1、 Reference numberISO 11664-4:2008(E)CIE S 014-4/E:2007ISO 2008INTERNATIONAL STANDARD ISO11664-4CIE S 014-4/EFirst edition2008-11-01Colorimetry Part 4: CIE 1976 L*a*b* Colour space Colorimtrie Partie 4: Espace chromatique L*a*b* CIE 1976 ISO 11664-4:2008(E) PDF disclaimer This PDF file may contain em
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5、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 ISOs member body in the country of the re
6、quester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 All rights reservedISO 11664-4:2008(E) ISO 2008 All rights reserved iiiForeword ISO (the International Organizatio
7、n 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
8、 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. ISO 1
9、1664-4 was prepared as Standard CIE S 014-4/E by the International Commission on Illumination, which has been recognized by the ISO Council as an international standardizing body. It was adopted by ISO under a special procedure which requires approval by at least 75 % of the member bodes casting a v
10、ote, and is published as a joint ISO/CIE edition. The International Commission on Illumination (abbreviated as CIE from its French title) is an organization devoted to international cooperation and exchange of information among its member countries on all matters relating to the science and art of l
11、ighting. ISO 11664-4 was prepared by CIE Technical Committee 1-57 of Division 1, Vision and colour. ISO 11664 consists of the following parts, under the general title Colorimetry: Part 1: CIE standard colorimetric observers Part 2: CIE standard illuminants Part 4: CIE 1976 L*a*b* Colour space ISO 11
12、664-4:2008(E) CIE S 014-4/E:2007 CIE 2007 All rights reserved ISO 2008 All rights reserved vStandardColorimetry - Part 4: CIE 1976 L*a*b* Colour Space Colorimtrie - Partie 4: Espace chromatique L*a*b* CIE 1976 Farbmessung - Teil 4: CIE 1976 L*a*b* Farbenraum CIE Standards are copyrighted and shall n
13、ot be reproduced in any form, entirely or partly, without the explicit agreement of the CIE. CIE Central Bureau, Vienna CIE S 014-4/E:2007 Kegelgasse 27, A-1030 Vienna, Austria UDC: 535.65:006 Descriptor: Standardisation of colour measurement 535.643.2 Standard colorimetric systems CIE S 014-4/E:200
14、7 ISO 11664-4:2008(E) CIE S 014-4/E:2007 vi CIE 2007 All rights reserved ISO 2008 All rights reserved CIE, 2007 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
15、 microfilm, without permission in writing from CIE Central Bureau at the address below. CIE Central Bureau Kegelgasse 27 A-1030 Vienna Austria Tel.: +43 1 714 3187 0 Fax: +43 1 714 3187 18 e-mail: ciecbcie.co.at Web: www.cie.co.at ISO 11664-4:2008(E) CIE S 014-4/E:2007 CIE 2007 All rights reserved I
16、SO 2008 All rights reserved viiFOREWORD Standards produced by the Commission Internationale de lEclairage (CIE) are a concise documentation of data defining aspects of light and lighting, for which international harmony requires such unique definition. CIE Standards are therefore a primary source of
17、 internationally accepted and agreed data, which can be taken, essentially unaltered, into universal standard systems. This CIE Standard has been prepared by the Technical Committee TC 1-57* of Division 1 “Vision and Colour“ and was approved by the National Committees of the CIE. The following ISO a
18、nd IEC committees and working groups co-operated in the preparation of this standard: IEC TC100/TA2 (Audio, Video and Multimedia Systems) ISO TC6 (Paper, Board and Pulps) ISO TC35/SC9/WG22 (Paint and Varnishes) ISO TC38/SC1/WG7 (Textiles) ISO TC42 (Photography) ISO TC130 (Graphic Technology) ISO/IEC
19、/JTC1/SC28 (Office Systems) * The chairperson of this TC was A.R. Robertson (CA), members were: P.J. Alessi (US), J.A. Bristow (SE), J. Campos Acosta (ES), R. Connelly (US), J.-F. Decarreau (FR), R. Harold (US), R. Hirschler (HU), H. Ikeda (JP), B. Jordan (CA), C. Kim (KR), D. McDowell (US), P. McGi
20、nley (AU), Y. Ohno (US), M.R. Pointer (GB), K. Richter (DE), G. Rsler (DE), J.D. Schanda (HU), R. Sve (FR), K. Smith (GB), K. Witt (DE), H. Yaguchi (JP), J. Zwinkels (CA). ISO 11664-4:2008(E) CIE S 014-4/E:2007 viii CIE 2007 All rights reserved ISO 2008 All rights reservedTABLE OF CONTENTS FOREWORD
21、viiINTRODUCTION 1 1. SCOPE 1 2. NORMATIVE REFERENCES 1 3. DEFINITIONS, SYMBOLS AND ABBREVIATIONS 1 4. CALCULATION METHOD 2 4.1 Basic coordinates 2 4.2 Correlates of lightness, chroma and hue 3 4.3 Colour differences 4 ANNEX (INFORMATIVE): REVERSE TRANSFORMATION 6 BIBLIOGRAPHY 7 ISO 11664-4:2008(E) C
22、IE S 014-4/E:2007 CIE 2007 All rights reserved ISO 2008 All rights reserved 1COLORIMETRY - PART 4: CIE 1976 L*a*b* COLOUR SPACE INTRODUCTION The three-dimensional colour space produced by plotting CIE tristimulus values (X,Y,Z) in rectangular coordinates is not visually uniform, nor is the (x,y,Y) s
23、pace nor the two-dimensional CIE (x,y) chromaticity diagram. Equal distances in these spaces do not represent equally perceptible differences between colour stimuli. For this reason, in 1976, the CIE introduced and recommended two new spaces (known as CIELAB and CIELUV) whose coordinates are non-lin
24、ear functions of X, Y and Z. The recommendation was put forward in an attempt to unify the then very diverse practice in uniform colour spaces and associated colour difference formulae (Robertson, 1990; CIE, 2004). Both these more-nearly uniform colour spaces have become well accepted and widely use
25、d. Numerical values representing approximately the magnitude of colour differences can be described by simple Euclidean distances in the spaces or by more sophisticated formulae that improve the correlation with the perceived size of differences. The purpose of this CIE Standard is to define procedu
26、res for calculating the coordinates of the CIE 1976 L*a*b* (CIELAB) colour space and the Euclidean colour difference values based on these coordinates. The standard does not cover more sophisticated colour difference formulae based on CIELAB, such as the CMC formula (Clarke et al., 1984), the CIE94
27、formula (CIE, 1995), the DIN99 formula (DIN, 2001), and the CIEDE2000 formula (CIE, 2001), nor does it cover the alternative uniform colour space, CIELUV. 1. SCOPE This CIE Standard specifies the method of calculating the coordinates of the CIE 1976 L*a*b* colour space including correlates of lightn
28、ess, chroma and hue. It includes two methods for calculating Euclidean distances in this space to represent the perceived magnitude of colour differences. The Standard is applicable to tristimulus values calculated using colour-matching functions of the CIE 1931 standard colorimetric system or the C
29、IE 1964 standard colorimetric system. The Standard may be used for the specification of colour stimuli perceived as belonging to a reflecting or transmitting object, where a three-dimensional space more uniform than tristimulus space is required. It does not apply to colour stimuli perceived as belo
30、nging to an area that appears to be emitting light as a primary light source, or that appears to be specularly reflecting such light. This Standard does apply to self-luminous displays, like cathode ray tubes, if they are being used to simulate reflecting or transmitting objects and if the stimuli a
31、re appropriately normalized. 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) appli
32、es. CIE 17.4-1987. International Lighting Vocabulary (Joint publication IEC/CIE). CIE S 014-1:2006. Colorimetry Part 1. CIE Standard Colorimetric Observers. ISO 11664-1:2007CIE S 014-2:2006. Colorimetry Part 2. CIE Standard Illuminants. ISO 11664-2:20073. DEFINITIONS, SYMBOLS AND ABBREVIATIONS For t
33、he purposes of this International Standard, the terms and definitions given in CIE 17.4-1987 (International Lighting Vocabulary), as amended by this standard and the following symbols and abbreviations apply. X, Y, Z tristimulus values of test stimulus calculated using the colour-matching functions
34、of the CIE 1931 standard colorimetric system (also known as the CIE 2 standard colorimetric system) ISO 11664-4:2008(E) CIE S 014-4/E:2007 2 CIE 2007 All rights reserved ISO 2008 All rights reservedXn, Yn, Zntristimulus values of a specific white colour stimulus calculated using the colour-matching
35、functions of the CIE 1931 standard colorimetric system L* CIELAB lightness a*, b* CIELAB a*, b* coordinates C*abCIELAB chroma habCIELAB hue angle L* CIELAB lightness difference a*,b* CIELAB a*, b* difference C*abCIELAB chroma difference habCIELAB hue angle difference H*abCIELAB hue difference E*abCI
36、ELAB colour difference If the character “ is not available, it may be replaced by the character “D“. The phrase “CIE 1976 L*a*b*“ and the term “CIELAB“ may be used interchangeably. Where tristimulus values are calculated using the colour-matching functions of the CIE 1964 standard colorimetric syste
37、m (also known as the CIE 10 standard colorimetric system), a subscript 10 shall be added to all the above symbols. 4. CALCULATION METHOD 4.1 Basic coordinates The CIE 1976 L*a*b* colour space is a three-dimensional, approximately uniform colour space produced by plotting in rectangular coordinates,
38、L*, a*, b*, quantities defined by the equations: ()16/116*n= YYfL (1) ()()nn/500* YYfXXfa = (2) ()()nn/200* ZZfYYfb = (3) where ()( )3/1nn/ XXXXf = if ( )3n)29/6(/ XX (4) () () 29/4/)108/841(/nn+= XXXXf if ( )3n)29/6(/ XX (5) and ()()3/1nn/ YYYYf = if ( )3n)29/6(/ YY (6) () () 29/4/)108/841(/nn+= YY
39、YYf if ( )3n)29/6(/ YY (7) and ()()3/1nn/ ZZZZf = if ( )3n)29/6(/ ZZ (8) () () 29/4/)108/841(/nn+= ZZZZf if ( )3n)29/6(/ ZZ (9) where X, Y, Z are the tristimulus values of the test colour stimulus based on the CIE 1931 standard colorimetric system defined in CIE S 014-1, and Xn, Yn, Znare the corres
40、ponding tristimulus values of a specified white stimulus. ISO 11664-4:2008(E) CIE S 014-4/E:2007 CIE 2007 All rights reserved ISO 2008 All rights reserved 3In the case of simulated reflecting or transmitting objects produced on a self-luminous display, all the tristimulus values shall be first norma
41、lized by the same factor so that Y would be equal to 100 for an object with 100% reflectance or transmittance. If the angle subtended at the eye by the test stimulus is between about 1 and 4 the tristimulus values X, Y, Z calculated using the colour-matching functions of the CIE 1931 standard colori
42、metric system should be used. If this angular subtense is greater than 4 the tristimulus values X10, Y10, Z10calculated using the colour-matching functions of the CIE 1964 standard colorimetric system should be used. The same colour-matching functions and the same specified white stimulus shall be u
43、sed for all stimuli to be compared with each other. When tristimulus values based on the CIE 1964 standard colorimetric system defined in CIE S 014-1 are used, a subscript 10 shall be added to all the symbols in equations (1) to (9). If the tristimulus values X, Y, Z are obtained by spectrophotometr
44、y, the tristimulus values Xn, Yn, Znof the specified white stimulus shall be calculated using the same method as used for the test stimulus (same colour-matching functions, same range and interval of wavelength, and same bandwidth). If the tristimulus values X, Y, Z are obtained by direct measuremen
45、t using a tristimulus colorimeter, Xn, Yn, Znshall be measured using the same tristimulus colorimeter and a white reflectance standard calibrated relative to a perfect reflecting diffuser. NOTE 1 For real object colours, the specified white stimulus normally chosen for Xn, Yn, Znis light reflected f
46、rom a perfect reflecting diffuser illuminated by the same light source as the test object. In this case, Xn, Yn, Znare the tristimulus values of the light source normalized by a common factor so that Ynis equal to 100. For simulated object colours, the specified white stimulus normally chosen is one
47、 that has the appearance of a perfect reflecting diffuser, again normalized by a common factor so that Ynis equal to 100. NOTE 2 Examples of values of Xn, Ynand Znfor specific illuminants and specific calculation methods have been published (CIE, 2004). NOTE 3 Equations (5), (7) and (9) are based on
48、 a suggestion by Pauli (1976). NOTE 4 A value of 7,787 is approximately equal to the term (841/108) in equations (5), (7) and (9). The approximate value may be used in practice. NOTE 5 A value of 0,008856 is approximately equal to the term (6/29)3in equations (4), (5), (6), (7), (8) and (9).The appr
49、oximate value may be used in practice. NOTE 6 The fractions 6/29 and 4/29 in equations (4) through (9) are exactly equal to the fractions 24/116 and 16/116 appearing in CIE 15:2004. NOTE 7 The term (841/108) in equations (5), (7) and (9) is derived from and exactly equal to (1/3)(29/6)2. NOTE 8 Equation (1) reduces to L* 903,3(Y/Yn) when Y/Yn (6/29)3. When CIELAB values are reported, they should be accompanied by
