Stereoscopic 3D Display Basics
Since 3D displays are by no means a common household item, most folks are likely to be somewhat uninformed when it comes to how a 3D display actually works. This calls for a short primer. Please keep in mind that we'll focus on the core points for the sake of simplicity.
A human being's ability to perceive the third dimension goes hand-in-hand with our binocular 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 television this is a bit of a challenge since there is only one screen to look at. How does a 3D display provide a separate image for each eye?
Surprisingly, there are a number of ways to achieve this goal, one of which involves the use of old-school anaglyph red-and-blue colored glasses. But when it comes to widespread and modern applications, there are two stereoscopic 3D systems that rule, or are about to rule, the world: alternate-frame sequencing and dual-projector polarization.
