How Does 3D Technology Work?

The
Innovative Entertainment Series is supported by
Dolby. “Like”
Dolby for a chance to have Adam West read your Facebook status update, live, on camera, February 18th.

In 1838, Sir Charles Wheatstone first described the process of stereopsis: the process by which humans perceive three dimensions from two highly similar, overlaid images. Or, the process by which Avatar looks like a mind-blowingly immersive alien landscape instead of a bunch of brightly colored fuzz.

3D technology has come a long way since Wheatstone developed his stereoscope, then used to view static images and eventually pictures. Now we get to wear Wayfarer knock-offs and enjoy 3D films, television shows and video games.

For some people, seeing cool images might be enough. But others might be curious how Pandora was brought to life, or how TRON: Legacy zapped them into its glowing world. The answer is both reassuringly simple and inordinately complex, depending on who you ask and how you look at it.

How do 3D films work? What’s the difference between polarity and anaglyph (we’ll get there), and what are the next steps for 3D gadgets and imagery? Have a look below for a breakdown of how today’s “it” technology functions. Plus, we put in some sweet looking pictures. What’s not to love?

A tremendous thank you to
David Leitner, Rob Willox and
Professor Ian Howard for their collective insight and help in describing the various forms of 3D technology below.

Stereoscopy 101

Big words! Academic nomenclature! Relax, this is actually the easy part. 3D, or “stereoscopy,” refers to how your eyes and brain create the impression of a third dimension. Human eyes are approximately 50 mm to 75 mm apart ? accordingly, each eye sees a slightly different part of the world. Don’t believe me? Hold up a pen, pencil or any other thin object. Close one eye. Now switch.

The image on either side should be pretty similar but slightly offset, like that line behind the woman’s head in the picture above. These two slightly different images enter the brain, at which point it does some high-powered geometry to make up for the disparity between the two images. This disparity is “3D” ? essentially, your brain making up for the fact that you’re getting two different perspectives of the same thing.

This is also, essentially, what modern 3D technology is trying to replicate. All those silly sunglasses and silver-coated projectors are all designed to feed your individual eyes different perspectives of the same image. Easy, right?

Well, yes. It is pretty easy for your brain to figure out the disparity between the two images. Your brain can automatically figure out all the angles and math and geometry to sync the images. The hard part is getting a camera to do the same thing, and to get those individual images to your individual eyes without butchering the whole effect.

What We Watch

Films

Film has been one of the pioneers of 3D, thanks to its hefty budgets and some technological daring. There are largely two ways 3D has been achieved in motion pictures: anaglyph and polarized glasses.

Anaglyph is a fancy way of referring to the red-and-blue glasses we used to wear. By projecting a film in those colors ? one in red, one in blue ? each eye would get an individual perspective and your brain would put the 3D effect together. Other colors could be used, providing they were distinct enough to be separated on screen. This technique, however, didn’t allow for a full range of color and had a tendency to “ghost,” or have the once-distinct images bleed into one another. Not cool.

Much more common is the use of polarized glasses, which take advantage of the fact that light can be polarized, or given different orientations. For example, one image can be projected in a horizontal direction while the second can be projected in a vertical direction. The corresponding glasses would allow horizontal polarization in one eye and vertical polarization in the other. The problem is that this kind of 3D requires you to keep your head still,

How Does 3D Technology Work?