Background Statement for SEMI Draft Document 5634 New Standard: TEST METHOD FOR COLOR REPRODUCTION AND PERCEPTUAL CONTRAST OF VISUAL DISPLAY

Transcription

1 Bckground Sttement for SEMI Drft Document 5634 New Stndrd: TEST METHOD FOR COOR REPRODUCTION AND PERCEPTUA CONTRAST OF VISUA DISPAY Notice: This bckground sttement is not prt of the blloted item. It is provided solely to ssist the recipient in reching n informed decision bsed on the rtionle of the ctivity tht preceded the cretion of this Document. Notice: Recipients of this Document re invited to submit, with their comments, notifiction of ny relevnt ptented technology or copyrighted items of which they re wre nd to provide supporting documenttion. In this context, ptented technology is defined s technology for which ptent hs issued or hs been pplied for. In the ltter cse, only publicly vilble informtion on the contents of the ptent ppliction is to be provided. Bckground As high qulity properties of digitl TV like HDTV, 4K UHDTV nd 8K UHDTV hve been demnded, it is necessry to present the highest imge qulity with rich nd uthentic color, subtle gry nd color tone nd dynmic contrst, nd set the suitble nd dvnced evlution methods of disply qulity. The im of vrious methods for mesuring color gmut, brightness, nd contrst bsed on humn perception hve been studied is to mtch the imge qulity with humn eyes. Even though there re conventionl mesuring methods like luminnce, tristimulus vlues for the objective evlution method, there re imperfect methods considering viewing condition, perceptul prmeters. The bsic rtionle of this document is the color ppernce model which is proposed t CIE in A new method is to clculte color volume nd contrst with color ppernce model which is uniform color spce with humn visul perception. Review nd Adjudiction Informtion Tsk Force Review Committee Adjudiction Group: To be reviewed t the Kore Perceptul Kore FPD Metrology Technicl Imge Qulity TF Meeting Committee Dte: Februry 14, 2014 Februry 14, 2014 Time & Time Zone: 13:00pm 15:00pm 15:30pm 17:00pm oction: SEMI Kore office SEMI Kore office City, Stte/Country: Seoul, Kore Seoul, Kore eder(s): Stndrds Stff: Jong Ho Chong (Smsung Disply) jongho.chong@smsung.com Ntlie Shim (SEMI Kore) eshim@semi.org JongSeo ee (Smsung Disply) jongseo2.lee@smsung.com Il-Ho Kim (MS) ihkim@lmscorp.co.kr Ntlie Shim (SEMI Kore) eshim@semi.org

2 SEMI Drft Document 5634 New Stndrd: TEST METHOD FOR COOR REPRODUCTION AND PERCEPTUA CONTRAST OF VISUA DISPAY 1 Purpose 1.1 This stndrd specifies mesurement conditions nd methods for describing the visul color qulity in 3- dimensionl color spce, nd the perceived contrst with perceptul prmeters in Orgnic ight Emitting Diode (OED) displys. 1.2 The CIE XYZ color spce is derived from the experimentl results nd it hs been used to set color performnce of displys in CIE xy or u v chromticity digrm without brightness. 1.3 For mesurement, setting test ptterns bsed on Averge Picture evel (AP) of IEC 62087:2011 re required, insted of full screen ptterns, which re composed with smll size of window box. The full screen ptterns re not suitble for OED displys which of luminnce re djusted with contents. 1.4 The contrst rtio hs been widely used lthough the clculted vlue is drmticlly chnged by drk stte luminnce. This metric does not consider humn visul chrcteristics. Therefore, it is more relible to consider the perceptul indices. 2 Scope 2.1 This stndrd is pplicble to the color OED displys. 2.2 This stndrd includes the mesurement for physicl dt, nlysis, clcultion methods with perceptul fctors. 2.3 The term perceptul is subject to CIECAM02 (CIE Color Appernce Model 2002) in this stndrd. NOTICE: This stndrd does not purport to ddress sfety issues, if ny, ssocited with its use. It is the responsibility of the users of this stndrd to estblish pproprite sfety nd helth prctices nd determine the pplicbility of regultory or other limittions prior to use. 3 imittion 3.1 Mesurements re subject to errors or imprecision due to the user, environmentl fctors, nd mis-clibrtion of mesurement system or mesurement system limittions. 3.2 Results my vry with mbient illumintion conditions or in the presence of uncontrolled stry light reflections. 4 Referenced Stndrds nd Documents 4.1 IDMS Informtion Disply Mesurement Stndrd (IDMS) CIE Stndrds 1 CIE 15.3 Colorimetry CIE 159 CIECAM IEC Stndrds 2 IEC OED Displys Mesuring methods of visul qulity nd mbient performnce IEC Methods of mesurement for the power consumption of udio, video nd relted equipment. NOTICE: Unless otherwise indicted, ll documents cited shll be the ltest published versions. 1 Commission Interntionle De 'eclirge (Interntionl Commission On Illumintion), Kegelgsse 27, A-1030 Vienn/AUSTRIA. Telephone: Fx : ; 2 Interntionl Electrotechnicl Commission, 3 rue de Vrembé, Cse Postle 131, CH-1211 Genev 20, Switzerlnd; Telephone: , Fx: , Pge 1 Doc SEMI

3 5 Terminology 5.1 Abbrevitions nd Acronyms AP verge picture level PC perceptul contrst length VCRC volume color reproduction cpbility 5.2 Definitions brightness the ttribute of visul senstion ccording to which n re ppers to emit more or less light color gmut boundry the outer surfce determined by color gmut form perceptul contrst length the difference of blck nd white brightness on the sme point of the screen volume color reproduction cpbility the volume of the perceived color gmut obtined in brightness color spce which is composed of colorfulness, hue nd brightness 6 Stndrd Mesurement Condition 6.1 Mesuring Conditions Environmentl conditions In order to obtin ccurte mesured dt, the following environmentl conditions re required. Temperture: 25±2 C Humidity: % reltive humidity Pressure: kp Air flow: no wind Vibrtion / Shock: no influence Ambient illumintion conditions Drk room condition The luminnce contribution from the bckground illumintion shll be less thn 0.01 cd/m Ambient illumintion conditions Uniform hemisphericl diffuse light source Directed light source NOTE 1: The type of light source used, nd its Correlted Color Temperture (CCT), should be noted in the mbient performnce report. This mesurement with directed light source should be performed in drk room which should be mintined with windowless nd gry or blck curtins nd rugs Mesuring equipment conditions In this stndrd, light mesuring device such s spectrordiometer, t lest the 380 nm to 780 nm wvelength rnge or filter photometer shll be used The photometric ccurcy of the instrument shll be within ±2 % The stndrd mesuring distnce is 3H (for H 20 cm) or 50 cm (for H<20 cm) where H is the height of the mesured disply device Viewing Direction In the cse of the uniform hemisphericl diffuse illumintion conditions, n integrting sphere, smpling sphere, or hemisphere shll be used. The configurtion shll follow the stndrd di/8 to di/10 illumintion/detection geometry, where di is the stndrd nottion for diffuse. The bsic viewing direction of this Pge 2 Doc SEMI

4 test is shown in Figure 1. However, for specific cse, other viewing directions, like perpendiculr to the disply cn be used. 7 Summry of Test Method 7.1 Test Ptterns Speculr Point θ θ Disply Mesurement Port θ 8-10 mp Figure 1 An exmple of mesuring configurtion with smpling sphere A centered window box occupying 4% of the screen re is used. The 100% intensity (e.g., 255 gry level in 8bits) for window box nd the 40% intensity (e.g., 102 gry level in 8bits) for bckground is pplied. One of the test ptterns is shown in Figure 2. Bffle Figure 2 Test pttern of 4% window box with 40% gry bckground Ech of the following eight colors in the 4% window box t the center of the screen is pplied. Red: (255, 0, 0) Green: (0, 255, 0) Blue: (0, 0, 255) Yellow: (255, 255, 0) Mgent: (255, 0, 255) Cyn: (0, 255, 255) Blck: (0, 0, 0) White: (255, 255, 255) Pge 3 Doc SEMI

5 NOTE 2: It my be necessry to use some kind of msk or stry-light-elimintion tube to void veiling glre in the detector when mesuring 4% window box colors. NOTE 3: The intensity of colors is bsed on 8 bits. However, for the other color bits, like 10 bits or 12 bits, the intensity of color should be chnged. 7.2 Mesuring Set-up Electricl conditions, wrm-up time nd dequte integrtion time follow section 3.2 of IDMS 1.0 methods. 8 Procedure 8.1 The following mesuring procedure is recommended for the mesuring of tristimulus vlues of ech of colors. Check nd mesure the conditions described in nd Set the mesured disply nd signl genertor for the test ptterns. Set the distnce between disply nd MD (ight Mesurement Device). Instll the ngle of MD ginst the disply. Apply the eight test ptterns t the disply. Mesure the luminnce nd chromticity t the center of the window box with eight test ptterns, respectively. Record the mesurement dt. Record the mesurement conditions which re room conditions, ging conditions, nd mbient conditions. 9 Clcultions 9.1 Anlysis Method for Color Reproduction The 17 interpolted grdtion points between blck nd the other six primry nd secondry (RGBYMC) colors using gmm 2.2 should be clculted. The clcultion method is described in Appendix The mesured nd interpolted dt for ll defined colors shll be trnsformed into the CIECAM02 3 dimensionl color spce, which is described in Appendix Color reproduction which is color gmut volume with brightness, colorfulness, nd hue of the trnsformed dt is clculted. Serch the color boundry surfce in 3-dimensionl color spce, which is determined by color gmut s extremes. Figure 3 An exmple of color reproduction Set the smllest tringultion of surfce points. Pge 4 Doc SEMI

6 Figure 4 The geometry of trigonl pyrmid of connecting points with n inside point Clculte the color volume of trigonl pyrmid nd dd up ll volume of trigonl pyrmids. V N 1 where N {1,2,3,, MAX} ( pn qn ) rn Anlysis Method for Perceptul Contrst Color Volume N V (1) PC is the length between blck nd white brightness. The clcultion method for brightness is described in Appendix 1. Clculte the contrst length between blck nd white brightness. N PC white brightness blck brightness (2) 10 Report 10.1 The color reproduction nmed VCRC (Volume Color Reproduction Cpbility) in 3D color spce is represented with percent reltive to srgb color volume in CIECAM02. An exmple result is shown in Tble 1. Tble 1 An exmple of result report for the VCRC Volume of srgb 8.50x10 5 Color volume of disply 8.50x10 5 VCRC 100 % 10.2 For the PC, there is tble of the result report which is shown in Tble 2. Tble 2 A worked Exmple of result report for the Perceptul Contrst ength uminnce(cd/m 2 ) Brightness PC Blck White Pge 5 Doc SEMI

7 APPENDIX 1 COOR SPACE CONVERSION METHOD NOTICE: The mteril in this Appendix is n officil prt of SEMI [designtion number] nd ws pproved by full letter bllot procedures on [A&R pprovl dte]. A1-1 CIECAM02 color model A1-1.1 A color ppernce model provides viewing condition specific method for trnsforming tristimulus vlues to nd from perceptul ttribute correltions. The CIECAM02 is useful for color mngement pplictions. This model consists of chromtic dpttion trnsform nd equtions for computing set of perceptul ttribute correltions. A set of perceptul ttributes is only focused on dim condition for TV ppliction. Also, brightness color spce for color reproduction is used, insted of lightness color spce of CIEAB or CIEUV. Brightness is defined by the CIE s the ttribute of visul senstion ccording to which n re ppers to emit more or less light. A1-1.2 The normlized tristimulus vlues to long, medium nd short wvelength sensitive spce conversion M ct02 R G M B A1-1.3 The degree of dpttion to the white point clcultion A : one-fifth of the mesured white luminnce. D ct 02 X Y Z e 3.6 ( A + 42) 92 (2) (3) (4) A1-1.4 The weighted chromtic dpttion with D fctor clcultion R G B c c c [( YW D / RW) + (1 D) ] R (5) [( YW D / GW) + (1 D) ] G ( Y D / B ) + (1 D) [ ]B RW, GW, nd BW: the RGB vlues computed for the white point. W W A1-1.5 The viewing condition dependent constnts clcultion Yb: 20, Yw: 100 k 1/(5 + 1) 4 2 1/ F 0.2k (5 ) + 0.1(1 k ) (5 ) n Y / Y N bb b N W cb A z n 4 3 (6) A A 0.725(1/ n) 0.2 Pge 6 Doc SEMI

8 A1-1.6 Hunt-Pointer-Estevez spce conversion for pplying the post-dpttion non-liner compression M HPE 1 ct02 A1-1.7 Post-dpttion non-liner compression R G' M B' HPE M 1 ct02 Rc Gc B c ' (7) M (8) 400( F R'/100) R' ( F R'/100) 400( FG'/100) G' ( F G' /100) 400( F B'/100) B' ( F B'/100) A1-1.8 Temporry Crtesin representtions nd hue clcultion (9) 1 h tn ( b / ) R' 12G' /11+ B' /11 (10) b (1/ 9)( R' + G' 2B' ) A1-1.9 The chromtic response clcultion [ 2R' + G' + (1/ 20) B' 0. ] Nbb A 305 (11) A ightness is clculted from the chromtic signls of A nd A W J 100( A / (12) 0.59z A w ) A Brightness clcultion 0.25 ( 4 / 0.59) J /100( A w 4) F Q + (13) A Temporry mgnitude quntity, t clcultion t 0.9(50000/13) N e + b R' + G' + (21/ 20) B' 2 2 cb t (14) π e 1/ 4 cos( h + 2) (15) t 180 A chrom, C clcultion C 0.9 n 0.73 t J /100( ) (16) Pge 7 Doc SEMI

9 A colorfulness, M clcultion A1-2 Color conversion 0.25 M CF (17) A1-2.1 uminnce of interpolted grdtion points should be clculted, s follows: Qmx: mximum luminnce for mesured color Q Qmin: luminnce of blck Q: red, green, blue, cyn, mgent, yellow 2.2 n (18) ( Q mx Q min) + Q min 255 n {0, 17, 33, 49, 65, 81, 97, 113, 129, 144, 160, 176, 192, 208, 224, 240, 255} A1-2.2 Tristimulus vlues between blck nd the other six primry nd secondry (RGBYMC), which is interpolted grdtion points should be clculted with. Q: red, green, blue, cyn, mgent, yellow X Y Z x y Q Q 1 xq yq y n {0, 17, 33, 49, 65, 81, 97, 113, 129, 144, 160, 176, 192, 208, 224, 240, 255} Q (19) A1-2.3 The interpolted grdtion points shll be trnsformed into the CIECAM02, which is described in A1-1. NOTICE: (SEMI) mkes no wrrnties or representtions s to the suitbility of the Stndrds nd Sfety Guidelines set forth herein for ny prticulr ppliction. The determintion of the suitbility of the Stndrd or Sfety Guideline is solely the responsibility of the user. Users re cutioned to refer to mnufcturer s instructions, product lbels, product dt sheets, nd other relevnt literture, respecting ny mterils or equipment mentioned herein. Stndrds nd Sfety Guidelines re subject to chnge without notice. By publiction of this Stndrd or Sfety Guideline, SEMI tkes no position respecting the vlidity of ny ptent rights or copyrights sserted in connection with ny items mentioned in this Stndrd or Sfety Guideline. Users of this Stndrd or Sfety Guideline re expressly dvised tht determintion of ny such ptent rights or copyrights, nd the risk of infringement of such rights re entirely their own responsibility. Pge 8 Doc SEMI