1、 Recommendation ITU-R BT.2035(07/2013)A reference viewing environment for evaluation of HDTV program material or completed programmesBT SeriesBroadcasting service(television)ii Rec. ITU-R BT.2035 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and e
2、conomical 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 performed
3、 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 be
4、 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 found.
5、 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, radiod
6、etermination, 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 SNG
7、 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, 2013 ITU 2013 All rights reserved. No part of this
8、publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R BT.2035 1 RECOMMENDATION ITU-R BT.2035 A reference viewing environment for evaluation of HDTV program material or completed programmes (2013) Scope This Recommendation prescribes a method allowing H
9、DTV producers or broadcasters to establish a reference viewing condition for evaluation of HDTV program material or completed programmes that can provide repeatable results from one facility to another when viewing the same material. This includes the display device and the surrounding environment.1
10、The ITU Radiocommunication Assembly, considering a) that HDTV CRT displays are no longer available and revised criteria for subjective evaluation of HDTV images is required; b) that the picture rendering characteristics differ between CRT and non-CRT displays; c) that the impact of the viewing envir
11、onment can significantly change the perceived image characteristics; d) that a defined reference display is required to minimize differences in display technology; e) that other ITU Recommendations such as Recommendation ITU-R BT.2022 define other viewing conditions for specific applications; f) tha
12、t repeatable visual evaluations are required to confirm image representations, recommends 1 that for evaluation of HDTV program material or completed programmes, the characteristics of a reference viewing condition described in Annex 1 should be used. 2 that for the greatest degree of displayed imag
13、e uniformity, the same display technologies be used between facilities when comparisons are to be made. NOTE 1 Not all the possible parameters have been defined and it is assumed that the display device has been qualified for any obvious deficiencies prior to the evaluation process. Display devices
14、intended for consumer displays should not be used for professional evaluation. 1High quality, critical viewing facilities can and will continue to be established in many ways by entities involved in editing, colour correction, screening and the like, and this Recommendation is not intended to sugges
15、t a need for absolute uniformity in such facilities. 2 Rec. ITU-R BT.2035 Annex 1 Overview For the purposes of assessing the performance of a display device, it is necessary to measure or characterize a very large number of parameters such as those described in Report ITU-R BT.2129. For everyday ima
16、ge evaluation it is impractical to perform these measurements; it is therefore suggested that this sub-set of these parameters be used for daily use. This Recommendation also recommends a reference viewing condition. The huge range of technologies employed in flat panel displays makes the task of de
17、fining a single set of parameters for a reference display near impossible. Unlike the CRT where a single technology was deployed for the conversion of electrical signals to a viewable image, the various flat panel technologies provide an infinite number of variables. The intent of the Recommendation
18、 is to provide guidance on the parameter values to be measured to set up the environment and the display parameters keeping in mind that measurement and adjustment of all possible parameters could be very extensive and time consuming. As a further cautionary note, commercially available measurement
19、instruments may yield different results; these differences may be as a result of different technologies used to sense the light on the display. The manufacturers instruction manuals should be consulted. 1 Reference viewing conditions The reference viewing environment is intended to provide an enviro
20、nment which can be replicated from one facility to another. The display devices using different technologies may influence the extent to which uniformity of the displayed image can be achieved. This reference viewing environment is intended as a guideline for a practical implementation: 1.1 Viewing
21、environment for subjective assessment a) Room illumination: 10 Lux b) Chromaticity of background: D65(optionally D93in some regions) c) Ratio of luminance of background behind picture monitor to peak luminance of picture: Between 10% 2% of reference white value 1.2 Viewing distance The viewing dista
22、nce is based on the screen size and it can be selected according to two distinct criteria: the preferred viewing distance (PVD) and the design viewing distance (DVD). For this application the DVD criteria is used. 1.2.1 Design viewing distance The design viewing distance (DVD), or optimal viewing di
23、stance, for a digital system is the distance at which two adjacent pixels subtend an angle of 1 arc-min at the viewers eye; and the optimal horizontal viewing angle as the angle under which an image is seen at its optimal viewing distance. Rec. ITU-R BT.2035 3 Image system Reference Aspect ratio Pix
24、el aspectratio Optimal horizontal viewing angle Optimal viewing distance 1 920 1 080 Rec. ITU-R BT.709 16:9 1 31 3.2 H 1.3 Observation angle The maximum observation angle relative to the normal should be constrained so that deviations in reproduced colour on the screen should not be visible to an ob
25、server. The optimal horizontal viewing angle of an image system under test should also be considered to determine the observation angle. As a guide to an acceptable numerical value, u, v (CIE 1976 chromaticity differences) should be less than 0.01 for any of the colours within the Recommendation ITU
26、-R BT.709 gamut. As a guide to an acceptable numerical value, the luminance value should drop less than 10% for viewing angles within 30 horizontally, vertically, and diagonally, and less than 20% for viewing angles within 30 and 45 horizontally, vertically, and diagonally. 1.4 Room environment-colo
27、ur scheme The colour of the display background should be the same as the reference white point; for the remaining room surfaces dark matte surfaces should be used. The objective is to minimize stray light on the display screen. 2 Display characteristics There are a number of display technologies ava
28、ilable all with different characteristics. The following text in this section gives a general overall set of criteria that should be used to minimize display technology differences. 2.1 Image size Images to be evaluated should fill the complete screen. Screen sizes between 25 inches and 60 inches ar
29、e recommended. Larger screen sizes are not prohibited. 2.2 Display image processing Monitor processing such as image scaling, frame rate conversion, image enhancement, if implemented, should be done in such a way as to avoid introducing visible artifacts. Any report should indicate whether a de-inte
30、rlacer is used or not for the presentation of interlaced signals. For interlace images it is preferable not to use a de-interlacer; the displayed image should preferably be presented as interlace. 2.3 Display pixel array The minimum pixel array should be at least 1 920 1 080. 2.4 Ringing Ringing or
31、overshoots should not be introduced by any processing in the display. Ringing “in the image signal” should be displayed. Monitors should not cut off under- and over-shoots, or sub-black and super-white levels that do not violate protected values used for synchronization. 4 Rec. ITU-R BT.2035 2.5 Tem
32、poral characteristics Care should be paid to the temporal characteristics of the display for the following reason. Temporal characteristics of displays vary according to display technologies and display processing parameters. In the past CRT technology was virtually the only display device for telev
33、ision image display; its characteristics were predictable and it ensured the consistency of the temporal characteristics of the displays both in studio and at home. 3 Display adjustment The topic of display adjustment and setting of values continues to be covered in many industry forums. In many cas
34、es the individual manufacturers provide information on individual products that may be necessary to achieve the desired result. 3.1 Interface The HDTV signal interface defined in Recommendation ITU-R BT.1120 should be used as the input source. 3.2 Reference white and reference black Reference white
35、(value 940) should correspond to 100 cd/m2and reference black (Value 64) should be less than 0.01 cd/m2 2. The waveform defined in Recommendation ITU-R BT.815 may be used to set these levels. 3.3 White point i) For a D65white point, the coordinates should be: Y = 100 cd/m2, x = 0.3127, y = 0.3290. I
36、f CIE1931 XYZ colorimetric system and the colour matching functions are used by the measurement instrument, the measurement instrument may give an erroneous result. The application of the Judd modification3to these measurements can greatly improve matching results between different technologies. If
37、other CIE reference scales are used appropriate conversions are required. ii) In some regions D93is used as the reference white point, in that case: x = 0.2831 and y = 0.2971. 3.4 Gamma characteristics The gamma characteristics (electro-optical transfer characteristic) of the display should be adjus
38、ted to the values of the curve over the full range contained in Recommendation ITU-R BT.1886 Reference electro-optical transfer function for flat panel displays used in HDTV studio production. 2This measurement may prove to be difficult under some conditions. 3CIE 1988 2 Spectral Luminous Efficiency
39、 Function for Photopic Vision. Rec. ITU-R BT.2035 5 3.5 Test pattern The test pattern, as defined by Recommendation ITU-R BT.1729 Common 16:9 or 4:3 aspect ratio digital television reference test pattern, may be used to confirm linearity of the display device. Confirm that clipping does occur beyond
40、 the reference white level (and reference black level). Recommendation ITU-R BT.1729 defines all signal parameters that may be used to set up the display device other than the parameters contained in 3.1 through 3.5, which correspond to Recommendation ITU-R BT.815. 3.5.1 100% Colour Bar x, y values
41、(Zone 4) FIGURE 1 Multi-format test pattern as seen on screen BT.2035-011 080AB 7204:2:04:2:2Left side zone 4 3 zone Right side zoneHorizontal moving barwith audio sync signalUSER-DEFINED TEXT100%75%12.5% 7.0%2.5%9%3.5%2.5%9%3.5%12.5%100%3.5%3.5%9.3%(Diagram copied from Recommendation ITU-R BT.1729.
42、) 6 Rec. ITU-R BT.2035 FIGURE 2 1080/720-line systems, colour bar waveforms, 100/100/0 bars BT.2035-02100%50% 100% 100% 100% 100% 100% 0% 50%100%502(126)877(219)940(235) 754(188)691(173)313(78)250(63)127(32)64(16)502(126)YCBCR512(128)512(128)64(16)615(154)(42)857(214)409(102)960(240)512 512512(128)5
43、12(128)553(138)64(16)167105(26)919(230)960(240)471(128) (128)512(128)512(128)(118)WhiteGrey Yellow Cyan Green Magenta Red Blue Black Grey(Diagram copied from Recommendation ITU-R BT.1729.) TABLE 1 Test pattern zone 4 typical values Colour/Y value L (cd/m2) x y Reference Black (6410) 0.0001 0.3889 0.
44、3701 Reference White (94010) 100.001 0.3127 0.3290 Yellow (87710) 91.9090 0.4165 0.5027Cyan (75410) 76.2150 0.2179 0.3283 Green (69110) 69.2110 0.2876 0.6001Magenta (31310) 29.3650 0.3279 0.1585 Red (25010) 22.2500 0.6373 0.3304Blue (12710) 7.2947 0.1501 0.0605 The above values are not absolute valu
45、es and are provided as a sample of measured values. Rec. ITU-R BT.2035 7 TABLE 2 Test pattern zone 4 calculated values Colour/Y value x y Black (6410) 0.3889 0.3701 White (94010) 0.3127 0.3290 Yellow (87710) 0.4193 0.5053 Cyan (75410) 0.2246 0.3287 Green (69110) 0.2876 0.6001 Magenta (31310) 0.3209
46、0.1542 Red (25010) 0.6400 0.3300 Blue (12710) 0.1501 0.0605 3.5.2 Grey scale tracking (Zone 11) The 10 step grey scale in zone 11 should be measured to confirm that there is no non-linear processing distorting the grey scale. There should be no visual coloration of the grey scale. 3.6 Display motion
47、 artefacts The display should not introduce motion artifacts that are introduced by specific display technologies. Motion effects included in the input signal should be represented on the display. In addition the refresh rate of flat panel displays (FPDs) may not be at the same rate as the native ra
48、te of the image. Care should be taken to ensure that no difference in motion rendition is introduced. Appendix 1 (Informative) Display characteristics in general Note that using different display technologies may yield different image characteristics. Thus, it is strongly recommended that characteri
49、stics of the display used should be checked beforehand. Recommendation ITU-R BT.1886 Reference electro-optical transfer function for flat panel displays used in HDTV studio production, and Report ITU-R BT.2129 User requirements for a flat panel display (FPD) as a master monitor in an HDTV programme production environment, may be referred to when professional FPD monitors are used for subjective image assessment.
