The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 01, 1997
Filed:
Sep. 13, 1995
Applicant:
Inventor:
Rainer Gehrmann, Alsbach-Hahnlein, DE;
Assignee:
U.S. Philips Corporation, New York, NY (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04N / ;
U.S. Cl.
CPC ...
348591 ; 348590 ; 348595 ;
Abstract
A method and a circuit for generating a composite video signal formed from a foreground signal and a background signal in accordance with the luminance self-key mode is described, in which the key signal is derived from the luminance foreground signal in dependence upon a clipping level. To avoid a quadratic dependence of the luminance signal during product formation of the key signal with the foreground signal (referred to as 'double multiplication'), the linear key signal should be replaced by a control signal which is hyperbolically formed in such a way that the unwanted quadratic dependence is eliminated.