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Appendix D: Glossary
• Reference levels
The zero and full-scale levels of an analog-to-digital converter. Voltages below a
black reference level
are converted to a zero pixel value; voltages above a
white
reference level
are converted to the maximum pixel value. Together with the analog
gain factor, the reference levels affect the brightness and contrast of the resulting
image.
• RGB
A color space that represents color using the primary colors (red, green and blue)
as components.
• Synchronous function
A function that does not return control to the caller until it has finished executing.
See also
asynchronous function
.
• Vertical sync
The part of a video signal that indicates the end of a frame and the start of a new
one.
See also
horizontal sync
.
• VIA
Video Interface ASIC
. A custom ASIC that connects all the data buses on the board
(the grab, VMChannel, and PCI bus) to one another, and directs and monitors
data flow "traffic". It is a video interface that provides various ways of inputting
and outputting data.
•
VMChannel
Vesa Media Channel
. An industry standard 32-bit bus designed for carrying video
data. On Matrox Meteor-II boards, it is used primarily to share data with other
Matrox imaging boards.
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