1、 Rec. ITU-R BT.814-2 1 RECOMMENDATION ITU-R BT.814-2 Specifications and alignment procedures for setting of brightness and contrast of displays (Question ITU-R 211/11) (1992-1994-2007) Scope This Recommendation defines a test signal for the adjustment of Cathode Ray Tubes (CRTs) and Flat Panel Displ
2、ay (FPD) devices. The signal may be used to set displayed image values for both standard definition television and high definition television. The ITU Radiocommunication Assembly, considering a) that precision CRT picture monitors or FPDs are used in a variety of applications including subjective la
3、boratory testing and control room monitoring of operational systems; b) variations in the set-up and adjustment of displays may lead to variations in displayed pictures; c) that special waveforms that assist with the set-up and adjustment of monitors have been developed and have been in operational
4、use for many years, recommends 1 that the PLUGE test signal (see Note 1) described in Annex 1 should be used for setting of displays used for subjective assessments, and for operational monitoring of systems described in Recommendations ITU-R BT.17001, ITU-R BT.6012, ITU-R BT.7093, and ITU-R BT.1358
5、4. The procedure for the use of the test signal is described in Annex 2. NOTE 1 The acronym, PLUGE, was originally derived from “Picture Line Up Generating Equipment”. 1Recommendation ITU-R BT.1700 Characteristics of composite video signals for conventional analogue television systems. 2Recommendati
6、on ITU-R BT.601 Studio encoding parameters of digital television for standard 4:3 and wide-screen 16:9 aspect ratios. 3Recommendation ITU-R BT.709 Parameter values for the HDTV standards for production and international programme exchange. 4Recommendation ITU-R BT.1358 Studio parameters of 625- and
7、525-line progressive scan television systems. 2 Rec. ITU-R BT.814-2 Annex 1 Specifications of PLUGE waveforms The PLUGE waveform (see Fig. 1) is composed of: a) three closely spaced narrow vertical stripes on the left-hand side of the picture. The central vertical stripe is at waveform black level.
8、The left-hand stripe is slightly darker, and the right-hand stripe is slightly lighter than the central stripe; b) a broad bar signal located on the right-hand side of the picture. It is divided into four areas, one at white level and the other three at descending grey levels. This grey scale is in
9、approximately equal steps, as seen by eye, over a contrast range of 30:1. The peak white area is sufficiently large to enable the peak luminance to be set by a measuring instrument; c) a uniform background surrounding the vertical stripes and the broad bar described above. Two different levels for t
10、his background are specified according to the application: for operational monitoring the background level is set to waveform black level; for subjective assessments the background level is set to the grey level shown in Table 1. This background level has been optimized to give a picture display of
11、subjective quality similar to that used in sequences used in subjective assessment. Rec. ITU-R BT.814-2 3 To take account of the characteristics of the human eye, the luminance specified for the vertical stripes described in c) is slightly different for the two applications (see Table 1). To ensure
12、that in analogue composite systems the colour decoder of a display is working in its colour mode, it is recommended that a standard colour burst is included in the analogue waveform. The horizontal sample count is less than the 720 horizontal samples defined in Recommendation ITU-R BT.601. The PLUGE
13、 signal should be centred within the active line of digital and analogue systems 2 samples. 4 Rec. ITU-R BT.814-2 TABLE 1 Levels of waveform Operational monitoring Subjective assessment monitoring % Level mV digital % Level mV digital 625-line 525-line 625-line 525-line A black level 0% 0 mV (16)64
14、0% 0 mV (16)64 7.5% 54 mV (16)64 0% 0 mV (16)64 0% 0 mV (16)64 7.5% 54 mV (16)64 B white level 100% 700 mV (235)940 100% 714 mV (235)940 100% 714 mV (235)940 100% 700 mV (235)940 100% 714 mV (235)940 100% 714 mV (235)940 C grey level 3 63.0% 441 mV (154)616 63.0% 450 mV (154)616 65.8% 470 mV (154)61
15、6 63.0% 441 mV (154)616 63.0% 450 mV (154)616 65.8% 470 mV (154)616 D grey level 2 35.2% 246 mV (93)372 35.2% 251 mV (93)372 40.0% 286 mV (93)372 35.2% 246 mV (93)372 35.2% 251 mV (93)372 40.0% 286 mV (93)372 E grey level 1 15.1% 105 mV (49)196 15.1% 108 mV (49)196 21.4% 153 mV (49)196 15.1% 105 mV
16、(49)196 15.1% 108 mV (49)196 21.4% 153 mV (49)196 F background level 0% 0 mV (16)64 0% 0 mV (16)64 7.5% 54 mV (16)64 70.3% 492 mV (170)680 70.3% 502 mV (170)680 72.5% 518 mV (170)680 G black stripe level 1.8% 13 mV (12)48 1.8% 13 mV (12)48 5.8% 42 mV (12)48 2.7% 19 mV (10)40 2.7% 20 mV (10)40 5.0% 3
17、5 mV (10)40 mid-level between G black stripe and background levels NA NA NA 33.8% 237 mV (90)360 33.8% 237 mV (90)360 38.8% 277 mV (90)360 H grey stripe level 1.8% 13 mV (20)80 1.8% 13 mV (20)80 9.2% 66 mV (20)80 2.7% 19 mV (22)88 2.7% 20 mV (22)88 10.0% 72 mV (22)88 mid-level between H grey stripe
18、and background levels NA NA NA 36.5% 256 mV (96)384 36.5% 256 mV (96)384 41.3% 295 mV (96)384 Note 1 The 10 bit digital levels are defined as the primary values, and the rest are derived. The 8 bit digital levels are in parentheses. Note 2 Digital levels are expressed in the same way as described in
19、 Recommendation ITU-R BT.601. Note 3 For the subjective assessment monitoring waveform, mid-levels between stripes and background are introduced to avoid ringing due to the sharp transition of the waveform. Note 4 NA: the mid-level is not applied, and the level for this area is the same as the backg
20、round. Rec. ITU-R BT.814-2 5 Annex 2 Procedure for use of PLUGE test signals These adjustments are very dependent on the viewing conditions and it is preferable to conform to the conditions for viewing distance and ambient illumination contained in Recommendation ITU-R BT.500: the brightness control
21、 is reduced until the blackest stripe disappears, whilst the brighter stripe remains visible. This setting shall correspond to the pre-set brightness condition; using a photometer, the contrast is adjusted until the centre of the white area (100% video level) has a luminance value of 70 cd/m2. This
22、setting shall correspond to the pre-set contrast control condition; before a result that is entirely satisfactory is obtained, the procedure described above will usually be repeated, so as to reduce the effects of interactions between these two controls. Annex 3 PLUGE for HDTV systems A PLUGE signal
23、 for HDTV displays is shown in Figs. 2 and 3. The peak white patch is used to set the peak luminance by means of the contrast control. Two types of signal can be used to set the brightness of the black level of the display by means of the brightness control. The signal on the left-hand side of the p
24、icture consists of narrow horizontal stripes (a width of 10 scanning lines). The stripes extend from approximately 2% above the black level of the waveform to approximately 2% below the black level. The signal on the right-hand side of the picture consists of two coarse stripes (a width of 138 lines
25、) one stripe is approximately 2% above black level the other is approximately 2% below black level. This signal is suitable for setting display values for both CRT and FPD type displays. As in Annex 2, the black level of the display is adjusted by the display brightness control such that the negativ
26、e horizontal stripes disappear, whilst the positive horizontal stripes remain visible. 6 Rec. ITU-R BT.814-2 Parameter values, Figs. 2 and 3 8 bit digital value 10 bit digital value Peak white 235 940 Black level 16 64 Slightly lighter level 20 80 Slightly darker level 12 48 FIGURE 2 PLUGE signal for adjusting black level Rec. ITU-R BT.814-2 7 0814-03Peak whiteSlightly lighter levelSlightly lighter levelBlack levelSlightly leveldarkerSlightly darker levelFIGURE 3Analogue waveform of the signal for adjusting black level
