Lecture 19 - Lecture 21: Vision

Question 1

Light is a form of electromagnetic radiation generated by the oscillation of electrically charged particles called __________?

Answer 1

Photons

Question 2

What are the two most important qualities we perceive from light?

Answer 2

Color and brightness

Question 3

The length of the light’s wavelength produces

Answer 3

Color

Question 4

As the length of the light wave increases, ___________________________

Answer 4

The sensation of the color changes

Question 5

The brightness of a couloir is related to it’s ____________, which is directly proportional to the density of photons in the wave.

Answer 5

Amplitude

Question 6

The more photons in the wave, (brighter/lighter) the light or color will appear to be.

Answer 6

Brighter

Question 7

Light is a pattern of _________________ and _______________, along the many wavelength they create, that allow us to see the shapes and surfaces of objects.

Answer 7

Reflection and absorption

Question 8

What is used to measure light?

Answer 8

Nanometer

Question 9

Tendency for colors to remain fix despite changes in illumination In which they are embedded

Answer 9

Color constancy

Question 10

Two types of reflection

Answer 10

1. Speculation reflection

2. Diffuse reflection

Question 11

What is specular reflection

Answer 11

Mirror like reflection

Question 12

What is diffuse reflection

Answer 12

Reflection of the rough

Question 13

The first step in color perception begins with the _________ in the retina

Answer 13

Cones

Question 14

What are the 3 different types of cones?

Answer 14

1. Absorbs light in short wavelengths (445 nm-blue)
2. Absorbs light at medium wavelengths (535nm-green)
3. Absorbs light at long wavelengths (570nm-red)

Red sensitive cones do not respond exclusively to long wavelengths of light, they just respond better - the same principle holds for the other 2 cones p. 71

Question 15

We detect all these different wavelengths because the light energy reaching our eyes is __________ by the cones into neural impulses

Answer 15

Transduced

Question 16

______________ are special molecules imbedded in their membrane consisting of opsin and retinal

Answer 16

Photopigments

Question 17

What are the 3 trichromatic colors?

Answer 17

Red, green, and blue

Question 18

The trichromatic theory is also known as?

Answer 18

Young-Helmholtz

Question 19

What is the problem with the trichromatic theory?

Answer 19

It could not explain the effect of negative after-images

Question 20

What is the most common form of color blindness

Answer 20

Red (protanopia) - green (dueteranopia)
followed by the rarer blue-yellow form
(no such thing as red -blue or green-yellow color blindness)

Question 21

Who proposed the opponent theory of color vision

Answer 21

Weald Hering

Question 22

Where does yellow come from?

Answer 22

It is made up from inputs arriving from the red and green cones

Question 23

The perceived color of an object remains the same under very difficult lighting conditions

Answer 23

Color constancy

Question 24

What colors do people who suffers are red-green color blind sees?

Answer 24

Blue, yellow, and grey

Question 25

Why does red-green color blindness predominantly affect the males

Answer 25

Because the protan and duet an genes are located on the X-chromosomes, of which men have one and women have two. Women are rarely red-green blind because if one of their X chromosome is defective the other one can compensate for it. Daughters of men who handed down color blindness to his children will normally be unaffected

Question 26

What type of color blindness would it be if a person lacks blue cones (unable to distinguish between blue and yellow).

Answer 26

Tritanopia

Question 27

_________________ causes total color blindness

Answer 27

Achromatopsia

Question 28

First region to receive input from the lateral geniculate nucleus

Answer 28

Visual area 1 or v1 or area17 or primary visual cortex 18 and 19 or V2 and V3 make up the visual association cortex

Question 29

Condition where people suffer from bilateral damage to the posterior regions of the parietal lobes

Answer 29

Balint's syndrome

Question 30

Difficulty in shifting one's gaze into a new stimulus. Difficulty in focusing in on a particular object. Their eyes wander around so that objects came into view for a while and are then replaced by others

Answer 30

Ocular apraxia

Question 31

Inability to reach for objects under visual guidance. Result to person fumbling and misreaching for objects and being unable to point accurately to a visual stimulus although the they can see it clearly

Answer 31

Optic ataxia

Question 32

A person's inability to see the totality of their visual scene. Have a very narrow visual attention field which will result in their being unable to see two objects at once. E.g. Toothbrush and pen

Answer 32

Simultanagnosia

Question 33

A person being unable to recognize the faces of their family and friends

Answer 33

Prosopagnosia

Question 34

The stimulus for activity ting the visual system is ________?

Answer 34

Light

Question 35

What makes a colored objected appear to be that color (I.e. Blue)?

Answer 35

When light strikes an object, the long wavelength is reflected and the other wavelength is absorbed

Question 36

Sensitive to light at low energy

Answer 36

Rods

Question 37

What are combined pigments?

Answer 37

Selectively removing all the wavelengths of light

Question 38

What are the 2 main receptor types

Answer 38

1. Cones | 2. Rods

Question 39

What is the difference between cones and rods

Answer 39

Cones - daylight; gives color Rods - nighttime *cones sensitivity to light is lower than the rods

Question 40

What are the 4 receptors

Answer 40

1. Short wavelengths (445 nm-blue) 2. medium wavelengths (535nm-green) 3. long wavelengths (570nm-red) 4. Rods

Question 41

What the peak of the cone tells you?

Answer 41

Sensitivity

Question 42

What states that all absorbed photons generate the same response independently of wavelength

Answer 42

Principle of univariance

Question 43

________________ same pattern of activation in the cone and will have the same colour experience. - why monitors, colored TVs, cameras, etc. work

Answer 43

Metameters

Question 44

_______ is all about trichromatic. Type of adaptation. Receptors become unresponsive

Answer 44

Color after image

Question 45

What are the 3 opponent aces that you need? And what is the neutral color?

Answer 45

1. Blue-yellow 2. Red-green 3. Black-white -Grey is neutral

Question 46

What is color?

Answer 46

Capacity to experience differences between wavelengths

Question 47

Why do you experience color?

Answer 47

Because you have more than 1 cone while rods look at the same visible spectrum

Question 48

What is color vision?

Answer 48

Capacity to experience different wavelength of light

Question 49

What does trichromatic count for?

Answer 49

Photons

Question 50

What is a single wavelength of light

Answer 50

Saturation

Question 51

Mixing colors from any points on the opposite sides of the perimeter takes you through a __________. What colour is it?

Answer 51

Neutral point; grey

Question 52

What theory states that certain colors cancels each other out

Answer 52

Opponent process theory

Question 53

What corresponds grossly to the height of the 3D representation?

Answer 53

Brightness

Question 54

Corresponds to the radial distance from the achromatic point

Answer 54

Saturation

Question 55

Equal intensity plane of colour space

Answer 55

Isssiluminate plane

Question 56

What colors you get from an unusual spectrum

Answer 56

Spectral locus

Question 57

The 4 colors: red, green, blue and yellow are part of the spectral locus

Answer 57

Unique hues

Question 58

What do you mean by impure red?

Answer 58

Impure because it's a mixture of red and blue

Question 59

A color that is evoked by a single wavelength of light in the visible spectrum

Answer 59

Spectral color

Question 60

Most saturated point

Answer 60

Grey

Question 61

Subtractive color can be used for?

Answer 61

Printing

Question 62

What is used for printing?

Answer 62

CMYK

Question 63

Used for presentations?

Answer 63

RGB

Question 64

What is the principle that says that it has the same colour but the surround affects it?

Answer 64

Simultaneous contrast

Question 65

How do you decompose luminance into their physical sources?

Answer 65

Using Shadows

Question 66

What are shadows?

Answer 66

Difference on how they are illuminated

Question 67

What are the 4 edge classification problem?

Answer 67

1. Reflectance (changes in surface lightness or color) 2. Shape (folds) 3. Illumination (shadows; spotlights) 4. Occlusions (which could include one or more f the above)

Question 68

What is illiuminance

Answer 68

Light falling on a surface

Question 69

What is reflectance?

Answer 69

Proportion or percentage of light that a surface reflects

Question 70

What is luminance?

Answer 70

Total amount of light reaching the eye

Question 71

What is the formula for luminance

Answer 71

Luminance = illiuminance X reflectance

Question 72

What is important about shadows?

Answer 72

The edge of the shadow

Question 73

Yellow and blue will give you what color?

Answer 73

Grey

Question 74

what is a single (different) wavelength of light at a particular intensity (say 550)

Answer 74

photoreceptor curves

Question 75

what do you call the total response in all lights of each individual wavelength?

Answer 75

weighted sum

Question 76

what does photoreceptor curves mean?

Answer 76

the curve tells the weights of the wavelength

Question 77

how many receptors do you need to tell about the wavelength composition of light?

Answer 77

you need the 3 receptors/cones

Question 78

what do you experience when you excite the cones in the same way. Thi is why monitors, TV's, colour cameras film, etc worl

Answer 78

metamers

Question 79

mixing colors from any points in the opposite sides of the perimeter takes you through a neutral point. what colour would this be?

Answer 79

grey