Color Perception and Applications SIGGRAPH 99 Course: Fundamental - - PDF document

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Color Perception and Applications SIGGRAPH 99 Course: Fundamental - - PDF document

Jan 13, 2023 280 likes •695 views

Color Perception and Applications SIGGRAPH 99 Course: Fundamental Issues of Visual Perception for Effective Image Generation Penny Rheingans University of Maryland Baltimore County Overview Characteristics of Color Perception

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SLIDE 1

Color Perception and Applications

SIGGRAPH ‘99 Course: Fundamental Issues of Visual Perception for Effective Image Generation

Penny Rheingans

University of Maryland Baltimore County

Overview

  • Characteristics of Color Perception
  • Mechanisms of Color Perception
  • Color Specification
  • Using Color to Represent Information
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SLIDE 2

Characteristics of Color Perception

  • Fundamental, independent visual process

– after-images – color deficient vision

  • Relative, not absolute
  • Interactions between color and other visual

properties

Physiology: Receptors

  • Rods

– active at low light levels (scotopic vision) – only one wavelength sensitivity function

  • Cones

– active at normal light levels – three types: sensitivity functions with different peaks

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SLIDE 3

Cone Sensitivity Functions

  • Glassner ‘95, p. 16.

Physiology: Ganglia

  • Transform incoming SML into opponent color

responses

– G - R – Y - B (Y = R+G) – W (W ≅ R+G)

  • Characteristics

– concentric receptive fields – logarithmic response of receptors – adaption

Long (R) Medium (G) Short (B)

+

  • R - G

Y-B Achromatic Yellow

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SLIDE 4

Physiology: Brain

  • Lateral geniculate nuclei

– assemble data for single side of visual field – 2 monochromatic layers => magnocellular path – 4 chromatic layers => parvocellular path

  • Visual cortex

– visual area 1: blobs – visual area 2: thick stripes – visual area 4

Visual Pathway

  • Murch, ‘87.
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SLIDE 5

Parvocellular Division

  • Role in vision

– discrimination of fine detail – color

  • Characteristics

– color: sensitive to wavelength variations – acuity: small RF centers – speed: relatively slow response

Color Models

  • Device-derived

– convenient for describing display device levels – RGB, CMY

  • Intuitive

– based in familiar color description terms – HSV, HSB, HLS

  • Perceptually uniform

– device independent, perceptually uniform – CIELUV, CIELAB, Munsell

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SLIDE 6

Color Models

  • Device-derived

– convenient for describing display device levels – RGB, CMY

  • Intuitive

– based in familiar color description terms – HSV, HSB, HLS

  • Perceptually uniform

– device independent, perceptually uniform – CIELUV, CIELAB, Munsell

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SLIDE 7

Color Models

  • Device-derived

– convenient for describing display device levels – RGB, CMY

  • Intuitive

– based in familiar color description terms – HSV, HSB, HLS

  • Perceptually uniform

– device independent, perceptually uniform – CIELUV, CIELAB, Munsell

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SLIDE 8
  • Hill et al. ‘97, pg. 136

Uses of Color

  • Show classification
  • Mimic reality
  • Show value
  • Draw attention
  • Show grouping
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SLIDE 9

Uses of Color

  • Show classification
  • Mimic reality
  • Show value
  • Draw attention
  • Show grouping
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SLIDE 10

Uses of Color

  • Show classification
  • Mimic reality
  • Show value
  • Draw attention
  • Show grouping
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SLIDE 11

Uses of Color

  • Show classification
  • Mimic reality
  • Show value
  • Draw attention
  • Show grouping
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SLIDE 12

Uses of Color

  • Show classification
  • Mimic reality
  • Show value
  • Draw attention
  • Show grouping
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SLIDE 13
  • Ware and Beatty ‘85, p. 22

Perceptual Distortions

  • Color-deficiency
  • Interactions between color components

– saturation - brightness (Helmholtz-Kohlraush effect) – brightness - hue (Bezold-Brucke Phenomenon)

  • Simultaneous contrast

– brightness – hue

  • Small field achrominance
  • Effects of color on perceived size
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SLIDE 14

Bezold-Brucke Phenomenon

  • Hurvich ‘81, pg. 73.

Perceptual Distortions

  • Color-deficiency
  • Interactions between color components

– saturation - brightness (Helmholtz-Kohlraush effect) – brightness - hue (Bezold-Brucke Phenomenon)

  • Simultaneous contrast

– brightness – hue

  • Small field achrominance
  • Effects of color on perceived size
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SLIDE 15

Simultaneous Contrast Simultaneous Contrast

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SLIDE 16

Perceptual Distortions

  • Color-deficiency
  • Interactions between color components

– saturation - brightness (Helmholtz-Kohlraush effect) – brightness - hue (Bezold-Brucke Phenomenon)

  • Simultaneous contrast

– brightness – hue

  • Small field achrominance
  • Effects of color on perceived size

Small Field Achrominance

  • Wandell ‘95, cp. 3.
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SLIDE 17

Perceptual Distortions

  • Color-deficiency
  • Interactions between color components

– saturation - brightness (Helmholtz-Kohlraush effect) – brightness - hue (Bezold-Brucke Phenomenon)

  • Simultaneous contrast

– brightness – hue

  • Small field achrominance
  • Effects of color on perceived size

Color-size Illusion

  • Cleveland and McGill ‘83.
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SLIDE 18

Some Color Scales

  • Univariate

– color model component – optimal scales – double-ended

  • Multivariate

– color model components – Census Bureau TVCM – complementary display parameters

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SLIDE 19
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SLIDE 20

Some Color Scales

  • Univariate

– color model component – optimal scales – double-ended

  • Multivariate

– color model components – Census Bureau TVCM – complementary display parameters

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SLIDE 21

Some Color Scales

  • Univariate

– color model component – optimal scales – double-ended

  • Multivariate

– color model components – Census Bureau TVCM – complementary display parameters

  • Olson ‘97, fig. 11-8.
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SLIDE 22

Some Color Scales

  • Univariate

– color model component – optimal scales – double-ended

  • Multivariate

– color model components – Census Bureau TVCM – complementary display parameters

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SLIDE 23

Some Color Scales

  • Univariate

– color model component – optimal scales – double-ended

  • Multivariate

– color model components – Census Bureau TVCM – complementary display parameters

  • Tufte ‘83, pg. 153.
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SLIDE 24

Some Color Scales

  • Univariate

– color model component – optimal scales – double-ended

  • Multivariate

– color model components – Census Bureau TVCM – complementary display parameters

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SLIDE 25

Evaluating Color Scales

  • Trumbo’s Principles

– Order: ordered values should be represented by

  • rdered colors

– Separation: significantly different levels should be represented by distinguishable colors – Rows and columns: to preserve univariate information, display parameters should not obscure

  • ne another

– Diagonal: to show positive association, displayed colors should group into three perceptual classes: diagonal, above, below

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SLIDE 26
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SLIDE 27

Evaluating Color Scales

  • Trumbo’s Principles

– Order: ordered values should be represented by

  • rdered colors

– Separation: significantly different levels should be represented by distinguishable colors – Rows and columns: to preserve univariate information, display parameters should not obscure

  • ne another

– Diagonal: to show positive association, displayed colors should group into three perceptual classes: diagonal, above, below

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SLIDE 28

Evaluating Color Scales

  • Trumbo’s Principles

– Order: ordered values should be represented by

  • rdered colors

– Separation: significantly different levels should be represented by distinguishable colors – Rows and columns: to preserve univariate information, display parameters should not obscure

  • ne another

– Diagonal: to show positive association, displayed colors should group into three perceptual classes: diagonal, above, below

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SLIDE 29
  • Tufte ‘83, pg. 153.
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SLIDE 30

Evaluating Color Scales

  • Trumbo’s Principles

– Order: ordered values should be represented by

  • rdered colors

– Separation: significantly different levels should be represented by distinguishable colors – Rows and columns: to preserve univariate information, display parameters should not obscure

  • ne another

– Diagonal: to show positive association, displayed colors should group into three perceptual classes: diagonal, above, below

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SLIDE 31

Evaluating Color Scales (cont.)

  • Ware’s experiments

– metric (quantitative) judgements – surface (qualititative) judgements – redundant color scales

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SLIDE 32
  • Tufte ‘97, pg. 77.
  • Tufte ‘97, pg. 76.
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SLIDE 33

Ware’s Color Scales

  • Ware ‘88.
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SLIDE 34
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SLIDE 35

Considerations

  • Consider goals
  • Consider data
  • Consider audience
  • Consider color connotations
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SLIDE 36

Final Consideration

  • Does this work?
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SLIDE 37

Principles of Color Representation

  • Avoid distortions
  • Exploit the familiar
  • Emphasize the interesting
  • Say it again (redundant mappings)
  • Select appropriate level of detail
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SLIDE 38

Color Models: Device-derived

White Blue Cyan Red Yellow Magenta Green Black

  • Red-Green-Blue
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SLIDE 39

Color Models: Intuitive

Black White Red Yellow Green Cyan Blue Magenta V = 0 V = 1 Hue = 0 S = 0 S = 1 Hue

Black White Red Yellow Green Cyan Blue Magenta L = 0 L = 1 Hue = 0 S = 0 S = 1 Hue

  • Hue-Saturation-Value
  • Hue-Lightness-Saturation

Color Models: Perceptually Uniform

White Purple Purplish red Reddish purple Bluish green Greenish blue Blue Green Pink Purplish pink Red Reddish orange Yellowish green Yellow green Orange Yellow Purplish blue Orange Yellow Greenish Yellow Yellowish pink

u'

.100 .200 .300 .400 .500 .600 .700 .000 .100 .200 .300 .400 .500

v'

  • CIELUV
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SLIDE 40

Opponent Channel Recoding

Long (R) Medium (G) Short (B)

+

  • R - G

Y-B Achromatic Yellow