week 5

Question 1

binocular disparity

Answer 1

• difference in the image seen by each eye due to different angles
• used to perceive depth
• brain stitches the images together
• stereogram

Question 2

corresponding retinal points

Answer 2

• locations on both retinae that would overlap perfectly if the 2 eyeballs were superimposed
• allows for focus on an object

Question 3

horopter

Answer 3

• imaginary arc through the visual field where objects at the same distance as the point of focus fall on corresponding retinal points, single image when viewed with both eyes
• objects outside the horopter produce images on non corresponding retinal points, may appear doubled

Question 4

crossed disparity

Answer 4

• image of an object falls to the left on the left retina and the right on the right retina
• requires the eyes to cross to focus on it

Question 5

uncrossed disparity

Answer 5

• image of an object falls to the right on the left retina and to the left on the right retina
• requires the eyes to uncross to focus on it

Question 6

role of binocular cells in depth perception

Answer 6

• receive input from corresponding and non-corresponding retinal areas
• tuned to visual disparities, assess depth

Question 7

texture gradient visual illusions

Answer 7

• trick the brain into perceiving surfaces differently

Question 8

adanson jumping spider

Answer 8

• 4 photosensitive layers, each sensitive to different wavelengths
• each layer assesses depth, comparing focus across layers
• spiders rely on multiple retinal layers, humans use comparisons between the eyes

Question 9

cue approach

Answer 9

• humans infer depth using visual cues

Question 10

depth cue
pictorial

Answer 10

• depth cues in static images
• imply depth without motion

Question 11

depth cue
movement

Answer 11

• depth cues inferred from motion
• moving objects or self motion
• closer objects shift more dramatically than distant ones

Question 12

depth cue
occlusion

Answer 12

• one object partially obstructs another
• infer the hidden object is further away
• indicates what is in front but not distance between objects

Question 13

depth cue
relative height

Answer 13

• objects closer to the horizon are seen as more distant

Question 14

depth cue
size

Answer 14

• farther an object the smaller it’s retinal image
• judge distance based on size
• comparing size of identical objects, can infer whats closer based on size

Question 15

size constancy

Answer 15

• perception adjusts for distance, smaller image isn’t mistaken for a smaller object
• unfamiliar objects can mislead perception

Question 16

depth cue
linear perspective

Answer 16

• parallel lines converge as they recede, indicating depth

Question 17

why are monocular (one eye) cues still accurate distance judgement

Answer 17

• visual cues, sufficient depth information

Question 18

depth cue
texture gradient

Answer 18

• monocular depth cue
• textures appear finer and closer together as they recede into the distance

Question 19

depth cue
atmospheric perspective

Answer 19

• distance objects appear blurred with a blue tinge due to atmospheric light scattering

Question 20

depth cue
shadows

Answer 20

• angle and position of the shadow provides depth information
• eg curved surface we can see what parts of the surface are closer or farther based on the light
• can appear as a bump or indentation based on shadow direction relative to light source

Question 21

depth cue
motion parallax

Answer 21

• objects closer to the viewer appear to move faster across the retina than distant objects
• relies on different views across time and space to create depth, similar to binocular disparity

Question 22

deletion

Answer 22

• gradual occlusion of an object

Question 23

accretion

Answer 23

• reappearance from occlusion
• signals it’s position as farther away than the obstruction

Question 24

depth cue
optic flow

Answer 24

• objects move relative to the observer, forward or backward motion

Question 25

oculomotor depth cues

Answer 25

• eye muscle movements, accomodation (lens shape), convergence (eye rotation)

Question 26

depth cue
accomodation

Answer 26

• process where the eye’s lens adjusts to focus on near or distant objects
• less effective daylight, constricts pupils, less precise

Question 27

depth cue
convergence

Answer 27

• inward bending of eyes when focusing on an object
• brain senses inward/outward rotation of eyes and estimate distance

Question 28

depth cue
stereopsis

Answer 28

• depth from comparing slightly different images from each retina
• develops 4-5 months in human infants

Question 29

panum area of fusion

Answer 29

• small area around the horopter where objects’ images can be fused into single perception

Question 30

diplopia

Answer 30

• double images of an object
• often due to excessive disparity beyond panum’s area of fusion

Question 31

shifted focus horopter effect

Answer 31

• adjusts the horopter’s position
• creates a new area where depth cues are aligned for clear vision

Question 32

random dot stereograms

Answer 32

• black and white dots that create depth perception
• shifting dots between the 2 images

Question 33

free fusion

Answer 33

• skill of viewing stereograms by controlling eye convergence

Question 34

hofeldt

Answer 34

• mlb players with better stereoscopic ability perform better in batting