SIST EN ISO 15008:2003

Road vehicles - Ergonomic aspects of transport information and control systems - Specifications and compliance procedures for in-vehicle visual presentation (ISO 15008:2003)

Migrated from Progress Sheet (TC Comment) (2000-07-10): This WI is the result of the splitting of WI 062 (TC res 278/018/06/1997; ZM). ++ May be processed in // VA/5.1 (ISO 15008-2) - See also note in WI 00278062. ++ (NT/1998-01-27) ++ BP : To be transferred to ISO. (NT/1999-01-19).

Straßenfahrzeuge - Ergonomische Aspekte von Fahrerinformations- und Assistenzsystemen - Anforderungen und Bewertungsmethoden der visuellen Informationsdarstellung im Fahrzeug (ISO 15008:2003)

Diese internationale Norm stellt Mindestanforderungen an die Bildqualität von Anzeigen für die Darstellung von dynamischen (sich ändernden) visuellen Informationen, die dem Fahrer eines Straßenfahrzeuges von einem on-board Fahrerinformations- und Assistenzsystem (Transport Information and Control System - TICS) während der Fahrt so bereitgestellt werden, dass diese auf der Anzeige lesbar sind.
Die hier beschriebenen Anforderungen sind unabhängig von speziellen Anzeige-Technologien. Sie betreffen maßgeblich die Wahrnehmungskomponenten, sowie einige grundlegende kognitive Komponenten visueller Information (z.B. Lesbarkeit der Zeichen, Farbwahrnehmung). Andere Faktoren, welche die Wahrnehmungsleistung und den Komfort beeinflussen (wie z.B. Kodierung, Format und Dialogformen) werden in anderen Normen behandelt.
Die Test- und Bewertungsmethoden zur Prüfung der Übereinstimmung mit diesen Spezifikationen sind - soweit erforderlich - in dieser Norm enthalten.
Die Spezifikationen sind nicht anwendbar auf Anzeige-Systeme, die
3 Informationen dem externen Sichtfeld überlagern (z.B. Head-up Displays)
3 eine bildhafte Information darstellen (z.B. Monitorbild einer Rückfahrkamera)
3 Karten und topographische Darstellungen anzeigen (z.B. bei Navigationssystemen)
3 statische Informationen darstellen (z.B. Beschriftungen, Statusanzeigen)

Véhicules routiers - Aspects ergonomiques des systemes d'information et de contrôle du transport - Spécifications et modes opératoires de conformité pour la présentation visuelle a bord du véhicule (ISO 15008:2003)

Cestna vozila – Ergonomski vidiki transportnih informacij in kontrolnih sistemov – Specifikacije in postopki ugotavljanja ustreznosti za vizualno predstavitev v vozilu (ISO 15008:2003)

General Information

• Status: Withdrawn
• Publication Date: 30-Sep-2003
• Withdrawal Date: 11-Mar-2009
• ICS: 13.180 - Ergonomics
• ICS: 43.040.15 - Car informatics. On board computer systems
• Technical Committee: ITC - Information technology
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 04-Mar-2009
• Due Date: 27-Mar-2009
• Completion Date: 12-Mar-2009
• Ref Project: EN ISO 15008:2003 - Road vehicles - Ergonomic aspects of transport information and control systems - Specifications and compliance procedures for in-vehicle visual presentation (ISO 15008:2003)

Relations

• Replaced By: SIST EN ISO 15008:2009 - Road vehicles - Ergonomic aspects of transport information and control systems - Specifications and test procedures for invehicle visual presentation (ISO 15008:2009)
• Effective Date: 01-Apr-2009

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 15008:2003
01-oktober-2003
Cestna vozila – Ergonomski vidiki transportnih informacij in kontrolnih sistemov –
Specifikacije in postopki ugotavljanja ustreznosti za vizualno predstavitev v vozilu
(ISO 15008:2003)
Road vehicles - Ergonomic aspects of transport information and control systems -
Specifications and compliance procedures for in-vehicle visual presentation (ISO
15008:2003)
Straßenfahrzeuge - Ergonomische Aspekte von Fahrerinformations- und
Assistenzsystemen - Anforderungen und Bewertungsmethoden der visuellen
Informationsdarstellung im Fahrzeug (ISO 15008:2003)
Véhicules routiers - Aspects ergonomiques des systemes d'information et de contrôle du
transport - Spécifications et modes opératoires de conformité pour la présentation
visuelle a bord du véhicule (ISO 15008:2003)
Ta slovenski standard je istoveten z: EN ISO 15008:2003
ICS:
13.180 Ergonomija Ergonomics
43.040.15 $YWRPRELOVNDLQIRUPDWLND Car informatics. On board
9JUDMHQLUDþXQDOQLãNLVLVWHPL computer systems
SIST EN ISO 15008:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 15008:2003

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SIST EN ISO 15008:2003
EUROPEAN STANDARD
EN ISO 15008
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2003
ICS 13.180; 43.040.15
English version
Road vehicles - Ergonomic aspects of transport information and
control systems - Specifications and compliance procedures for
in-vehicle visual presentation (ISO 15008:2003)
Véhicules routiers - Aspects ergonomiques des systèmes Straßenfahrzeuge - Ergonomische Aspekte von
d'information et de contrôle du transport - Spécifications et Fahrerinformations- und Assistenzsystemen -
modes opératoires de conformité pour la présentation Anforderungen und Bewertungsmethoden der visuellen
visuelle à bord du véhicule (ISO 15008:2003) Informationsdarstellung im Fahrzeug (ISO 15008:2003)
This European Standard was approved by CEN on 11 March 2003.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15008:2003 E
worldwide for CEN national Members.

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SIST EN ISO 15008:2003
EN ISO 15008:2003 (E)
CORRECTED  2003-07-16
Foreword
This document (EN ISO 15008:2003) has been prepared by Technical Committee ISO/TC 22
"Road vehicles" in collaboration with Technical Committee CEN/TC 278 "Road transport and
traffic telematics", the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by September 2003, and conflicting national
standards shall be withdrawn at the latest by September 2003.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium, Czech
Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and
the United Kingdom.
Endorsement notice
The text of ISO 15008:2003 has been approved by CEN as EN ISO 15008:2003 without any
modifications.
2

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SIST EN ISO 15008:2003


INTERNATIONAL ISO
STANDARD 15008
First edition
2003-03-15


Road vehicles — Ergonomic aspects of
transport information and control
systems — Specifications and
compliance procedures for in-vehicle
visual presentation
Véhicules routiers — Aspects ergonomiques des systèmes de
commande et d'information du transport — Spécifications et modes
opératoires de conformité pour la présentation visuelle à bord du
véhicule




Reference number
ISO 15008:2003(E)
©
ISO 2003

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SIST EN ISO 15008:2003
ISO 15008:2003(E)
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©  ISO 2003
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
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Published in Switzerland

ii © ISO 2003 — All rights reserved

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SIST EN ISO 15008:2003
ISO 15008:2003(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 2
4 Specifications and measurement methods. 4
4.1 General. 4
4.2 Design viewing position and illumination range . 4
4.3 Luminance contrast . 6
4.4 Colour. 8
4.5 Alphanumerical character dimensions (see Annex C). 9
4.6 Pixel matrix character format. 10
4.7 Reflections and glare. 10
4.8 Characteristics of presentation . 10
Annex A (informative) Daylight contrast measurement method . 12
Annex B (informative) Sunlight contrast measurement method . 17
Annex C (normative) Definition and measurement of character dimensions. 21
Annex D (informative) Raster modulation and fill factors . 24
Bibliography . 25

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SIST EN ISO 15008:2003
ISO 15008:2003(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 15008 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 13,
Ergonomics applicable to road vehicles.
iv © ISO 2003 — All rights reserved

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SIST EN ISO 15008:2003
ISO 15008:2003(E)
Introduction
Driver and vehicle form an integrated system that includes the environment, the primary vehicle controls, the
instrumentation and the transport information and control systems (TICS). The driving task, as well as human
capabilities and limitations, are other important factors in the performance of this system.
TICS are intended to support the driver in his or her primary task, and it is therefore expected that the overall
workload of the driver will not be negatively influenced by their use, while performance and comfort are
increased.
The visual characteristics of display systems are only one set of factors influencing this process. They
therefore have to be considered, along with human capabilities, in relation to the other elements of the driving
environment.
Visual specifications fall within a wide range of environmental conditions, and constitute only a necessary
condition for adequate performance, comfort and workload. Thus they refer to the relevant range of
illumination conditions and to the location of the display with respect to the driver.

© ISO 2003 — All rights reserved v

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SIST EN ISO 15008:2003

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SIST EN ISO 15008:2003
INTERNATIONAL STANDARD ISO 15008:2003(E)

Road vehicles — Ergonomic aspects of transport information
and control systems — Specifications and compliance
procedures for in-vehicle visual presentation
1 Scope
This International Standard gives minimum specifications for the image quality and legibility of displays
containing dynamic (changeable) visual information presented to the driver of a road vehicle by on-board
transport information and control systems (TICS) used while the vehicle is in motion. These specifications are
intended to be independent of display technologies, while test methods and measurements for assessing
compliance with them have been included where necessary.
This International Standard is applicable to mainly perceptual, and some basic cognitive, components of the visual
information: these include character legibility and colour recognition. It is not applicable to other factors affecting
performance and comfort such as coding, format and dialogue characteristics, or to displays using
 superimposed information on the external field (e.g. head-up displays),
 pictorial images (e.g. closed-circuit TV for reversing),
 maps and topographic representations (e.g. those for setting navigation systems), or
 static information (e.g. control labels, telltales).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 2575, Road vehicles — Symbols for controls, indicators and tell-tales
ISO 4513, Road vehicles — Visibility — Method for establishment of eyellipses for driver’s eye location
ISO 9241-3:1992, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 3:
Visual display requirements
1)
CIE 15.2, Colorimetry
CIE 17.4, International Lighting Vocabulary
CIE 85-1989, Solar spectral irradiance

1) Commission Internationale de l'Eclairage/International Commission on Illumination.
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SIST EN ISO 15008:2003
ISO 15008:2003(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. For terms and definitions
relations to photometric quantities, including illuminance, luminance, luminance contrast, luminance
modulation, saturation, chromatic aberration and CIELUV, see CIE 17.4.
3.1
adaptation
adjustment of the eye’s sensitivity to the brightness of the observed visual field
NOTE Dark adaptation occurs at a slower rate than does light adaptation.
3.2
blink
intended periodic variation of the luminance of a light or visual information, normally from “OFF” to a given
value, typically used for attracting attention
3.3
brightness
subjective attribute of light sensation by which a stimulus appears to be more or less intense or to emit more
or less light
3.4
critical specular line
CSL
line from the centre of the display to the centre of the eyellipse
3.5
critical specular light direction
CSLD
line symmetrical to the CSL in respect of the normal direction to the centre of the display
3.6
critical specular light cone
specular light cone with apex angle ε + β (10°) all around
3.7
chromatic
having hue or being coloured: appearing different in quality from a neutral grey having the same brightness
NOTE Related to the colour properties of a visual stimulus.
3.8
contrast ratio
C
R
ratio between the luminance L of an area in its “bright” state (e.g. the strokes of a character in the case of
high
negative polarity) and the luminance L of the same area in its “dark” state
low
3.9
fill factor
〈matrix display〉 ratio between the area occupied by the physical pixel area and the active pixel area
3.10
flicker
unintended perceived temporal variation of the brightness of a visual stimulus, usually generated by refresh
displays such as cathode ray tube devices
3.11
glare
〈disability〉 dazzling (disabling) effect produced by a bright light: retinal effect, primarily caused by light scatter
in the eye, which produces a luminous veil over the retinal image, and thus reduces contrast
2 © ISO 2003 — All rights reserved

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SIST EN ISO 15008:2003
ISO 15008:2003(E)
3.12
glare
〈discomfort〉 distracting or disrupting effect of bright point sources in the field of view: perceptual effect,
interfering with visual attention and selection
3.13
jitter
unintended periodic movement of an image or parts of it
3.14
legibility
visual properties of a character or graphics representation that determine the ease with which it can be
recognized
3.15
map
representation on plane surface of the features of a connected part of the earth surface (especially of the road
and traffic environment), shown in their representative forms, sizes and relationship according to some
convention of representation
3.16
pixel
〈general〉 smallest selectively addressable area of a display
NOTE It is an abbreviation for “picture element.”
3.17
pixel
〈multicolour display〉 smallest selectively addressable area of the display capable of producing the full colour
range
3.18
polarity
relationship in a display between the brightness of a symbol and background
NOTE It is negative if symbols are lighter than the background, positive if symbols are darker than the background.
3.19
raster
ensemble of the adjacent lines in a display composed by sequentially addressable points
3.20
resolution
ability of display to represent fine detail
NOTE It can be expressed quantitatively in terms of the number of distinguishable lines per unit length or subtended
angle.
3.21
segment
pixel with definite geometric form to give a basic entity of a character or symbol
EXAMPLE Stroke.
3.22
specular light cone
cone symmetrical to the viewing cone in respect of the normal direction to the centre of the display
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SIST EN ISO 15008:2003
ISO 15008:2003(E)
3.23
transparent diffuser
material that allows the light to pass through it while scattering the light evenly in all directions
2)
EXAMPLE Sanded white glass, white Mylar .
3.24
viewing cone
cone with opening angle, ε, formed by lines from the centre of the display tangential to the eyellipse surface
3.25
night
condition under which the adaptation level of the driver is mainly influenced by
 the portion of the road ahead covered by the vehicle's own headlights and surrounding street lights, and
 display and instrument brightness
See 4.2.2.
3.26
day
condition under which the adaptation level of the driver is mainly influenced by the external environment of a
cloudy sky
See 4.2.2.
3.27
sunlight
condition under which the viewing conditions are mainly influenced by direct light from the sun on the display
surface
See 4.2.2.
4 Specifications and measurement methods
4.1 General
The following minimum specifications have been chosen to help ensure that visual displays used in TICS are
legible. The specifications are accompanied by standard measurement conditions in terms of ambient
illuminance and observer positions.
4.2 Design viewing position and illumination range
4.2.1 Design viewing position
These specifications are applicable to displays in their installed vehicle locations as seen from any point in the
95th percentile driver eyellipse according to ISO 4513 (for passenger vehicles only). Four viewing angles shall
be defined, in accordance with Figure 1, from the display centre to the opposite sides of the top and side view
eyellipses, and referred to the display perpendicular direction. The 95th percentile eyellipses shall be used.

2) Mylar is the trade name of a product supplied by DuPont. This information is given for the convenience of users of this
International Standard and does not constitute an endorsement by ISO of the product named. Equivalent products may be
used if they can be shown to lead to the same results.
4 © ISO 2003 — All rights reserved

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SIST EN ISO 15008:2003
ISO 15008:2003(E)
If the display is fixed to the vehicle, the relevant specifications shall be complied with for each of the four
angles. If the angle and position of the display are adjustable, the display may be adjusted for each viewing
angle in order that a position can be found in which all the relevant specifications are complied with
simultaneously.

Key
1 display
2 side view
3 top view
Figure 1 — Design viewing angles (display at right-hand side of driver)
4.2.2 Illumination range
The design illumination range establishes the three conditions of night, day and sunlight.
 Night condition is replicated in a dark environment such that the maximum illuminance on the object to be
measured shall not exceed 2 lx.
 Day condition is replicated with ambient light omni-directional to the point of measurement. The ambient
light measured on the surface of the display (on the standard diffuse reflector) shall be 3 klx. See
Annex A for suggested methodologies.
 Sunlight condition is replicated with a standard measurement condition. The light intensity at the point of
measurement shall measure W 45 klx. See Annex B for details.
For day and sunlight conditions, an artificial illumination system with light type close to that of CIE 85:1989,
Table 4 (± 20 %) shall be used. Light sources with large spikes in the spectrum (such as fluorescent lamps)
should be avoided. The colour temperature is secondary to this issue.
Due to the very wide range of ambient illuminations that determine the adaptation level of the driver, a
brightness control which allows adjustment over a suitable range should be provided.
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SIST EN ISO 15008:2003
ISO 15008:2003(E)
4.3 Luminance contrast
4.3.1 Minimum contrast
The minimum contrast ratio (higher to lower luminance) between symbol and background shall be
 5:1 for night conditions,
 3:1 for day conditions, and
 2:1 for sunlight conditions.
This is especially important if characters are close to the minimum specifications for the dimensions (see 4.5).
Lower contrast should be avoided unless dimensions are properly increased or the reading task is simple or
when both these apply.
The contrast ratio shall be calculated from two measurements in the centre of the display. For matrix display,
the measurements shall be taken with a luminance meter having a field of view (FOV) of 10′ to 20′ over an
area covering at least 5 × 5 pixels (see Figure 2).
For segment displays, the measurement shall be taken within a single segment using a luminance meter
having a FOV angle of 10′ to 20′. The diameter of the collection area shall be less than 80 % of the relevant
dimension of the segment to be measured, for all measurement directions.
The measurements shall be taken at four angles, derived in accordance with 4.2.1, in night and day conditions.

Key
1 collection area
2 pixel “bright”
3 pixel “dark”
Figure 2 — Measurement on matrix displays
4.3.2 Luminance balance
The ratio of area average luminance of the display and of the surrounding (luminance balance) should not
exceed 10:1 (higher to lower luminance). Higher ratios are often acceptable. However, a ratio of 100:1 (higher
to lower luminance) would be expected to produce a small but significant drop in performance.
Luminance balance is measured as the ratio between the average luminance of the display over nine points in
its active area with all pixels in bright state and the average luminance over eight points of the immediate
surrounding as shown in Figure 3. The measurements shall be taken in daylight. The measurement direction
shall be determined by a line passing through the centre of the display and the centre of the eyellipses as
shown in Figure 4. The other points shall be reached by rotating the measuring instrument.
6 © ISO 2003 — All rights reserved

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SIST EN ISO 15008:2003
ISO 15008:2003(E)

Key
1 display
2 surrounding
Figure 3 — Luminance balance measurement

Key
1 display
2 side view
3 top view
a
Mean value of eyellipse.
Figure 4 — Measurement angles for luminance balance (display at right hand side of the driver)
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SIST EN ISO 15008:2003
ISO 15008:2003(E)
4.3.3 Polarity
Display luminance is intended as the symbol luminance if the display is driven in negative polarity (i.e. light
symbols on a dark background), or as the background luminance if the display is in positive polarity (i.e. dark
symbols on a light background).
Either polarity is known to give satisfactory performance. The choice is determined by the area average
luminance of those areas frequently viewed in sequence. Therefore, negative polarity should be used under
the night condition. In day condition both are acceptable, while taking into account the often dark immediate
surroundings of displays in vehicles (i.e. the dashboard). For non-sheltered displays, positive polarity can be
preferable for reducing the visibility of reflections.
4.4 Colour
4.4.1 Colour combinations
When a symbol and its background are of different colours, minimum luminance contrast (see 4.3.1) shall be
provided. For physiological and psychological reasons, not all symbol/background colour combinations are
acceptable. Because of this, when selecting colours in full multicolour displays, symbol/background colour
combinations should be chosen in accordance with Table 1.
Table 1 — Symbol/background colour combinations
Background colour Symbol colour
a a
White Yellow Orange Red , Purple Green, Cyan Blue , Violet Black
White − o + + ++ ++
Yellow − − o o + ++
Orange o − − − o +
a
Red , Purple + o − − − +
Green, Cyan + o − − − +
a
Blue , Violet ++ + o − − −
Black ++ ++ + + + −
++ Preferred

+ Recommended
o Acceptable with high saturation differences

− Not recommended
a
Pure red and blue should be avoided because the eyes may have trouble focusing on these colours because of eye chromatic
aberration.

4.4.2 Colour discriminability
For minimum colour discriminability, there shall be a minimum colour difference of ∆E = 20, in accordance
UV
with the ∆E colour difference metric defined in the CIE 1976 colour space model CIELUV (See
UV
CIE 15.2:1986). Reference white is the white produced by the display. The measurement shall be taken using
a colour meter with a FOV of 20′ with the same geometry used for the luminance contrast measurement, and
shall be performed for all colours intended to be used for colour coding, both in night and day conditions. All
relevant pairs of colours shall be evaluated using this ∆E colour difference metric. Reference white is the
UV
white produced by the display in each condition.
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SIST EN ISO 15008:2003
ISO 15008:2003(E)
4.4.3 Colour contrast
For legibility, the relevant metric (standard of measurement) is luminance contrast (see 4.3.1).
4.5 Alphanumerical character dimensions (see Annex C)
4.5.1 Height
For alphanumeric characters, height — measured as the subtended angle from the farthest design view
point — shall be in accordance with Table 2.
4.5.2 Width-to-height ratio
The alphanumeric character width-to-height ratio should be between 0,6 and 0,8. A wider range of from 0,5 to
1 is acceptable, especially if factors such as line length or proportional spacing are important.
4.5.3 Stroke width-to-height ratio
The alphanumeric characters' stroke width-to-character height ratio shall be between 0,08 and 0,16.
Table 2 — Character heights
a
arcminutes radians Suitability level
−3
24 6,98 × 10 Recommended
−3
20 5,82 × 10 Acceptable if colour is a coding dimension
−3
18 5,24 × 10 Acceptable if colour is not a coding dimension
−3 b
15 4,36 × 10 Conditional
a
If multiplied by the viewing distance, it gives (in the same units) the actual character height.
b
When requirements for accuracy and speed of reading are modest, or when readability is incidental to the task (e.g. subscripts).

4.5.4 Spacing
For character fonts without serifs, the between-character spacing shall be a minimum of one stroke width. If
characters have serifs, the between-character spacing shall be one stroke width between the serifs of
adjacent characters.
A minimum of one character width (“N” for proportional spacing) shall be used between words.
A minimum of one stroke width shall be used for spacing between lines of text. This area may not contain
parts of characters or diacritics.
For displays with discrete pixel matrices the character dimensions shall be measured using a measuring
microscope of at least 20 × magnification.
For displays with pixels having continuous luminance distributions microphotometric techniques shall be used
in accordance with Annex C (see also ISO 9241-3:1992, 6.6).
© ISO 2003 — All rights reserved 9

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