Ironbridge 3D Laser Scanning for English Heritage
Ironbridge, Britain's best known industrial monument is situated in Ironbridge Gorge on the River Severn in Shropshire. Built in 1779 it is a 30m cast-iron bridge, the first in the world to use cast iron construction on an industrial scale. It is a Scheduled Ancient Monument and the bridge, the adjacent settlement of Ironbridge and the Ironbridge Gorge form the UNESCO Ironbridge Gorge World Heritage Site. It is of great importance as world’s earliest major iron span and was the prototype for iron bridge construction.
APR Services were commissioned to create a highly detailed and accurate point cloud of the structure and surrounding area for English Heritage with the specification requiring a 2mm spacing point cloud over every surface of the structure.
3D Laser Scanning was undertaken using a Faro Focus Scanner and RIEGL VZ-400 laser scanner.
The bridge surroundings were scanned in 2 days using the Riegl scanner, ideal for long range scanning. The bridge itself was scanned in 6 days using the Faro scanner, a shorter range but higher accuracy instrument. A special hydraulic mast was used to lift the scanner to a variety of heights and locations under the bridge as well as extending it out over the sides of the bridge in order to scan the underside of the bridge and tops of iron beams, triggering the scanner to record wirelessly.
Due to the nature of the bridge the temperature had to be monitored at all times during the acquisition of data. Iron expands when the temperature varies, so a 'reference' temperature had to be chosen and the scanning had to be done to within +/- 3C of this. All scans were referenced using a combination of spheres and flat targets to ensure the scans registered together.
The many gigabytes of scan points were cleaned and compiled carefully and finally averaged to provide the dense 2mm accuracy point cloud required.
A highly accurate 3D point cloud was provided alongside Spheron 360˚ photography.
APR laser scan to 3D model visualisation