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Y'CbCr (601) from R'G'B'7 d: a! e+ R& h* |/ u- H" \/ U
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$ d, l7 l' G& P: v- EY' = 16 + ( 65.481 * R' + 128.553 * G' + 24.966 * B')
& X" I2 |0 E8 o( h" z: g; qCb = 128 + (-37.797 * R' - 74.203 * G' + 112.0 * B')
3 `) {3 q! i4 \4 SCr = 128 + (112.0 * R' - 93.786 * G' - 18.214 * B')/ d( J& P, b- A. s$ C3 ]
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R', G', B' in [0; 1]
w0 @2 Q y5 ]. s# LY' in {16, 17, ..., 235}
! ?9 h5 d( L, s, V! J with footroom in {1, 2, ..., 15}2 y' S- r! B9 M% {' U
headroom in {236, 237, ..., 254}
8 S7 ]/ i/ a2 k sync. in {0, 255}: e" v% p$ e* Y9 N G
Cb, Cr in {16, 17, ..., 240}3 J; G! p- ]: i8 c4 M. w
您說的128應該是指Cb Cr 的grayscale, 當RGB每channel輸入皆為0時Cb Cr 輸出128, Y 輸出16, 此時應該對應到RGB domain gray level的0, 這就是ADC的DC offset.! U% R; Q3 k' O, @' R W9 [6 c
此時, 若Cb 或 Cb 輸出值為131表示輸出的Cb 或 Cr 相位有旋轉, 色度值非正確值; I6 q% [7 o) I4 m4 X* y
您可以參考以下的網頁/ B3 Z3 [ f( k8 Y- e
http://en.wikipedia.org/wiki/Color_matrix2 P: D3 B X% V
或是去找一些color matirx的書籍 |
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