Modern Technology: How does Stereoscopic 3D TV work?
How does 3D technology work?
In terms of perception we, as humans, naturally experience what is known as binocular vision. In simpler terms, this means that because we have two eyes we actually perceive two different images at one time which is what allows us to perceive depth.
This theory can be proven in practice by placing an object in front of you and closing one eye and then closing that eye and opening the other one. When you do this It appears like the object shifts to either the left or the right a little bit depending on which eye you close.
When using both eyes simultaneously our brain uses this distance in order to calculate and perceive depth and distance, so that we can 'see' it.
3D Television & Active Shutter Glasses
When viewing a 3D movie on a 3D television, the screen actually displays two alternate images at the same time, one superimposed over the other. The distance between these two images is approximately three inches to coincide with the average distance between a person's eyes. This is known as stereoscopic 3D.
However, because the two alternate images are being displayed simultaneously we need to wear 3D glasses to perceive the depth and distance properly. A set of 3D glasses contains an active shutter on each lens. Each of these lenses opens and closes alternately at a speed so rapid that it's impossible to notice with the naked eye and therefore alternating between the two images thereby 'fooling' our perception into seeing depth which isn't really there.
3D Gaming Without Glasses & Active Shutter Screens
Recently released is the Nintendo 3DS which offers the ability of 3D gaming without the need for active shutter glasses. Technically the 3DS still offers stereoscopic 3D in exactly the same way that a television set does.
However, because there is no need for glasses the quality of the 3D experience and quality is not so good, as you cannot have images seemingly pop out of the screen and come hurtling towards you like you can with 3D glasses, due to the active shutters being right in front of your eyes providing the amount of distance between the glasses (ie you) and the television set.
The Nintendo 3DS (and other handheld 3D devices) work by having the active shutter built into the screen in front of the display. Once again the active shutter works by opening and closing at a rate too fast for the human eye to decipher and displays two alternating (rather than two together) images at a rate so fast that those two images are perceived by the brain as one image with depth. However, because the active shutter is built into the screen (or in front of it) each eye cannot be fooled individually.
3DTV Without Glasses
The ability to watch television in 3D without the need to wear glasses is possible by having an active shutter built into the television screen. However, as mentioned above, without glasses each eye cannot be fooled individually, so both eyes must be 'fooled' at the same time which can, at the most, only offer depth and this means that the two alternating images cannot be shown simultaneously.
3D television without glasses may be a possibility in the future as there are still many controversial issues surrounding the consequences of active shutter glasses on our health.