Patent ID: 7006155

Claim:
Apparatus for formation of a composite video image, the apparatus comprising: a shadow control module that receives a foreground video image signal and generates a shadow key that identifies at least one selected pixel for which foreground shadowing is activated; a shadow generation module that receives the foreground image signal and the shadow key and generates and issues a foreground shadow signal FGSh, in which each selected pixel appears in a shadow format; and a shadowing module that receives the foreground shadow signal and a background video image signal BG and generates a modified background image signal, in which a foreground shadow is impressed on each selected pixel of the background image, wherein said shadowing module forms a sum signal β·FGSh+(1−β′)·BG, as said modified background image signal, where β and β′ are real numbers lying in a range [0,1], selected so as to limit either an intensity of the foreground shadow or an intensity of the background image, wherein β is less than β′ thereby limiting the intensity of the background image.