SIST EN 61966-2-5:2008

Multimedia systems and equipment - Colour measurement and management -- Part 2-5: Colour management - Optional RGB colour space - opRGB

This part of IEC 61966 is applicable to the encoding and communication of RGB colours optionally used in computer systems and similar applications by defining encoding transformations for use in defined reference conditions. If actual conditions differ from the reference conditions, additional rendering transformations may be required. Such additional rendering transformations are beyond the scope of this standard.

Multimediasysteme und -ger�te - Farbmessung und Farbmanagement - Teil 2-5: Farbmanagement - Optionaler RGB-Farbraum - opRGB

Mesure et gestion de la couleur dans les syst�mes et appareils multim�dia - Partie 2-5: Gestion de la couleur - Espace chromatique RVB optionnel - opRVB

Večpredstavnostni sistemi in oprema - Merjenje in upravljanje barv - 2-5. del: Upravljanje barv - Izbirni barvni prostor RGB - opRGB (IEC 61966-2-5:2007)

General Information

• Status: Published
• Publication Date: 10-Feb-2008
• ICS: 17.180.20 - Colours and measurement of light
• ICS: 33.160.60 - Multimedia systems and teleconferencing equipment
• Technical Committee: AVM - Audio, video and multimedia systems and equipment
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 25-Jan-2008
• Due Date: 31-Mar-2008
• Completion Date: 11-Feb-2008
• Ref Project: EN 61966-2-5:2008 - Multimedia systems and equipment - Colour measurement and management - Part 2-5: Colour management - Optional RGB colour space - opRGB

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 61966-2-5:2008
01-marec-2008
9HþSUHGVWDYQRVWQLVLVWHPLLQRSUHPD0HUMHQMHLQXSUDYOMDQMHEDUYGHO
8SUDYOMDQMHEDUY,]ELUQLEDUYQLSURVWRU5*%RS5*%,(&
Multimedia systems and equipment - Colour measurement and management - Part 2-5:
Colour management - Optional RGB colour space - opRGB (IEC 61966-2-5:2007)
Multimediasysteme und -geräte - Farbmessung und Farbmanagement - Teil 2-5:
Farbmanagement - Optionaler RGB-Farbraum - opRGB (IEC 61966-2-5:2007)
Mesure et gestion de la couleur dans les systèmes et appareils multimédia - Partie 2-5:
Gestion de la couleur - Espace chromatique RVB optionnel - opRVB (CEI 61966-2-
5:2007)
Ta slovenski standard je istoveten z: EN 61966-2-5:2008
ICS:
17.180.20
33.160.60
SIST EN 61966-2-5:2008 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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EUROPEAN STANDARD
EN 61966-2-5

NORME EUROPÉENNE
January 2008
EUROPÄISCHE NORM

ICS 17.180.20; 33.160.60


English version


Multimedia systems and equipment -
Colour measurement and management -
Part 2-5: Colour management -
Optional RGB colour space -
opRGB
(IEC 61966-2-5:2007)


Mesure et gestion de la couleur  Multimediasysteme und -geräte -
dans les systèmes Farbmessung und Farbmanagement -
et appareils multimédia - Teil 2-5: Farbmanagement -
Partie 2-5: Gestion de la couleur - Optionaler RGB-Farbraum -
Espace chromatique RVB optionnel - opRGB
opRVB (IEC 61966-2-5:2007)
(CEI 61966-2-5:2007)



This European Standard was approved by CENELEC on 2007-12-01. CENELEC 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 Central Secretariat or to any CENELEC member.

This European Standard exists in two official versions (English and German). A version in any other language
made by translation under the responsibility of a CENELEC member into its own language and notified to the
Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels


© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61966-2-5:2008 E

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EN 61966-2-5:2008 - 2 -
Foreword
The text of document 100/1212/CDV, future edition 1 of IEC 61966-2-5, prepared by technical area 2,
Colour measurement and management, of IEC TC 100, Audio, video and multimedia systems and
equipment, was submitted to the IEC-CENELEC parallel Unique Acceptance Procedure and was
approved by CENELEC as EN 61966-2-5 on 2007-12-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2008-09-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2010-12-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61966-2-5:2007 was approved by CENELEC as a European
Standard without any modification.
__________

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- 3 - EN 61966-2-5:2008
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.

Publication Year Title EN/HD Year

IEC 60050-845 1987 International Electrotechnical Vocabulary - -
(IEV) -
Chapter 845: Lighting


ISO 3664 2000 Viewing conditions - Graphic technology - -
and photography


1)
ISO/CIE 10527 1991 CIE standard colorimetric observers - -


CIE 15 2004 Colorimetry - -


CIE 17.4 1987 International Lighting Vocabulary - -


CIE 122 1996 The relationship between digital and - -
colorimetric data for computer-controlled
CRT displays


2)
CIE 1931 - CIE XYZ color space - -



1)
ISO/CIE 10527:1991 is replaced by ISO 10527:2007.
2)
Undated reference.

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IEC 61966-2-5
Edition 1.0 2007-11
INTERNATIONAL
STANDARD

Multimedia systems and equipment – Colour measurement and management –
Part 2-5: Colour management – Optional RGB colour space – opRGB


INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
S
ICS 17.180.20; 33.160.60 ISBN 2-8318-9350-X

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– 2 – 61966-2-5 © IEC:2007(E)
CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope.6
2 Normative references .6
3 Terms and definitions .6
4 Reference conditions.8
4.1 Reference image display system characteristics.8
4.2 Reference viewing conditions .8
4.3 Reference observer.9
5 Encoding transformations .9
5.1 Introduction .9
5.2 Transformation from opRGB values to CIE 1931 XYZ values.9
5.3 Transformation from CIE 1931 XYZ values to opRGB values.9

Annex A (normative) Transformation between opRGB values and YCC values for
image compression.11
Annex B (informative) Example transformation between opRGB values and sYCC
values.14
Annex C (informative) Example interpretation for colour image encoding specifications .19

Bibliography.21

Table 1 – CIE chromaticities and CIE standard illuminant .8

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61966-2-5 © IEC:2007(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

MULTIMEDIA SYSTEMS AND EQUIPMENT –
COLOUR MEASUREMENT AND MANAGEMENT –

Part 2-5: Colour management –
Optional RGB colour space –
opRGB


FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61966-2-5 has been prepared by technical area 2: Colour
measurement and management, of IEC technical committee 100: Audio, video and multimedia
systems and equipment.
The text of this standard is based on the following documents:
CDV Report on voting
100/1212/CDV 100/1282/RVC

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

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– 4 – 61966-2-5 © IEC:2007(E)
The list of all parts of the IEC 61966 series, under the general title Multimedia systems and
equipment – Colour measurement and management, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

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61966-2-5 © IEC:2007(E) – 5 –
INTRODUCTION
The colour gamut for various image I/O devices has been gradually extended in recent years.
IEC 61966-2-1 “Multimedia Systems and Equipment – Colour Measurement and
Management – Part 2-1: Colour Management – Default RGB Colour Space – sRGB” is the
International Standard issued in 1999, based on the colour characteristics of contemporary
CRT displays.
Subsequently, displays with a wider colour gamut have been commercialized in order to better
cover the colour gamut that is available for digital still cameras, printers and other devices.
This International Standard specifies a colour image encoding similar to the sRGB encoding,
but based on a wider gamut colour space than sRGB. The rendering of the image for specific
applications is beyond the scope of this standard. A display that has a colour gamut wider
than conventional displays has been selected as the “Reference image display system
characteristics” in this standard. These wider colour gamut displays provide advantages in
commercial printing industry workflows and are intended to be used by professional
photographers, prepress industry including DTP and designers.
.

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– 6 – 61966-2-5 © IEC:2007(E)
MULTIMEDIA SYSTEMS AND EQUIPMENT –
COLOUR MEASUREMENT AND MANAGEMENT –

Part 2-5: Colour management –
Optional RGB colour space –
opRGB



1 Scope
This part of IEC 61966 is applicable to the encoding and communication of RGB colours
optionally used in computer systems and similar applications by defining encoding
transformations for use in defined reference conditions.
If actual conditions differ from the reference conditions, additional rendering transformations
may be required. Such additional rendering transformations are beyond the scope of this
standard.
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.
IEC 60050(845):1987, International Electrotechnical Vocabulary (IEV) – Chapter 845:
Lighting / CIE 17.4:1987, International Lighting Vocabulary (Joint IEC/CIE publication)
ISO 3664:2000, Viewing conditions – Graphic technology and photography
ISO/CIE 10527:1991, CIE standard colorimetric observers
CIE 15:2004, Colorimetry, 3rd ed.
CIE 122:1996, The relationship between digital and colorimetric data for computer-controlled
CRT displays
CIE 1931, CIE XYZ color space
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. Definitions of
colour space, illuminance, luminance, tristimulus and other related lighting terms are provided
in IEC 60050(845).
3.1
ambient illuminance level
illuminance level due to lighting in the viewing environment, excluding that from the display,
measured in the plane of the display faceplate

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61966-2-5 © IEC:2007(E) – 7 –
3.2
ambient white point
coordinate point in the CIE 1931 XYZ chromaticity coordinate defined by ISO/CIE 10527 and
CIE 15.2 due to lighting in the viewing environment, excluding that from the display, measured
in the plane of the display faceplate
3.3
display illuminant white point
point in the CIE 1931 XYZ chromaticity diagram defined by ISO/CIE 10527 and CIE 15.2, at
which the red, green and blue intensities are at 100 %, measured in a direction perpendicular
to the display faceplate
3.4
display background
environment of the colour element, extending typically for about ten degrees from the edge of
the proximal field in all, or most, directions. When the proximal field is the same colour as the
background, the latter is regarded as extending from the edge of the colour element
considered
3.5
display black level
the luminance level characteristic measured in a direction perpendicular to the display
faceplate, including unwanted leak light through the faceplate and veiling glare from ambient
illumination, at which the red, green and blue intensities are at 0 %
3.6
veiling glare
light, reflected from an imaging medium, that has not been modulated by the means used to
produce the image
NOTE In CIE 122, the veiling glare of a CRT display is referred to as ambient flare.
3.7
display model offset
parameter measured consistently with CIE 122, representing the black offset level of the
display grid voltage
3.8
display input/output characteristic
transfer characteristic relating the normalised digital code value and the normalised output
luminance as represented by a power function
3.9
display luminance level
luminance of the display measured consistently with CIE 122
3.10
display surround
field outside the background, filling the field of vision
3.11
display proximal field
immediate environment of the colour element considered, extending typically for about two
degrees from the edge of the colour element considered in all, or most, directions

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– 8 – 61966-2-5 © IEC:2007(E)
4 Reference conditions
4.1 Reference image display system characteristics
The reference image display system is a computer controlled display and shall be as follows.
2
160 cd/m
• Display luminance level
• Display white point x = 0,312 7, y = 0,329 0 (D65)

X = 152,07
W

Y = 160,00
W

Z = 174,25
W
0,0
• Display model offset (R, G and B)
2,2
• Display input/output characteristic (R, G and B)
2
0,4 cd/m
• Display black level

The CIE chromaticities for the red, green and blue reference display primaries, and for CIE
standard illuminant D65, are given in table 1.
Table 1 – CIE chromaticities and CIE standard illuminant
Red Green Blue D65
x 0,640 0 0,210 0 0,150 0 0,312 7
y 0,330 0 0,710 0 0,060 0 0,329 0
z
0,030 0 0,080 0 0,790 0 0,358 3

The reference display characterization is based on the characterization in CIE 122. Relative
to this methodology, the reference display is characterised by the equation below, where
is the normalised digital count and is the output normalised luminance.
′
V V
opRGB opRGB
2,2
′
V =()V + 0,0 (1)
opRGB opRGB

4.2 Reference viewing conditions
Specifications for the reference viewing environments are derived from ISO 3664 and shall be
as follows:
a) Reference background for the background as part of the display screen,
the background is 20 % of the reference display
2
luminance level (32 cd/m ); the chromaticity should
x =
average to 0,312 7, y = 0,329 0 (D65).
b) Reference surround 20 % diffuse reflectance of the maximum reference
2
ambient illuminance level (4,07 cd/m); the
chromaticity should average to x = 0,345 7,
y = 0,358 5 (D50).
NOTE This is the luminance of the adapting field.

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61966-2-5 © IEC:2007(E) – 9 –
c) Reference proximal field 20 % of the reference display luminance level
2
(32 cd/m ); the chromaticity should average to
x = 0,312 7, y = 0,329 0 (D65).
d) Reference ambient illuminance level 64 lx.
e) Reference ambient white point x = 0,345 7, y = 0,358 5 (D50).
4.3 Reference observer
The reference observer shall be the CIE 1931 two-degree standard observer from
ISO/CIE 10527.
5 Encoding transformations
5.1 Introduction
The encoding transformations between CIE 1931 XYZ values and N -bit RGB values provide
unambiguous methods for representing optimum image colorimetry when viewed on the
reference display in the reference viewing conditions by the reference observer. The CIE 1931
XYZ values are normalized by display luminance level and are scaled 0.0 to 1.0. The opRGB
tristimulus values are linear combinations of the normalized CIE 1931 XYZ values as
measured on the faceplate of the display. The non-linear opR′G′B′ values represent the
colorimetry of the image as displayed on the reference display.
5.2 Transformation from opRGB values to CIE 1931 XYZ values
The digital code values are converted to non-linear opR′G′B′ values.
N
This standard specifies a black digital count of 0 and a white digital count of 2 −1 for
N -bits/channel encoding. The resulting non-linear opR′G′B′ values are formed according to
the following equations.
N
⎫
R′ = R ÷ (2 − 1)
o
...