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Rediscovering History by Documenting the Present with 3D Laser Scanners

By Administrator - Posted on 18 April 2011

LiDAR News | April 16, 2011 - For hundreds of years Mont Orgueil Castle on the Channel Island of Jersey was England’s frontline defence against armies from continental Europe. Built in the early 13th Century, the castle has endured a life of change from castle to prison, to spy station, and to seat of government. Throughout all the changes Mont Orgueil remained an icon for Jersey’s pride and independence.

Why all the change? Mont Orgueil was perfect for its time, but alas time changed faster than the castle. While the castle was Jersey’s primary defence when first constructed, the invention and widespread adoption of gunpowder ultimately rendered the castle indefensible from an adjacent hill overlooking the castle.

Keen to maintain her defences, at the end of the 16th century Britain started construction on Elizabeth Castle near Saint Helier. And as the armies moved to their new fortification, Mont Orgueil was transformed into Jersey’s only prison which it remained for another 100 years. Then in 1693, Mont Orgueil was declared uninhabitable and the prison was also moved to St Helier.

The castle continued to change in the centuries that followed and in 1800 parts of the castle were reoccupied and for use as the headquarters of the secret service organisation Britain was running in northern France. Then more recently, during the Second World War, the Germans occupied the castle and added modern fortifications camouflaged to blend in with existing structures.

All in all this beautiful castle has endured many lives, its form changing with each incarnation to best configure itself for the job at hand.

Fast forward to the 21st Century, and a new group ‘invaded’ – at least for a few days. Channel 4’s flagship programme Time Team, which has been unearthing the archaeological mysteries of the British Isles since 1994, deployed a team of historians, archaeologists, and professional surveyors to reveal the hidden history of the castle which has long-since vanished from view. Using sophisticated 3D laser scanning technology to measure and model the current castle the team revealed dilapidated elements of the old 13th Century castle walls and fortifications. Processed using Pointools software, the laser scan data was ultimately used to create a series of high-definition fly-though animations complete with advanced lighting effects which featured in the final TV broadcast.

“Initially the producers thought the 3D laser scanner would only be used to record measurements to help the team make decisions, explain their discoveries, and support any conclusions they may come to.” commented Ben Bennett, Director of Digital Surveys. “That’s because they had already employed their own 3D modeller to recreate the ‘original’ castle.” He continued, “However, after viewing the point cloud model captured during the first day’s survey work, the team agreed that it’s visual quality and clarity was far superior to the manual ‘reverse-engineering’ modelling efforts. As a result, the visualisations and animations created using Pointools software were used instead, greatly enhancing the show’s visual appeal.”

Due to a tight production schedule Digital Surveys was given just three days on site to measure the whole castle. This was no mean feat; just as the challenging topography posed difficulties to would be attackers centuries ago, it also created technical challenges for the survey team. Using a Leica Scanstation 2 scanner, eighteen 360 degree scans were completed to record the external defensive walls (the Upper Grand Battery), the internal middle wall, the keep roof, and internal rooms. Afterwards, the data was imported using Pointools software and cleaned to remove noise.

“Pointools is the proven market leader for point cloud visualisation and animation and was therefore the obvious choice for creating ortho-rectified images and fly-through movies,” continued Bennett. “The software is capable of handling billions of points seamlessly and the point cloud model can be sliced and filtered to create accurate cross sections.”

“We were very pleased with the high quality 3D model created by Digital Surveys using Pointools software,” commented Time Team Director and owner Tim Taylor. “We look forward to using 3D laser scanning technology on the show again.” Indeed as I write I believe Time Team now plans to use 3D laser scanning technology on every new project it undertakes.  

See full article here.