1、 CIE 1iLb 95 II 900b145 0005297 786 4L PJ f ISBN 3 900 734 60 7 COMMISSION INTERNATIONALE DE LCLAIRAGE INTERNATIONAL COMMISSION ON ILLUMINATION INTERNATIONALE BELEU CHTUNGSKOM M ISSION INDUSTRIAL EVALUATION COLOUR-DIFFERENCE CIE 116-1995 UDC: 159.937 Descriptor: Perception of colour 535.65 Colour me
2、asurement, colorimetric methods 535.66 Colours of objects 6 12.843.31 Colour vision COPYRIGHT International Commission on IlluminationLicensed by Information Handling ServicesCIE 11b 95 9006345 0005298 bL2 This Technical Report has been prepared by CIE Technical Committee 1-29 of Division I Vision e
3、s ist zur Vetwendung durch CIE-Mitglieder und durch andere Interessierte bestimmt. Es sollte jedoch beachtet werden, da das Dokument eine Empfehlung und keine Vorschrift ist. Die neuesten CIE-Tagungsberichte oder das CIE NEWS sollten im Hinblick auf mgliche sptere Anderungen zu Rate gezogen werden.
4、Any mention of organisations or products does not imply endorsement by the CIE. Whilst every care has been taken in the compilation of any lists, up to the time of going to press, these may not be comprehensive. Toute mention dorganisme ou de produit nimplique pas une prfrence de la CIE. Malgr le so
5、in apport a la compilation de tous les documents jusqu la mise sous presse, ce travail ne saurait tre exhaustif. Die Erwhnung von Organisationen oder Erzeugnissen bedeutet keine Billigung durch die CIE. Obgleich groe Sorgfalt bei der Erstellung von Verzeichnissen bis zum Zeitpunkt der Drucklegung an
6、gewendet wurde, ist es mglich, da diese nicht vollstndig sind. CIE 1995 II COPYRIGHT International Commission on IlluminationLicensed by Information Handling ServicesCIE 116 95 Is 9006345 0005299 559 M CIE 116-1995 The following members of TC 1-29 Industrial Colour-Difference Evaluation took part in
7、 the preparation of this technical report. TC 1-29 comes under CIE Division 1 (Colour and Vision). Members: D. H. Alman (chairman) R. S. Berns T. F. Chong E. Hita T. Kehlibarov H. Komatsubara T. O. Maier R. McDonald C. D. Reilly A. R. Robertson R. Sve H. S. Shah K. J. Smith K. Witt Advisers: VJ. A.
8、Larsen M. Melgosa U.S.A. U.S.A. Hong Kong Spain Bulgaria Japan U.S.A. Great Britain U.S.A. Canada France India Great Britain Germany U.S.A. Spain III COPYRIGHT International Commission on IlluminationLicensed by Information Handling ServicesCIE 11b 95 m 7006345 0005300 OTO CIE 116-1995 INDUSTRIAL CO
9、LOUR-DIFFERENCE EVALUATION Contents 1. 1.1 I .2 1.3 I .4 2. 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 3. 3. i 3.2 3.3 4. 5. INTRODUCTION Statement of the colour-difference problem Goal Development strategy Historical review RECOMMENDATION Scope Reference conditions Uniform colour space Perceptual cor
10、relates of lightness, chroma and hue Components of colour difference Total colour-difference Weighting functions Parametric factors Nomenclature Development GUIDELINES FOR FUTURE WORK Objectives Experimental conditions Report formats REFERENCES APPENDIX Page 1 -l 2 2 3 6 6 6 7 7 8 8 9 10 10 IO 12 12
11、 12 13 15 17 IV COPYRIGHT International Commission on IlluminationLicensed by Information Handling ServicesCIE LLb 75 U 7006345 000530L T3i U CIE 116-1995 SUMMARY INDUSTRIAL COLOUR-DIFFERENCE EVALUATION Recommended practice for industrial colour-difference evaluation is presented. The recommended mo
12、del is an extension of the CIE 1976 (L*a*b*) colour-difference model with correction for chroma-dependent variation in colour-difference perception. Reference conditions define material and viewing environment characteristics to which the colour-difference model applies. Factors are introduced to co
13、rrect for the parametric effects of various conditions of use. Guidelines for further research on colour-difference perception are given. RESUME EVALUATION INDUSTRIELLE DES DIFFERENCES DE COULEUR Le document prsente une mthode recommande pour Vvaluation industrielle des diffrences de couleur. Le mod
14、le recommand est une extension de la formule de diffrence de couleur CIE 1976 L*a*b*, qui corrige la perception des diffrences de couleur des effets lis au chroma. Des conditions de base definissent, pour les matriaux et pour les modalits dobservation, les situations pour lesquelles le modle sappliq
15、ue. Des paramtres introduits dans le modle corrigent les effets rsultant de conditions demploi diffrentes. Des indications sont donnes pour un travail ultrieur de recherche sur la perception des difrences de couleur. ZUSAMMENFASSUNG INDUSTRIELLE FARBABSTANDSBEWERTUNG Es werden Empfehlungen zur Praxi
16、s der industriellen Farbabstandsbewertung vorgestellt. Das empfohlene Modell stellt eine Erweiterung der “L*, a*, b*-Farbabstand CIE 1976“-Formel dar, mit Korrekturen fr buntheitsabhngige hderungen der empfundenen Farbunterschiede. Bezugsbedingungen legen Material und Gestaltung der Sehaufgabe fest,
17、 fr die das Farbabstandsmodell gilt. Parameter zur Korrektur der Auswirkungen verschiedener Anwendungsbedingungen werden eingefhrt. Fr weitere Untersuchungen ber die Empfindung von Farbunterschieden werden Richtlinien formuliert. COPYRIGHT International Commission on IlluminationLicensed by Informat
18、ion Handling ServicesCIE 116-1995 1. INTRODUCTION I. I Statement oftbe colour-difierence problem Many industries employ colouring processes to provide products designed to enhance colour uniformity, colour recognition or aesthetic appeal. The producer must deliver a product of the desired colour wit
19、h its variation controlled to an extent appropriate for the products use and the customers expectations. Colour measurement and colour-difference evaluation are essential tools to help manufacturers accomplish these goals with efficient colour production processes. CIE colorimetry is employed to det
20、ermine whether the colour of a sample is a match to the aim-colour of the product for an average observer under specified viewing conditions. As an industrial practice it is successful and is almost universally used for quantitative colour measurement. The extension from measurement of coiours which
21、 match to measurement of the magnitude of the difference between colours which do not match is less successful. Colourdifference assessment involves advanced colorimetry; the description of the perceptual response to colour appearance. There is significantly greater variability in judgements of the
22、magnitude of a difference between two colours than in judgements of whether two colours match. Furthermore, many factors which do not influence a matching judgement do affect the perception of a colour difference. Thus there is significant variation between different experimental studies of colourdi
23、fference perception. Colourdifference evaluation models have been, and continue to be, developed. Recognising the complexity of the colour-difference problem, and the continuing research into colour- difference perception, it is expected there will be further improvement in colour-difference models
24、for industrial applications. There are several independent models in active use in industry. This leads to difficulty in dour communications between organisations employing different models. The CIE, through its technical committees, has periodically established recommended practices for colour-diff
25、erence evaluation to promote uniformity of industrial practice. In addition each recommendation has aimed to incorporate the latest research so that it represents best practice consistent with the present state of knowledge on colour- difference perception. The last CIE recommendation on this subjec
26、t was made in 1978 (CIE, 1978). Accumulated research since then indicates it is now possible to identify a model with improved agreement with visual colour-difference judgements. CIE Technical Committee 1-29 Industrial Colour-Difference Evaluation was assigned the task to investigate available colou
27、r- difference models and to make a recommendation for industrial applications of colour- difference evaluation. There are two principal problems a colourdifference model must address. The first is uniformity of colourdifference magnitudes over all colours and for all directions of colour difference.
28、 The second is applicability over the range of experimental conditions and material characteristics employed in the manufacture of coloured materials. A colour-difference model exhibits uniformity if the model predicts a constant magnitude of colour difference for all colour pairs which have equal p
29、erceived colour difference. In a perfectly uniform three-dimensional colour space the locus of constant visual colour-difference from an aim colour is a sphere centred on the aim colour and the equivalent loci for all possible aim coiours are spheres of equal radius. Colour-difference models are app
30、roximations to this ideal of colour-difference uniformity. The development of colour-difference models depends on experimental data relating perceived colour differences to colorimetric measurements of the colour-difference pairs. An implicit assumption is frequently made that the primary factors in
31、 such experiments are the location, direction and magnitude of the stimulus differences. However, a number of additional variables inff uence perceived colour differences. CIE Technical Committee 1-28 Parameters Affecting Coiour-Difference Evaluation has identified and reported on the influence of t
32、hese additional variables, or parametric effects (CIE, 1993). These variables include characteristics COPYRIGHT International Commission on IlluminationLicensed by Information Handling Services CIE Llb 95 II 900b145 0005303 BOT = CIE 116-1995 of the material, the viewing environment and the stimulus
33、 presentation. Material characteristics include colour uniformity, material structure or texture, and surface reflection characteristics (matte or glossy). Presentation factors include the size of viewing field and separation between stimuli. Viewing environment factors include the spectral power di
34、stribution of the illumination, its illuminance level and the background colour. In addition experimental results may be influenced by the observers task, individual differences among observers, size of the colourdifference magnitude, appearance mode, experimental methodology and method of analysis.
35、 Psychological factors, prior experiences and the context of the judgement task (acceptability or perceptibility) may also influence observers colour-difference responses. The combined impact of these parametric effects is not well defined but is believed to be a major contributor to the inconsisten
36、cy between the results of colour-difference perception experiments. A full understanding of colour-difference perception will require knowledge about the influence of parametric effects in addition to knowledge about the way colour-difference perception varies as colour location and direction vary.
37、Industrial applications of colourdifference evaluation are made under various parametric conditions and it is not currently possible to account for all these effects. A set of reference conditions are specified which are typical of those employed in industry and are consistent with several experimen
38、tal data sets. Models based on these data sets can be expected to perfonn well when applied to visual assessments close to the reference conditions. If the conditions of application vary significantly from the reference conditions, a parametric correction to the colour-difference model may be requir
39、ed to achieve agreement with visual perception. 1.2 Goal The goal of the recommendation on industrial colour-difference evaluation is to provide a quantitative model of colourdifference perception that agrees well with visual colour-difference perception for an average observer under conditions typi
40、cal of industrial applications. In addition the recommendation should provide guidance to the user concerning the conditions to which the model applies (the reference conditions) and the means to correct for parametric effects. 1.3 Development strategy TC1 -29 has adopted a strategy for on-going dev
41、elopment of industrial cobur-difference evaluation. The elements of this strategy are a commitment to sustain the good features of existing models, to co-ordinate new research on colour-difference perception and to enhance the recommended colour-difference model through either empirical corrections
42、or advanced model development The CIE 1976 L*a*b* colour-difference recommendation has achieved a useful level of acceptance by industry. Generally users find the rectangular co-ordinate space based on opponent responses, L*, a, b“, to be an intuitive and readily understood basis for industrial colo
43、urdifference practice. Furthermore, the perceptual correlates of lightness, chroma and hue provided by lightness, L*, chroma, Cab, and hue angle, hab, scales are also regarded as effective. These good features have led a majority of industrial users to adopt CIELAB or CIELAB-based colour-difference
44、models. The Committee wishes to retain the strong features of CIELAB. Co-ordination of research on colourdifference perception is the second element of our strategy. A previous CIE technical committee concerned with colour-difference evaluation published guidelines for research (Robertson, 1978). Th
45、is has led to a focus on experimental conditions typical of industrial applications (object mode, small to moderate coiour-difference magnitude) and use of similar test colours, enabling comparison of experimental results. Several experimental data sets developed within the research guidelines have
46、been very useful to TC1 -29. The CIE plans to continue this effort by periodic announcement of research guidelines. These may include guidance on research objectives, parametric conditions, experimental methodologies and communication of results. 2 COPYRIGHT International Commission on IlluminationL
47、icensed by Information Handling ServicesCIE 116-1995 As new research accumulates, and the understanding of colour-difference perception improves, there will be opportunities to enhance the performance of the colour-difference model. One path to improved models is empirical corrections to uniformity
48、or to account for parametric effects. Whenever an opportunity for significant improvement is presented by new research, it can be readily implemented by updates to the model incorporating these effects. A second path to improvement is to develop advanced colour-difference perception models which com
49、e closer to the goa! of uniformity or which integrate parametric effects without empirical corrections. Either approach requires increased model complexity to achieve improved model performance. The CIE would like to manage development of industrial colour-difference evaluation so that significant, positive, improvements through more general models are periodically implemented with minimum disruption to industrial users. i. 4 Historical review The development of experimental colour-difference results and models is briefly outlined in
