New Scientist Article
Stealthy surfaces make for psychedelic laser scanning
by Rowan Hooper_New Scientist_22 April 2014
THERE hasn’t been a light show like this on central Berlin’s Oberbaum Bridge since April 1945, when the Nazis blew up its middle section. The bridge was bombed in an attempt to slow the entry of Russia’s Red Army into the city. Later, during the cold war, it was a link between the US and Soviet sectors of the divided city. Opened in its current form in 1896, suffice it to say, the bridge is historic.
So of course it needs to be laser scanned. This will provide a beautifully detailed three-dimensional record of the bridge in all its classic Brick Gothic glory. Lidar is the go-to technique. A laser illuminates the subject and the reflected light is captured and analysed to produce a picture, recording points at a rate of up to 960,000 per second. But for all the impressive tech, laser beams are quickly scattered and scanners easily misled. They do not see the world perfectly.
“In the case of the Oberbaum Bridge there is a massive glass facade, a shiny railing and the running water of the Spree river, all within the scanner’s field of view,” says Matthew Shaw of ScanLAB Projects, a 3D-scanning company based in London. “These ‘stealthy’ surfaces confuse, offset, reflect, refract and obstruct the scanner’s vision, forcing the machinery to make mistakes.”
And in fact that’s exactly what Shaw wants. “The idea is to show the technology and process laid bare, without the automised tidying and filtering that would usually refine these scans down to a minimal set of trustworthy points,” he says. ScanLAB’s images are on display at the Noise: Error in the Void exhibition at the Surface Gallery in London until 15 May.
This article appeared in print under the headline “Everything is illuminated”