3D - 2

If 3D Television (or film) is actually just a specially constructed 2D image, why do you need a special TV?

I can't get my head around this. 3D just works by manipulating a 2D image (with the use of the glasses and all that) so why is a special television necessary? What can a 3D television do that a regular one cant?

Public Comments

1. The TV needs to do what your vision does - present a slightly different view of a scene to each eye. In most 3D TVs, it does this by alternating the left and right eye views in sequence, synchronizing them with active shutter glasses so that your left eye sees only the left images and your right eye sees only the right images. By the way, the best 3D is created with two cameras, separated by some distance, simultaneously recording the scene. 3D generated from old 2D content uses computer analysis to determine depth cues, then sythesizes left and right eye views.
2. This is why. A 3d movie has 2 2d movies, slightly different from each other, shown on the screen at the same time. 1 2d movie can only go to the left eye, the other 2d movie can only go to the right eye. A normal tv was not made to project 2 2d movies on the screen at the same time. Only 1 for both eyes at the same time. So modifications of some kind have to be made to do this. You can not pop a 3d disk into your dvd player with 2 2d movies on it and then expect the tv or dvd player to know what to do with the added information. Each 2d movie for each eye is a complete movie by itself. To get the 2d version of Avatar they just show the right eye movie or left eye movie by itself. The images of both 2d movies just don't match up exactly all the time, why you often see double images of things without glasses on. Each eye is actually looking at different spot on the screen when looking at the same image with glasses on.