Tag Archives: 3D

Experiments in Photogrammetry

Recently we experimented with producing a set of 3D models of items from the collection using a process called photogrammetry. Rose Attu, a Digital Humanities MA Student from UCL, who’s currently on placement at the BPMA, talks us through the process.

To create a 3D model a series of overlapping photographs of a single object are taken from different positions, and then a piece of software is used to triangulate the coordinates of each image and align them, reconstructing the whole object in 3D. With each shot, the digital camera also records metadata including the focal distance between the lens and the object; this enables the software to recreate the position the camera was in when each photo was taken.

Curator Emma Harper holding the stamp snake

Curator Emma Harper holding the stamp snake

The objects we chose were the prosthetic Postman’s Hand and the Stamp Snake. An object covered in a repeating pattern, or one without any distinguishing features at all, will affect the software’s ability to rebuild the depth of an object. Both these objects have plenty of distinctive features, so the software could detect the details from photo to photo and build accurate models without distortions.

Postman's prosthetic hand being photographed

Postman’s prosthetic hand being photographed

Our first object was the Postman’s Hand. Once it was in frame and in focus, and evenly lit to avoid shadows, we could begin the capture process. To capture our objects from multiple angles we used a turntable to rotate them through 360°. The turntable was also covered in a distinctive image, which gave the software more common points to identify. The turntable was edited out at a later stage, so that our final models were just of the hand and the stamp snake.

Stamp snake being photographed

Stamp snake being photographed

On average it took 30 photos to complete one rotation, after which the camera was raised for a second sequence capturing the object from a higher angle. For more consistent results we kept the camera settings the same until a rotation was complete, and used a tripod and remote shutter release to keep the camera static. We output the raw image data as a set of TIFFs and corrected the white balance, and then our images were ready to be transformed.

Based on the estimated camera positions and the details in the images, the software built a point cloud, which is essentially a 3D model made up of dots. It then added a more detailed polygonal mesh layer representing the object surface. The final step was to add the textures; because we photographed our objects in high resolution, even the tiniest details were visible on the final models.

Snapshot of the 3D model of the stamp snake. Manipulate the model on Sketchfab.

Snapshot of the 3D model of the stamp snake. Manipulate the model on Sketchfab!

We were surprised with how little effort and technology it took, and the results were fantastic!  For our set-up we used:

  • Lazy Susan turntable with a nonrepeating pattern on it
  • Digital SLR camera and tripod
  • Light box or tent
  • Studio lights or some source to help get rid of shadows
  • Photogrammetry software – we used Agisoft which was great and you get a 30 day free trial

Have a go yourself– we would love to see your models!

– Rose Attu

Capturing Mail Rail in 3D: The Next Steps

Imagine a place frozen in time, left exactly as it was the day that everyone left it. That is what it’s like in Mail Rail today. After it was mothballed in 2003, everything was left as it was that day, down to the newspapers, rota and personal belongings. This time capsule effect is part of what makes Mail Rail unique and exciting; however when we start construction later this year to convert it into a ride and visitor attraction we’ll have to make a few changes to ensure it’s safe and accessible for visitors. We are keen that the space remains as true to how it is now as possible, but these changes mean that the little things could be lost. We thought long and hard about how we could preserve Mail Rail exactly as it is today. The solution we came up with was 3D scanning.

Just before Christmas ScanLAB Projects, a 3D scanning and visualisation company based in East London, spent a week down in Mail Rail and captured the Mount Pleasant depot, loop and platforms in 3D. In total they completed over 223 terrestrial laser scans with incredible and accurate results.

View of the Mount Pleasant platforms

View of the Mount Pleasant platforms

The scans that ScanLAB have created show all the minute detail of the spaces, preserving Mail Rail as it is now for us all to explore in years to come, including parts of Mail Rail that visitors to the site won’t be able to see, such as the train graveyard.

Capture

Fly-through of the train graveyard

 

Of course the results have got our creative gears spinning. Increasingly visitors are expecting an increased level of digital interactivity from a visitor to a museum, allowing them to interact with exhibits and collections through devices such as smart phones and tablets, before, during and after their visit – but how can we use these scans to enhance the visitor experience, both physically and remotely?

The guys at ScanLAB gave us a demo of just this; using an Oculus Rift headset we explored the train graveyard and the depot. BPMA staff delighted in walking around, reaching out to touch trains and walls, and even ‘sitting’ in one of the trains!

Looking around the Mount Pleasant Depot through Oculus Rift headset

Other possibilities include augmented reality apps for smart devices, projections or 3D printed installations –the options are endless– so what would you do with them?

Capturing Mail Rail: 3D survey of the depot, loop and platforms

Last week was an exciting one for the Digital team here at BPMA! For the past five days, Rachel and I have been accompanying ScanLAB Projects Ltd. while they undertake a 3D survey of Mail Rail.

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Scanner capturing the west platform.

 

ScanLAB have been targeting the areas of the network that are to be the focus of our Mail Rail  visitor attraction – that is the work depot at Mount Pleasant, the platforms beneath Mount Pleasant and the tunnel loop from the depot to the platforms – just about 1km of tunnels.

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Will from Scanlab discusses the technology with guests from FARO, New Scientist and Harry (BPMA Communications Manager).

 

The 3D scanning of Mail Rail is important in that it captures the industrial heritage of an unexplored and little-known feature of central London. The survey records the details and the features of Mail Rail as a working space, with all the flotsam and jetsam left behind when the service was suspended. From tools and equipment to newspapers and calendars from over a decade ago, Mail Rail is a time capsule just waiting to be explored. These features will inevitably be tidied up when we open it to the public so it is crucial to capture that detail for posterity.

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Thomas and Will from Scanlab sharing the raw data.

 

The survey will allow users to see these features in three dimensions – bringing the platforms to life in ways not possible even when the train ride is running. The survey can be shown via the web and used in the exhibitions we create at the Postal Museum and Mail Rail attraction to offer a truly explorative experience of Mail Rail in a way that the train ride cannot. Imagine navigating the tunnels and platforms for yourself?

Scanner on the platform.

Scanner on the platform.

Using the latest scanning technology from FARO, and using the surveying and imaging expertise of ScanLAB, we will be obtaining as faithful a representation of the site as we possibly can. From the work depot to the platforms and the tunnels in the loop around Mount Pleasant, we will be recording a truly significant piece of Britain’s industrial history.

-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!

From Vault to View: Object Selection

Earlier this year we announced  our 3D scanning project with UCL to capture objects from our philatelic collection. Over the past month, the Philatelic team has been selected just a few objects from its vast collection to scan. Joanna Espin, our Philatelic Assistant, introduces the objects in this post.

We have a large collection of three dimensional objects to do with the production of postage stamps; ranging from metal dies and transfer rollers, to printing plates. There are also three dimensional objects to do with the design of stamps and other aspects of postal operations. We have chosen a range of objects, of various sizes and materials, which are important to understanding postal history.

The objects selected are some of the most treasured in the Philatelic collection, and concern the history of the Penny Black, Machin Head and letterpress printing.

Wyon Medal, 1838

The Wyon Medal was the inspiration behind the engraving of Queen Victoria featured on the Penny Black.

Wyon Medal front

Wyon Medal front.

Wyon medal reverse

Wyon medal reverse.

‘Old Original’ Penny Black Die, 1840

The ‘Old Original’ Penny Black die, from which all Penny Black plates and most Penny Red plates were made.

‘Old Original’ Penny Black Die, 1840.

‘Old Original’ Penny Black Die, 1840.

Elizabeth II Machin head plaster cast, 1966

Arnold Machin intended his portrait of Queen Elizabeth to allude to the Penny Black: both were designed from a relief portrait and both monarchs are wearing the George IV State Diadem.

Elizabeth II Machin head plaster cast, 1966

Elizabeth II Machin head plaster cast, 1966

Machin Stamp roller, 1968

This object’s shiny surface has prohibited successful digital rendering. 3D scans would, in connection with the Machin curved plate, explain recess printing.

Machin Stamp roller, 1968

Machin Stamp roller, 1968

Machin curved plate, 1968

The 1968 high value Machin £1 stamp recess printing plate.

Machin curved plate, 1968

Machin curved plate, 1968

Edward VII Die, 2d Tyrian Plum, 1910

Almost 200,000 sheets of this iconic stamp were printed yet only one was ever used, as King Edward VII died before the stamp was issued. We plan to scan the die and box.

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

This object incorporates interesting shape, detail and colour. It connects with the 1924 Wembley slogan die and letterpress printing.

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

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

Downey Head ½d Skin, 1911

The first definitive stamps of King George V’s reign were based on a photograph taken in 1910 by W. & D. Downey. The Downey Head skin we plan to scan is an important part of the history of letterpress printing.

Downey Head ½d Skin, 1911

Downey Head ½d Skin, 1911

Edward VII embossing punch, 1902

Successfully capturing the detail and embossing on the punch would enable effective demonstrations of embossing technique.

Flintlock Pistol, 1816 – 1841

This object demonstrates the diversity of the BPMA Philatelic collection. A 3D rendering of the pistol will highlight the engravings on the end of the barrel, which state that the gun was for official GPO mail coach use.

Flintlock Pistol, 1816 - 1841

Flintlock Pistol, 1816 – 1841

Aerial Handstamp, 1911

The world’s first scheduled airmail service began in 1911 as part of the celebrations for the coronation of King George V. This handstamp, commemorating the event, has wide historical appeal. The object’s shape and material make it ideal for 3D scanning, as reflective surfaces are notoriously difficult to capture.

Aerial Handstamp, 1911

Aerial Handstamp, 1911

Slogan Die, Wembley, 1925

Issued as part of the celebrations marking the British Empire Exhibition, this slogan die has wide historical appeal and, due to its shape and material, is another interesting object on which to experiment 3D scanning techniques.

We will initially test various techniques, a process expected to take several hours for each object, and compare the results to existing two dimensional photographs. The processes to be employed are highly experimental and will shape recommendations for a standardised approach to 3D imaging. The results will enable ground-breaking access to treasured objects in the Philatelic collection and, ultimately, audiences will virtually handle important postal history objects.

Stay tuned next week to find out about the different techniques we will be using!

–  Joanna Espin, Philatelic Assistant

Stamp printing plates, dies and rollers: from vault to view

Over the next year, our Philatelic and Digital teams will be working with UCL’s Mona Hess, Research Associate and PhD candidate at UCL, to digitise objects from our collections, including printing dies, rollers and plates. These objects are difficult to photograph and not available for consultation by the public. This project, funded by Share Academy, will provide access to these important objects through a combination of a number of technologies. The final output will be set of 3D digital objects for use by philatelic enthusiasts, researchers and the general public. This blog will regularly update you on what is happening along the way.

Mona discusses various imaging techniques and engagement outputs for the 3D objects. A stamp plate sits at the centre of the table.

Mona discusses various imaging techniques and engagement outputs for the 3D objects. A stamp plate sits at the centre of the table.

Last Friday (24 January), we held a kick-off meeting for our Philatelic 3D digitisation project, a Share Academy project partnership with UCL. Because of the highly-reflective surfaces of these objects, a combination of technologies will be trialled to see which works best.  Some of the objects can be captured at the BPMA’s premises using techniques such as photogrammetry. Others, however, may need to be transported to UCL to be digitised with their large-format 3D scanning device.

Original Heath die of Penny Black with various other dies. (POST 118/1733)

Original Heath die of Penny Black (centre) with various other dies. (POST 118/1733). The reflective and finely-engraved surface makes them difficult to photograph.

Another highlight of the meeting was the demonstration of a possible output for the 3D objects: a mobile/tablet application. The Petrie Museum engages visitors using an application that explores the history of the Nile Valley with 3D digitised objects that can be manipulated by users.

Over the next month, our Philatelic team will be selecting various objects to be captured in the trials (due to take place from March), as well as planning any transportation of objects, where necessary, to UCL.

Are there any particular objects in the Philatelic collection that you want to see as 3D objects? 

-Rachel Kasbohm, Digital Media Manager