Lecture 15 Size and Depth Flashcards
Describe how the trichromat’s brain converts relative differences to colour.
- detect significant differences in the pattern of firing across the 3 cone types
- i.e. distinguish green and yellow as more distinct representations, which their perceptual system would then create more distinct experiences of colour for
Describe how the protanope’s (missing long cone) brain converts relative differences to colour. How does it compare to the trichromat?
- like the trichromat, this type of dichromat has similar responses to both 500 and 570 nm light
- only difference is a SLIGHT CHANGE in how their short cones respond (to green vs yellow)
- therefore, less differentiated response to 500 and 570 nm light
- perceive only SLIGHTLY DIFFERENT colour experiences
What is the cue approach to depth perception?
focuses on information in the retinal image that is correlated with depth in the scene
How does the association between cue and depth become automatic for us?
by repeated exposure
What are oculomotor cues?
cues based on sensing the position of the eyes and muscle tension
What is convergence in terms of oculomotor cues?
inward movement of the eyes when we focus on NEARBY objects
What is accommodation in terms of oculomotor cues?
shape of the lens changes when we focus on objects at different distances
What are monocular cues?
information that can be based on the image from a single eye
What are pictorial cues? are they monocular or bionocular?
- monocular
- sources of depth information that comes from 2D images (e.g. pictures)
What is occlusion? Is it a monocular or binocular cue?
- monocular
- when one object partially covers another
What kind of information does relative height give us? Is it a monocular or binocular cue?
- monocular
- 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
What is perspective convergence? Is it a monocular or binocular cue?
- monocular
- parallel lines appear to come together in the distance
What is relative size? Is it a monocular or binocular cue?
- monocular
- when objects are equal size, the closer one will take up more of your visual field
What is atmospheric perspective? Is it a monocular or binocular cue? Why does this occur?
- monocular
- distance objects appear more ‘fuzzy’
- occurs because the farther away something is, the more air/particles we have to look through to see it
Why do farther objects tend to appear more blue?
our atmosphere preferentially scatters short wavelengths and looking ‘through’ more of it increases the ‘blueness’ (i.e. atmospheric perspective)
What is texture gradient? Is it a monocular or binocular cue?
- monocular
- equally spaced elements are more closely packed as distance increases
How do shadows enhance depth? Is it a monocular or binocular cue?
- monocular
- indicates where objects/features are located
What is motion parallax? Is it a monocular or binocular cue? Explain how it works in terms of the retina.
- monocular
- CLOSE objects in direction of movement glide RAPIDLY past, but DISTANT objects appear to move SLOWLY
- the image of something CLOSER to us travels LARGER DISTANCE across the retina, vs something farther away, in an equivalent amount of time
What is deletion and accretion? Is it a monocular or binocular cue?
- monocular
- objects are covered or uncovered as we move relative to them
- deletion = covering an object
- accretion = uncovering an object
Which of the following indicate relative depth:
- occlusion
- deletion and accretion
- motion parallax
- convergence
- relative size
- atmospheric perspective
- relative height
- texture gradients
- accommodation
- occlusion
- deletion and accretion
- relative height
- atmospheric perspective
Which of the following indicate actual depth:
- occlusion
- deletion and accretion
- motion parallax
- convergence
- relative size
- atmospheric perspective
- relative height
- texture gradients
- accommodation
- relative size
- texture gradients
- motion parallax
- accommodation
- convergence
Which cues are optimized for 0-2 meters?
- occlusion
- deletion and accretion
- motion parallax
- convergence
- relative size
- atmospheric perspective
- relative height
- texture gradients
- accommodation
- occlusion
- relative size
- motion parallax
- accommodation
- convergence
Which cues are optimized for 2-20 meters?
- occlusion
- deletion and accretion
- motion parallax
- convergence
- relative size
- atmospheric perspective
- relative height
- texture gradients
- accommodation
- occlusion
- deletion and accretion
- relative height
- relative size
- texture gradients
- motion parallax
Which cues are optimized for above 20 meters?
- occlusion
- deletion and accretion
- motion parallax
- convergence
- relative size
- atmospheric perspective
- relative height
- texture gradients
- accommodation
- occlusion
- deletion and accretion
- relative height
- atmospheric perspective
- relative size
- texture gradients
