Depth perception Flashcards
Image from the real world is essentially…?
a. 2D
b. 3D
a. 2D
Our perception of the world is…?
a. 2D
b. 3D
b. 3D
Generally, people are quite accurate in judging ambient distances up to about 20 feet. How is this typically demonstrated?
Having people survey the scene, closing their eyes and walking to a predesignated object
What are the 4 cues to depth?
1) Oculomotor cues
2) Pictorial cues (monocular cues)
3) Motion-produced cues
4) Binocular disparity
What are oculomotor cues?
Cues that depend on our ability to sense the position of our eyes and tension in our eye muscles
What are pictorial cues (monocular cues)?
Cues that can be depicted in a still picture
What are motion-produced cues?
Cues that depend on the movement of the observer, or the movement of objects in the environment
What are binocular disparity cues?
A cue that depends on the fact that slightly different images of a scene are formed on each eye
Cues that depend on our ability to sense the position of our eyes and the tension in our eye muscles
This is known as…?
Oculomotor cues
Cues that can be depicted in a still picture
This is known as…?
Pictorial cues (monocular cues)
Cues that depend on the movement of the observer, or the movement of objects in the environment
This is known as…?
Motion-produced cues
A cue that depends on the fact that slightly different images of a scene are formed on each eye
This is known as…?
Binocular disparity
Look at your finger as you hold it at arm’s length. Then slowly move your finger towards your nose. Be aware of how, as your finger moves closer, you feel your eyes looking inward and you feel increasing tension inside your eyes.
What cue is this?
Oculomotor cues
What are the 2 feelings you experience when following Oculomotor cues?
1) Convergence as your eye muscles cause your eyes to look inward
2) Accommodation as the lens bulges to focus on a near object)
When following oculomotor cues, you’ll experience convergence. What happens during convergence?
Your eye muscles cause your eyes to look inward
When following oculomotor cues, you’ll experience accommodation. What happens during accommodation?
Our eye lens bulges to focus on a near object
The shape of the lens and position of the eyes are correlated with …?
The distance of the object we are observing
Which cues are only effective at distances closer than 5-10 feet?
Oculomotor cues
Oculomotor cues are only effective at what distance?
Distances closer than 5 – 10 feet
The closer the object the (weaker/greater) the convergence
Greater
How does the eye accommodate for close vision?
By contracting/tightening the ciliary muscles, allowing the pliable crystalline lens to become more rounded
The eye contracts/tightens the ciliary muscles, allowing the pliable crystalline lens to become more rounded
Why does it do this?
To accommodate for close/near vision
The closer you are looking at an object, the (less/more) contraction there will be
More
How does the eye accommodate far vision?
The eye relaxes the ciliary muscles, allowing the pliable crystalline lens to be at minimum strength for distant vision
Do fibres taut or slack for far vision?
Taut
Do fibres taut or slack for near vision?
Slack
Do lenses round or flatten for near vision?
Round
When the eye accommodates far vision, what happens to light rays coming into the eye?
Light rays from distant objects are nearly parallel and don’t need as much refraction to bring them to a focus
When the eye accommodates near vision, what happens to light rays coming into the eye?
Light rays from close objects diverge and require more refraction for focusing
What is considered normal vision in terms of light rays hitting the retina?
Light is focused on the retina exactly
What is considered myopic vision in terms of light rays hitting the retina?
Light focused in front of the retina (too much-focusing power)
What is considered hyperopic vision in terms of light rays hitting the retina?
Light focused behind the retina (too weak focusing power)
Is myopia short-sightedness or long-sightedness?
Short-sightedness
Is hyperopia short-sightedness or long-sightedness?
Long-sightedness
What happens when myopia is corrected?
Light focused on the retina exactly by using a spectacle lens
Which depth cues do not require viewing with both eyes to work?
Pictorial cues
True or False
Pictorial cues require viewing with both eyes to work
False
They do not require viewing with both eyes to work
Which depth cue is often better to view monocularly?
Pictorial cues
True or False?
Pictorial cues are often better to view binocularly
Pictorial cues are often better to view monocularly
Define interposition or occlusion (pictorial cue)
One object obscures part of another or overlaps with it
A visual-perceptual task in which the participant is required to synthesize elements from fragmented, ambiguous pictures of items to form a “whole.”
This is known as…?
Gastault completion
What are the types of pictorial cues? List 9
1) Overlap/interposition/occlusion
2) Relative size
3) Relative height
4) Atmospheric Perspective
5) Familiar size
6) Linear perspective
7) Shading and shadows
8) Texture gradient
9) Movement-produced cues
Define relative size (pictorial cue)
The retinal size of objects gets smaller as they get further away
The retinal size of objects gets smaller as they get further away
This is known as…?
Relative size