3D imaging articles

[dracodraconis]

3D is becoming big business, so I'm devoting this post to the plethora of 3D-related technologies that are emerging. I have a particular interest in this area, given that I am a researcher in 3D measurement technologies.

3D Imaging

Some of you may be aware of DARPA's "Urban Challenge" competition in which vehicles must navigate a course through an abandoned urban setting. This year's semi-finalist was the "Spirit of Berlin", designed by the Fraunhofer Institute for Intelligent Analysis and Information Systems (which is a mouthful in itself). The car used a back-to-back pair of rotating high-speed laser range scanner to generate a 3D image of it's immediate environment, after correcting for the vehicle's motion. This information was then used to detect obstacles and compare the environment to the onboard map for course corrections. A variant of this system is being used by the researchers to determine whether billboards are visible or blocked by obstructions. They hope that the system will eventually be used on trucks to detect narrow tunnels, or to detect low street lights or bridges.

3D imaging can be used for even more mundane tasks, such as scanning a crime scene. The aforementioned Fraunhofer Institute, never the slouch, have also designed a wireless 3D imaging system to assist in capturing the details of a crime scene. The Kolibri CORDLESS projects a striped pattern which is then detected by two cameras. The deformation of the stripes is used to generate a 3D surface model of whatever the camera was pointed at, then sends it to a laptop. The camera is small (about the size of a shoe box) and fast (the image is available in a few seconds). Pattern projection systems tend to be small because all you need is, essentially, the equivalent of an overhead projector. All the work is in the software so the real challenge is creating a unit that can produce a bright enough light to be useful under a variety of situations while still being portable.

Another mundane, yet important, application is in mapping mines and tunnels. 3D Laser Mapping has developed a robotic survey system that can generate a complete volumetric map of a mine in a few days, depending on the size and complexity of the mine. For those interested in Canadian tie-ins, they use the powerful Polyworks software currently marketed by Innovmetric Software of Quebec and used in our lab here in Ottawa.

On a much smaller scale, the FINCH system is a 3D microscope with a twist. Normally, light reflected from a surface is blurred as it passes through a lens. One way to picture this blur is to imagine that light rays, also being wave-like, generate sub-harmonics as they interact with things in their path (like lenses), generating what is known as a "diffraction pattern". In a round lens, this appears as what is referred to as an "Airy disc" resulting from light waves interacting with the edges of the lens. In the FINCH system, they compensate for the diffraction pattern by canceling it out. This allows the system to resolve features far smaller than what is referred to as the "diffraction limit".

Even cameras are getting into the act with new systems to allow the average (or not so average) person to acquire 3D images. The camera shown here is not a great example, it being a film camera so would only generate 3D images viewable with special glasses. The camera uses stereoscopic imaging from three views of the same scene to generate a 3D image.

A more recent approach to generating 3D images is to learn from insects. The camera shown here uses a separate lens for each 256-pixel square of a 3.0 megapixel photodetector array. The system generates a depth map of the surface being imaged. Surprisingly, this camera can be made for less than a digital camera because most of the complex optics in your typical point-and-shoot are avoided. The researchers who developed this system at Stanford are currently investigating how this system can be built on a production line.

3D Display

Meanwhile, 3D movies are making the move into mainstream, or at least that's what some companies are banking on. Disney has announced that all their Pixar-generated films will be in 3D format, and even George Lucas has announced plans to remaster Star Wars yet again, this time in 3D. The hope is that by offering something that most home theatres can't reproduce they will boost supposedly flagging sales (although, despite all the complaints about piracy, this year saw record profits for movie companies). As a result, they are moving to make all theatres digital, a pre-requisite to displaying movies in 3D (often paid for by the theatres, who hand 55% of all ticket sales to the studios. See previous statement about record profits).

Virtual Interaction

Researchers at the Max Plank Institute have taken us one step closer to the "holodeck" of Star Trek with their CyberCarpet system (video at the link). Rolland Piquepaille has a well-written article on the technology at his blog site. In short, the 4.5-m by 4.5-m platform is a 2-D treadmill, able to move along two axes so that the person walking on it feels as if they are moving when they are, in fact, standing still. When combined with a set of 3D stereoscopic goggles, the participant will soon be able to walk through a reproduction of ancient Pompeii. I suspect they will forgo covering the participant in hot ash to complete the experience. The track can move fast enough to allow the participant to jog (to outrun the incandescent  gas cloud bearing down on the populous?)

Meanwhile, even social networking is making an attempt to break into 3D. Vivaty is described by its makers as a merger of Facebook, MySpace and Second Life. In other words, it takes the 3D avatar aspect of Second Life and attempts to imbue it with the more social aspects of Facebook and MySpace. Users are given a virtual room that they can decorate with photos and video. Users can interact by having their avatars "talk" with each other. They plan to offer Vivaty accounts to Facebook users later this year.

3D printing

New devices are coming into the market to let you turn your 3D dream into a physical reality. The device shown here is a Craftman CompuCarve that takes a block of wood or plastic, then accepts a CAD image via memory card (to avoid having to put a computer in a workshop full of dust). Yours for only $1,800(US).

Closing Notes

To end off, here is a tattoo, best seen with Red/Blue filtered 3D glasses