Video signal color correction with dual function memories and color window

US5355225A · kind A · utility

Assignee

• BTS Broadcast Television Systems GmbH · DE

Inventors

• Peter Bachmann · Ottobrunn, DE
• Dieter Poetsch · Ober-Ramstadt, DE

Key dates

• Filing date: Feb 28, 1992
• Grant date: Oct 11, 1994
• Expiry date: Feb 28, 2012

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N9/643
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

Memories are provided for correction signal values respectively for a hue signal, a saturation signal and a luminance signal derived from a digital color television signal. Each of the memories consists of two memory units which are alternately used for storing new correction signal values and for reading out previously stored correction signal values. The corrected signal values are modified by a key signal, if present, in each case and are then supplied to calculation circuits to each of which a signal derived from the saturation signal is applied. The resulting fully corrected hue and saturation signals are converted back into color difference signals, but the finally corrected luminance signal requires no conversion. The correction signal values are supplied from a computer into which control magnitudes can be entered to produce them. These control magnitudes can be used to define corner points of a deflected line function from which the raw correction signals are derived. Monitors and cursors are used to facilitate correct entry of control magnitudes.