Depth Perception

Yay more eye stuff

What are the three types of cues used for depth perception?

Oculomotor, Binocular and Monocular

What are the two types of oclulomotor cues?

Convergence and accomadation

Outline accommodation

Brain detects changes in the lens shape as we focus on near objects

Outline Convergence

Brain detects the inward movement of the eyes at near-sight

What is a binocular depth cue?

Stereopsis

Outline Stereopsis

Depth is calculated by the difference of the image perceived in each eye

How is Stereopsis able to happen in humans?

Human eyes are in different lateral positions to each other

What are the two types of monocular depth cues?

Pictorial and Movement based

Outline 5 types of pictorial cues?

Occlusion, Cast Shadows, Relative size, atmospheric perspective and linear perspective

True or false, Pictorial cues are top down knowledge

True

Outline Motion Parallax

Near objects appear to move quicker past you than objects that are far away (Car window effect)

Outline size constancy

Objects stored in our memory appear to retain their original dimensions from perception

True or False: Perceived size depends on the depth of the object in space

True

What is meant by the term visual angle?

The size of the angle in the retina when an image is projected onto it

If the visual angle in the retina is big, what is the depth of the object?

Near

If the visual angle in the retina is small, what is the depth of the object?

Far

Outline the method of the Holway and Boring experiment for size and depth perception

1. Observer place in intersection of 2 halls

2. Control circle was placed in left hall at fixed distance

3. Experimental circles of differing size and depth were placed in right hall

4. Observer had to match circles in right hall with size of the control circle

With depth cues, was the observer accurate at guessing the size of the circles?

Yes

Without depth cues, was the observer accurate at guessing the size of the circles?

No

Outline the distance scaling equation

S = K(RxD)

What does the silly little equation actually mean?

Perceived size (is proportional to) Retinal image size x perceived distance