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Tektronix provides test and measurement instruments, solutions and services for the computer, semiconductor, military/aerospace, consumer electronics and education industries worldwide.
The process of using BitBLT to copy video data such as a bitmap from one area in memory to another.
Industry:Entertainment
Geometric representation of colours in space, usually of three dimensions. There are three reference spaces recognised by ISO 8613: CMYK colour space; CIELuv colour space; and R, G, B colour space.
Industry:Entertainment
An 8-row by 8-column matrix of pels, or 64 DCT coefficients (source, quantized or dequantized). A block is the entity on which the DCT operates. Please note, that the term “block” is used for both the actual picture information, and the corresponding DCT coefficients. A block represents luminance or chrominance information.
Industry:Entertainment
The signal used to modulate the colour information in the colour encoder and demodulate the colour information in the colour decoder. For (M) NTSC the frequency of the colour subcarrier is about 3.579545 MHz and for (B, D, G, H, I) PAL it’s about 4.43 MHz.
Industry:Entertainment
A method of motion estimation. A search for the picture area that best matches a specific macro block of preceding and/or subsequent pictures.
Industry:Entertainment
Used to indicate the amount and colour of light being given off by an object and is based on the concept of a “black body.” A black body is one which absorbs all incident light rays and reflects none (therefore, a theoretical concept only). If the black body is heated, it begins to emit visible light rays, first dull red, then red, then through orange to “white heat.” It can be likened to the heating of metal. If a metal object is heated enough, the metal body will emit the array of colours mentioned above until the object achieves a bluish-white light. The amount of light being emitted by the body can then be correlated to the amount of “heat” it would take to get the body that hot and that heat can be expressed in terms of degrees Kelvin. Objects that give off light equivalent to daylight have a Kelvin temperature of about 6,500 degrees Kelvin. colours with a bluish tint, have a colour temperature of about 9,000 degrees Kelvin.
Industry:Entertainment
The process of moving blocks of data from one place to another rather than a byte at a time in order to save processor time and to expedite screen display in operations such as vertical rolling of video.
Industry:Entertainment
Over a wide range of conditions of observation, many colours can be matched completely by additive mixtures in suitable amounts of three fixed primary colors. The choice of three primary colors, though very wide, is not entirely arbitrary. Any set that is such that none of the primaries can be matched by a mixture of the other two can be used. It follows that the primary colour vectors so defined are linearly independent.
Therefore, transformations of a metameric match from one colour space to another can be predicted via a matrix calculation. The limitations of colour gamut apply to each space. The additive colour generalisation forms the basis of most image capture, and of most self-luminous displays (i.e., CRTs, etc.).
Industry:Entertainment
An artefact that refers to the tile-like appearance of a compressed image where the 8x8 blocks have become visible due to a (too) hard compression.
Industry:Entertainment
A) The colours of three reference lights by whose additive mixture nearly all other colours may be produced. b) The primaries are chosen to be narrow-band areas or monochromatic points directed toward green, red, and blue within the Cartesian coordinates of three-dimensional colour space, such as the CIE x, y, z colour space. These primary colour points together with the white point define the colorimetry of the standardised system. c) Suitable matrix transformations provide metameric conversions, constrained by the practical filters, sensors, phosphors, etc. employed in order to achieve conformance to the defined primary colours of the specified system. Similar matrix transformations compensate for the viewing conditions such as a white point of the display different from the white point of the original scene. d) Choosing and defining primary colours requires a balance between a wide colour gamut reproducing the largest number of observable surface colours and the signal-to-noise penalties of colorimetric transformations requiring larger matrix coefficients as the colour gamut is extended. e) There is no technical requirement that primary colours should be chosen identical with philtre or phosphor dominant wavelengths. The matrix coefficients, however, increase in magnitude as the available display primaries occupy a smaller and smaller portion of the colour gamut. (Thus, spectral colour primaries, desirable for improved colorimetry, become impractical for CRT displays.) f) Although a number of primary colour sets are theoretically interesting, CCIR, with international consensus, has established the current technology and practise internationally that is based (within measurement tolerances) upon the following: Red – x = 0.640, y = 0.330; Green – x = 0.300, y = 0.600; Blue – x = 0.150, y = 0.060.
g) SMPTE offers guidance for further studies in improving colour rendition by extending the colour gamut. With regard to colour gamut, it is felt that the system should embrace a gamut at least as large as that represented by the following primaries: Red – x = 0.670, y = 0.330; Green – x = 0.210, y = 0.710; Blue – x = 0.150, y = 0.060.
Industry:Entertainment
