Chapter 6 Vocab-Space/Binocular

Question 1

absolute metrical depth cue

Answer 1

A depth cue that provides quantifiable information about distance in the third dimension (e.g., his nose sticks out 4 centimeters in front of his face).

Question 2

accommodation

Answer 2

The process by which the eye changes its focus (in which the lens gets fatter as gaze is directed toward nearer objects).

Question 3

aerial perspective (or haze)

Answer 3

A depth cue based on the implicit understanding that light is scattered by the atmosphere. More light is scattered when we look through more atmosphere. Thus, more distant objects are subject to more scatter and appear fainter, bluer, and less distinct.

Question 4

anamorphosis (or anamorphic projection)

Answer 4

Use of the rules of linear perspective to create a two-dimensional image so distorted that it looks correct only when viewed from a special angle or with a mirror that counters the distortion.

Question 5

Bayesian approach

Answer 5

A way of formalizing the idea that our perception is a combination of the current stimulus and our knowledge about the conditions of the world—what is and is not likely to occur.

Question 6

binocular depth cue

Answer 6

A depth cue that relies on information from both eyes.

Question 7

binocular disparity

Answer 7

The differences between the two retinal images of the same scene. Disparity is the basis for stereopsis, a vivid perception of the three-dimensionality of the world that is not available with monocular vision.

Question 8

binocular rivalry

Answer 8

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 9

binocular summation

Answer 9

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 10

binocular

Answer 10

With two eyes.

Question 11

continuity constraint

Answer 11

In stereopsis, the observation that, except at the edges of objects, neighboring points in the world lie at similar distances from the viewer. This is one of several constraints that have been proposed to help solve the correspondence problem.

Question 12

convergence

Answer 12

The ability of the two eyes to turn inward, often used in order to place the two images of a feature in the world on corresponding locations in the two retinal images (typically on the fovea of each eye).

Question 13

correspondence problem

Answer 13

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. The problem is particularly vexing when the images consist of thousands of similar features, like dots in random dot stereograms.

Question 14

corresponding retinal points

Answer 14

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 15

critical period

Answer 15

A period of time during development when the organism is particularly susceptible to developmental change.

Question 16

crossed disparity

Answer 16

The sign of disparity created by objects in front of the plane of fixation (the horopter).

Question 17

Cyclopean

Answer 17

Referring to stimuli that are defined by binocular disparity alone.

Question 18

depth cues

Answer 18

Information about the third dimension (depth) of visual space; may be monocular or binocular.

Question 19

Information about the third dimension (depth) of visual space; may be monocular or binocular.

Answer 19

Referring to the presentation of two different stimuli, one to each eye.

Question 20

diplopia

Answer 20

Double vision. If visible in both eyes, stimuli falling outside of Panum’s fusional area will appear double.

Question 21

divergence

Answer 21

The ability of the two eyes to turn outward, often used in order to place the two images of a feature in the world on corresponding locations in the two retinal images (typically on the fovea of each eye).

Question 22

esotropia

Answer 22

Strabismus in which one eye deviates inward.

Question 23

Euclidean

Answer 23

Referring to the geometry of the world, named in honor of the ancient Greek geometer of the third century BCE. Parallel lines remain parallel as they are extended in space, objects maintain the same size and shape as they move around in space, the internal angles of a triangle always add to 180 degrees, and so forth.

Question 24

exotropia

Answer 24

Strabismus in which one eye deviates outward.

Question 25

familiar size

Answer 25

A depth cue based on knowledge of the typical size of objects like humans or pennies.

Question 26

free fusion

Answer 26

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

Question 27

horopter

Answer 27

The location of objects whose images lie on corresponding points. The surface of zero disparity.

Question 28

ideal observer

Answer 28

A theoretical observer with complete access to the best available information and the ability to combine different sources of information in the optimal manner.

Question 29

linear perspective

Answer 29

A depth cue based on the fact that lines that are parallel in the three-dimensional world will appear to converge in a two-dimensional image.

Question 30

metrical depth cue

Answer 30

A depth cue that provides quantitative information about distance in the third dimension.

Question 31

monocular depth cue

Answer 31

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

Question 32

monocular

Answer 32

With one eye.

Question 33

motion parallax

Answer 33

An important depth cue that is based on head movement. The geometric information obtained from an eye in two different positions at two different times is similar to the information from two eyes in different positions in the head at the same time.

Question 34

nonmetrical depth cue

Answer 34

A depth cue that provides information about the depth order (relative depth) but not depth magnitude (e.g., his nose is in front of his face).

Question 35

occlusion

Answer 35

A cue to relative depth order in which, for example, one object obstructs the view of part of another object.

Question 36

Panum’s fusional area

Answer 36

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

Question 37

pictorial depth cue

Answer 37

A cue to distance or depth used by artists to depict three-dimensional depth in two-dimensional pictures.

Question 38

positivism

Answer 38

A philosophical position arguing that all we really have to go on is the evidence of the senses, so the world might be nothing more than an elaborate hallucination.

Question 39

projective geometry

Answer 39

For purposes of studying perception of the three-dimensional world, the geometry that describes the transformations that occur when the three-dimensional world is projected onto a two-dimensional surface. For example, parallel lines do not converge in the real world, but they do in the two-dimensional projection of that world.

Question 40

random dot stereogram (RDS)

Answer 40

A stereogram made of a large number (often in the thousands) of randomly placed dots containing no monocular cues to depth.

Question 41

realism

Answer 41

A philosophical position arguing that there is a real world to sense.

Question 42

relative height

Answer 42

As a depth cue, the observation that objects at different distances from the viewer on the ground plane will form images at different heights in the retinal image. Objects farther away will be seen as higher in the image.

Question 43

relative metrical depth cue

Answer 43

A depth cue that could specify, for example, that object A is twice as far away as object B without providing information about the absolute distance to either A or B.

Question 44

relative size

Answer 44

A comparison of size between items without knowing the absolute size of either one.

Question 45

stereoacuity

Answer 45

A measure of the smallest binocular disparity that can generate a sensation of depth.

Question 46

stereoblindness

Answer 46

An inability to make use of binocular disparity as a depth cue. This term is typically used to describe individuals with vision in both eyes.

Question 47

stereopsis

Answer 47

The ability to use binocular disparity as a cue to depth.

Question 48

stereoscope

Answer 48

A device for simultaneously presenting one image to one eye and another image to the other eye.

Question 49

strabismus

Answer 49

A misalignment of the two eyes such that a single object in space is imaged on the fovea of one eye, and on a nonfoveal area of the other (turned) eye.

Question 50

suppression

Answer 50

In vision, the inhibition of an unwanted image; occurs frequently in persons with strabismus.

Question 51

texture gradient

Answer 51

A depth cue based on the geometric fact that items of the same size form smaller images when they are farther away. An array of items that change in size smoothly across the image will appear to form a surface tilted in depth.

Question 52

tilt aftereffect

Answer 52

The perceptual illusion of tilt, produced by adaptation to a pattern of a given orientation.

Question 53

uncrossed disparity

Answer 53

The sign of disparity created by objects behind the plane of fixation (the horopter).

Question 54

uniqueness constraint

Answer 54

In stereopsis, the observation that a feature in the world is represented exactly once in each retinal image. This constraint simplifies the correspondence problem.

Question 55

vanishing point

Answer 55

The apparent point at which parallel lines receding in depth converge.

Question 56

Vieth-Müller circle

Answer 56

The location of objects whose images fall on geometrically corresponding points in the two retinas. If life were simple, this circle would be the horopter, but life is not simple.