Question 1

In order to switch focus from one object to the other object, an observer in this situation would have to increase the angle of convergence between the eyes. Hence, the disparity of objects closer than the horopter is called _____ disparity.

Accepted Answer

Crossed disparity refers to the situation where objects closer than the horopter require the eyes to converge more, thus the images of such objects appear to cross over the midline to achieve single binocular vision.

Question 2

Marr and Poggio (1979) suggested that the visual system determines the correspondences in the two retinal images, and thus it is possible to compute the binocular disparities by making two simple and quite reasonable assumptions about the world when matching features in the left and right retinal images. Here, one of these assumptions states that:

Accepted Answer

Marr and Poggio's theory of stereopsis includes the assumption that each feature in one retinal image corresponds to a single feature in the other retinal image, facilitating the computation of binocular disparities. This is known as the uniqueness constraint.

Question 3

Binocular cells are neurons that:

Accepted Answer

Binocular cells are specialized neurons that respond optimally when the receptive fields in both eyes are stimulated simultaneously, indicating their role in binocular vision and depth perception.

Question 4

Objects on the horopter produce _____ disparity.

Accepted Answer

The horopter is an imaginary line or curve in space, and objects located on it will be imaged at corresponding points on the two retinas, producing zero disparity.

Question 5

In the context of perceptual constancy, size constancy is a tendency to:

Accepted Answer

Size constancy refers to the perception of an object as having a constant size, even when its distance from the observer changes, which alters the size of the object's image on the retina.

Question 6

Objects that are either closer to an observer or farther away from the observer than the horopter will project retinal images that fall:

Accepted Answer

Objects that are farther away from the observer than the horopter will project retinal images that fall on noncorresponding points.

Question 7

John leans against a wall and watches a squirrel approach a tree. As the squirrel crosses behind the tree, its body gradually disappears. This illustrates the process of:

Accepted Answer

Deletion is the process where an object is gradually obscured by another object, as seen when the squirrel disappears behind the tree.

Question 8

In real-world situations, integrating depth cues provide us with:

Accepted Answer

Integrating depth cues in real-world situations allows our visual system to gather the same or complementary information about the depths of objects and surfaces in the scene, enhancing our perception of three-dimensional space.

Question 9

Research findings of random dot stereograms have shown that:

Accepted Answer

Correspondence matching precedes object recognition in the process of viewing random dot stereograms. This is because the visual system first determines which elements in the two images correspond to each other (correspondence matching) before it can interpret these elements as part of coherent objects (object recognition).

Question 10

An anaglyph:

Accepted Answer

An anaglyph requires two slightly different superimposed images, typically in red and cyan, which are viewed through colored lenses to create a stereoscopic 3D effect.

Question 11

_____ is an imaginary surface defined by the locations in a scene from which objects would project retinal images at corresponding points.

Accepted Answer

The horopter is an imaginary surface that represents the set of points in space where objects would project images to corresponding points on the two retinas. This concept is crucial in understanding binocular vision and depth perception.

Question 12

Stereopsis is a depth cue arising from the visual system's processing of the:

Accepted Answer

Stereopsis is the perception of depth and 3-dimensional structure obtained on the basis of visual information deriving from two eyes by individuals with normally developed binocular vision. It specifically arises from the brain's analysis of the different retinal images seen by each eye, due to their different perspectives. This binocular disparity is a crucial cue for depth perception.

Question 13

As the distance between an object and the horopter increases, the binocular disparity for the object _____, regardless of whether disparity is crossed or uncrossed.

Accepted Answer

As the distance between an object and the horopter (the region in space where objects are seen single with binocular vision) increases, the binocular disparity (the difference in image location of an object seen by the left and right eyes) for the object increases. This is because objects farther from the horopter deviate more from the points where the visual axes of the eyes intersect, leading to greater disparity.

Question 14

In the context of binocular disparity, a point on the left retina and a point on the right retina are _____ points if they would coincide if the two retinas were superimposed.

Accepted Answer

Corresponding points on the left and right retinas are points that would overlap if the two retinas were superimposed. This concept is fundamental in understanding binocular vision and disparity, as it relates to how the brain perceives depth from the slight differences in the images projected on each retina.

Question 15

Optic flow is a critical cue to depth when a person is driving, though it also operates, of course, when a person moves slowly through a scene. The objects and surfaces near the point toward which the person is heading is called _____, which move(s) outward slowly in the retinal image.

Accepted Answer

The focus of expansion refers to the point in the visual field towards which a person is moving, from which optic flow emanates. As a person moves, objects and surfaces near this point appear to move outward slowly in the retinal image, providing critical information about direction and speed of movement.

Question 16

A dynamic depth cue-the gradual revealing ("de-occlusion") of an object as it emerges from behind another one-is called:

Accepted Answer

Accretion refers to the gradual revealing or uncovering of an object as it moves from behind another object, serving as a dynamic depth cue in visual perception.

Question 17

Researchers have examined what happens when they manipulate the number of depth cues available and the degree to which those cues conflict. Such experiments have revealed a few basic principles. Identify a basic principle of depth cues.

Accepted Answer

Depth perception is a complex process that integrates multiple cues. These cues can vary in their importance depending on the context, and no single cue is essential for depth perception to occur. This flexibility allows for accurate depth perception across a wide range of situations, even if some cues are missing or less reliable.

Question 18

In the context of binocular disparity, the horopter is an imaginary surface defined by the locations in the scene from which objects would:

Accepted Answer

The horopter is an imaginary curve or surface that passes through the point of fixation and defines the locations in a scene from which objects appear at corresponding points on the two retinas. Objects on the horopter are perceived as being at the same depth as the fixation point, leading to no binocular disparity.

Question 19

The process of gradual hiding of an object as it passes behind another one is called:

Accepted Answer

The correct answer is A because deletion is the process of gradual hiding of an object as it passes behind another one.

Question 20

As David drives down a long straight road with his eyes focused on the steep cliff straight ahead, the entire landscape at the side of the car whizzes by in a blur and then disappears out the edges of his field of view. Only the point where David is heading remains stationary in his retinal image. This illustrates the depth cue of:

Accepted Answer

Optic flow refers to the pattern of apparent motion of objects as an observer moves relative to them. In this scenario, the landscape moving past as David drives illustrates optic flow, where objects closer move faster across the field of view than those farther away, helping to perceive depth and motion direction.

Quiz 6: Perceiving Depth