 3D imaging.

Stay in touch with me by following @Mona3Dimaging .

-Mona Hess, UCL

For the time being, we would love to hear your thoughts on this project. How would you use these 3D objects? Would you like to see them in an exhibition? We look forward to hearing what you have to say!