Tag Archives: snake

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

Year of the Snake stamps

To mark the start of the Year of the Snake, Royal Mail has issued a limited-edition stamp sheet featuring celebrations by Chinese communities around the UK alongside intricate designs representing all five elemental snake types.

Year of the Snake stamp sheet.

Year of the Snake stamp sheet.

The striking and multi-faceted sheet comprises 20 fireworks Smilers stamps alongside images of five UK Chinatowns. These are joined by the elemental snake types – Metal, Earth, Fire, Wood and Water – as well as images reflecting the aspirations of Hope, Heritage, Success, Togetherness and Good Fortune.

Elemental snake types stamps - Water, Wood, Fire, Earth and Metal.

Elemental snake types stamps – Water, Wood, Fire, Earth and Metal.

Good Fortune, Togetherness, Success, Heritage and Hope stamps.

Good Fortune, Togetherness, Success, Heritage and Hope stamps.

Stamps representing the Chinatowns in Belfast, Glasgow and Manchester are adorned with traditional Chinese dragons, with London and Cardiff the other cities featured. The sheet also features four large illustrations of red and orange snakes winding their way around the outside of the sheet.

Chinatowns stamps - London, Belfast, Cardiff, Glasgow and Manchester.

Chinatowns stamps – London, Belfast, Cardiff, Glasgow and Manchester.

The stamps follow on from the huge success of Royal Mail’s first ‘Lunar New Year: Year of the Dragon’ sheet from 2012.

London boasts one of the oldest Chinese communities in the UK with records showing some of the earliest settlers in Bow, east London.

Today there are significant Chinese communities in cities all across the country, most notably; London; Manchester; Birmingham; Liverpool; Sheffield and Edinburgh – with most featuring a Chinatown – an area rich in Chinese culture and business. The original Chinatown was situated in Liverpool – however this was destroyed during the Second World War.

A Statistical Bulletin published in May 2011 for the Office for National Statistics (ONS) estimated the Chinese population in the UK as 451,500.

Cantonese is the predominant language spoken by Chinese living in the UK, followed by Mandarin Chinese and Hakka Chinese.

The Lunar New Year Commemorative Sheet is available in 350 local Post Offices across the UK, online at www.royalmail.com/snake and from Royal Mail Tallents House (tel. 08457 641 641), 21 South Gyle Crescent, Edinburgh, EH12 9PB.

For Chinese customers, the sheets can be purchased from Emily Lee at Stanley Gibbons on elee@stanleygibbons.com or from Stanley Gibbons (Asia) Ltd.,10/F Central Building, 1-3 Pedder Street, Central, Hong Kong.

See Year of the Snake stamps from around the world on our Chinese New Year Pinterest board.