task 5

Question 1

dept cues

Answer 1

thanks to depth cues, our brain transfers the 2 D image on the retina into a 3 dimensional perception (based on previous experience)

Question 2

types of cues

Answer 2

1.oculomotor cues - based on the tension in our eye muscles
2.monocular cues- based on the visual information in one eye
3.binocular cues - depend on visual information from both eyes

Question 3

convergence

Answer 3

the inward movement of the eyes when we look at nearby objects -> more effective

Question 4

accommodation

Answer 4

the change in the shape of the lens when we focus on objects at various distances

Question 5

monocular cues

Answer 5

accommodation
pictorial cues- can be depicted in a picture
1. occlusion- one object is partially hidden by another-> the hidden object is farther away

2. relative height- objects that are higher in the field of a fire appear to be farther away

Question 6

3. familiar size

Answer 6

judging distances based on our pior knowledge of the sized of objects

ex: different coins and distance experiment - don’t work using both eyes

Question 7

4. relative size

Answer 7

when 2 objects have a similar size, the one that is farther away will appear smaller

Question 8

5. perspective convergence

Answer 8

parallel lines seem to converge in distance-> projective geometry (when 3 D gets transformed into 2 D)

Question 9

6. atmospheric perspective

Answer 9

distant objects appear less sharp than nearer objects and have a slight blue tint (because the atmosphere preferentially scatters (separates) short-wavelength light, which we see as blue) -> same reason why sky appear blue. Also called “ Haze”

Question 10

7. texture gradient

Answer 10

when a number of similar objects are placed in a scene, the ones that are closer together are seen as farther

Question 11

shadows

Answer 11

provide information regarding the location of objects and enhance their 3-dimensionality

Question 12

motion produced cues

Answer 12

appear when the observer is moving

Question 13

motion parallax

Answer 13

when, as we move, nearby objects appear to glide rapidly, but distant objects seem to pass by us more slowly

ex: watching out a car window, closer trees move very fast, while trees in the distance more very slowly
->most important depth perception source for Many animals

Question 14

based on a head movement

Answer 14

because the tree is closer, its image moves farther across the retina than the house

Question 15

deletion and accretion

Answer 15

when the observer moves sideways, some objects become covered by others (deletion), while other things become uncovered (accretion)

Question 16

binocular view (stereoscopic vision)

Answer 16

stereoscopic depth perception
What Happens:
With your left eye open and right eye closed, the near finger may appear to overlap or cover the far finger.
With your right eye open and left eye closed, the near finger may shift, and both fingers become visible, appearing separate.

Question 17

stereoscopic vision

Answer 17

when learning 3d glasses, the sense separate the 2 overlapping images y using polarized light(= light waves that vibrate in only one direction)

Question 19

binocular disparity

Answer 19

the difference between the image on the left and right retinas

Question 20

correspondence problem

Answer 20

challenge the visual system face in matching images from the left and right eyes

we match them based on similar features and find the disparities /difference to create a perception of depth

Question 21

corresponding points

Answer 21

points that are in the same place in both eyes

Question 22

horopter

Answer 22

the surface of zero disparity , any object faced on this imaginary surface will form images on corresponding retinal points.

The horopter and the Vieth-Muller circle are different but different

Question 23

non corresponding points

Answer 23

correspond to the images of objects that aren’t on the horopter

Question 24

absolute disparity

Answer 24

the degree to which an objects image deviates from falling on the corresponding points is called absolute disparity

Question 25

angle of disparity

Answer 25

the amount of absolute disparity (blue arrow)

Question 26

angle of disparity

Answer 26

the angle of disparity gives information on the distance of objects from the horocopter if in front of the horopter- bigger angle of disparity

Question 27

crossed disparity

Answer 27

the right and left eyes see the object on different sides of the fixation point -> occurs when the objects is in front of the horocopter non corresponding points

Question 28

uncrossed disparity

Answer 28

same thing, occurs when the object is behind the horocopter this time

Question 29

stereopsis

Answer 29

the impression of depth that results from information provided by binocular disparity demonstrated though the random-dot stereogram and measured though stereoscope

Question 30

how does the visual system match the parts of the images in the let and right eyes that correspond to one another?

Answer 30

the correspondence problems- unknown answer one way the visual system might do this is by matching the images on the left and right retinas on the basis of the specific features of the objects. free fusion: binocular disparity-> angle of disparity-> distance= depth cue

Question 31

binocular depth cells/ disparity selective cells

Answer 31

neurons in both the striate and extrastriate cortex that respond to disparity

Question 32

disparity tuning curve

Answer 32

disparity tuning curve for a neuron sensitive to an about disparity of about 1 °

Question 33

perceiving size

Answer 33

the perception of size is intertwined with the perception of distance - remember the helicopter pilot story

Question 34

visual angle

Answer 34

the angle of an object relative to the observer's eye depends on the size of the stimulus and the distance from the observer when the object is bigger or is closer, the visual angle is larger

Question 35

the holway and boring experiment

Answer 35

a person is between 2 hallways sees a luminous test circle in the right hallway and a luminous comparison circle in the left-> shows that when there is good depth information, we can estimate the size of an object based on it's actual size, but if there is bad depth information, we can't when depth cues are present, participants correctly identified the : -small but close circle -large but farther away test circles size estimation is based on the actual size of objects when depth cues are present - when there are no depth cues, visual angle because the main estimation of size

Question 36

size constancy

Answer 36

our perception of an objet's size is relatively constant even when we view the object from different distances size consistency decreases under conditions of poor depth cues.

Question 37

size- distance scaling

Answer 37

S= K (R x D) id D is low then R is high S- objects perceived size R- size of retinal image D- perceived distance

Question 38

The muller-lier illusion (depth cue based)

Answer 38

2 lines seem to be different lengths but are the same due to: * misapplied size constancy calling - the right line looks like a corner view from the inside-`. we see the left line as being farther away , perceptions in the 3D world sometimes create illusions when applied to 2D *conflicting cues theory (size cue based)- our perception of line length depends on 2 cues: the actual length of the lines and the overall length of the figure there are 2 cues responsible: the length of the vertical line the size of the object - if the object is longer, the lines appear big

Question 39

the Ponzo illusion

Answer 39

depth cues (convergence) make the top animal appear farther away => D high, R same =S high 2 same animals, 1 on the top and one under are the same size but seem different based on convergence also due to misapplied size constancy scaling

Question 40

Ames rooms

Answer 40

2 people of equal size on opposite sides seem to be different sizes, due to the setting around them-> one corner is twice as far as the other D the same for both people for r Low on the right -> s smaller

Question 41

monocular cues revision

Answer 41

pictorial cues- give depth info, in a 2 D image * occlusion- 1 object is in front of of the other, works best at any range * relative height- objects higher in the field of the view are usually farther away-> works best at far range * familiar size - judging the distance based on prior knowledge of the seize of objects * relative size - when 2 objects are equal physical size, the one further away takes up less of our field of view (seems smaller) * perspective convergence - parallel lines seem to converge in the distance -> works best at close range * atmospheric perspective- distance objects appear less sharp than near objects (looks more blue because are and particles) -> works best at far range * texture gradient - when similar objects are equally spaced in a scene -> works best at far range * shadows - provide information regarding the location of objects moment based / motion produced cues-give depth info based on movement- works best at close range * motion parallax -as we move, nearby objects seem to glide fast past us, where distance objects seem to move more slowly. * deletion - when we move our head or eyes, making an object become covered/ obscured * accretion- when we move our head or eyes, making an object become apparent/ uncovered

Question 42

binocular cues revision

Answer 42

* Binocular disparity - the 2 retinas have slightly different images of the same scene due to the different position of the eyes (so different position of the objects in the images of both eyes). * corresponding retinal points- point of the retina that would overlap of the eyes were superimposed on each other. horopter- invisible line on which all corresponding retinal points fall * non- corresponding points- points on the retina that are not on the the horopter * absolute disparity - degree to which the image of the object deviate from the corresponding points-> helps determinate if the object is in front or behind the point of fixation. * crossed disparity - when the object is in front of the horopter, so the left eye seen can object to the right of the fixation point and the right eye sees it to the left - small disparity * uncrossed disparity- when the object is behind the horopter, so the left eye sees an object to the left of the fixation point and the right eye see it to the right- big disparity

Question 43

stereopsis

Answer 43

disparity creates stereopsis- brain natural ability to combine the slightly different images from each eye into cohesive 3D image. It relies on binocular disparity. artificial way to separate 2 images - stereoscope: one lens focuses on one eye and the other lens focuses on other eye