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Y'CbCr (601) from R'G'B'
5 J. k4 Z( D; E$ B. _2 V========================================================; n3 D$ f: D0 G! a
Y' = 16 + ( 65.481 * R' + 128.553 * G' + 24.966 * B')- W- s8 W) g i
Cb = 128 + (-37.797 * R' - 74.203 * G' + 112.0 * B')0 Q0 n5 l5 |6 J0 t7 ^& `9 m' |
Cr = 128 + (112.0 * R' - 93.786 * G' - 18.214 * B')3 Q9 [& n' ?5 U5 Z4 t0 J1 r" [
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- R. L+ B2 Z+ s; A; a9 X9 kR', G', B' in [0; 1]
# A1 E) J( N8 |, }" l4 |Y' in {16, 17, ..., 235}
1 A% T. X+ \5 z5 r with footroom in {1, 2, ..., 15}+ w( I- W. L- C1 |% q/ f! R5 n
headroom in {236, 237, ..., 254}
, _5 E5 o! ]& N" v1 s sync. in {0, 255}
8 [4 T! ?2 c6 ~1 ?8 E2 E8 [Cb, Cr in {16, 17, ..., 240}# x! [0 Y5 J' ^9 q! s. \ o, H$ J
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." d# d$ o. {( t3 ^5 v( I6 d
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
) |- M/ k A4 A0 Y7 |您可以參考以下的網頁# }7 Y4 x. H, X2 E, C
http://en.wikipedia.org/wiki/Color_matrix
; m8 P' N, B0 \或是去找一些color matirx的書籍 |
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