A Quick 3D Primer

(The following primer is copied from our recent article Wall-Sized 3D Gaming, Just like The Theaters Do It. If you've read that, feel free to continue on to the next page.)

A human being's ability to perceive the third dimension is primarily achieved by our binocular (stereoscopic) vision. Put simply, we can see in 3D because we have two eyes. Each of our eyes sees the world from a slightly different perspective, and our brain combines these perspectives to give us a sense of how close or far an object is. Because there are two separate perspectives, this is commonly referred to as stereoscopic vision.

An easy way to demonstrate stereoscopic vision is with a quick exercise (best performed when you're not looking in the direction of a PC monitor). Close your left eye and put your right hand about four inches in front of your right eye. Wiggle your hand a little. Now, open both eyes and do the same thing, with one hand in front of your right eye. You will experience a big difference in your sense of depth and the position of your hand in 3D space. When both of your eyes are providing an alternate perspective, your brain is able to put together that rich sense of relative placement and provide an accurate indication of how far your hand actually is from your face. If you stop moving your hand and close each eye alternatively, you will notice that each eye provides a different view of where your hand sits in your field of vision.

The key to a 3D display, then, is to provide each eye with an alternate view of the same scene. As you can imagine, in the theater or on TV, this is a bit of a challenge since there is only one screen at which to look. How does a 3D display provide a separate image for each eye?

Surprisingly, there are a number of ways to achieve this goal, and one involves the use of old-school anaglyph red-and-blue colored glasses. When it comes to LCD computer monitors and TVs, 120 Hz alternate-frame sequencing is the technology that the TV industry and Nvidia are investing heavily in promoting. Alternate-frame sequencing is being groomed as the de-facto standard of full-resolution 3D home displays for the foreseeable future.