Visual Perception 4

Question 1

points on the retina that overlap if the eyes are superimposed on each other

Answer 1

corresponding retinal points

Question 2

if we superimpose the 2 eyes then the two retinal images….

Answer 2

overlap

Question 3

what is a horopter

Answer 3

hypothetical surface

-objects that fall on the horopter create corresponding retinal points

Question 4

objects that don’t fall on the horopter create what

Answer 4

non-corresponding points

Question 5

the difference btwn the non-correspoding retinal points from the hypothetical corresponding points is called

Answer 5

disparity

Question 6

corresponding retinal points have ___ dispartity while noncorr points have ____ dispartiy

Answer 6

corr: 0

non-corr: greater than 0

Question 7

the horopter is a surface of ___ disparity and its position in the vf depends on the ____ of the eye (fixation)

Answer 7

0

convergence

Question 8

objects with 0 disparity are seen as ___ objects

objects w/ dispartiy diff from 0 are seen as ____

Answer 8

single

2-known as diplopia

Question 9

what is panum’s fusional area

Answer 9

the area close to the horopter that can generate objects w/ 0 disparity

Question 10

objects that are further away from the horopter have ___ angle of disparity (or abs dispartity) from objects that are closer to it

Answer 10

larger

Question 11

what does absolute disparity indicate

Answer 11

distance from the horopter (or the plane we are focusing on)

Question 12

what is relative dispartiy

what can this give us info about

Answer 12

the difference btwn the absolute disparities of 2 objects

-can give us info about the object’s position relatve to each other

Question 13

relative disparity remains always the ___ btwn 2 objects as we move our eyes and scan a scene

Answer 13

same

Question 14

-this constant diff in disparity gives us info about the ______ of objects

Answer 14

relative position

Question 15

for depth perception, we use _____

Answer 15

absolute and relative disparity

Question 16

for depth perception, we use absolute dispartiy for…

relative disparity for…

Answer 16

absolute: to judge an object’s distance from the plane of focus (horopter)
relative: judge the relative positions of objects

Question 17

what are the 2 kinds of dispartity

Answer 17

crossed and uncrossed

Question 18

what dispartiy is the objects always in front of the horopter

Answer 18

crossed disparity

Question 19

what disparity is it when the object is always behind the horopter

Answer 19

uncrossed

Question 20

crossed and uncrossed disparity is also called the ….

Answer 20

sign of disparity as we can tell whether an object is (+) or (-) the horopter

Question 21

what is the perception of depth called

Answer 21

stereopsis

Question 22

what is the geometrical description of how the objects are projected on the retina

Answer 22

disparity

Question 23

the stereoscope, view master, 3D movies and 3D tvs all use the same principles, they project lightly diff images on the retina causing…

Answer 23

disparity and therefore depth info

Question 24

what project different images on each eye through an optical system

Answer 24

stereogram (steroscope?) and view master

Question 25

how do 3D movies work with imgs of different color

Answer 25

2 slightly diff images are having diff color characteristics usually one greenish one reddish -by using tinted filters, one red and one green, the red img will be transmitted through the green filter and a diff image will be projected on each eye -disparity btwn 2 diff image=depth perception

Question 26

how do 3D images work with polarized light

Answer 26

one image reflects polarized light in one direction while the other image reflects polarized light in another direction -polarized lenses used that permit only one polarization to go through

Question 27

what is the passive method for 3D TV

Answer 27

polarized images are generated by the TV and again by using polarized glasses each image is projected only on one eye

Question 28

what is the active method for 3D TV

Answer 28

2 images are fast alternating on the screen - special glasses have an electronic componenet/shutter - each shutter is synchronized to only be open only when the first image is presented while the other remains shut and therefore there is no image on the other eye - the alternation must be higher thant he CFF so you don't detect flicker

Question 29

how is steropsis used in military and medicine

Answer 29

military: usd to help appreciate the height, size, and shape of a target medicine: taking x-rays from diff positions to create retinal dispartiy and would be able to see a tumor popping out

Question 30

all these methods provide steropsis bc of ____ | but all the images we see (either in movie theatre, tv, or stereoscope) provide ______

Answer 30

``` disparity monocular cues (ex. occlusion) ```

Question 31

what are random-dot stereograms

Answer 31

presenting only binocular disparity w/ no monocular cues | -the fact that people perceive floating objects here suggest that disparity alone is a sufficient cue for stereopsis

Question 32

what is the corresponding problem

Answer 32

in order for disparity to work, the visual system matches the corresp points on the left and right retina -for real world scenes, the visual system may match objects using specific features ex. round with round, corner w/ corner -most objects in the real world are discriminable (can tell part from other objects) -our perceptual system corresponds one point to another even though it is complicated and our visual system calculates disparities NO ANSWER TO CORRESPONDING PROBLEM. -dont know how our visual system matches the corresponing points and calculates the disparities to create the perception of depth

Question 33

why is the visual system unable to calculate disparity for steropsis in stabismus

Answer 33

there are no corresponding points on the left and right retina

Question 34

the perception of ____ is affected by stereopsis

Answer 34

size | cant judge that an object is distant or near and therefore can't judge its size

Question 35

what is the holway and boring experiment

Answer 35

aka hallway experiement - test stimulus can move back and forth and can change size so as to have the same visual angle on the retina - task for observer is to look at the stimulus and change the size of the comparison stimulus to be the same size as the test stimulus

Question 36

when the conditions were ______ the observers did a good job matching the sizes of the 2 stimuli

Answer 36

free-viewing

Question 37

size estimation is based on the....

Answer 37

physcial sizes of objects when depth cues are available

Question 38

size estimation is influenced by...

Answer 38

the objects visual angle when depth info isn't available

Question 39

what is size constancy

Answer 39

our perception of an objects size is relatively constant, even when we see it from different distances (diff visual angles)

Question 40

what is it called when a mechanism uses a mathematical equation proposed to explain size constancy

Answer 40

size-distance scaling

Question 41

size-distance takes what into account

Answer 41

objects distance

Question 42

what is the equation to size-distnace scaling which ones change together and what remians the same

Answer 42

S=a(RxD) S=perceived img R=retinal img D=viewing dist a=constan R and D chnage together (direct rel'n) so S remains the same

Question 43

what is emmert's law

Answer 43

the farther away an afterimage appears, the larger it will be perceived

Question 44

when the size constancy euqation is not applied correctly, forcing us to perceive different sizes, what is this called

Answer 44

misapplied size constancy

Question 45

what does the misapplied size contancy fail to explain

Answer 45

similar illusions w/ no obvsious perspceticve