Editing Glasses (section)

=== 3D glasses ===
{{Main|Stereoscopy#3D viewers|l1=3D Viewers}}
The [[stereoscopy|illusion of three dimensions]] on a two-dimensional surface can be created by providing each eye with different visual information. 3D glasses create the illusion of three dimensions by filtering a signal containing information for both eyes.  The signal, often light reflected off a movie screen or emitted from an electronic display, is filtered so that each eye receives a slightly different image. The filters only work for the type of signal they were designed for.

[[Anaglyph 3D]] glasses have a different colored filter for each eye, typically red and blue or red and green. A [[polarized 3D system]] on the other hand uses [[polarization (waves)|polarized]] filters. Polarized 3D glasses allow for color 3D, while the red-blue lenses produce an image with distorted coloration. An [[active shutter 3D system]] uses electronic [[Shutter (photography)|shutter]]s. [[Head-mounted display]]s can filter the signal electronically and then transmit light directly into the viewer's eyes.

Anaglyph and polarized glasses are distributed to audiences at [[3D film|3D movies]].  Polarized and active shutter glasses are used with many home theaters.  Head-mounted displays are used by a single person, but the input signal can be shared between multiple units.