RGB-to-YCBCR Conversion Matrices:
Transformation between YCbCr to RGB generally occurs within the DTV after it receives a YCbCr encoded picture. Conversion between YCbCr color component samples and RGB color component samples can be accomplished by applying one of the four conversion matrices: ITU-R BT.601 [6], ITU-R BT.709 [7], ITU-R BT.2020 [40] constant luminance, or ITU-R BT.2020 [40] non-constant luminance.
By default, an SD video format is encoded according to ITU-R BT.601 [6] color space, an HD video to 2k format is encoded according to ITU-R BT.709 [7] color space, and ITU-R BT.2020 [40] is used for 4k video.
The ITU-R BT.601 [6] color conversion matrix is shown below for convenience.
Y’= 0.299 R’ + 0.587 G’ + 0.114 B’
CR’ = ((R’ – Y’) * 0.71327)
CB’ = ((B’ – Y’) * 0.56433)
The ITU-R BT.709 [7] color conversion matrix is shown below for convenience.
Y’= 0.2126 R’ + 0.7152 G’ + 0.0722 B’
CR’ = ((R’ – Y’) / 1.5748)
CB’ = ((B’ – Y’) / 1.8556)
The ITU-R BT.2020 [40]constantluminance color conversion matrix is shown below for convenience.
YC’= (0.2627 R + 0.6780 G + 0.0593 B)’
CRC’ = ((R’ – YC’) / 1.7184) for -0.8592 ≤ (R’ – YC’) ≤ 0
CRC’ = ((R’ – YC’) / 0.9936) for 0 < (R’ – YC’) ≤ 0.4968
CBC’ = ((B’ – YC’) / 1.9404) for -0.9702 ≤ (B’ – YC’) ≤ 0
CBC’ = ((B’ – YC’) / 1.5816) for 0 < (B’ – YC’) ≤ 0.7908
The ITU-R BT.2020 [40]non-constantluminance color conversion matrix is shown below for convenience.
Y’= 0.2627 R’ + 0.6780 G’ + 0.0593 B’
CR’ = ((R’ – Y’) / 1.4746)
CB’ = ((B’ – Y’) / 1.8814)
Prime values are transformed levels in non-linear color space.
Color Space plays a key role in Smart Phones, Laptops, Monitors and Home theatres. The color space is a key subject in Image capturing, storing, transforming, transmitting and re-producing. It is fast growing to meet the challenges given by Consumer Electronics, Animation and Image processing industries. Stay tuned, read our recent blogs on displayhere
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