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How 3D technology is capturing the world

BBC Technology 07 Oct 2019 11:21
By Chris Baraniuk Technology of Business reporter
The perspective machine at Sample & HoldImage copyright Sample & Hold

London design studio Sample & Hold has been asked to scan all kinds of things: a shoe, a carrot, the heads of every member of the Barcelona FC team.

The firm has even worked with a company in Knightsbridge, London, that makes casts of babies' feet and heads.

"Occasionally they have a client who wants a head scan of their kid," explains Sample & Hold director Sam Jackson.

Those scans have been used for bronze casts of the child's head, and the 3D scan speeds up that process.

Sample & Hold doesn't need lasers to do this 3D scanning. Instead, it uses plain old 2D cameras. The trick is to use lots of them - 67 in total.

Image copyright Btf GmbH

It is called photogrammetry, the process of simultaneously capturing visual and spatial information. As a technology it is surprisingly old. People have been experimenting with different forms of it for more than 150 years but it is currently "having a moment", in part thanks to the low cost of digital cameras.

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"It's the colour information that's the important part," he says. Sometimes, though, the technique does not work quite as well as intended - for example with people whose skin is exceptionally smooth and clear.

I explain that he would have no trouble scanning me in this regard.

Photogrammetry is increasingly being used to insert lifelike character models into video games and to digitise real-world scenery.

And a recent indie game, Trueberbrook, features scenes that were handmade as real models and then scanned in a variety of different light settings using photogrammetry. These were then digitised.

"Everybody has a camera and cameras have dropped dramatically in price," explains Jan Boehm, an expert in photogrammetry at University College London.

Instead of sending staff up onto council building roofs to check them, some local authorities in the UK are now using drones to scan them in 3D instead, says James Dunthorne, a consultant for Uplift.

"Instead of inspecting the asset physically it can be done on a computer," he explains.

Rail companies, for instance, use such cameras to make ultra-detailed 3D models of track. Staff can then check that the track is in place with all crossings and switches correctly aligned.

Drone-based photogrammetry is cropping up everywhere. In the US, the Washington state transport department's aviation division recently trialled the technology as a means for detecting obstructive objects on the runway at two airports, Prosser Airport and Sunnyside Municipal Airport.

A spokeswoman for the department confirms to the BBC that the work will continue.

Often, though, third-party contractors provide the drones or software to make photogrammetry surveys possible.

"In 2018, our users mapped more than 450,000 sq km," she says. "This is ten times Switzerland."

Pix4D's clients like to make regular surveys of, for example, construction sites so that progress can be shown clearly in 3D. Or, a mining company might use photogrammetry to take measurements of the huge piles of earth or raw materials that are constantly being excavated.

"We've seen a great improvement in cameras in recent years… The stabilisation of drones is better and better," says Ms Guetcheva.

Polish firm FlyTech UAV makes a drone it calls "Birdie" that can be transformed from a fixed wing to vertical take-off and landing version with some attachments.

It's a way of mapping the world - one photograph at a time.

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