Problem 5: Depth perception

Question 1

binocular disparity

Answer 1

difference in image between two eyes (stereoscopic vision is the basis for disparity)

Question 2

what are corresponding points

Answer 2

when looking at an object, the image is at relatively the same location in both eyes, allowing you to see it as one object

Question 3

what is the horopter

Answer 3

imaginary surface on which corresponding points lie

Question 4

what is absolute disparity

Answer 4

degree to which an image deviates from a corresponding point (changes with every new fixation, the difference in space between the objects on your retina)

Question 5

what is relative disparity

Answer 5

stays the same between two objects in your visual field (the difference in actual space between the objects)

Question 6

uncrossed and crossed disprity

Answer 6

crossed: when an object is in front of the horopter (your eye’s need to cross to focus on it)
uncrossed: behind the horopter (your eyes need to uncross to focus on it)

Question 7

correspondence problem + possible answer

Answer 7

how come two images become one in our mind
- our visual system would line up the common features in the two retinal images ( does not hold up with stereograms)

Question 8

what are binocular neurons / disparity selective cells

Answer 8

neurons that best respond to a certain amount of absolute disparity

Question 9

experiment on depth perception

Answer 9

stereopsis: trying to prove disparity, creating a 3D image without using any depth cues except from disparity

Question 10

Pictorial monocular cues

Answer 10

• occlusion: overlapping
• relative height: height relative to horizon
• relative size: when two objects are of equal size, the one that appears smaller is further away
• familiar size: helps us determine size of objects
• perspective convergence: parallel lines further away seem to converge
• atmospheric perspective: things further away seem blurrier and bluer
• texture gradient: when you know elements are equally spaced, the ones more packed are further away
• shadows: give information about object location

Question 11

motion-produced monocular cues:

Answer 11

• motion parallax (closer objects move by faster)
• deletion (when an object is covered as a result of movement)
• accretion (when an object is uncovered as a result of movement)

Question 12

accommodation

Answer 12

change in the shape of lens when you focus at different points

Question 13

convergence

Answer 13

your eyes moving inwards when you focus on something close

Question 14

convergence

Answer 14

your eyes moving inwards when you focus on something close

Question 15

visual angle

Answer 15

determines the size of an image on the retina (a small object that is near can have the same size on the retina as a large object that is far away)

Question 16

holway and boring experiment:

Answer 16

one hallway with a comparison circle and one with a circle that changes
in phase 1: depth cues are available
phase 2: depth cues are absent
–> when all depth cues are eliminated they started comparing the size of the circles to the sizes of the previously seen circles, because no depth information was available

Question 17

size perception and constancy formula

Answer 17

S = K (R * D)
S = perceived size
K = scaling factor
R = retinal image size
D = perceived distance

Question 18

myers-lyer arrow illusion:

Answer 18

explanation: the fins are outer and inner corners of a room, which would influence our perception –> doesn’t hold
explanation: conflicting cues theory: perception depends on the actual cue of the line + the overal length of the figure

Question 19

moon illusion:

Answer 19

apparent distance theory: the horizon has depth cues, the sky has no depth cues
Angular size contrast theory: moon appears smaller when there’s a lot of empty sky around it