binocular vision

Question 1

what is euclidian geometry?

Answer 1

parallel lines remain parallel as they are extended in place

Question 2

are the images projected onto the retina euclidean?

Answer 2

no

Question 3

how can euclidian geometry be explained?

Answer 3

objects maintain in the same size and shape as they move around space

Question 4

whats binocular summation?

Answer 4

the combination of signals from each eye in ways that make performance on many tasks better with both eyes than with either eye alone

Question 5

what is binocular disparity?

Answer 5

the differences between the two retinal images of the same scene

Question 6

what is stereopsis?

Answer 6

a vivid perception of the three dimensionality of the world that is not available with monocular vision

Question 7

what is a depth cue?

Answer 7

information about the third dimension of visual space

Question 8

what is a monocular depth cue?

Answer 8

a depth cue that is available even when the world is viewed with one eye alone

Question 9

what is a monocular depth cue?

Answer 9

a depth cue that relies on info from both eyes

Question 10

what is a binocular depth cue?

Answer 10

a depth cue that relies on info from both eyes

Question 11

what is occlusion?

Answer 11

a cue to relative depth order in which, one object obstructs the view of another

Question 12

what is a metrical depth cue?

Answer 12

a depth cue that provides quantitative info about distance in the third dimension

Question 13

what is a nonmetrical depth cue?

Answer 13

a depth cue that provides info about the depth order but not depth magnitude

Question 14

what is relative size cue?

Answer 14

a comparison of size between items without knowing the absolute size of either one

Question 15

what is relative height?

Answer 15

below the horizon, objects higher in the visual field appear further away. above, objects lower in the field appear to be further

Question 16

what is texture gradient?

Answer 16

a depth cue based on the geometric fact that items of the same size form smaller images when they are further away

Question 17

whats the cause of texture gradients?

Answer 17

results from a combination of the cues of relative size and relative height

Question 18

what is familiar size?

Answer 18

a cue based on knowledge of the typical size of objects

Question 19

what is aerial perspective?

Answer 19

a depth cue based on the implicit understanding that light is scattered by the atmosphere

Question 20

what is the effect of the aerial perspective?

Answer 20

more light is scattered when we look through more atmosphere so more distant objects appear fainter and bluer

Question 21

what is linear perspective?

Answer 21

lines that are parallel in the three dimensional world will appear to converge in a two dimensional image as they extend into the distance

Question 22

what is the vanishing point?

Answer 22

the apparent point at which parallel lines receding in depth converge

Question 23

what is the motion parallax?

Answer 23

images closer to the observer move faster across the visual field than images further away

Question 24

what is accomodation?

Answer 24

the process by which the eye changes its focus

Question 25

what happens when the eye accomodates?

Answer 25

the lens gets fatter as gaze is directed toward nearer objects

Question 26

what is convergence?

Answer 26

the ability of the two eyes to turn inward, often used to focus on nearer objects

Question 27

what is divergence?

Answer 27

the ability of the two eyes to turn outward, often used to focus on farther objects

Question 28

what are corresponding retinal points?

Answer 28

a geometric concept stating that points on the retina of each eye where the monocular retinal images of a single object are formed are at the same distance from the fovea in each eye

Question 29

what is binocular disparity?

Answer 29

the difference between the two retinal images of the same scene

Question 30

what is the vieth muller circle?

Answer 30

the location of objects whose images fall on geometrically corresponding points on the two retinas

Question 31

what is horopter?

Answer 31

the location of objects whose images lie on the corresponding points. surface of 0 disparity.

Question 32

how are objects on the horopter seen?

Answer 32

as single images when viewed with both eyes

Question 33

what is panum's fusional area?

Answer 33

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

Question 34

how are images seen when objects are closer or further away from the hotopter?

Answer 34

if they fall on noncorresponding points in the two eyes they are seen as two images

Question 35

what is diplopia?

Answer 35

double vision

Question 36

what happens if stimuli falls outside of panum's?

Answer 36

if visible in both eyes it will appear diplopic

Question 37

what is crossed disparity?

Answer 37

the sign of disparity created by objects in front of the plane of the horopter

Question 38

how are images dispaced in front of the horopter?

Answer 38

displaced to the left in the right eye and to the right in the left eye

Question 39

what is free fusion?

Answer 39

the technique of converging or diverging (uncrossing) the eyes in order to view a stereogram without a stereoscope

Question 40

what is stereoblindness?

Answer 40

an inability to make use of binocular disparity as a depth cue

Question 41

what is the correspondence problem?

Answer 41

in binocular vision, the problem of figuring out which bit of the image in the left eye should be matched with which bit in the right eye

Question 42

what are ways to solve the correspondence problem?

Answer 42

- blurring the image - uniqueness constraint - continutity constraint

Question 43

how does blurring the image help with correspondance?

Answer 43

leaves only the low spatial frequency info which reduces the number of features

Question 44

how does uniqueness constraint help correspondence?

Answer 44

the observation of a feature in the world is represented exactly once in the retinal image

Question 45

how does continuity constraint help correspondence?

Answer 45

the observation that except at the edges of objects, neighbouring points in the world lie at similar distances from the viewer

Question 46

how do most binocular neurons respond best when the retinal images are on corresponding points?

Answer 46

with zero disparity

Question 47

what is another way neurons respond best?

Answer 47

when similar images occupy slightly different positions on the retinas of the two eyes

Question 48

what is binocular rivalry?

Answer 48

the competition between the two eyes for control of visual perception, which is evident when completely different stimuli are presented to the two eyes

Question 49

what is forced perspective?

Answer 49

when near and far objects are carefully aligned so that they appear to be interacting with eachother