Stereoscopy (also called stereoscopic or 3-D imaging) refers to a technique for creating or enhancing the illusion of depth in an image by presenting two offset images separately to the left and right eye of the viewer.
Both of these 2-D offset images are then combined in the brain to give the perception of 3-D depth.
Three strategies have been used to accomplish this:
- Have the viewer wear eyeglasses to combine separate images from two offset sources (Stereopsis)
- Have the viewer wear eyeglasses to filter offset images from a single source separated to each eye
- Have the lightsource split the images directionally into the viewer’s eyes (no glasses required)