Sensation & Perception - Lecture 6

Question 1

Realism

Answer 1

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

Question 2

Positivism

Answer 2

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 3

Binocular

Answer 3

Referring to two eyes.

Question 4

Probability summation

Answer 4

The increased detection probability based on the statistical advantage of having two detectors rather that one.

Question 5

Binocular summation

Answer 5

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

Question 6

Binocular disparity

Answer 6

The differences between the two retinal images of the same scene.

Question 7

Monocular

Answer 7

Referring to one eye.

Question 8

Stereopsis

Answer 8

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

Question 9

Monocular depth cue

Answer 9

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

Question 10

Binocular depth cue

Answer 10

Binocular depth cues rely on input from both eyes. Stereopsis is a prime example in humans, but convergence and the wider field of vision provided by two eyes also contribute to these cues.

Question 11

Pictorial depth cue

Answer 11

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

Question 12

Nonmetrical depth cue

Answer 12

A depth cue that provides information about the depth order but not depth magnitude.

Question 13

Metrical depth cue

Answer 13

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

Question 14

Projective geometry

Answer 14

In the context of studying perception, describes how the three-dimensional world transforms when projected onto a two-dimensional surface.

Question 15

Texture gradient

Answer 15

A depth cue based on the geometric fact that items of the same size from 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 16

Relative height

Answer 16

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 17

Relative size

Answer 17

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

Question 18

Familiar size

Answer 18

A depth cue based on knowledge of the typical sizes of objects, such as humans or pennies.

Question 19

Relative metrical depth cue

Answer 19

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

Question 20

Absolute metrical depth cue

Answer 20

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

Question 21

Haze or Aerial perspective

Answer 21

A depth cue based on the implicit understanding that light is scattered by the atmosphere. More distance object are subject to more scatter and appear fainter, bluer, and less distinct.

Question 22

Linear perspective

Answer 22

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 23

Vanishing point

Answer 23

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

Question 24

Anamorphosis

Answer 24

Use of the rule of linear perspective to create a two-dimensional image so distorted that it looks correct only when viewed from a special angle.

Question 25

Triangulation

Answer 25

In vision, this refers to the triangle formed by the two eyes and the point on which they fixate in the 3D world. The angles of that triangle are related to the location if the fixated point in depth.

Question 26

Motion parallax

Answer 26

An important depth cue that is based on head movement. Geometric data gathered from an eye at two separate times resembles the information gathered from two eyes positioned differently in the head simultaneously.

Question 27

Optic flow

Answer 27

The pattern of apparent motion of objects in a visual scene produced by the relative motion between the observer and the scene.

Question 28

Accommodation

Answer 28

The process by which the eye changes its focus.

Question 29

Convergence

Answer 29

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

Question 30

Divergence

Answer 30

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

Question 31

Vergence angle

Answer 31

The angle formed by by lines from each eye to the current object of fixation. A larger vergence angle implies a closer object.

Question 32

Absolute disparity

Answer 32

The difference in the angular distance of the images of an object from the foveas of the two eyes.

Question 33

Relative disparity

Answer 33

The difference in the absolute disparities of two objects.

Question 34

Corresponding retinal points

Answer 34

Two monocular images of an object in the world are said to fall on corresponding points if those points are the same distance from the fovea in both eyes.

Question 35

Horopter

Answer 35

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

Question 36

Diplopia

Answer 36

Double vision.

Question 37

Panum’s fusional area

Answer 37

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

Question 38

Crossed disparity

Answer 38

The sign of disparity created by objects in front of the plane of fixation. The term crossed is used because images of objects located in front of the horopter appear to be displaced to the left in the right eye and to the right in the left eye.

Question 39

Stereoscope

Answer 39

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

Question 40

Free fusion

Answer 40

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

Question 41

Correspondence problem

Answer 41

In reference to binocular vision, the problem of figuring out which bit of the image in the eye should be matched with which bit in the right eye.

Question 42

Binocular rivalry

Answer 42

The competition between the two eyes for control of visual perception.

Question 43

Dichoptic

Answer 43

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

Question 44

Strabismus

Answer 44

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 eye.

Question 45

Esotropia

Answer 45

Strabismus in which one eye deviates inward.

Question 46

Exotropia

Answer 46

Strabismus in which one eye deviates outward.