1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationMultimedia systems and equipment Colour measurement and management Part 2-5: Colour management Optional RGB colour space opRGBBS EN 61966-2-5:2008National forewordThis British St
2、andard is the UK implementation of EN 61966-2-5:2008. It is identical to IEC 61966-2-5:2007.The UK participation in its preparation was entrusted to Technical CommitteeEPL/100, Audio, video and multimedia systems and equipment.A list of organizations represented on this committee can be obtained onr
3、equest to its secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. BSI 2010ISBN 978 0 580 57514 3ICS 17.180.20; 33.160.60Compliance with a British Standard cannot confer immunity fromlegal obligations.Thi
4、s British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 28 February 2010Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 61966-2-5:2008EUROPEAN STANDARD EN 61966-2-5 NORME EUROPENNE EUROPISCHE NORM January 2008 CENELEC
5、European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr 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 worldwid
6、e for CENELEC members. Ref. No. EN 61966-2-5:2008 E 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 dans les systmes et
7、 appareils multimdia - Partie 2-5: Gestion de la couleur - Espace chromatique RVB optionnel - opRVB (CEI 61966-2-5:2007) Multimediasysteme und -gerte - Farbmessung und Farbmanagement - Teil 2-5: Farbmanagement - Optionaler RGB-Farbraum - opRGB (IEC 61966-2-5:2007) This European Standard was approved
8、 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
9、 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 notif
10、ied 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
11、, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 61966-2-5:2008EN 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, Col
12、our 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 imp
13、lemented 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 Internatio
14、nal Standard IEC 61966-2-5:2007 was approved by CENELEC as a European Standard without any modification. _ BS EN 61966-2-5:2008- 3 - EN 61966-2-5:2008 Annex ZA (normative) Normative references to international publications with their corresponding European publications The following referenced docum
15、ents 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 modification
16、s, 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 - - ISO/CIE 10527 19911)CIE standard colorimetric
17、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 - - CIE 1931 -2)CIE XYZ color space - - 1)ISO/CIE 10527:1991 is replaced by ISO 10527:2007. 2)Undated
18、 reference. BS EN 61966-2-5:2008 2 61966-2-5 IEC:2007(E) CONTENTS INTRODUCTION.5 1 Scope.6 2 Normative references .6 3 Terms and definitions .6 4 Reference conditions8 4.1 Reference image display system characteristics8 4.2 Reference viewing conditions 8 4.3 Reference observer.9 5 Encoding transform
19、ations .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 betwe
20、en opRGB values and sYCC values.14 Annex C (informative) Example interpretation for colour image encoding specifications 19 Bibliography21 Table 1 CIE chromaticities and CIE standard illuminant .8 BS EN 61966-2-5:200861966-2-5 IEC:2007(E) 5 INTRODUCTION The colour gamut for various image I/O devices
21、 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. S
22、ubsequently, 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
23、 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
24、gamut displays provide advantages in commercial printing industry workflows and are intended to be used by professional photographers, prepress industry including DTP and designers. . BS EN 61966-2-5:2008 6 61966-2-5 IEC:2007(E) MULTIMEDIA SYSTEMS AND EQUIPMENT COLOUR MEASUREMENT AND MANAGEMENT Part
25、 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 c
26、onditions 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
27、 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 (
28、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
29、, 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 leve
30、l due to lighting in the viewing environment, excluding that from the display, measured in the plane of the display faceplate BS EN 61966-2-5:200861966-2-5 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
31、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 %, mea
32、sured 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
33、 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 t
34、he 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
35、 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 lu
36、minance 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
37、considered in all, or most, directions BS EN 61966-2-5:2008 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. Display luminance level 160 cd/m2 Display white p
38、oint =x 0,312 7, =y 0,329 0 (D65) =WX 152,07 =WY 160,00 =WZ 174,25 Display model offset (R, G and B) 0,0 Display input/output characteristic (R, G and B) 2,2 Display black level 0,4 cd/m2The CIE chromaticities for the red, green and blue reference display primaries, and for CIE standard illuminant D
39、65, 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 th
40、is methodology, the reference display is characterised by the equation below, where opRGBV is the normalised digital count and opRGBVis the output normalised luminance. ()2,2opRGBopRGB0,0+= VV (1)4.2 Reference viewing conditions Specifications for the reference viewing environments are derived from
41、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 luminance level (32 cd/m2); the chromaticity should average to =x 0,312 7, =y 0,329 0 (D65). b) Reference surround 20 % diffuse reflectance of t
42、he maximum reference ambient illuminance level (4,07 cd/m2); the chromaticity should average to =x 0,345 7, =y 0,358 5 (D50). NOTE This is the luminance of the adapting field. BS EN 61966-2-5:200861966-2-5 IEC:2007(E) 9 c) Reference proximal field 20 % of the reference display luminance level (32 cd
43、/m2); 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 E
44、ncoding 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 1
45、931 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 opRGB values represent the colorimetry of the image as displayed
46、on the reference display. 5.2 Transformation from opRGB values to CIE 1931 XYZ values The digital code values are converted to non-linear opRGB values. This standard specifies a black digital count of 0 and a white digital count of 12 Nfor N -bits/channel encoding. The resulting non-linear opRGB val
47、ues are formed according to the following equations. =)12()12()12(opRGB(N)opRGBopRGB(N)opRGBopRGB(N)opRGBNNNBBGGRR(2)The non-linear opRGB values are transformed to CIE 1931 XYZ values as follows: ()()()=2,2opRGBopRGB2,2opRGBopRGB2,2opRGBopRGBBBGGRR(3)and =opRGBopRGBopRGB39910707000027030750462703297
48、0218806185075760BGR, , , , , , ,ZYX(4)5.3 Transformation from CIE 1931 XYZ values to opRGB values For 24 bit encoding (8-bit/channel), the opRGB tristimulus values can be computed using the following relationship: BS EN 61966-2-5:2008 10 61966-2-5 IEC:2007(E) =ZYX, , , , , , ,BGR20151411804013060410
49、0876129690734400565060412opRGBopRGBopRGB(5)other N-bit/channel encoding is supported ( 8N ), the relationship is defined as; =ZYX, , , , , , ,BGR175015136211804440130555041096887512449690731344000756505880412opRGBopRGBopRGB(5)In the RGB encoding process, negative opRGBtristimulus values and opRGB tristimulus values g
