Photo-masking a bell from HMS Hood before conservation


Overall progress: 100% completed Start Contributing Now!


This application enables the creation of a high quality 3D model of an archaeological artefact via process known as photo-masking. There has been a revolution in 3D modelling in recent years and it is now relatively easy to construct such models from ordinary digital photographs. Isolating the object depicted in these photographs, and masking out the background, is an important first step to achieving high quality results. The final 3D model will be made publicly available and is useful not only for basic documentation purposes, but also for graphical displays in museums, for inclusion in gaming and virtual reality environments, or for identifying different sub-styles in otherwise similar types of artefact (that might tell us about the date of the artefact, where it was made, or by whom).

This particular photo-masking application is an experiment as we are attempting to model a bell from HMS Hood before the bell underwent conservation work.

HMS Hood was a British Battle Cruiser that was sunk on 24th May 1941 by the German Battleship Bismarck during the Battle of the Denmark Strait. In 2001 the wreck was located by Blue Water Recoveries, with the ship’s bell found lying on the seabed, away from the hull. In August 2015, Paul G. Allen (co-founder of Microsoft) led an expedition supported by Blue Water Recoveries to retrieve the bell and, soon afterwards, the bell was sent to Mary Rose Archaeological Services for conservation. The bell was presented to the HMS Hood when she was launched, in 1918, by the widow of Rear-Admiral Sir Horace Hood, great-great grandson of Sir Samuel Hood, after whom the ship was named. Sir Horace died at the Battle of Jutland on 31 May 1916, one of 1,026 officers and men who died in seconds when the battlecruiser HMS Invincible blew up and sank, and the bell is inscribed to that effect. The bell of the HMS Hood is now on display in the new exhibition '36 Hours: Jutland 1916, The Battle That Won The War' at the National Museum of the Royal Navy, in Portsmouth Historic Dockyard. The bell has been installed as a memorial to the 1,415 men who lost their lives when the ship sank in 1941. These photos of the bell pre-conservation show the condition the bell was in after it had undergone some initial treatments to stabilise it following its time in a marine environment.

What we want you to do

We would like people to draw a polygon around the object that they see in each photograph in order to identify its outline and exclude the image background. This allows the 3D modelling process to concentrate on the object itself and ignore irrelevant background information.

If you are interested in what our 3D completed models look like, please have a look at our Sketchfab profile.

This project is on behalf of:

The Mary Rose Trust.

[The Mary Rose logo British Museum UCL

Find the code on GitHub


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