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Colorimetric characteristics of analog television systemsColorimetric characteristics of analog television systems are presented in Table 3.1, in which it is marked:
3.4 Colorimetric characteristics of digital television systems Colorimetric characteristics of standard definition and high definition digital television systems are presented in Table 3.2, where:
In Recommendation ITU-R BT.601 [3.4] for digital SDTV systems 8 bit and 10 bit coded representation is used and decimal values of the quantized signals are: ‒ for gamma-corrected
TABLE 3.1
TABLE 3.2
TABLE 3.2
‒ for luminance and colour difference
where D takes either the value 1 or 4, corresponding to 8 bit and 10 bit quantization respectively. The operator int ( ) returns the value of 0 for fractional parts in the range of 0 to 0.4999 … and +1 for fractional parts in the range 0.5 to 0.999 ..., i.e. it rounds up fractions above 0.5. Equations for derivation quantized luminance and color-difference signals via quantized gamma-corrected
where k′ and m denote the integer coefficients and the bit-lengths of the integer coefficients, respectively k′ coefficients are presented in Table 3.3. TABLE 3.3
The same digital coding in Recommendation ITU-R BT.1358 [3.5] is defined for SDTV systems with progressive scanning. In Recommendations ITU-R BT.709 [3.6], ITU-R BT.1543 [3.7] and ITU-R BT.1847 [3.8] for digital HDTV systems 8 bit and 10 bit coded representation is used and decimal values of the quantized signals are: ‒ for gamma-corrected
‒ for luminance and colour difference signals:
where n denotes the number of the bit length of the quantized signal. Derivation of luminance and colour-difference signals via quantized RGB signals is realised using equations:
Colorimetric parameters and related characteristics to be used for future television and imaging systems with conventional and extended (based on use negative values of In the case of derivation of luminance and color-difference signals via quantized RGB signals digital luminance and color-difference signals may take slightly different values depending on the signal processing sequence, i.e. the discrepancy between signals quantized after analogue matrixing and signals digitally matrixed after quantization of RGB signals. In Recommendation ITU-R BT.1361 [3.9] following equations with optimized coefficients are derived: – for conventional color gamut system:
where coefficients – for extended color gamut system:
where coefficients Date: 2014-12-22; view: 1356
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– relative luminance levels of 
-components;
– gamma-corrected 
-signals relative levels ( 
);
– luminance signal;
– color-difference signals of the PAL system;
– color-difference signals of the SECAM system.
– relative luminance levels of 
-image components;
– gamma-corrected 
-signals relative levels ( 
);
, 
, 
, 
– color-difference signals, normalized to the interval 
.
signals:
(3.6)
(3.7)
(3.8)
Electro–optic conversion:
Note. Conversion for 
corresponds to systems with extended color gamut.
signals:
(3.9)
(3.10)
(3.11)
signals are
(3.12)
(3.13)
(3.14)
signals:
(3.15)
(3.16)
(3.17)
(3.18)
(3.19)
(3.20)
(3.21)
(3.22)
(3.23)
signals) colorimetry compatible with Recommendation ITU-R BT.709 [3.6] are specified in Recommendation ITU-R BT.1361 [3.9]. In Table 3.4 equations for quantization of RGB luma and chroma signals and equations for derivation of luma and chroma signals via quantized RGB signals are presented. In the following, m and n denote the bit-lengths of the integer coefficients and digital signals, respectively.
(3.24)
(3.25)
(3.26)
are presented in Table 3.5;
(3.27)
(3.28)
(3.29)
are presented in Table 3.6.