Ppmv Facts

Front 1

In method of limits testing the examiner

Back 1

Manipulates the stimulus – either ascending or descending

Front 2

In method of adjustment the subject

Back 2

Manipulates the stimulus to match a standard

Front 3

In method of constant stimuli the subject responds to

Back 3

Independent measure – most accurate – a psychometric function is constructed – 50%response level – response independent

Front 4

Scaling methods are used to determine the

Back 4

Intensity of the sensation experienced by the subject

Front 5

In direct scaling the subject

Back 5

Assigns appropriate numbers to a series of stimuli according to the subjective impressions

Front 6

Indirect scaling is broken down into

Back 6

Comparative judgment and Categorical judgment

Front 7

The four basic measurement scales are

Back 7

1) nominal 2) ordinal 3) interval 4) ratio

Front 8

Probability of correctly identifying a + = (sensitivity)

Back 8

TP / (TP + FN) = hit rate

Front 9

Probability of correctly identifying a – = (specificity)

Back 9

TN / (TN + FP) =

Front 11

Positive predictive value =

Back 11

TP/ (TP +FP) probability that if labeled + is in fact +

Front 12

Negative predictive value =

Back 12

TN / (TN + FN) probability that if labeled – is in fact –

Front 14

3 variables to describe color

Back 14

1) hue 2) saturation 3) brightness

Front 15

Hue is correlated with the

Back 15

Wavelength of the light – photometric equivalent is dominant wavelength

Front 16

Hue is best detected at

Back 16

Blue green (490nm) and yellow red (590nm)

Front 17

Saturation is a measures of the degree to which the

Back 17

Stimulus is mixed with white – photometric equivalent is purity

Front 18

Brightness is the

Back 18

Luminosity of the color – photometric equivalent is luminance

Front 19

Abney effect refers to

Back 19

A change in hue associated with a change in purity (saturation)

Front 20

Benzold Brucke effect refers to

Back 20

A change in hue associated with a change in luminance - stimuli below 500nm look more blue with increased intensity- stimuli above 500nm look more yellow with increased intensity

Front 21

Purdy effect is a

Back 21

Change in saturation with a change in luminance

Front 22

Best color discrimination for normals is

Back 22

At 480-490nm (blue green) and 580nm (yellow)

Front 23

For dicromats the best discrimination is at the ProtanopesDeuteranopesTritanopes

Back 23

Neutral point 490nm495nm570nm

Front 24

Additive primary colors are

Back 24

Red, green, blue (yellow is a psychological primary)

Front 25

Complementary colors when mixed produce

Back 25

White or gray -

Front 26

Additive color mixtures are a

Back 26

Superimposition of 2 or more lights to produce a color

Front 27

Metameric colors are colors that

Back 27

Match in appearance but are composed of different wavelength mixtures

Front 28

Simultaneous color contrast refers to the change in

Back 28

The appearance of an object with a change in the surround color

Front 29

Successive color contrast refers to a

Back 29

Negative afterimage being the color of the complementary color

Front 30

Color contingent aftereffects are due to

Back 30

Fatigue/ adaptation of he system

Front 31

The McCollough effect refers to an adaptation to

Back 31

Orientation and color

Front 32

Color constancy refers to the fact that

Back 32

Relative colors remain constant with changes in luminance

Front 33

Tristimulus values are the

Back 33

Boundaries of visible spectrum (380-760nm)

Front 34

Munsell color system attempts to have the

Back 34

Notation correspond to the sensory experience

Front 35

Munsell hues are located around a circle numbered

Back 35

1-10 – there are 10 major hues and 100 total hues

Front 36

The Munsell “value” refers to

Back 36

Lightness and is along the vertical axis

Front 37

The Munsell “chroma” refers to

Back 37

Whiteness and is represented by a horizontal line from the center of the circle – scale form 0 to a maximum

Front 38

The Munsell notation is given in

Back 38

H/V/C hue/value/chroma

Front 39

MacAdams ellipses are perceptual areas in the CIE diagram where

Back 39

All colors will appear the same – even if physically different

Front 40

Cones have the greatest sensitivity at

Back 40

555nm (green/yellow)

Front 41

Rods have the greatest sensitivity at

Back 41

505nm (blue/green)

Front 42

Anomalous trichromats Deuteranomaly ProtanomalyTritanomaly

Back 42

Require 3 primary colors to create a match Most common of all deficiencies – requires more green to match color mixtures – M cones are mutated (535nm)Requires more red to match color mixtures – L cone defectiveRequires more blue to match color mixtures – S cone defective

Front 43

Dichromats Protanope Deuteranope Tritanope

Back 43

Require 2 primary colors to make a match Missing erythrolabe – confuse red with any other color and B-G with white – best color discrimination for 492nm (blue green) – cannot discriminate at long wavelengthsMissing chlorolabe – confuse green with white – nearly normal photopic spectral sensitivity – discriminate best for 498nm (greener blue green) Missing cyanolabe – confuse yellow with white – normal photopic spectral sensitivity – best discrimination for 570nm (yellow green)

Front 44

Rayleigh equation is the ratio of

Back 44

Red to green needed to match yellow in an anomaloscope

Front 45

Protanomalous trichromats will have one ratio but will

Back 45

Require more red than normal

Front 46

Deuteranomalous trihromats will have one ratio but

Back 46

Require more green than normal

Front 47

Protanopia causes a px to require

Back 47

Less luminance of yellow to match brightness of pure red

Front 48

Deuteranopia requires equal

Back 48

Luminance to match yellow with pure red or green

Front 49

Kollner’s rule Diseases of retina and ocular mediaDiseases of the ON and visual pathway

Back 49

Applies to acquired color vision defects Blue yellow defectRed green defects

Front 50

Brightness can be predicted by

Back 50

The activity of non opponent cells

Front 51

Hue can be predicted by

Back 51

The activity of opponent cells

Front 52

Saturation can be predicted by

Back 52

The ratio of opponent to non opponent cells

Front 53

Oculocentric localization references objects in space to

Back 53

The entrance pupil of the observing eye (monocular)

Front 54

Every point on the retina has a visual direction

Back 54

Associated with it = local sign

Front 55

Primary visual direction is the

Back 55

Local sign associated with the fovea

Front 56

Secondary visual directions are associated with

Back 56

All other retinal elements – are relative to the primary visual dir

Front 57

Oculocentric visual direction refers to the fact that

Back 57

Secondary visual direction is always relative to the primary visual direction

Front 58

In egocentric localization direction is in reference to

Back 58

The cyclopean eye – occurs at the cortical level – requires the input of two oculocentric locatozations – binocular

Front 59

Around a horoptor, binocular disparity is

Back 59

Zero

Front 60

Geometric effect occurs with magnification in the

Back 60

Horizontal meridian (X90) – floor slants down and toward magnified eye – facing wall is skewed away from eye

Front 61

Induced effect occurs with magnification in the

Back 61

Vertical meridian (X180) – floor slants up and away from the magnified eye – facing wall is skewed toward the eye

Front 62

Visually guided behavior is controlled by the

Back 62

Superior colliculus

Front 63

Minimum visual acuity determines the

Back 63

Presence or absence of a target – rod function

Front 64

Resolution refers to a

Back 64

Response to separation between elements of a pattern

Front 65

Recognition requires

Back 65

Naming of the test object or a critical aspect of it

Front 66

Contrast =

Back 66

(Target luminance – background) / background luminance

Front 67

Contrast =

Back 67

(Lmax- Lmin) / (Lmax + Lmin)

Front 68

In an Ames room the

Back 68

Perceived distance is constant but retinal image size varies

Front 69

Mueller Lyer illusion refers to

Back 69

Lines of same length appearing unequal due to arrow heads

Front 71

Weber’s law states that

Back 71

The higher the background, the higher the change in stimulus necessary for the detection of an absolute difference

Front 72

DeVries-Rose Law predicts the

Back 72

Ideal threshold of a stimulus upon a background

Front 73

Ricco’s law deals with

Back 73

Spatial summation – better in scotopic system

Front 74

Block’s law deals with

Back 74

Temporal summation – better in photopic system

Front 75

The critical duration for temporal summation is

Back 75

100msec for rods; 10-15msec for cones

Front 76

Korte’s law summarizes the optimum stimulus

Back 76

For apparent motion

Front 77

Alpha motion is a type of apparent motion where there

Back 77

Is apparent expansion and ceontration – 2nd target is larger

Front 78

Gamma motion is a type of apparent motion where

Back 78

The second target is brighter

Front 79

Sigma motion occurs when the target is constantly on

Back 79

The fovea

Front 80

Stroboscopic movement (Phi phenomena) is where the

Back 80

Presentation of stationary stimuli gives rise to apparent motion

Front 81

Brucke-Bartley effect refers to a

Back 81

Flickering light looking brighter than a steady light

Front 82

Granit Harper law refers to the fact that as the

Back 82

Size of a CFF stimulus increases the CFF becomes higher

Front 83

Ferry Porter law states that the

Back 83

CFF is directly proportional to the log of the stimulus intensity

Front 84

Backward masking aka metacontrast is when the

Back 84

Mask stimulus is presented immediately after the test stimulus

Front 85

Forward masking aka paracontrast occurs when the

Back 85

Mask precedes the stimulus