Overview of ARIB Technical Report (TR-B28)
|TR Number||ARIB TR-B28|
|Technical Report Name||User requirements for a flat panel display as Master Monitor in an HDTV programme production environment|
This technical report assembles user requirements for a flat plane display used as a master monitor in program production.
The master monitor is regarded to be a monitor placed as a measuring instrument to manage final video quality by evaluating deterioration occurred by luminance, color reproduction, compression, and transmission. Therefore it is considered to be important to display an input signal on the monitor accurately.
In late years the picture quality of the flat panel display has been improved.
However, since the picture quality, presentation method, and characteristics are different from that of a CRT monitor, ITU-R recommends to have enough attention when it is used to manage the picture quality strictly.
On the other hand, as for the CRT master monitor, the attention needs to be paid to the trend on a supply side in future.
This technical report assembles ‘user requirements for the flat plane display (LCD, PDP) used as the master monitor.’ The report allows a broadcasting station to produce TV programs with full management of the picture quality and no confusion. Also it allows manufactures to grasp a condition that the broadcasting station demands and to answer a request to put a production into the market immediately.
The committee from manufactures of production equipment, display, measuring instrument and broadcasting stations have worked together to investigate, measure and test to make the report.
This is regarded, among monitors in a broadcasting station, to be a monitor placed as a measuring instrument to manage final video quality by evaluating deterioration occurred by luminance, color reproduction, compression, and transmission.
It is required that a video producer has to manage video quality under a constant condition with precise adjustment of the color temperature, brightness, and resolution of the master monitor.
Therefore it is regarded to be important that it displays the input signal to the monitor more accurately than beautifully.
|3 primary color chromaticity point||
Rec. ITU-R BT 709, SMPTE274M, Rec. 470 ITU-R BT system B/G (hereinafter called EBU), system M (hereinafter called NTSC) are the studio standards for program production and international program exchange.
The 3 primary color chromaticity defined here is for a production equipment, and is regarded as 3 primary color chromaticity in a television receiver set assumed by a camera.
The color of the source of light is called a light source color, and a range where colorless is felt by color adaptation is called a white light source.
Color temperature is used to express the color condition of the white light source.
The material called the black body which does not exist practically is assumed.
If the color emitted at a certain temperature (T) matches to the color of the black body in T, T in absolute temperature is called the color temperature of the source of light.
D93 is used as a reference in NTSC 525 system in Japan. The reference white in the standard of Rec. ITU-R BT 709 and SMPTE274M is D65.
In the actual program production, NTSC 525 system and HDTV 1125 system co-exist. It is desirable that the color temperature of a monitor is unified under the same environment in operation.
This is a brightness per unit area of a screen surface excluding light reflected from outside. The unit is cd/m2.
For LCD, it is the brightness displayed when a certain drive signal is inputted. It is determined by the brightness of a backlight, and light transmission rates of a panel and a color filter.
|Gamma characteristic||The relationship of input signal voltage (V) and optical power (L) in a CRT monitor can be approximated with L = Vγ, when V, L is normalized. This is called the gamma characteristic of the monitor. Its value is expressed in γ.|
This is the luminance ratio of black area( input black signal (0%)) and white area (input white signal (100%)).
Light reflected from outside is excluded.
Generally, the value of a maximum contrast ratio measured at the screen front is mentioned.
There are two "definitions" for a visibility angle.
One is the range (angle) that can secure more than 1/10 of the contrast ratio measured from the front.
The other is the angle that can secure more than 10:1 of the contrast ratio.
This is the degree of separation of an image.
It is expressed by a number of monochrome alternate perpendicular lines or horizontal lines reproduced on a screen. Each black and white line is counted with one.
In the case of a matrix display, addressing is possible by a dot (subpixel) unit so that the number of pixels accords with resolution in general.
This means irregular appearance on a display with regular pixel arrangement when an even gray signal is inputted.
It appears in a certain limited area where there are relatively few level difference and not even luminance.
It is caused by the physical change of a liquid crystal.
As an example, in an LCD display, it occurs when liquid crystalline material in itself is heterogeneous or impurities in the liquid crystal are distributed heterogeneously.
It also occurs in a CRT, a PDP and other display devices.
This is a time duration that a screen reaches to a certain level of luminance when step-formed input is applied to a liquid crystal panel module.
In the case of a liquid crystal, a time to changes the screen from black to white and vice versa differs. So that response time may be defined as the sum of both time.
This is a time duration from inputting a video signal into a monitor to appearing an image on a screen.
In the case of a CRT, the delay time is almost zero because of beam scanning.
In the case of an FPD, it is often accompanied by more than 1 frame delays, because it generally requires signal processing such as I/P (interlace scanning / progressive scanning) conversion, and scaling processing.
2. Amendment History
|Ver.||Amendment or Enactment Date||Amendment summary|
The requirement of gamma characteristic is revised to match that of a present CRT master monitor.
- The description of the gamma characteristic is revised in the requirement about picture quality to the master monitor. (the graph of the result of a measurement is added)
- The description relating to the gamma characteristic is delete in the requirement about peak luminance / white luminance.
- The explanation of the gamma characteristic in the explanation of a term is revised.
- The requirement of the gamma characteristic in appendix 1 is revised and a method for measurement is added.
- The re-result of measurement about the gamma characteristic in appendix 9 is added.
The version number is changed due to the revision of Rec. ITU-R BT.814 and BT.1120.