School of Mechanical, Industrial,and Manufacturing Engineering

Displays

School of Mechanical, Industrial,and Manufacturing Engineering

Human-Machine System

Displays

Controls

OtherSubsystems

Environment

Human(s)

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MD-11 Cockpit

Copyright Harri Koskinen, used with permission, downloaded from http://www.airliners.net/open.file/463667/M/ 30 Jun 04

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Classifying Displays

● Display physical properties/technologies– mechanical– electronic– etc.

● Tasks they support, e.g.,– status monitoring– system control– navigation– procedural guidance (“how-to ...”)– surveillance– etc.

● Characteristics of human users– level of expertise– etc.

● Static/dynamic● Sensory modality

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Visual Displays

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OIL

FUEL

Circular Analog Linear Analog

Annunciators

Digital

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Thirteen Principles of Display Design

● Perceptual Principles● Mental Model Principles● Principles Based on Attention● Memory Principles

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Perceptual Principles

1. Make displays legible (contrast, VA, font characteristics, etc.)*

2. Avoid absolute judgment limits (< 5-7)3. Exploit top-down processing4. Exploit redundancy5. Utilize discriminability (similarity causes confusion)

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Legibility

● Oxford English Dictionary: “The quality of being legible, esp. of being clear enough to read ...”

● Operational definition for IE 545: The extent to which a representation (e.g., a printed word or numeral, graphical symbol, or sound) is sufficiently sensible, recognizable, and distinct to a user of unexceptional sensory acuity working under any expected environmental conditions, that he or she can at least begin to make out its meaning.

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Legibility

● Character/Symbol Size (MIL-STD-1472G)● Character height > 4.5 milliradian (15 min) VA● Character Width = 0.9 height● Symbol height > 2.9 milliradians (10 min) VA

● Font (MIL-STD-1472G)● Standard, common font

– e.g., Arial, Times New Roman, Courier, Verdana● Adverse conditions: sans serif

– e.g., Arial, Verdana, Helvetica● Contrast (Human Factors Design Handbook,

Woodson, Tillman, & Tillman)● Average quality illumination

– black on white– black on yellow– white on black– dark blue on white

● Poor quality illumination– black on white

Character Distance (in)

Character Height (in)

12 0.052

18 0.079

24 0.105

30 0.131

36 0.157

42 0.183

48 0.209

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Perceptual Principles

1. Make displays legible (contrast, VA, font characteristics, etc.)

2. Avoid absolute judgment limits (< 5-7)3. Exploit top-down processing4. Exploit redundancy5. Utilize discriminability (similarity causes confusion)

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Coding

● Color– < 9 discriminable colors (absolute discrimination)– < ? (relative discrimination)

● Shape– alphanumeric: < 82

(A-Z, a-z, 0-9, <, (, +, &, …)– geometric: < 15– pictorial: < ?

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Coding (cont’)

Magnitude < 7 (± 2)● area

● line length

● number of primitives

● luminance

● stereoscopic depth● inclination

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Mental Model Principles

6. Apply pictorial realism7. Apply principle of the moving part

(and other principles of movement compatibility)

Mental Models for● understanding● prediction● control

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Pictorial Realism

Source: www.audiworld.com

Source: www.united.com

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Principle of the Moving Part

F

ESource: vehicle-maintenance.wonderhowto.com

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Principles Based on Attention

8. Minimize information access costs9. Apply proximity compatibility principle

● mental proximity → display proximity● e.g., aircraft primary flight instruments

10.Utilize multiple resources/modalities (visual + auditory)

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Proximity Compatibility:Aircraft Primary Flight Instruments

Source: Wikimedia commons, downloaded 2 Nov 10 from http://en.wikipedia.org/wiki/File:Six_flight_instruments.JPG

Source: Wikimedia commons, downloaded2 Nov 10 from http://upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Primary_Flight_Display.svg/2000px-Primary_Flight_Display.svg.png

Conventional Electronic

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Memory Principles

11.Replace knowledge in the head with knowledge in the world, e.g.,• checklists• written procedures• placards• etc.

12.Provide predictive aiding13.Be consistent!

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Displays

● Special-Purpose Displays● Examples● Application of Principles

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Alerting Displays

● Alert levels (e.g., Engine Indication and Crew Alerting System [EICAS])– Advisory

● normal but noteworthy● noticable but non-intrusive

– Caution● non-normal● salient, perhaps auditory

– Warning● non-normal & requiring immediate attention● most salient

● Another attention principle: Use salince to manage it.

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Labels

● Examples of static displays:● Control/display label● Placard: instructions, operating limits/parameters

● Design criteria1. Visibility & legibility2. Discriminability3. Meaningfulness4. Location (close & unambiguous)

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Monitoring Displays

● Used to display changing quantities ● Design criteria

1. Legibility2. Analog vs digital3. Analog form & direction

● pictorial realism, moving part4. Prediction & sluggishness

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Check Reading

● Examples– RPM ok?– Temperature ok?

● Types– FSMP– FPMS

● Technologies– Mechanical– Electronic (CRT, LCD, …)

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Check Reading (2)

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Check Reading (3)

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Display Layout

● Primary visual area● Principles

1. Frequency of use: minimize info access costs2. Importance: ''3. Display relatedness → integration (e.g., aircraft “6-pack”)4. Sequence of use, to facilitate procedures5. Functional grouping, engine speed, EGT displays6. Stimulus-response compatibility, e.g., near related display7. Clutter avoidance8. Proximity compatibility: near in mind, near on panel9. Standardization: like earlier, similar systems

● Conflicts? → Tradeoffs!

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Head-Up Displays

windscreen

mirrorprojector

pilot’seye

combiner

HUD image (at optical infinity)

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C-130 HUD

source: Wikimedia Commons, http://commons.wikimedia.org/wiki/File:Australian_airman_performing_pre-flight_checks_on_a_RAAF_C-130_Hercules.jpg

source: Wikimedia Commons, http://commons.wikimedia.org/wiki/File:C-130J_Co_Pilot%27s_Head-up_display.jpg

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Head-Up Displays

● Advantages– Far-near in parallel (together in FOV)– Conformal display, e.g., “runway” becomes runway– Optical infinity: no need for accommodation

● Disadvantages– Cost: expensive– Clutter: too much info, confusion, distraction

● Also Head-Mounted Displays(HMDs)

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Head-Mounted Display+: Google Glass

source: http://www.google.com/glass/

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Configural/Object Displays

● Configural displays (object displays)– See p. 206, Fig. 8.11

– Taking advantage of emergent features

Configural Respiration Monitoring Display

Conventional Respiration Monitoring Display

Resp

Pt

Vol Rate

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Configural/Object Displays

● Configural displays (object displays)– See p. 206, Fig. 8.11

– Taking advantage of emergent features

Conventional NPP Display Nuclear Power Plant Object Display

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Navigation Displays and Maps

● Tasks– Guidance– Planning– Recovery (if lost)

● Route lists and command displays● Maps - principles

– Legibility (under all conditions)– Clutter & overlay (declutter, color coding)– Position representation (YAH)– Orientation (N-up, Track-up)– Scale (appropriate)– 3D maps– Data Visualization

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Quantitative Information Displays:Tables and Graphs

● Choice– Precision → tables (“digital”)– Relationships, trends → graphs (“analog”)

● Legibility– Adequate contrast– Discriminability– Redundant coding

● Clutter: maximize “data/ink” ratio● Proximity: things to be compared should be close● Format: many data points → visualization

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Display Design

● Driven by requirements from task analysis.

● 13 Principles of Display DesignPerceptual Principles1. Make displays legible2. Avoid absolute judgment limits3. Exploit top-down processing4. Exploit redundancy5. Utilize discriminabilityMental Model Principles6. Apply pictorial realism7. Apply principle of the moving

part

Principles Based on Attention8. Minimize information access

costs9. Apply proximity compatibility

principle10.Utilize multiple

resources/modalities (visual + auditory)

Memory Principles11.Replace knowledge in the

head with knowledge in the world

12.Provide predictive aiding13.Be consistent!