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Y'CbCr (601) from R'G'B') ~! V. K' @7 H7 B
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Y' = 16 + ( 65.481 * R' + 128.553 * G' + 24.966 * B')" X" g9 v) c5 ?) F8 B1 b
Cb = 128 + (-37.797 * R' - 74.203 * G' + 112.0 * B')
! W4 W) [7 [* u$ @% ~2 x0 H/ fCr = 128 + (112.0 * R' - 93.786 * G' - 18.214 * B')+ L- H* v$ T! u3 {
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R', G', B' in [0; 1]
$ S$ {5 I# a% I; NY' in {16, 17, ..., 235}1 s% `- O$ `1 X
with footroom in {1, 2, ..., 15}, ^2 c) y1 T: I: |
headroom in {236, 237, ..., 254}
; N% M; K$ {* k# f sync. in {0, 255}4 n1 G; O0 e- W
Cb, Cr in {16, 17, ..., 240}4 F! S' v& F; l6 I0 Y
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.5 A5 k, @- c' ^8 D7 p$ ]
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
0 _5 S5 ]3 I4 [. ~4 Z& I1 v您可以參考以下的網頁' q; C7 @# O2 E" ^
http://en.wikipedia.org/wiki/Color_matrix
/ g8 H" m( G) p0 V% j L或是去找一些color matirx的書籍 |
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