Mathew Ingram: Lasers - the final frontier

For obvious reasons, it's fairly difficult to look at things up close when you're out in space.

In most cases, you're looking out a tiny window in the space shuttle or the International Space Station, and even if you're drifting around in your space suit, it's still difficult to get a very good look at anything, what with the darkness of space and/or the brightness of the sun.

That's why cameras - like the one on the end of the special inspection boom the space shuttle Discovery carries with it - are so useful.

In the case of the shuttle, the inspection boom will act as an extension to the Canadarm, letting the crew scan the surface of the shuttle for damage, such as the hole in the wing of Columbia that caused it to explode on re-entry on February 1, 2003, killing the crew.

The damage was caused by a briefcase-sized piece of foam that flew off during launch and hit the edge of the wing.

The boom will perform that surface scan using a special 3D laser camera system from an Ottawa-based company called Neptec Design Group, which licensed the technology from Canada's National Research Council.

But the ability to detect very small cracks and holes with great accuracy, even from far away - and even in the blackness of space or the glare of the sun - is something that has applications other than just checking over space shuttles.

That's why Neptec and other companies that are working on similar technology, such as Germany's Gesellschaft fur Optisch Messtechnik (GOM) and Konica Minolta, have been trying to branch out and introduce their equipment and techniques into new areas.

After all, if a 3D laser camera can detect a crack the thickness of a credit card (about 300 microns) from 1.2 metres away even in darkness - as Neptec's can - it should be able to recognise other things as well, including parts on an assembly line or faulty semiconductor panels.

Laser-based 3D imaging is already fairly popular in the geological surveying business, and in industrial and real estate design fields. I-Site, based in Australia, sells systems that can generate a detailed 3D scan of buildings, as well as locations such as the Hoover Dam, which the company recently produced a 3D scan of for a company that is building a new bridge at the site (just south of Las Vegas).

Neptec's camera, like those made by GOM and Konica Minolta, uses a process known as laser triangulation to generate a precise 3D image. By shining a laser from one side of the unit on to a surface, and then picking up the signal as it is reflected into a mirror on the opposite side of the unit, Neptec's camera can gauge the distance from the camera to the object (if you know the length of one side of a triangle and the angle of one corner, you can figure out the length of the other sides).

The breakthrough for Neptec - according to Dr Iain Christie, head of research and development - was producing a unit that could do a detailed scan quickly, so that a 3D picture could be produced in real time.

Although the principle of laser triangulation was well established, he said, most 3D scanners produced too much information too slowly, and it had to be processed later in order to generate any useful data. Neptec's technology provided "more information and a lot less data".

Neptec is also working on newer and faster systems, including one based on "lidar" - light detection and ranging - which is a version of radar that uses light.

In that device, the laser is bounced off an object and the unit determines the pattern of the surfaces being scanned by judging the amount of time it takes for the laser light to return. According to Christie, prototypes of the new system can detect cracks 300 microns thick from about 200m away, and he says the team at Neptec expects it will soon extend that to two kilometres.

The company is also working on a higher-resolution version of the camera used on the shuttle, which would be able to detect a crack 20 microns thick.

Among other things, the company is working on a scanning device that could be used for targeting by the military, by recognising 3D shapes of objects such as tanks or missiles at long distances.

The technology could also be used in almost any assembly line manufacturing process, Christie says, since it could scan all the parts of a system in real time and see whether the configuration was correct or not.

One thing is clear: when the thing you're trying to see is as small as a hair and is moving past you at a couple of metres per second you either need one heck of a pair of eyeglasses or a 3D laser camera.