1、 Rep. ITU-R BT.2129 1 REPORT ITU-R BT.2129 User requirements for a Flat Panel Display (FPD) as a Master*monitor in an HDTV programme production environment (2008) Introduction Flat panel displays will replace CRT based master monitors in TV programme production, and monitoring, it is therefore urgen
2、t that a set of user requirements be addressed. Flat panel displays have recently shown display performance closely emulating that of the CRT, as with most technologies the performance characteristics improves over time. It is the aim of this Report to be technology agnostic, although it should be r
3、emembered that certain technologies have characteristics that can not be ignored. As of this writing, technologies such as Plasma, LCD, and FED may all be contenders for consideration as Master monitors. In all cases, commercial products may well vary in their performance, generally based on price.
4、In developing this Report the following assumptions are being made: 1 A master monitor is a measuring instrument of image quality in TV programme production. The purpose of a monitor is to faithfully and reliably display the signal as it is, and it must not attempt to “enhance” or otherwise alter th
5、e image. To do this, the input signal should be subjected to as little signal processing as possible. 2 A FPD will be used in the same way as a CRT master monitor in daily operation of TV programme production. 3 The focus of this Report is the display of HDTV images. 4 Recommendation ITU-R BT.709 wa
6、s developed based on the assumed characteristics of CRT monitors (ex. colour gamut, gamma characteristics). Master monitors play a critical role of being utilized as a measuring instrument which displays the image in accordance with the specification of Recommendation ITU-R BT.709. FPD when used as
7、a master monitor should have the same or similar characteristics as those of the CRT. 5 The input signals should have 10 bit pixel depth. *The term Master monitor is also called Reference monitor, or Grade 1 monitor in different regions. 2 Rep. ITU-R BT.2129 CONTENTS Page Introduction 1 1 User requi
8、rements Image quality. 4 1.1 Peak luminance/all-white luminance 4 1.2 Black. 4 1.3 Contrast ratio 4 1.4 Gamma characteristics 4 1.5 Tone reproduction (Grey scale) 5 1.6 Colour gamut 5 1.7 Colour temperature (White) 5 1.8 Viewing-angle dependency 5 1.9 Motion artefacts 5 1.10 Screen resolution 5 1.11
9、 Image scaling, de-interlacing and overscan 6 1.12 Uniformity 6 1.13 Mura 6 1.14 Smear (vertical and horizontal crosstalk) . 6 1.15 Stability. 6 1.16 Screen size 6 1.17 Pixel defects 7 1.18 Ringing . 7 1.19 Image sticking (long-term after-image) 7 1.20 Interface signal 7 2 User requirements Function
10、ality of a master monitor (Informative) 7 2.1 Input signal format and interface 7 2.2 Display range on display for each input signal. 7 2.3 Selection of display range (scan selection). 7 2.4 Backlight intensity control 8 2.5 Reference white 8 2.6 Black and white/colour display switch . 8 2.7 Delay t
11、ime. 8 Rep. ITU-R BT.2129 3 Page 2.8 Aspect ratio markers . 8 2.9 Safe area markers 9 2.10 Selection of plain colour R, G, B 10 2.11 Gain control (RGB independent gain control) 10 2.12 Bias control (RGB independent pedestal (Black level) control). 10 2.13 Brightness control (Black level) . 10 2.14 C
12、ontrast control (RGB gain control). 10 2.15 Auto set-up 10 3 Guide to measurement techniques (Informative) 10 3.1 Base line conditions 11 3.2 Input signal . 11 3.3 Peak luminance/all-white luminance 11 3.4 Black. 11 3.5 Contrast ratio 11 3.6 Gamma characteristics 12 3.7 Tone reproduction. 12 3.8 Col
13、our gamut 12 3.9 Colour temperature (White point) 12 3.10 Viewing-angle dependency 12 3.11 Motion blur . 13 3.12 Resolution. 13 3.13 Uniformity 13 3.14 Mura 13 3.15 Vertical and horizontal crosstalk 13 3.16 Stability. 14 3.17 Pixel defects 14 3.18 Ringing . 14 3.19 Image sticking (long-term afterima
14、ge) . 15 Appendix A 15 Appendix B 16 Appendix C Illustration of the direction and the four planes in measurement . 19 4 Rep. ITU-R BT.2129 1 User requirements Image quality In reviewing the user requirements, the reader should be cautioned that the parameter values noted are a moving target and the
15、performance will no doubt be improved over time. 1.1 Peak luminance/all-white luminance When a luma signal of level 940 (100% white) is input, the display should be adjusted so that the peak luminance on the screen can be set at any luminance level within the range of 100 to 250 cd/m2. When a luma s
16、ignal of level 64 (black) through 1 019 (109% white) is input, grey scale tracking should be performed on each level between level 64 and 1 019. The above conditions must be met for a colour temperature of 6 500 K (D65) (in some regions the above conditions must be met for a colour temperature of 9
17、300 K (D93). ABL (Automatic Brightness Limiter) function if provided should be disabled. 1.2 Black When a luma signal of level 64 (black) is input, the luminance level on the screen should be less than 0.01 cd/m2. Measurement for this item must be conducted after adjustment of the display using the
18、PLUGE test signal specified in Recommendation ITU-R BT.814, in case of LCD monitors, neither automatic nor manual control of backlight intensity should be active during the measurement of black level. This measurement may prove to be difficult under some conditions. 1.3 Contrast ratio Contrast ratio
19、 should be more than 350:1. The FPD is adjusted using the PLUGE test signal as specified in Recommendation ITU-R BT.814 so that the luminance setting of the 100% white part on the screen becomes 100 cd/m2. Then, contrast ratio is measured as the ratio between the luminance of the part displaying 100
20、% white (luma signal of value 940) on the screen, and that corresponding to displaying only the black level (luma signal of value 64) in a completely dark room when the signal specified in Recommendation ITU-R BT.815 for measurement of contrast ratio is input. Neither automatic control nor manual co
21、ntrol of backlight intensity should be active during the measurement of contrast ratio. 1.4 Gamma characteristics The gamma characteristics (electro-optical transfer characteristic) of the display should be equivalent to those of a reference CRT. The value for Gamma is still under discussion, the in
22、tent is that the final value should emulate the CRT or at minimum produce image characteristic that closely match the CRT. Appendixes A and B These appendixes reflect the finding of two industry bodies that have been investigating this issue. This information should be considered informative. It is
23、expected that further information will be available in 2008/2009. Rep. ITU-R BT.2129 5 1.5 Tone reproduction (Grey scale) Grey scale tracking in R, G and B components should be performed with no less than 10-bit precision. Grey scale tracking between colour channels shall be within ellipses defined:
24、 0.0010 u, 0.0015 v (CIE 1976 chromaticity differences) for luminances from 1 cd/m2to 100 cd/m2and deviation from grey should not be visible for luminances below 1 cd/m2. The suggested tolerances may need further definition in the range above reference white up to the limit of 109% white (1019). 1.6
25、 Colour gamut The FPD should display images with the colour gamut specified in Recommendation ITU-R BT.709. 1.7 Colour temperature (White) The FPD should display pictures with a reference white colour temperature of 6 500 K(D65) 0.0010 u, 0.0015 v (CIE 1976 chromaticity differences) or (in some regi
26、ons of the world 9 300 K (D93) is used)1. 1.8 Viewing-angle dependency Deviations in reproduced colour on the screen should not be visible to a human observer when viewing the screen from an angle of up to 45 horizontally and vertically in any direction from the perpendicular axis to the centre of t
27、he screen (see Appendix C). 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-R BT.709 gamut. As a guide to an acceptable numerical value, the luminance value should drop less than 10% f
28、or viewing angles within 30 horizontally, vertically, and diagonally, and less than 20% for viewing angles within 30 and 45 horizontally, vertically, and diagonally. The black level, when measured from viewing angles up to 20 in any direction from the perpendicular axis to the centre of the screen,
29、horizontally and vertically, = u, v = 0.01. When measured from viewing angles between 20 45 horizontally and vertically = u, v = 0.02. 1.9 Motion artefacts Motion blur on FPD screens should be comparable to those of the CRT, or to a degree at which it cannot be detected. Work continues on decreasing
30、 the visibility of motion artefacts. Different FPD technologies require different solutions and produce different artefacts. In addition the refresh rate of FPDs may not be at the same rate as the native rate of the image. Care should be taken to ensure that no difference in motion rendition is intr
31、oduced. 1.10 Screen resolution The horizontal and vertical pixel counts on the screen must be equal to the number of active samples per line and the number of active lines per frame of TV system for R, G and B, respectively. The desire is to have a one to one pixel mapping without the use of image s
32、calers. In some cases, scaling may be required in order for the image to completely fill the screen End users are advised to determine the characteristics of the scaler before performing any critical evaluation. 1If the colour temperature is designed for either D65 or D93 only, the other colour temp
33、erature must be realized by signal processing. Under these circumstances, 10-bit precision may not be obtained. 6 Rep. ITU-R BT.2129 1.11 Image scaling, de-interlacing and overscan a) Image scaling should be done in such a way as to avoid the introduction of artefacts, such as excessive ringing, ali
34、ases or banding, noise, etc. b) It is desirable that monitors display the image in the native interlace or progressive format that is present on the input interface. De-interlacing of interlace images, if equipped, should be able to be turned off. c) The default mode should be to display without ove
35、rscan, that is, showing the full active image area right to its edges. This should be the optimal mode for scaling quality, and often may be one-to-one pixel mapping. d) Monitors should offer optional programmable overscan/underscan mode of up to 5%. 1.12 Uniformity The luminance values measured at
36、many points for each luma signal level on the whole screen should meet the following conditions when the signal of the grey level is input: (the maximum measured value the minimum measured value)/the average value 0.10. This measurement should be performed at a mid grey level, and white level. 1.13
37、Mura2Mura should not be visually detected on the screen regardless of reproduced luminance levels or colour saturation. This artefact is not expected to be a problem however in the interest of completeness it is included in this Report. 1.14 Smear3(vertical and horizontal crosstalk) When the input s
38、ignal has a rectangle of luma signal of value 64 (black) or 940 (100% white) near the centre and has a grey area in its surroundings (see Fig. 2), the difference in luminance between the horizontal and vertical belt-like portions and the other grey portions should not be greater than 0.5%. 1.15 Stab
39、ility a) A 30-min warm-up period from a “cold” start should be allowed before any observations or measurements are taken. b) After this warm-up time, the measurements shall remain within the specifications given for 24 h. 1.16 Screen size The screen size of the display is at the discretion of users,
40、 but may need to be larger (because of the target viewing distance of 3 times picture height) for adequate monitoring of HD. Production spaces 2“Mura” is a defect that looks like a small-scale crack with very small changes in luminance or colour. “Mura” is likely to be noticeable in the flat portion
41、s of images even if the size of the mura is very small. 3“Smear” is a term for capturing devices with CCD, and it means the phenomenon that a vertical bright bar occurs when such strong light source as the sun or electric bulbs is shot. In case of CRT monitors, when a much brighter or darker spot th
42、an the surrounding area causes vertical or horizontal bars, this phenomenon is also often called as smear. The similar phenomenon is called as “crosstalk” for LCD and “image streaking” for PDP. Here, smear means the phenomenon that the data on one part of the display influences what is displayed els
43、ewhere. Rep. ITU-R BT.2129 7 are still designed for the same size CRT monitors previously used, because there are often constraints which make moving to larger screen sizes difficult. This may have an impact on the ability to adequately monitor HD quality. It is suggested that screen sizes in the ra
44、nge of 18-32 inches may suite current environments. It is anticipated that larger screen sizes will be required in the future. 1.17 Pixel defects The ideal situation would be that there are no pixel defects. A more pragmatic approach may that there should be no visible pixel defects. Specific image
45、content may expose pixel defects differently. 1.18 Ringing Ringing or 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. 1.19 Image sticking
46、(long-term after-image) The characteristics for image sticking (long-term afterimage) on the screen of a FPD should be less than a CRT monitor. 1.20 Interface signal The input interface should comply with Recommendation ITU-R BT.1120 for both 4:2:2 signals and 4:4:4 signals. 2 User requirements Func
47、tionality of a master monitor (Informative) Defining master monitor functionality is NOT intended to be a product design, manufacturers are encouraged to design products with features and functionality as they see fit. This list of functional requirements is not intended to be a complete list. These
48、 requirements are intended to be guidelines only. 2.1 Input signal format and interface The input signal format should be HD-SDI interface specified in Recommendation ITU-R BT.1120. 2.2 Display range on display for each input signal The default aspect ratio should be 16:9, all pixels contained in th
49、e pixel matrix 1 920 x 1 080 should be displayed without rescaling. In some cases, when a 4 3 aspect ratio image is carried by the interface, the image should be 1 440 1 080 pixels mapped within the 1 920 1 080 interface format. 2.3 Selection of display range (scan selection) Normal (100%) displays all active image area of the input signal. Over-scan (105%)/under-scan (95%) display format is optional, and should not be used for image evaluation. The over-scan/under-scan programmable functionality may be used to verify consumer v
