Lecture 10: Depth Perception

Question 1

Why is having two eyes close together important?

Answer 1

Our two eyes have slightly diff views of the world, the combination of the two gets us depth and is called stereopsis - this means our eyes have retinal disparity

Question 2

Retinal Disparity

Answer 2

the difference between the visual images that each eye perceives because of the different angles in which each eye views the world

Question 3

Ways of getting different images into each eye

Answer 3

• Red : green anaglyphs
• Polaroid over each eye 4
• Mirrors
• Free fuse
• Auto stereograms (Magic eye)
• The 3 – D movies film with two camerias 6 cm apart (like the two eyes and overlap them both to converge the image

Question 4

describe random dot stereo grams

Answer 4

between two images there is very early/low level info to detect - one image has a pattern of dots shifted to one side, both eyes together will detect the retinal disparity

Question 5

neural basis of disparity sensitivity

Answer 5

Need to combine images from eyes - the first place this happens is in the striate cortex in V1 - cells are driven by both eyes have are disparity sensitive (Barlow et al 1968)

Question 6

stereoblindess

Answer 6

Stereo vision develops early in life, if problems in early life never learn to join the input from both eyes

Question 7

motion parallax and study

Answer 7

movment in the world or eyes causes retina to move - things closer to us move faster which helps us detect depth (Roger and Graham 1979 - got p to move head with moving dots)