GRASS VALLEY Kayak HD 100C, User Manual

Page: 56 / 558

56 Kayak — User Manual
Section 2 — Concepts
Coring
Coring helps reduce video noise in chroma keys. Coring is used when a key
fill signal has noise in areas that are supposed to be transparent. When
noise exists in these areas it can appear in the background portion of the
keyed composite. Coring replaces the noisy black areas outside the shaped
fill with clean black before it is summed, eliminating the noise.
Show Key
Although the key control signal is not directly visible in the final video
output, this signal can be previewed as a black and white image using the
Show Key function. White areas of a show key indicate areas of complete
opacity, black indicate complete transparency, and gray areas indicate
translucent areas of the key. The whiter the show key signal, the more
opaque the key will be. This key preview signal reflects all the adjustments
that have been made to the key control signal.
Linear Key
A linear key typically uses separate key cut and key fill input signals that
are intended to be used for linear keying. The key cut and key fill are
usually anti-aliased (soft edged) shaped signals created by a character gen-
erator or graphics system. There may also be translucent areas intended to
allow some background to show through the key (watermarks). The level
of the key cut signal determines where and how deeply the hole will be cut
into the background. The intended soft edge and translucency of the key
can then be faithfully reproduced.