YDbDr

YDbDr, sometimes written ${\displaystyle YD_{B}D_{R}}${\displaystyle YD_{B}D_{R}}, is the colour space ^[1] used in the SECAM (adopted in France and some countries of the former Eastern Bloc) analog colour television broadcasting standard.^{[2] [3] [4]} 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.^{[5] [6]}

${\displaystyle YD_{B}D_{R}}${\displaystyle YD_{B}D_{R}} is composed of three components: ${\displaystyle Y}${\displaystyle Y}, ${\displaystyle D_{B}}${\displaystyle D_{B}} and ${\displaystyle D_{R}}${\displaystyle D_{R}}. ${\displaystyle Y}${\displaystyle Y} is the luminance, ${\displaystyle D_{B}}${\displaystyle D_{B}} and ${\displaystyle D_{R}}${\displaystyle D_{R}} are the chrominance components, representing the red and blue colour differences.^[7]

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

These formulae approximate the conversion between the RGB colour space and ${\displaystyle YD_{B}D_{R}}${\displaystyle YD_{B}D_{R}}.

${\displaystyle {\begin{aligned}R,G,B,Y&\in \left[0,1\right]\\D_{B},D_{R}&\in \left[-1.333,1.333\right]\end{aligned}}}${\displaystyle {\begin{aligned}R,G,B,Y&\in \left[0,1\right]\\D_{B},D_{R}&\in \left[-1.333,1.333\right]\end{aligned}}}

From RGB to YDbDr:

${\displaystyle {\begin{aligned}Y&=+0.299R+0.587G+0.114B\\D_{B}&=-0.450R-0.883G+1.333B\\D_{R}&=-1.333R+1.116G+0.217B\\{\begin{bmatrix}Y\\D_{B}\\D_{R}\end{bmatrix}}&={\begin{bmatrix}0.299&0.587&0.114\\-0.450&-0.883&1.333\\-1.333&1.116&0.217\end{bmatrix}}{\begin{bmatrix}R\\G\\B\end{bmatrix}}\end{aligned}}}${\displaystyle {\begin{aligned}Y&=+0.299R+0.587G+0.114B\\D_{B}&=-0.450R-0.883G+1.333B\\D_{R}&=-1.333R+1.116G+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{aligned}}}

From YDbDr to RGB:

${\displaystyle {\begin{aligned}R&=Y+0.000092303716148D_{B}-0.525912630661865D_{R}\\G&=Y-0.129132898890509D_{B}+0.267899328207599D_{R}\\B&=Y+0.664679059978955D_{B}-0.000079202543533D_{R}\\{\begin{bmatrix}R\\G\\B\end{bmatrix}}&={\begin{bmatrix}1&0.000092303716148&-0.525912630661865\1円&-0.129132898890509&0.267899328207599\1円&0.664679059978955&-0.000079202543533\end{bmatrix}}{\begin{bmatrix}Y\\D_{B}\\D_{R}\end{bmatrix}}\end{aligned}}}${\displaystyle {\begin{aligned}R&=Y+0.000092303716148D_{B}-0.525912630661865D_{R}\\G&=Y-0.129132898890509D_{B}+0.267899328207599D_{R}\\B&=Y+0.664679059978955D_{B}-0.000079202543533D_{R}\\{\begin{bmatrix}R\\G\\B\end{bmatrix}}&={\begin{bmatrix}1&0.000092303716148&-0.525912630661865\1円&-0.129132898890509&0.267899328207599\1円&0.664679059978955&-0.000079202543533\end{bmatrix}}{\begin{bmatrix}Y\\D_{B}\\D_{R}\end{bmatrix}}\end{aligned}}}

You may note that the ${\displaystyle Y}${\displaystyle Y} component of ${\displaystyle YD_{B}D_{R}}${\displaystyle YD_{B}D_{R}} is the same as the ${\displaystyle Y}${\displaystyle Y} component of ${\displaystyle Y}${\displaystyle Y}${\displaystyle U}${\displaystyle U}${\displaystyle V}${\displaystyle V}. ${\displaystyle D_{B}}${\displaystyle D_{B}} and ${\displaystyle D_{R}}${\displaystyle D_{R}} are related to the ${\displaystyle U}${\displaystyle U} and ${\displaystyle V}${\displaystyle V} components of the YUV colour space as follows:

${\displaystyle {\begin{aligned}D_{B}&=+3.059U\\D_{R}&=-2.169V\end{aligned}}}${\displaystyle {\begin{aligned}D_{B}&=+3.059U\\D_{R}&=-2.169V\end{aligned}}}

• YUV - related colour system

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

• Color space

• Articles with short description
• Short description matches Wikidata