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

Stamps: Why the Portrait?

As an Art Historian (now Philatelic Assistant) I have always been fascinated by the portrait and a stamp in itself is a miniature piece of art. To understand why the Queen’s head appears as it does on GB stamps we need to first understand the significance of the portrait historically.

Some of the earliest profile portraits were produced by the Romans for their coins and medals.  Images of the Emperors illustrated their power and importance and thus the profile became synonymous with these characteristics. It was also a way of distributing the face of their leader, who many would never have seen.

Roman Coin

Roman Coin

We can see the influence of these artefacts in the work of Renaissance artists who tried to recreate this sense of power in their portraits of the wealthy. This is evident in the portrait of the Duke of Urbino and his wife by Piero della Francesca who are both depicted in profile facing one another. Yet this composition had to be used as the Duke had previously lost his right eye in a tournament. You can also see the significance of the medal in Sandro Botticelli’s ‘Portrait of a Man with a Medal of Cosimo De Medici’ c.1474-75.

Piero della Francesca 'Duke of Urbibo' c1467-1470

Piero della Francesca ‘Duke of Urbino’ c.1467-1470

Sandro Botticelli 'Portrait of a Man with a Medal of Cosimo the Elder' c1474-75

Sandro Botticelli ‘Portrait of a Man with a Medal of Cosimo the Elder’ c.1474-75

However the initial portrait of Queen Elizabeth II used for postage was not in fact a profile. Instead it was a three quarter view of Her Majesty photographed by Dorothy Wilding in 1952. Though adequate as a Definitive stamp –  the Wilding design was found to be overly challenging for many stamp designers as it took up to one third of the stamp’s area and subsequently compromised the design of the stamp.

Wilding High Value Definitives 1955

Wilding High Value Definitives 1955

As a solution to this problem Tony Benn (Post Master General 1964-66) along with designer David Gentleman introduced the idea of removing the Queen’s head altogether. Initial ideas were produced, however in 1965 the Queen decided she wished to remain on the stamp. This led to the small profile silhouette on commemorative stamps being used instead, reminiscent of those produced in the 18th century of the English high society.

1965 Churchill Commemorative

Churchill Commemorative without the Queen’s Head 1965

A traditional silhouette portrait of the late 18th century

A traditional silhouette portrait of the late 18th century

To produce a profile portrait of the Queen, The Royal Mail approached the British sculptor Arnold Machin. He took inspiration from the simplicity of the Penny Black portrait, which was based on a medal of Queen Victoria by William Wyon. This again acknowledges the historical importance of the profile.

Arnold Machin Plaster Cast

Arnold Machin Plaster Cast

William Wyon Medal

William Wyon Medal

The image of the Queen we see today is not only practical for producing stamps but also evokes the idea of power and importance, circulating her image to the nation. The significance of the portrait on a stamp is not merely a representation of the person but as a symbol of their significance. Commemorative stamps elevate the importance of an individual by allowing them to feature prominently on the stamp, though the Queen still remains dominant as the accompanying silhouette.

Winston Churchill 1st (October 14 2014)

Winston Churchill 1st NVI (October 14 2014)

Next time you see a photograph of yourself have a think what you would look like on a postage stamp?

– Georgina Tomlinson Philatelic Assistant.

Volunteer Week: Spotlight on Post Office Architecture expert Julian Osley

Our volunteers have a range of interests, from design to postal history and everything in between. Some of these interests are what motivate them to join us, others they discover while here. To celebrate volunteer’s week Julian Osley tells us about Post Office architecture, a passion he discovered while volunteering at the BPMA.

The Uniform Penny Post prompted an enormous increase in the level of business, however the Post Office was slow to provide suitable premises in which to manage the transaction of business.

By 1840 major post offices had been built in London, Edinburgh and Dublin but, it was not until the 1860s that serious attention was given to improving the quality of post office buildings in provincial urban areas. For the most part these buildings were designed by architects in the Office of Works, and followed prevailing architectural fashions, such as the Italianate style of design which can be seen today in the former post offices at Derby, Maidstone, Sheffield, Newcastle-upon-Tyne, Hull and Wakefield, to name just a few.

Maidstone post office

Maidstone post office

 

Typical of the more flamboyant Edwardian era are the buildings at West Hartlepool, Aldershot, Esher, Canterbury and Sheffield. After the First World War, for reasons of economy, and also to foster the image of post office as an approachable, yet solid and dependable institution, the style known as “Post Office Georgian” was adopted, its characteristics being the use of brick on a domestic scale in order to achieve harmony with the local environment.  A ‘Brighter Post Office’ campaign was launched in the late 1920s in order to make post office interiors more attractive. For a few years after Second World War, new post office buildings followed the Georgian tradition (although in a stripped-down format), but following the Festival of Britain of 1951, this was finally abandoned in favour of a modern approach.

Wakefield post office

Wakefield post office

Because the post office became so important in the lives of a community after the introduction of the Uniform Penny Post, the opening of a new building was an event to be celebrated. Often it was made available for inspection before the official opening ceremony, to be attended by Post Office officials and local dignitaries, who would make congratulatory speeches; on occasion, the architect would be invited to give a tour of the building, and then tea would be taken in the sorting office. A programme of the day’s events might be printed, and the local newspaper would report the proceedings at length, while at the same time providing a detailed description of the building. Critics would use the correspondence pages of the paper to air their views over the poor location of the building, the lack of an external clock and inadequate street lighting, but in general these buildings were praised for their “commodious” accommodation and regarded as having contributed significantly to civic pride.

Maidstone post office

Maidstone post office

To find out more about volunteer’s week visit http://volunteersweek.org/about or head to our twitter page see what other exciting things our volunteers get up to.

Volunteer Week: Curatorial Volunteer Muriel

Here at the BPMA we are lucky to have some wonderful volunteers who provide invaluable assistance to us, helping catalogue items, assisting with conservation projects and preparing collections for the move to The Postal Museum. One of our Curatorial Volunteers, Muriel Bailly, gives you a sneak peak at what it’s like to volunteer at the BPMA.

While packing uniforms today I found a 1988 5p coin in a pocket!

While packing uniforms today I found a 1988 5p coin in a pocket!

Since September 2014 I have been volunteering at the BPMA, assisting Curators Emma Harper and Joanna Espin packing, auditing, recording and labeling the collection, ahead of the museum’s move in 2016.

Over the past months I have had the chance to gain hands on experience working with a wide variety of unique objects including prints, uniforms and evidence from the 1963 Great Train Robbery.

Pink ribbon= objects audited and freshly packed = Productive day

Pink ribbon= objects audited and freshly packed = Productive day

By working with such a varied collection, I have become familiar with conservation issues and procedures for different materials and have gained experience in object handling which will be crucial for my career development.

I work with all sorts of objects like these handstamps which I need to repack.

I work with all sorts of objects like these handstamps which I need to repack.

I am currently working full-time as a Visitor Experience Assistant at Wellcome Collection and hope to pursue a career in curating. The Curatorial Volunteer opportunity at the BPMA was a rare opportunity to gain hands-on, practical experience of collection management in a very competitive sector.

I also help clean objects - have you ever seen the top of a telephone kiosk?

I also help clean objects – have you ever seen the top of a telephone kiosk?

Volunteering has already helped me gain more responsibilities in my job where I was recently given responsibility for the handling collection and I am confident it will lead to future career development.

If this has piqued your interest then visit the volunteering page of our website to see a list of our current volunteer vacancies.

June Evening Talk – Letter’s from a Long Road with Julian Sayarer

On 4 June record breaking cyclist Julian Sayarer will be joining us to talk about his remarkable journey that took him around the world with just his notebook and letters for company. Here he gives us a taste of what we can expect.

It would be hard to argue that my twenties were defined by riding bicycles and writing, with the two things eventually combining to form what probably became my preferred means of travelling the world.

IMG_3492

Aged 20, I finished my final politics exam of a first year at Sussex University, rode to Portsmouth and there met a friend for the Channel ferry and then the ride to Lisbon. The next year I rode to Istanbul through Eastern Europe. The following year to Istanbul along the Adriatic and through the Balkans. The following year I rode home to London through the Ukraine, and the year after that – in 2009 – I rode 18,049 miles around world in 169 days, breaking a world record in protest of the means by which it had the previous year been set by an alpha-male in cahoots with big finance. I didn’t like the inaccessible and foreboding depiction of travelling the world by bicycle, and I felt that the ideal of cycling towards an empty horizon had always been an experience too special to sell to a bank for its marketing campaigns.

IMG_1770

The slow pace of modern publishing bears a good deal of the responsibility for why I am talking about this experience in 2015 and a year after the release of Life Cycles. I always wanted this book to constitute snapshots of the world – its people and its politics – at the start of the twenty-first century, rather than be only an account of what it is to ride a bicycle a long way. As much as the waiting often felt far too long, I came to enjoy the reflection that the passing of time allows.

Words and writing have always been a good companion on the road, especially so in remote and foreign places. Surrealism can help make light of dehydration in a desert or sleep deprivation in a long night of riding. Amongst foreign languages, a written self can become conversation; the appearance of thoughts upon a page a frame of reference when otherwise alone. Some descents – of 30 effortless miles out of a mountain – I feel compelled to try and write and record, whilst others happen in moments that make all words feel cumbersome. When cycling around the world, I sent text messages to an obscure, new programme called Twitter, which in-turn displayed them on a website, and eventually went on to become quite successful.

Life Cycles cover 480

The bicycle remains altogether quite timeless in a changing world; the endeavours to chronicle those trips – in books, in letters, sometimes in tweets – is an ongoing journey mixed with challenges and rewards, always throwing new light on travel writing, letters, and forms of communication both obvious and hidden.

The event will take place on 4 June 19.00-20.00 at The Phoenix Centre, Phoenix Place, London, WC1X 0DL

To book tickets please visit www.lifecycles.eventbrite.co.uk or telephone 020 7239 2570.

You can buy Life Cycles online or in all good bookshops.

 

My Favourite Object: Pentacycle

In this month’s edition of My Favourite Object, find out why the Pentacycle is Head of Fundraising Emma’s absolute favourite.

Perhaps the perfect symbol of the Victorian spirit of invention, often seen as eccentric by today’s standards, the Pentacycle was invented in 1882 – not long after the more famous “Penny-farthing” and before safety bicycles, more recognisable as ancestors of the bikes we ride today, were introduced.

Front of Player's Cycling cigarette card showing four postmen on Centre cycles, otherwise known as 'Hen and Chicks'.

Front of Player’s Cycling cigarette card showing four postmen on Centre cycles, otherwise known as ‘Hen and Chicks’.

Designed by Edward Burstow, an architect from Horsham in Sussex, the Pentacycle was conceived to enable larger postal loads to be carried and delivered with ease. Although popular with postal delivery workers in Horsham, it did not catch on more widely, and certainly does not look an easy or comfortable ride by today’s standards!

I have a couple of reasons for choosing the Pentacycle as ‘My Favourite Object'; firstly because it is just such a fantastic looking machine. It is large, awkward-looking and, although I have no idea what it would be like to ride, certainly does not look user-friendly (and that’s with its capacious mail baskets empty). Yet, despite all of this the very concept feels ambitious and visionary…why wouldn’t it catch on? It’s this sense of optimism and spirit of adventure that really make me connect with the Pentacycle.

Me with the Pentacyle at our Museum Store in Debden.

Selfie with the Pentacyle at our Museum Store in Essex.

I also love its nick-name “the Hen and Chicks”. The reason for this excellent name can be understood simply from viewing the image below, and lends such personality to this ungainly invention. It perhaps conveys the affection with which the postmen who rode the bikes referenced them, and the interest visitors to the collection are still compelled to show the Pentacycle on seeing for the first time.

Pentacycle Debden

Pentacyle at our store in Essex.

 

Although the Pentacycle, or a 1930s replica of one, is currently housed at the BPMA’s Museum Store in Debden, Essex, it will be the central object on display in the ‘Revolutionising Communications’ exhibition zone of The Postal Museum when it opens. This gives it an important role, along with many other unique and surprising objects which will be on permanent display to the public from late 2016, in providing a window on the past through the perspective of the postal service.

View from below

View from below

Working at the BPMA I feel uniquely privileged to have more of an insight into the collection, and to be able to explore and connect with items such as the Pentacycle or ‘Hen and Chicks’. Bringing remarkable items, such as this, to a wider audience than ever before is exactly why The Postal Museum and Mail Rail will be so important. I, for one, am looking forward to seeing visitors of all ages explore, experience and be inspired by this history of adventure and the pioneering spirit that has driven communications forward over the past 500 years and will continue to do so into the future.

-Emma Jhita, Head of Fundraising

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?