- Industrie:
- Number of terms: 20560
- Number of blossaries: 0
- Company Profile:
Tektronix provides test and measurement instruments, solutions and services for the computer, semiconductor, military/aerospace, consumer electronics and education industries worldwide.
One of the colour difference signals used in the NTSC system, obtained by subtracting luminance from the blue camera signal. This is the signal that drives the horizontal axis of a vectorscope. The human visual system has much less acuity for spatial variation of colour than for brightness.
Rather than conveying RGB, it is advantageous to convey luma in one channel, and colour information that has had luma removed in the two other channels. In an analogue system, the two colour channels can have less bandwidth, typically one-third that of luma. In a digital system each of the two colour channels can have considerably less data rate (or data capacity) than luma. Green dominates the luma channel: about 59% of the luma signal comprises green information. Therefore, it is sensible, and advantageous for signal-to-noise reasons, to base the two colour channels on blue and red. The simplest way to remove luma from each of these is to subtract it to form the difference between a primary colour and luma. Hence, the basic video color-difference pair is (B-Y), (R-Y) (pronounced “B minus Y, R minus Y”). The (B-Y) signal reaches its extreme values at blue (R = 0, G = 0, B = 1; Y = 0.114; B-Y = +0.886) and at yellow (R = 1, G = 1, B = 0; Y = 0.886; B-Y = –0.886). Similarly, the extreme of (R-Y), + –0.701, occur at red and cyan. These are inconvenient values for both digital and analogue systems. The colour spaces YPbPr, YCbCr, Photo YCC, and YUV are simply scaled versions of (Y, B-Y, R-Y) that place the extreme of the colour difference channels at more convenient values.
Industry:Entertainment
Specifies the standard for weighted and unweighted noise measurements. The weighted standard specifies the weighting philtre and quasi-peak detector. The unweighted standard specifies a 22 Hz to 22 kHz bandwidth limiting philtre and RMS detector.
Industry:Entertainment
Method for the Subjective Assessment of the Quality of Television Pictures. CCIR-500 is a detailed review of the recommendations for conducting subjective analysis of image quality. The problems of defining perceived image quality are reviewed, and the evaluation procedures for interval scaling, ordinal scaling, and ratio scaling are described – along with the applications for which each is best employed.
Industry:Entertainment
The physical parallel and serial interconnect scheme for ITU-R BT.601-2-601. CCIR 656 defines the parallel connector pinouts as well as the blanking, sync, and multiplexing schemes used in both parallel and serial interfaces. Reflects definitions in EBU Tech 3267 (for 625 line signals) and in SMPTE 125M (parallel 525) and SMPTE 259M (serial 525).
Industry:Entertainment
Consultative Committee International Radio. A standard that corresponds to the 4:2:2 format.
Industry:Entertainment
The recommendation considers that the HDTV studio standard must be harmonised with those of current and developing television systems and with those of existing motion-picture film. In a review of current systems, a consensus was identified in specifications for opto/electronic conversion, picture characteristics, picture scanning characteristics, and signal format (both analogue and digital representations). Work is underway in the editing of national and CCIR-related documents to determine whether these consensus values may be affirmed in the next review of the individual documents. The values in Rec 709 are considered interim, and CCIR notes that continuing work is expected to define target parameters for future improved image rendition.
Industry:Entertainment
At present, the first results on studies related to Study Programme 18U/11 have been collected. It must be recognised that these studies must be intensified in close cooperation with such organisations as the IEC and ISO to take fully into account the requirements for implementation of HDTV for media other than broadcasting, i.e., cinema, printing, medical applications, scientific work, and video conferencing. In addition, the transmission of HDTV signals via new digital transmission channels or networks has to be considered and taken into account.
Industry:Entertainment
