Patent ID: 6141063
Filing Date: 2000-10-31
Classification: H04N

Abstract:
A method of generating a video signal (V.sub.out) composed of a foreground signal and a background signal formed in accordance with a chroma-key method in which a background signal (BG) is inserted, in accordance with a subtractive method and with the aid of a control signal (k) derived from the foreground signal (FG), into parts of said foreground signal fixed by a predetermined key color (KC), wherein in said subtractive method, a part of a key color reference vector (KC) is subtracted from a vector of the foreground signal, (FG) and a corresponding part of a vector of the background signal (BG) is additively inserted in accordance with the equation:V.sub.out =FG-k.multidot.KC+k.multidot.BG,characterized in that, for suppressing key color spill in the foreground signal (FG), said method comprises the steps:deriving a modified control signal (k.sub.2) for the background signal (BG) from the control signal (k.sub.1) of the key color after an adjustable threshold value has been exceeded; andadding an artificial background spill signal (SP) weighted with a further control signal (k.sub.3) to the video output signal (V.sub.out) in accordance with the equation:V.sub.out =FG-k.sub.1 .multidot.KC+k.sub.2 .multidot.BG+k.sub.3 .multidot.SP.