depth perception and binocular vision

redundancy, increased fov, binocular summation, depth perception

why two eyes?

redundancy

if you lose one you can still see

increased fov

two eyes can contribute to an extended visual field, though this is generally much more a feature of the visual systems of prey rather than predator animals

binocular summation

pool twice as many samples of light in overlapping region of fov - eye chart is easier to read with both eyes than with one

vergence angle

triangulation based on the angle between two eyes

binocular disparity

the difference between the two retinal images

stereopsis

the depth perception that results from binocular disparity under normal viewing conditions (when the images from the two eyes are “compatible”) - this is what you get from 3D movies

horopter

the location of objects whose images lie on the corresponding points and form the surface of zero disparity

vieth-muller circle

the theoretical horopter, computed as the location of objects whose images fall on geometrically corresponding points in the two retinas in two spherical eyes

panum’s fusional area

the region of space in front of and behind the horopter, within which binocular single vision is possible

diplopia

objects significantly closer to or farther away from the horopter fall on noncorresponding points in the two eyes are seen as two images

stereoscope

a device for presenting one image to one eye and another image to another eye

free fusing

converging ( or diverging ) the eyes either nearer or farther than the image plane so that each eye sees a different image

random dot stereogram ( rds )

a streogram made of a large number of randomly placed dots

binocular rivalry

occurs when different and incompatible images are presented to the two eyes ( results in (usually transitory) suppression of one of the two presented images )

dichoptic

different image presented to each eye

strabismus

a misalignment of the two eyes such that a single object in space is imaged on the fovea of one eye and on the non foveal aera of the other (turned) eye

esotropia

strabismus in which one eye deviates inward

exotropia

strabismus in which one eye deviates outward

stereoblind

unable to use binocular disparity as a depth cue