Lecture 16 - Seeing Depth pt. 2

Question 1

depth cues themselves aren’t….

Answer 1

hardwired!

we learn them after repeated use, learning, experience with the environment = you gain them over time

if you don’t have certain visual experiences early on you would be less able to use depth cues

Question 2

We learn – through experience

dependent plasticity –

Answer 2

– the connection between the cue and

depth. (The brain changes connectivity as the result of
experience. )

• The association becomes automatic through repeated exposure.

Question 3

atmospheric perspective

Answer 3

pictorial cue based on real experience in 3-D

distance objects are fuzzy and have a blue tint.

the further the light has to go the more it can be impeded by little pockets of air in the atmosphere (fog, cloud, heat, haze)

the bluer light is less affected, so you have more of it coming through

Question 4

texture gradient

Answer 4

if you have some regular pattern (texture) the larger pattterns will be closer to you and the denser more compact patterns will be more distant

• equally spaced elements are more closely packed as
  distance increases

Question 5

shadows

Answer 5

• indicate where objects are located, relative to a light source

– Enhance 3-D nature of objects

using the assumption (light from above hueristic) we use shadow info so you know where light is coming from and now the object has depth

Question 6

monocular pictorial cues

Answer 6

- Occlusion 
• Relative height 
• Relative size 
• Perspective convergence 
• Familiar size 
- shadows
- texture gradient 
- atmospheric perspective

Question 7

occulsion

Answer 7

when one object partially covers another.

Question 8

relative height

Answer 8

objects below the horizon that are higher in the field of

vision are more distant. Objects above the horizon that are lower in the visual field are more distant.

Question 9

relative size

Answer 9

• when objects are
  equal size, the closer one will take
  up more of your visual field

Question 10

perspective convergence

Answer 10

• parallel lines appear to come together in the

distance

Question 11

familiar size

Answer 11

• distance information based on our knowledge of object

size

Question 12

motion produced cues

Answer 12

motion parallax

deletion and accretion

Question 13

motion parallax

Answer 13

seeing a difference in the relative speed of objects as they go past your retina

• Close objects in direction of movement glide rapidly past, but objects in the distance appear to move slowly.

using optic flow to pull out depth from motion

Question 14

deletion and accretion

Answer 14

• objects are covered or uncovered as we move relative to them

– Covering an object is deletion

– Uncovering an object is accretion

relative motion of the observer: are you deleting or accreting the object? - you can see how far away something is by seeing how far apart the object in front and the object behind are