Image Processing Reference
In-Depth Information
Luma samples
Chroma samples
Figure 5-32
4:2:0 sampling.
Luma samples
Chroma samples
Figure 5-33
Y'UV sampling.
You will find further discussion on color models and color space in Chapter 6, which
covers digital-imaging systems.
5.12
Video Formats
Video formats come in a variety of alternatives. Consumer formats are lower quality than
professional formats and are stored on lower-capacity devices. While there is a perform-
ance difference between them at present, Moore's Law provides for ever-increasing pro-
cessing capability. Eventually there is no economic reason why consumers should not
enjoy studio-quality presentation in their own homes.
5.12.1
Transport and Delivery of Video
Broadcast studios and the transmission systems deliver the video in an encoded form that
applies some analog compression. The luma value describes a basic black and white TV
signal. Subtracting the luma signal from the RGB color values derives two color compo-
nents. This color overlay does not have to be maintained at the same resolution because
the human eye is better at resolving brightness than color, so some compression is already
accomplished.
The delivery and transport mechanisms used to build TV systems are all based on
transferring this luma and chroma component information. A camera will rarely produce
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