LGN and V1

Question 1

How are oculomotor cues created?

1.

2.

Answer 1

1. Convergence- the inner movement of the eyes that occurs when we look at nearby objects
2. Accomodation- the change in the shape of the lens that occurs when we focus on objects at various distances

Question 2

Name all the monocular cues.

1-11

11 (a-c)

Answer 2

• Familiar size- based on previous knowledge. EX: People are larger than quarters.
• Relative size- when two objects are of equal size, the one that is father away will take up less of VF than the one that is closer.
• Brightness cues-
• occlusion- an object occludes another one
• shading and shadows
• Aerial perspective- when more distant objects appear less sharp and often have a slight blue tint.
• Linear perspective- when parallel lines extend out from an observer, they are perceived as converging as distance inceases.
• Height within an image-objects below horizon and higher in the VF are seen as more distant AND objects above horizon and lower in VF indicates more distant.
• Texture gradient- elelments that are equally spaced spaced in a scene appear to be more closely packed as distance increases
• Contours
• Accommodation and optical blur

• Motions cues:
a. Motion parallax- as we move, nearby objects appear to glide rapidly past us, but more distant objects appear to move more slowly.

b. Kinetic depth
c. Dynamic occlusion

Question 3

Name the binocular cues.

1.

2.

Answer 3

• Convergence- how much eyes are bending
• Disparity- crossed and uncrossed

Question 4

what is disparity?

Answer 4

the difference in the images in the left and right eyes.

Question 5

What is a horopter?

Answer 5

It’s an imaginary surface that passes through the point of fixation and indicated teh location of objects that falls on the foveas.

ZERO DISPARITY

Question 6

what is uncrossed disparity?

what is crossed disparity?

Answer 6

uncrossed- (diverge eyes to fixate on it) an object farther away from you than the horopter

crossed- (converge eyes to fixate on it) object closer than the horopter

Question 7

What is a random-dot stereogram?

Answer 7

Def: A pair of stereoscopic images made up of random dots.

When one section of this pattern is shifted slightly in one direction, the resulting disparity causes the shifted section to appear above or below the rest of the pattern when the patterns are viewed in a stereoscope.

Question 8

What is AMBLYOPIA?

Answer 8

It’s cortical blindness.

Its a general term for visual deficit that has nothing to do with the optics or structure of eye and retina.

The brain basically ignores inputs from one eye.

Question 9

What is the visual angle?

Answer 9

It tells us how large the object will be on the back of the eye.

Question 10

What is stereopsis?

Answer 10

Stereopsis (literally, “seeing solid”) - 3D vision resulting from slight differences in left and right eye images, arising because the two eyes view the world from slightly different perspectives

Question 11

What are the things that happen with two eyes?

1.

2.

3.

4.

Answer 11

1. Fusion
2. Suppression
3. Diplopia- double vision
4. Rivalry

Question 12

What is spatial vision measured in?

Answer 12

Spatial vision is measured in cycles per degree (the unit vision is measured in~10 degrees)
• Fewer cycles per degree when have larger bars
• More cycles per degree when have smaller bars

Question 13

What is contrast?

Answer 13

Contrast- differences between whites and blacks
• High contrast→ low spatial frequency
• You see better at the center with lowest contrast
• Frequency response plots
• Adaptation with frequency
o If you adapt to the right then when looking at straight lines after it will look to the left
o Adapt to left will see to the left when its taken away

Question 15

Name all the monocular cues.

1-11

11 (a-c)

Answer 15

• Familiar size- based on previous knowledge. EX: People are larger than quarters.
• Relative size- when two objects are of equal size, the one that is father away will take up less of VF than the one that is closer.
• Brightness cues-
• occlusion- an object occludes another one
• shading and shadows
• Aerial perspective- when more distant objects appear less sharp and often have a slight blue tint.
• Linear perspective- when parallel lines extend out from an observer, they are perceived as converging as distance inceases.
• Height within an image-objects below horizon and higher in the VF are seen as more distant AND objects above horizon and lower in VF indicates more distant.
• Texture gradient- elelments that are equally spaced spaced in a scene appear to be more closely packed as distance increases
• Contours
• Accommodation and optical blur

• Motions cues:
a. Motion parallax- as we move, nearby objects appear to glide rapidly past us, but more distant objects appear to move more slowly.

b. Kinetic depth
c. Dynamic occlusion