IEC 61 988 2 6 Edition 1 0 201 5 03 INTERNATIONAL STANDARD Plasma display panels – Part 2 6 Measuring methods – APL dependent gamma and colour characteristics IE C 6 1 9 8 8 2 6 2 0 1 5 0 3 (e n ) ® c[.]
I E C 61 8 -2 -6 ® Edition 201 5-03 I N TE RN ATI ON AL S TAN D ARD colour in sid e Pl as m a d i s pl ay pan el s – Part -6: M eas u ri n g m eth od s – AP L d epe n d en t g am m a an d col ou r IEC 61 988-2-6:201 5-03(en) ch aracteri s ti cs TH I S P U B L I C ATI O N I S C O P YRI G H T P RO TE C T E D C o p yri g h t © I E C , G e n e va , S w i tze rl a n d 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 IEC or IEC's member National Committee in the country of the requester If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or your local IEC member National Committee for further information IEC Central Office 3, rue de Varembé CH-1 21 Geneva 20 Switzerland Tel.: +41 22 91 02 1 Fax: +41 22 91 03 00 info@iec.ch www.iec.ch Abou t th e I E C The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes International Standards for all electrical, electronic and related technologies Ab o u t I E C p u b l i c a ti o n s The technical content of IEC publications is kept under constant review by the IEC Please make sure that you have the latest edition, a corrigenda or an amendment might have been published I E C C atal og u e - webs tore i ec ch /catal og u e E l ectroped i a - www el ectroped i a org The stand-alone application for consulting the entire bibliographical information on IEC International Standards, Technical Specifications, Technical Reports and other documents Available for PC, Mac OS, Android Tablets and iPad The world's leading online dictionary of electronic and electrical terms containing more than 30 000 terms and definitions in English and French, with equivalent terms in additional languages Also known as the International Electrotechnical Vocabulary (IEV) online I E C pu bl i cati on s s earch - www i ec ch /s earch pu b I E C G l os s ary - s td i ec ch /g l os s ary The advanced search enables to find IEC publications by a variety of criteria (reference number, text, technical committee,…) It also gives information on projects, replaced and withdrawn publications More than 60 000 electrotechnical terminology entries in English and French extracted from the Terms and Definitions clause of IEC publications issued since 2002 Some entries have been collected from earlier publications of IEC TC 37, 77, 86 and CISPR I E C J u st P u bl i s h ed - webs tore i ec ch /j u s u bl i s h ed Stay up to date on all new IEC publications Just Published details all new publications released Available online and also once a month by email I E C C u s to m er S ervi ce C en tre - webs tore i ec ch /cs c If you wish to give us your feedback on this publication or need further assistance, please contact the Customer Service Centre: csc@iec.ch I E C 61 8 -2 -6 ® Edition 201 5-03 I N TE RN ATI ON AL S TAN D ARD colour in sid e Pl as m a d i s pl ay pan el s – P art -6: M eas u ri n g m eth od s – AP L d epe n d en t g am m a an d col ou r ch aracteri s ti cs INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 31 260 ISBN 978-2-8322-2399-4 Warn i n g ! M ake s u re th at you obtai n ed th i s pu bl i cati on from an au th ori zed d i s tri bu tor ® Registered trademark of the International Electrotechnical Commission –2– I EC 61 988-2-6: 201 © I EC 201 CONTENTS FOREWORD Scope Normative references Terms, definitions and abbreviations Terms and definitions Abbreviations Measurement equipment Video signal generator Non-contact LMD (light measurement device) Contact LMD Measurement conditions General Setup conditions Measuring layout I nput signal level and picture level Measuring methods of tone characteristics Purpose I nput signals 1 2.1 General 1 2.2 1 -step grey bar with fixed APL 1 2.3 Single grey window with fixed APL 2.4 1 -step RGB bar and single colour window with fixed APL Measuring procedure Expression of results 4.1 Measurement report 4.2 Gamma calculation Measuring methods of colour gamut by APL Purpose Primary and secondary colour patterns by APL Measuring procedure Evaluation of colour accuracy 20 Evaluation of colour gamut 20 Expression of results 21 Annex A (informative) Use of ITU-R Rec BT 709-5 signal 25 Bibliography 26 Figure Figure Figure Figure Figure Figure Figure Figure − Measuring layout for non-contact measurement − Measuring layout for contact measurement – Input signals and signal processing in a PDP module – An example of an 1 -step grey-bar pattern – Example of % window pattern for measuring the tone characteristics − RGB bar and single window pattern − An example of results of gamma characteristics for each APL − Example plots for calculated gamma values by APL I EC 61 988-2-6: 201 © I EC 201 － 3－ Figure − Example plots for CCT characteristics by APL Figure − Example plots for ∆ u ’v ’ characteristics by APL Figure 1 − % C, M, and Y single window pattern Figure − ITU -R Rec BT 709-5 standard coordinates of primary and secondary colours 20 Figure – Example showing a measured primary, a reference, and an overlapped gamut area 21 Figure − The measured colour gamut plots by APL 24 Table Table Table Table Table − An example of a tone measurement report − Example of gamma reporting form (for each APL ) – An example of gamut areas for evaluation of colour gamut 21 − An example of primary and secondary colour measurement report 22 A.1 – Digital data and signal level in ITU -R Rec BT.709-5 25 –4– I EC 61 988-2-6: 201 © I EC 201 I NTERNATIONAL ELECTROTECHNI CAL COMMI SSI ON P L AS M A D I S P L AY P AN E L S – P a rt -6 : M e a s u ri n g m e t h o d s – AP L d e p e n d e n t g a m m a a n d c o l o u r c h a c t e ri s t i c s FOREWORD ) The I nternati onal El ectrotechnical Commi ssi on (I EC) is a worl d wi d e organizati on for stan dard izati on comprisi ng all nati onal electrotech nical committees (I EC N ational Comm ittees) Th e object of I EC is to promote i nternati on al co-operati on on al l q u esti ons cernin g standard izati on i n the el ectrical and el ectronic fi el ds To this end an d in ad di ti on to other acti vi ti es, I EC pu bli sh es I nternati onal Stand ards, Technical Speci fi cati ons, Technical Reports, Pu bl icl y Availabl e Specificati ons (PAS) and Gui d es (hereafter referred to as “I EC Pu blicati on(s)”) Their preparati on is entru sted to technical committees; any I EC N ati onal Committee interested i n the subj ect d eal t with may parti ci pate i n thi s preparatory work I nternati onal, g overn mental and nongovernm ental organizations l iaisi ng wi th the I EC al so participate in th is preparati on I EC coll aborates cl osel y wi th th e I nternati on al Org anizati on for Stand ard ization (I SO) i n accordance wi th cond i ti ons d etermin ed by agreement between th e two org anizati ons 2) Th e form al d ecision s or ag reements of I EC on technical matters express, as nearl y as possibl e, an i nternati onal consensus of opi ni on on the rel evant su bjects since each tech nical committee has representati on from all i nterested I EC N ati onal Commi ttees 3) I EC Pu blications have th e form of recommend ati ons for intern ati onal u se and are accepted by I EC N ati onal Comm ittees i n th at sense Whi le all reasonabl e efforts are mad e to ensu re that the techn ical content of I EC Pu blicati ons is accu rate, I EC cann ot be hel d responsi bl e for th e way i n wh i ch they are used or for an y misin terpretati on by any end u ser 4) I n ord er to promote i n ternational u ni formi ty, I EC N ati onal Commi ttees u nd ertake to appl y I EC Pu blicati on s transparen tl y to the maxi mum exten t possi bl e i n thei r nati onal and regi onal pu blicati ons Any di vergence between an y I EC Pu bl icati on and the correspond i ng n ati onal or reg ional publi cation shal l be cl earl y in d icated i n the l atter 5) I EC i tsel f does not provi d e any attestation of conformity I nd epend ent certi ficati on bod ies provi d e conformity assessment services an d , in some areas, access to I EC marks of conformi ty I EC i s not responsi bl e for any services carried ou t by i nd epend en t certi fication bodi es 6) All users sh ould ensu re that they h ave the l atest edi ti on of this pu blicati on 7) N o li abili ty shal l attach to I EC or i ts di rectors, empl oyees, servants or agents i ncl u di ng ind ivi du al experts and members of i ts tech ni cal comm ittees and I EC N ati onal Committees for any personal inju ry, property d amag e or other d amage of any n atu re whatsoever, whether di rect or in d i rect, or for costs (i n cl u d i ng l egal fees) and expenses arising out of the pu blication, use of, or reli ance u pon, this I EC Pu bl ication or any other I EC Pu blicati ons 8) Attention is d rawn to the N ormative references ci ted i n this pu bl icati on U se of the referenced publicati ons is i ndi spensabl e for the correct appli cati on of this publicati on 9) Attention is d rawn to the possibili ty that some of the elements of thi s I EC Pu bl icati on may be the su bj ect of patent ri ghts I EC shal l not be held responsi bl e for i d en ti fyi ng any or all such patent ri ghts I nternational Standard IEC 61 988-2-6 has been prepared by I EC technical committee 1 0: Electronic display devices The text of this standard is based on the following documents: FDI S Report on voti ng 1 0/636/FDI S 1 0/652/RVD 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/I EC Directives, Part － 5－ I EC 61 988-2-6: 201 © I EC 201 A list of all the parts in the IEC 61 988 series, under the general title Plasma display panels , can be found on the IEC website The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the I EC 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 I M P O R T AN T – T h e ' c o l o u r i n s i d e ' th a t it c o n ta i n s u n d e rs t a n d i n g c o l o u r p ri n t e r of c o l o u rs i ts wh i ch c o n te n ts l og o a re U s e rs on th e c o ve r p a g e o f th i s c o n s i d e re d shou l d to t h e re fo re be p u b l i ca ti o n u s e fu l p ri n t th i s fo r i n d i c a te s th e d o cu m e n t c o rre c t using a –6– I EC 61 988-2-6: 201 © I EC 201 P L AS M A D I S P L AY P AN E L S – P a rt -6 : M e a s u ri n g m e t h o d s – AP L d e p e n d e n t g a m m a a n d c o l o u r c h a c t e ri s t i c s Scope This part of I EC 61 988 defines the measuring methods for gamma and colour gamut characteristics as a function of the APL for a PDP module (plasma display module) Generally, the luminance level of a PDP module is dependent on the APL (average picture level) of input images Varying the input levels causes a change of the chromaticity of RGB primary colours This standard also defines the measuring methods of tone characteristics and chromaticity characteristics with varying APLs This standard is based on the assumption that the inversegamma circuit is inside the module N o rm a t i v e re fe re n c e s The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies I EC 60068-1 , Environmental testing – Part 1: General and guidance Methods of measurement on receivers for television broadcast transmissions − Part 1: General considerations − Measurements at radio and video frequencies I EC 601 07-1 , I EC 61 966-5, Multimedia system and equipment – Colour measurement and management – Part 5: Equipment using plasma display panels I EC 61 988-1 , Plasma display panels – Part 1: Terminology and letter symbols I EC 61 988-2-1 , Plasma display panels − Part 2-1: Measuring methods − Optical and optoelectrical CI E 5: 2004, Colorimetry I TU -R Rec BT 709-5, Parameter values for the HDTV standards for production and international programme exchange T e rm s , d e fi n i t i o n s a n d a b b re v i a t i o n s T e rm s a n d d e fi n i t i o n s For the purposes of this document, the terms and definitions given in I EC 60068-1 , I EC 601 07-1 and I EC 61 988-1 , as well as the following apply 3.1 to n e characteristics of the relationship between input signal level and output luminance I EC 61 988-2-6: 201 © I EC 201 － 7－ 3.1 colour difference difference between two colour stimuli, defined as the Euclidean distance between the points representing them in a specific colour space such as CIE 976 u’v’ colour space 3.1 colour gamut area two-dimensional maximum area of reproducible colours expressed in the CI E 976 colour space defined in CI E 3.2 Abbreviations For the purposes of this document, the following abbreviations apply APL Average picture level CCT Correlated colour temperature LMD Light measuring device PDP Plasma display Measurement equipment 4.1 Video signal generator An analogue video signal generator or a digital video signal generator is used The signal characteristics shall match with the measured PDP module I nput signal, in this document, means a pre-gamma signal and APL means a post-gamma APL 4.2 Non-contact LMD (light measurement device) When using a non-contact LMD, the non-contact LMD incorporates a spectroradiometer or a non-contact colorimeter as shown in Figure The detail conditions are defined in I EC 61 988-2-1 , where a non-contact LMD is described as an LMD N OTE: See I EC 61 966-5 4.3 Contact LMD When using a contact LMD, the measurement probe shall be placed perpendicular to the display surface and include at least 500 pixels in the measurement aperture I t shall be confirmed that the results measured by the contact LMD are the same as the results measured by the non-contact LMD Measurement conditions 5.1 General The following standard setup conditions shall be used Each condition shall be noted on the relevant specification whenever any different conditions other than the standard setup conditions are applied (See the measuring conditions in I EC 61 966-5 and I EC 61 988-2-1 ) 5.2 Setup conditions All measurements shall be carried out in a dark room I lluminance shall be less than lx anywhere on the screen of the PDP module When this illuminance significantly affects the measurement of the black level, the background subtraction method shall be used When a –8– I EC 61 988-2-6: 201 © I EC 201 different illuminance or the background subtraction method is used, this shall be noted on the report The warm-up time shall be longer than 30 minutes with a signal input set at % grey level on full screen without gamma correction, unless other specified measuring methods are used When different warm-up conditions are used, they shall be noted on the report For the measurement of tone characteristics, the conditions of contrast and colour enhancement functions to preserve the tone characteristics of the panel itself shall be applied and noted on the report The image sticking preventing function (for a still image) shall be turned off, or some procedures in which the function is kept inactive can be applied M eas u ri n g l a yo u t The measuring equipment shall be set as shown in Figure for a non-contact LMD and in Figure for a contact LMD The optical axis of the non-contact LMD should be normal to the centre of the display surface I t is recommended that the measuring distance ℓ0 of LMD is 2, V, where V is the effective screen height of the display PDP module V Pattern generator LMD ℓ0 M easuring distance Control PC (i f u sed ) IEC F i g u re − M eas u ri n g l a you t for n o n -con tact m e as u re m en t The measuring layout for a contact LMD is shown in Figure A measurement probe shall be set to the surface of the display – 14 – I EC 61 988-2-6: 201 © I EC 201 where D R, D G and D B are the digital data of the window of R, G and B, respectively, and the number of bits for the input signal N is The window is generated with each primary colour input data to be measured The background shall be changed to maintain a specific APL of the total screen area while measuring the window with the changing input signal level I from % to 00 %, i.e I0 % to I1 00 % as defined in 6.2 M easu rin g procedu re The following procedure shall be used: a) A PDP module shall be set in the measuring condition shown in Figure b) Turn off all functions that enhance the contrast and colour of the display to measure the tone characteristics of the PDP module c) Warm up the PDP module with an input signal of full screen white for an hour d) Set the APL to % e) I nput each of the window signals or grey pattern signals to be measured as shown in Figure 4, Figure 5, and Figure f) Measure the luminance and chromaticity coordinates ( u ’, v ’) at screen centre by changing the input signal level for each of the 1 input signal levels g) Change the APL and repeat e) to f) to measure the tone characteristics for each of the remaining APLs N OTE u ' and v ' are CI E 976 U CS di ag ram coordi nates defi ned i n CI E The valu es of u ' an d v ' coord inates are transformed from the measu red x and y val ues usi ng th e followi ng eq u ations: where x and y u' = x /(3 – x + y ) (9) v' = y /(3 – x + y ) (1 0) are CI E 931 chromati ci ty coord i nates Figure shows an example of the result of gamma characteristics in APLs － 5－ Luminance (cd/m 2) I EC 61 988-2-6: 201 © I EC 201 200 0% APL 20% APL 30% APL 40% APL 50% APL 60% APL 70% APL 80% APL 90% APL 80 60 40 20 00 80 60 40 20 0 10 20 30 40 50 60 70 80 90 00 Input signal level (%) IEC F i g u re − An e x a m p l e o f re s u l t s o f g a m m a c h a c t e ri s t i c s fo r e a c h A P L E x p re s s i o n o f re s u l t s M e a s u re m e n t re p o rt The measurement report shall include the following items: a) The measured result of the luminance shall be reported as a table, as shown in Table with input digital data Tabl e − An e x a m p l e o f a t o n e m e a s u re m e n t re p o rt I n pu t O u tpu t: Di s pl ay l u m i n an ce O u u t: P i c t u re l e ve l Si g n al s te p -b i t i n p u t d i g i ta l d a ta D i g i ta l d a ta o f I T U -R Re c I n pu t si g n al M e a s u re d l e ve l l u m i n an ce N o rm a l i z e d l u m i n an ce b C o n ve n ti o n a l 2,2 gamma B T -5 -b i t d i g i ta l vi d e o si gnal k 10 11 DM DM a I L (cd/m ) 0, 08 0, 95 4, 9, 6, 42 27, 48 40, 63 55, 96 75, 83 99, 96 28, 24 (0~255) (1 6~235) (%) 26 51 77 02 28 53 79 204 230 255 16 38 60 82 04 26 47 69 91 21 235 10 20 30 40 50 60 70 80 90 00 L n orm (%) (%) 0, 00 0, 68 3, 7, 1 2, 75 21 , 38 31 , 64 43, 60 59, 1 77, 93 00, 00 0, 00 0, 66 2, 90 7, 3, 32 21 , 58 32, 50 45, 35 61 , 21 78, 93 00, 00 a For the u se of the I TU -R Rec BT 709-5 8-bi t di gi tal vid eo si gnal, the di gi tal d ata incl ud i ng that of the backgrou nd , is mod ified b N ormal ized l u ance is ( L - L )/( L 0 - L ), where L , L and l evel % and the lu mi nance at l evel 00 % respectivel y L 00 are the measu red l u minance, the l um inance at – 16 – 4.2 I EC 61 988-2-6: 201 © I EC 201 Gamma calcu l ati on From the measurement result shown above, a nonlinear output characteristic g , i e, a relationship between output luminance and input signal level, is calculated Thus, the average gamma value, g j for the j th APL is calculated by the following equation: gj = n −1 log L norm, k ∑ log Inorm, n−2 k k =2 (1 ) where j refers to the jth APL (1 0, 20, 30, … … , 90 APL) and n is the number of input signal steps for an APL I n this measuring method 1 signal steps, where n is 1 , are used Inorm, k is the input signal level at each signal step k, which is the normalized value from to of input digital data L norm, k is the normalized value of the luminance having a value from to measured at each signal step k and is defined as follows: Lnorm, k = ( Lk − L ) (L1 00 − L0 ) (1 2) where, L k is the measurement luminance at the signal step k, L is the luminance at the input of level % and L 00 is the luminance at the input of level 00 % The average gamma value g T for all APLs, i e the average value of all gammas, g , g , g , , g m , is; gT = N OTE m g + g + g + + g m m (1 3) is the nu mber of APLs consi d ered, generall y 9, from %, 20 %, … , 90 % APL Additionally, the gamma accuracy (%) is quantified from the following equation gS −gT g accu = − × 00 g S (1 4) where g S is 2,2 for conventional 2,2 gamma and /0, 45 for I TU-R Rec BT 709-5 gamma N OTE See th e recomm endati on I TU -R Rec BT 709-5-5 for the I TU -R Rec BT 709-5 gamma The measured data and the result of the g calculation shall be reported as shown in Table － 7－ I EC 61 988-2-6: 201 © I EC 201 Table − Example of gamma reporting form (for each APL ) j APL (%) g 10 2, 20 2, 30 2, 20 40 2, 25 50 2, 23 60 2, 25 70 2, 33 80 2, 36 90 2, 37 Averag e ( g T ) ± stand ard devi ati on 2, 25 ± 0, 08 Calculated gamma value The result of the g calculation shall also be reported as plots for % APL to 90 % APL as shown in Figure 2,80 2,60 2,40 2,20 2,00 ,80 ,60 ,40 ,20 ,00 10 20 30 40 50 60 70 80 90 Input APL (%) IEC Figure − Example plots for calculated gamma values by APL The CCT values and ∆ u ’v ’ by APL shall also be plotted as curves, where the horizontal axis shall be the normalized input signal level from % to 00 %, as shown in Figure and Figure I f a light measuring device doesn’t provide the CCT, then the CCT is calculated from the chromaticity coordinates ( x , y ) using McCamy’s approximation as follows: CCT = 437 n + 601 n + 861 n + 51 where n = ( x − 0,332 ) ( 0,1 85 − y ) The colour difference ∆ u ’v ’ is defined as follows, (1 5) – 18 – I EC 61 988-2-6: 201 © I EC 201 Δu ' v' = (u 'i −u 'o )2 + (v'i −v'o )2 (1 6) CCT (correlated colour temperature) where u ' o , v' o are the pre-defined chromaticity coordinates and u ' i , v' i are the measured chromaticity coordinates The pre-defined chromaticity value shall be reported, and if the predefined chromaticity values vary with input level, these shall also be reported In this example, the pre-defined u ’v ’ value is (0,1 98, 0,468) for a CCT value of 500 K of daylight 000 0% APL 20% APL 30% APL 40% APL 50% APL 60% APL 70% APL 80% APL 90% APL 1 000 000 000 000 000 000 000 10 20 30 40 50 60 70 80 90 00 Input signal level (%) IEC Figure − Example plots for CCT characteristics by APL 0,040 0% APL 20% APL 30% APL 40% APL 50% APL 60% APL 70% APL 80% APL 90% APL 0,035 0,030 0,025 0,020 0,01 0,01 ∆u’ v’ 0,005 −0,005 −0,01 −0,01 −0,020 10 20 30 40 50 60 70 80 90 00 Input signal level (%) IEC Figure − Example plots for ∆u ’v ’ characteristics by APL － 9－ I EC 61 988-2-6: 201 © I EC 201 Measuring methods of colour gamut by APL 7.1 Purpose The purpose of this method is to measure primary and secondary colour accuracy and quantify the colour gamut of a PDP as a function of APL, and then to measure the following item: • Chromaticity coordinates x and and yellow) for each APL y of RGB primary and secondary colours (cyan, magenta N OTE Th e second ary colou r are cyan (C) = G(1 00 %) + B (1 00 %), magenta (M ) = R (1 00 %) + B (1 00 %), and yel l ow (Y) = R (1 00 %) + G (1 00 %), respecti vel y 7.2 Primary and secondary colour patterns by APL To measure the primary colour with a varying APL, the colour window pattern shown in Figure 6b) shall be used The secondary colours C, M, and Y can also be measured in the same manner as shown in the following Figure 1 The input level of each window shall be set at 00 % for the colour The input digital data of the background for each primary colour R, G and B single window pattern given in 6.2 c) is used For the input digital data for the background for each secondary colour C, M and Y single window pattern shown in Figure 1 , the following equations (1 7), (1 8), and (1 9) are used D BK , = (2 N-1 ) × ( (APL(%) −4 × × ( D C /(2 N-1 )) 2, /3)/96 ) /2, (1 7) D BK = (2 N-1 ) × ( (APL(%) −4 × × ( D M /(2 N-1 )) 2, /3)/96 ) /2, (1 8) D BK = (2 N-1 ) × ( (APL(%) −4 × × ( D Y /(2 N-1 )) 2, /3)/96 ) /2, (1 9) where D C, D M and D Y are the digital data of the window of C, M and Y, respectively, and the number of bits for the input signal In this measurement D C, D M and D Y are N-1 N is IEC Figure 1 7.3 − % C, M, and Y single window pattern Measuring procedure The following procedure shall be used for measuring the colour characteristics a) A PDP module shall be set in the measuring condition shown in Figure b) Turn off all functions that enhance the contrast and colour of the display to measure the tone characteristics of the PDP module c) Warm up the PDP module with an input signal of full screen white for an hour d) Set the APL to % e) I nput each R, G, B, C, M, and Y single window pattern as shown in Figure 6b) or Figure 1 , where the input signal level of each single colour window is 00 %, and measure the chromaticity coordinates ( u ’, v ’) and CCT at screen centre – 20 – I EC 61 988-2-6: 201 © I EC 201 f) Change the APL and repeat e) to measure the primary and secondary colour accuracy for each remaining APL 7.4 E va l u a t i o n o f c o l o u r a c c u c y The reference standard coordinates of the primary colours are generally available from I TU-R Rec BT.709-5 v’ The measured colour data is compared to the I TU -R Rec BT 709-5 values shown in Figure in order to check for deviation of ∆ u ’, v ’ 0,6 0,5 0,4 (0,1 25, 0,563) (0,204, 0,553) (0,451 , 0,523) (0,1 38, 0,456) (0,305, 0,330) 0,3 0,2 CIE u ’ v’ BT.709 Primary BT.709 Cyan BT.709 Magenta BT.709 Yellow (0,1 75, 0,1 58) 0,1 0,0 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 u’ IEC Ke y BT 709 means I TU -R Rec BT 709-5 F i g u re 7.5 − I T U - R R e c B T - s t a n d a rd c o o rd i n a t e s o f p ri m a ry a n d s e c o n d a ry c o l o u rs E va l u a t i o n o f c o l o u r g a m u t The colour gamut area is used to evaluate the colour range of the display Generally, it can be calculated with the u ’ v ’ coordinate system The area of the I TU-R Rec BT 709-5 colour gamut in the ( u ’, v ’) diagram is │ u ’ R v ’ G + u ’ G v ’ B + u ’ B v ’ R – v ’ R u ’ G – v ’ G u ’ B – v ’ B u ’ R │ /2 , which is 0, 064 and used for the reference colour gamut area Similarly, the area of n polygons for the overlapped colour gamut area between the reference and the display under test is calculated from the following equation (20) │ u ’ v ’ + u ’ v ’ + u ’ v ’ … + u ’ n-1 v ’ n + u ’ n v ’ – v ’ u ’ – v ’ u ’ – v ’ u ’ … − v ’ n-1 u ’ n – v ’ n u ’ │ /2 (20) From the results of the colour gamut area, the relative gamut ratio and gamut reproducibility are calculated as shown in equations (21 ) and (22) An example of gamut areas for the evaluation of the colour gamut is shown in Table Relative gamut ratio (%) = Display colour gamut area × 00 Reference colour gamut area (21 ) － 21 － I EC 61 988-2-6: 201 © I EC 201 Gamut reproducib ility (%) = Overlap colour gamut area × 00 Reference colour gamut area (22) Table – An example of gamut areas for evaluation of colour gamut Red sRGB (I TU -R Rec BT 709-5) M easu red col ou r gamut Green Blu e Col ou r gamu t area u’ R v’ R u’ G v’ G u’ B v’ B 0, 450 0, 522 0, 25 0, 562 0, 75 0, 57 u’R v’ R u’ G v’ G u’ B v’ B 0, 440 0, 533 0, 1 0, 552 0, 66 0, 67 0, 064 0, 061 Overl apped colou r gamu t 0, 057 v’ Figure shows an example of the measured colour, sRGB (I TU-R Rec BT.709-5), and of the overlapped gamut area for evaluation of the colour gamut 0,6 0,5 0,4 0,3 sRGB (ITU-R BT 709-5) Measured display Overlapped gamut area Intersection coordinate 0,2 0,1 0,1 0,2 0,3 0,4 0,5 u’ IEC Figure – Example showing a measured primary, a reference, and an overlapped gamut area 7.6 Expression of results The measured result and the colour coordinates data shall be reported as a table, as shown in Table with the reference colour standard Additionally, the colour gamut evaluation result can also be reported in Table Figure shows an example of the measured colour gamut plots by APL – 22 – Tabl e AP L Col ou r − An e x a m p l e o f p ri m a ry a n d s e c o n d a ry c o l o u r m e a s u re m e n t re p o rt I n pu t si g n al R e fe re n c e M e a s u re d l e ve l c o o rd i n a t e s c o o rd i n a t e s ( R, Red Green % AP L Bl u e Cyan M agen ta Yel l ow Red Green 20 % AP L Bl u e Cyan M agen ta Yel l ow Red Green 30 % AP L Bl u e Cyan M agen ta Yel l ow Red Green 40 % AP L Bl u e Cyan M agen ta Yel l ow Red Green 50 % AP L Bl u e Cyan M agen ta I EC 61 988-2-6: 201 © I EC 201 G, B) (1 00 %, %, %) (0 %, 00 %, %) (0 %, %, 00 %) (0 %, 00 %, 00 %) (1 00 %, %, 00 %) (1 00 %, 00 %, %) (1 00 %, %, %) (0 %, 00 %, %) (0 %, %, 00 %) (0 %, 00 %, 00 %) (1 00 %, %, 00 %) (1 00 %, 00 %, %) (1 00 %, %, %) (0 %, 00 %, %) (0 %, %, 00 %) (0 %, 00 %, 00 %) (1 00 %, %, 00 %) (1 00 %, 00 %, %) (1 00 %, %, %) (0 %, 00 %, %) (0 %, %, 00 %) (0 %, 00 %, 00 %) (1 00 %, %, 00 %) (1 00 %, 00 %, %) (1 00 %, %, %) (0 %, 00 %, %) (0 %, %, 00 %) (0 %, 00 %, 00 %) (1 00 %, %, 00 %) ∆ u ' v' u' v' u' v' 0, 451 0, 523 0, 390 0, 509 0, 062 0, 25 0, 563 0, 76 0, 502 0, 079 0, 75 0, 58 0, 79 0, 255 0, 097 0, 39 0, 456 – 0, 305 0, 330 – 0, 204 0, 553 – 0, 451 0, 523 0, 400 0, 51 0, 052 0, 25 0, 563 0, 64 0, 51 0, 060 0, 75 0, 58 0, 78 0, 242 0, 084 0, 39 0, 456 – 0, 305 0, 330 – 0, 204 0, 553 – 0, 451 0, 523 0, 41 0, 51 0, 041 0, 25 0, 563 0, 55 0, 529 0, 045 0, 75 0, 58 0, 77 0, 224 0, 066 0, 39 0, 456 – 0, 305 0, 330 – 204 0, 553 – 0, 451 0, 523 0, 420 0, 51 0, 032 0, 25 0, 563 0, 50 0, 532 0, 039 0, 75 0, 58 0, 76 0, 21 0, 055 0, 39 0, 456 – 0, 305 0, 330 – 0, 204 0, 553 – 0, 451 0, 523 0, 429 0, 51 0, 023 0, 25 0, 563 0, 46 0, 534 0, 035 0, 75 0, 58 0, 76 0, 208 0, 051 0, 39 0, 456 – 0, 305 0, 330 – R e l a t i ve G am u t g a m u t t i o re p ro d u c i b i l i t y (%) (%) 95, % 95, % 96, % 96, % 97, % 96, % 99, % 97, % 99, % 97, % － 23 － I EC 61 988-2-6: 201 © I EC 201 AP L Col ou r I n pu t si g n al R e fe re n c e M e a s u re d l e ve l c o o rd i n a t e s c o o rd i n a t e s ( R, Yel l ow Red Green 60 % AP L Bl u e Cyan M agen ta Yel l ow Red Green 70 % AP L Bl u e Cyan M agen ta Yel l ow Red Green 80 % AP L Bl u e Cyan M agen ta Yel l ow Red Green 90 % AP L Bl u e Cyan M agen ta Yel l ow G, B) (1 00 %, 00 %, %) (1 00 %, %, %) (0 %, 00 %, %) (0 %, %, 00 %) (0 %, 00 %, 00 %) (1 00 %, %, 00 %) (1 00 %, 00 %, %) (1 00 %, %, %) (0 %, 00 %, %) (0 %, %, 00 %) (0 %, 00 %, 00 %) (1 00 %, %, 00 %) (1 00 %, 00 %, %) (1 00 %, %, %) (0 %, 00 %, %) (0 %, %, 00 %) (0 %, 00 %, 00 %) (1 00 %, %, 00 %) (1 00 %, 00 %, %) (1 00 %, %, %) (0 %, 00 %, %) (0 %, %, 00 %) (0 %, 00 %, 00 %) (1 00 %, %, 00 %) (1 00 %, 00 %, %) u' v' ∆uv ' ' u' v' 0, 204 0, 553 0, 451 0, 523 0, 431 0, 51 0, 020 0, 25 0, 563 0, 44 0, 536 0, 032 0, 75 0, 58 0, 76 0, 202 0, 045 0, 39 0, 456 – 0, 305 0, 330 – 0, 204 0, 553 – 0, 451 0, 523 0, 435 0, 51 0, 01 0, 25 0, 563 0, 40 0, 541 0, 026 0, 75 0, 58 0, 74 0, 96 0, 038 0, 39 0, 456 – 0, 305 0, 330 – 0, 204 0, 553 – 0, 451 0, 523 0, 440 0, 520 0, 01 0, 25 0, 563 0, 36 0, 550 0, 01 0, 75 0, 58 0, 76 0, 88 0, 030 0, 39 0, 456 – 0, 305 0, 330 – 0, 204 0, 553 – 0, 451 0, 523 0, 446 0, 522 0, 005 0, 25 0, 563 0, 34 0, 556 0, 01 0, 75 0, 58 0, 72 0, 80 0, 022 0, 39 0, 456 – 0, 305 0, 330 – 0, 204 0, 553 – R e l a t i ve G am u t g a m u t t i o re p ro d u c i b i l i t y (%) (%) 00, % 98, % 00, % 99, % 02, % 99, % 05, % 00, % – I EC 61 988-2-6: 201 © I EC 201 v’ – 24 – 0, 0, 0, 0, CIE u v ITU-R Rec BT.709-5 primary Measured primary 0% APL 20% APL 30% APL 40% APL 50% APL 60% APL 70% APL 80% APL 90% APL ’ 0, 0, 0, 0, 0, 0, 0, 0, 0, ’ 0, 0, u’ IEC F i g u re − Th e m e as u re d col ou r g am u t p l ots b y AP L － 25 － I EC 61 988-2-6: 201 © I EC 201 An n e x A (informative) U s e o f I T U - R Re c B T - s i g n a l I n I TU-R Rec BT.709-5 the digital data of the 8-bit digital video signal is compressed to to 235, but not to to 255 The relationship between the input signal level and the digital data in I TU -R Rec BT 709-5 is shown in Table A T a b l e A – D i g i t a l d a t a a n d s i g n a l l e ve l Si g n al l e ve l in I TU -R Re c B T -5 D i g i ta l d a ta I DM 16 10 38 20 60 30 82 40 04 50 26 60 47 70 69 80 91 90 21 00 235 ( %) – 26 – Bibliography C S.McCamy, Co lo r Re s A p p l (1 992) _ I EC 61 988-2-6: 201 © I EC 201 INTERNATIONAL ELECTROTECHNICAL COMMISSI ON 3, rue de Varembé PO Box 31 CH-1 21 Geneva 20 Switzerland Tel: + 41 22 91 02 1 Fax: + 41 22 91 03 00 info@iec.ch www.iec.ch