# YDbDr

YDbDrSECAM制式規格電視所采用的色彩空間

1966年法国提出SECAM彩色电视制式，並制度YDbDr。

## 公式

Y, Db和Dr訊號是產生自RGB 三原色。R, G和B的權重儲存於Y信号，所代表的是该点亮度.

RGB 色彩空间和YDbDr轉換之近似公式。

 ${\displaystyle R,G,B,Y\in \left[0,1\right]}$ ${\displaystyle Db\in \left[-1.333,1.333\right]}$ ${\displaystyle Dr\in \left[-1.333,1.333\right]}$

 ${\displaystyle Y=}$ ${\displaystyle 0.299R}$ ${\displaystyle +0.587G}$ ${\displaystyle +0.114B}$ ${\displaystyle Db=}$ ${\displaystyle -0.450R}$ ${\displaystyle -0.883G}$ ${\displaystyle +1.333B}$ ${\displaystyle Dr=}$ ${\displaystyle -1.333R}$ ${\displaystyle +1.116G}$ ${\displaystyle +0.217B}$

 ${\displaystyle R=}$ ${\displaystyle Y}$ ${\displaystyle +0.000092303716148Db}$ ${\displaystyle -0.525912630661865Dr}$ ${\displaystyle G=}$ ${\displaystyle Y}$ ${\displaystyle -0.129132898890509Db}$ ${\displaystyle +0.267899328207599Dr}$ ${\displaystyle B=}$ ${\displaystyle Y}$ ${\displaystyle +0.664679059978955Db}$ ${\displaystyle -0.000079202543533Dr}$

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

${\displaystyle {\begin{bmatrix}R\\G\\B\end{bmatrix}}={\begin{bmatrix}1&0.000092303716148&-0.525912630661865\\1&-0.129132898890509&0.267899328207599\\1&0.664679059978955&-0.000079202543533\end{bmatrix}}{\begin{bmatrix}Y\\Db\\Dr\end{bmatrix}}}$

 ${\displaystyle Db=}$ ${\displaystyle +3.059U}$ ${\displaystyle Dr=}$ ${\displaystyle -2.169V}$

## 參考書目

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