YDbDr

{{Short description|Colour space used in the SECAM analog color TV standard}}

YDbDr, sometimes written $YD_BD_R$ , is the colour space{{cite book |url=https://books.google.com/books?id=R6VBtXAIi7oC&dq=YDbDr&pg=PA1146 |title=Issues in Electronic Circuits, Devices, and Materials: 2011 Edition |date=2012-01-09 |publisher=ScholarlyEditions |isbn=978-1-4649-6373-5 |pages=1146 |language=en}} used in the SECAM (adopted in France and some countries of the former Eastern Bloc) analog colour television broadcasting standard.{{cite book |url=https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.470-6-199811-S!!PDF-E.pdf |title=Recommendation ITU-R BT.470-6 - Conventional Television Systems |publisher=ITU-R |year=1998}}{{cite book |last1=Shi |first1=Yun-Qing |url=https://books.google.com/books?id=DkqMDwAAQBAJ&dq=YDbDr&pg=PT43 |title=Image and Video Compression for Multimedia Engineering: Fundamentals, Algorithms, and Standards, Third Edition |last2=Sun |first2=Huifang |date=2019-03-07 |publisher=CRC Press |isbn=978-1-351-57864-6 |language=en}}{{cite book |last=Dorf |first=Richard C. |url=https://books.google.com/books?id=N05sBgAAQBAJ&dq=YDbDr&pg=SA18-PA3 |title=Circuits, Signals, and Speech and Image Processing |date=2018-10-03 |publisher=CRC Press |isbn=978-1-4200-0308-6 |language=en}} It is very close to YUV (used on the PAL system) and its related colour spaces such as YIQ (used on the NTSC system), YPbPr and YCbCr.{{cite book |last1=Hoang |first1=Dzung Tien |url=https://books.google.com/books?id=AT8fAQAAIAAJ&q=YDbDr |title=Efficient Algorithms for MPEG Video Compression |last2=Vitter |first2=Jeffrey Scott |date=2002-02-21 |publisher=Wiley |isbn=978-0-471-37942-3 |language=en}}{{cite book |last1=Shum |first1=Heung-Yeung |url=https://books.google.com/books?id=93J3Z96ZVwoC&dq=YDbDr&pg=PA208 |title=Image-Based Rendering |last2=Chan |first2=Shing-Chow |last3=Kang |first3=Sing Bing|author3-link=Sing Bing Kang |date=2008-05-26 |publisher=Springer Science & Business Media |isbn=978-0-387-32668-9 |language=en}}

$YD_BD_R$ is composed of three components: $Y$ , $D_B$ and $D_R$ . $Y$ is the luminance, $D_B$ and $D_R$ are the chrominance components, representing the red and blue colour differences.{{cite book |last=ASC |first=David Stump |url=https://books.google.com/books?id=A1I_EAAAQBAJ&dq=YDbDr&pg=PA75 |title=Digital Cinematography: Fundamentals, Tools, Techniques, and Workflows |date=2021-11-18 |publisher=Routledge |isbn=978-0-429-88901-1 |language=en}}

Formulas

The three component signals are created from an original $RGB$ (red, green and blue) source. The weighted values of $R$ , $G$ and $B$ are added together to produce a single $Y$ signal, representing the overall brightness, or luminance, of that spot. The $D_B$ signal is then created by subtracting the $Y$ from the blue signal of the original $RGB$ , and then scaling; and $D_R$ by subtracting the $Y$ from the red, and then scaling by a different factor.

These formulae approximate the conversion between the RGB colour space and $YD_BD_R$ .

: $\begin{align}
R, G, B, Y &\in \left[ 0, 1 \right]\\
D_B, D_R &\in \left[ -1.333, 1.333 \right]\end{align}$

From RGB to YDbDr:

: $\begin{align}
Y &= +0.299 R +0.587 G +0.114 B\\
D_B &= -0.450 R -0.883 G +1.333 B\\
D_R &= -1.333 R +1.116 G +0.217B\\
\begin{bmatrix} Y \\ D_B \\ D_R \end{bmatrix} &=
\begin{bmatrix} 0.299 & 0.587 & 0.114 \\
-0.450 & -0.883 & 1.333 \\
-1.333 & 1.116 & 0.217 \end{bmatrix}
\begin{bmatrix} R \\ G \\ B \end{bmatrix}\end{align}$

From YDbDr to RGB:

: $\begin{align}
R &= Y +0.000092303716148 D_B -0.525912630661865 D_R\\
G &= Y -0.129132898890509 D_B +0.267899328207599 D_R\\
B &= Y +0.664679059978955 D_B -0.000079202543533 D_R\\
\begin{bmatrix} R \\ G \\ B \end{bmatrix} &=
\begin{bmatrix} 1 & 0.000092303716148 & -0.525912630661865 \\
1 & -0.129132898890509 & 0.267899328207599 \\
1 & 0.664679059978955 & -0.000079202543533 \end{bmatrix}
\begin{bmatrix} Y \\ D_B \\ D_R \end{bmatrix}\end{align}$

You may note that the $Y$ component of $YD_BD_R$ is the same as the $Y$ component of $Y$ $U$ $V$ . $D_B$ and $D_R$ are related to the $U$ and $V$ components of the YUV colour space as follows:

: $\begin{align}
D_B &= + 3.059 U\\
D_R &= - 2.169 V\end{align}$

References

Shi, Yun Q. and Sun, Huifang Image and Video Compression for Multimedia Engineering, CRC Press, 2000 {{ISBN|0-8493-3491-8}}

Category:Color space

YDbDr

Formulas

See also

References