1、 Recommendation ITU-R BT.1886(03/2011)Reference electro-optical transfer function for flat panel displays used in HDTVstudio productionBT SeriesBroadcasting service(television)ii Rec. ITU-R BT.1886 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and
2、 economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are perform
3、ed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to
4、be used for the submission of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be foun
5、d. Series of ITU-R Recommendations (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radi
6、odetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management S
7、NG Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2011 ITU 2011 All rights reserved. No part of thi
8、s publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R BT.1886 1 RECOMMENDATION ITU-R BT.1886 Reference electro-optical transfer function for flat panel displays1used in HDTV studio production (2011) Scope This Recommendation specifies the reference e
9、lectro-optical transfer function (EOTF) that the displays used in HDTV programme production should follow in order to facilitate consistent picture presentation2. The reference EOTF is specified as a simple equation, with exponent function, based on measured characteristics of the Cathode Ray Tube (
10、CRT). The ITU Radiocommunication Assembly, considering a) that reference displays play a crucial role in television programme production as they are used as reference for picture presentation; b) that the characteristics of reference displays should be unified to ensure consistent picture presentati
11、on of programmes produced for use in broadcasting; c) that historically, picture presentation characteristics were determined based on Cathode Ray Tube (CRT) characteristics, and the opto-electronic transfer characteristics were implicitly based on the CRT physical characteristics; e) that CRT refer
12、ence displays are no longer available; f) that the electro-optical transfer function (EOTF) of CRT displays differs amongst manufacturers, amongst models, and amongst regions, as well as varying with the settings of contrast and brightness; g) that for the consistency of picture presentation, it is
13、desirable that newly introduced display technologies have an EOTF that closely matches that of the CRT; h) that the reference EOTF for a non-CRT display has not been defined in any ITU-R Recommendation; j) that Recommendation ITU-R BT.709, provides specifications for the opto-electronic transfer cha
14、racteristics at the source, and a common electro-optical transfer function should be employed to display signals mastered to this format, recommends 1 that the reference EOTF for displays used in HDTV production and programme interchange should be the one specified in Annex 1; 1May also include proj
15、ectors and other display devices. 2The term picture presentation is intended to indicate the monitoring of picture characteristics to ensure that image characteristics do not vary between different signal sources, and different programme segments. 2 Rec. ITU-R BT.1886 2 that an alternative EOTF may
16、be used in some cases where programme interchange is not required, a suggested equation is contained in informative Appendix 1. Annex 1 Reference electro-optical transfer function The reference EOTF is specified by the equation: += )0),(max( bVaL where: L: Screen luminance in cd/m2LW: Screen luminan
17、ce for white LB: Screen luminance for black V: Input video signal level (normalized, black at V = 0, to white at V = 1. For content mastered per Recommendation ITU-R BT.7093, 10-bit digital code values “D” map into values of V per the following equation: V = (D64)/876 : Exponent of power function, =
18、 2.404a: Variable for user gain (legacy “contrast” control) = )(/1/1BWLLa b: Variable for user black level lift (legacy “brightness” control) =/1/1/1BWBLLLb Above variables a and b are derived by solving following equations in order that V = 1 gives L = LWand that V = 0 gives L = LB: = baLB+= )1( ba
19、LWNOTE 1 This Recommendation defines the reference EOTF equation, if it is required to confirm that a display device meets the reference equation it is recommended that the measurement be conducted in a dark room. 3For reference black, D = 64, for reference white, D = 940. 4This value has been shown
20、 to be a satisfactory match to the legacy CRT display. Rec. ITU-R BT.1886 3 Appendix 1 (Informative) EOTF-CRT matching The EOTF specified in Annex 1 is considered to be a satisfactory, but not exact, match to the characteristic of an actual CRT. When it is desired to match a CRT, the Lwand LBparamet
21、ers of the EOTF can be set to the corresponding values of the CRT that are being matched. For moderate black level settings, e.g. 0.1 cd/m2, setting the LBof the EOTF to 0.1 will give a satisfactory match to the CRT. In the event the CRT is operated at a lower black level, e.g. 0.01 cd/m2, the EOTF
22、will provide a better match with LBset to a lower value such as 0.0 cd/m2. When it is necessary to more precisely match a flat panel display characteristic to a CRT, the alternative EOTF formulation specified below may provide a solution. An example of an alternative approximation of an EOTF of a CR
23、T display An example of an EOTF that has alternative characteristics of a CRTs EOTF: 221)()( += bVbVckL for VcV L 0 where: L: luminance of the image 0 L 1 V: corresponding electrical signal 1.3 Chromaticity coordinates (CIE, 1931) Primary Red (R) Green (G) Blue (B) x y 0.640 0.300 0.150 0.330 0.600
24、0.060 1.4 Assumed chromaticity for equal primary signals (Reference white) ER= EG= EBD65x y 0.3127 0.3290 With the introduction of new display technologies which have entirely different characteristics to the CRT displays, it is necessary to define the EOTF of new devices that emulate that of the CR
25、T displays. In measuring the EOTF of a large number of CRTs it was determined that the EOTF of the CRT was in fact highly variable when the brightness/contrast was adjusted, it is therefore not possible to 100% emulate CRT capability (or limitations). Users of this Recommendation in combination with the new technologies should be able to achieve a higher degree of image presentation repeatability than that offered in the past.
