Stereoscopic Vision


Each eye gets a slightly different view of the world

The brain fuses the two views to get depth information

Artificial Stereo

Create two distinct images - one for each eye

Used since early 1800s

Stereo Viewing


Present each image separately to each eye

e.g. stereoscope, HMD

Stereo Viewing

With a projection screen, images must overlap

Glasses filter images - each eye sees only one

Active Stereo


Active Stereo


Passive Stereo


Uses polarization to separate images

Two projectors - one for each eye

Each eye's image is polarized differently

Linear Polarization

Linear Polarization


Circular Polarization

Linear polarizer + quarter-wave retarder = circular polarization

Polarization is left-handed or right-handed
(clockwise or counter-clockwise)

Immune to head-tilt problem

Circular Polarization

VR Screen

Circular Polarization


Other Methods

Anaglyphic Stereo


Uses colored filters

One image is red, other is blue/green/cyan

Only requires one projector (any type)


Filters make different colors appear at different depths

Red appears close, blue appears distant

Pulfrich effect

Images viewed through dark lens reach brain slower

Pulfrich glasses have one dark lens, one clear lens

When objects move, brain fuses images from slightly different times


Different eye-views are interleaved vertical strips

Barrier screen blocks all but one image from any viewpoint