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:
Jun. 26, 1990
Filed:
Dec. 28, 1988
Christopher M Engel, Arlington Heights, IL (US);
Zenith Electronics Corporation, Glenview, IL (US);
Abstract
A black expander circuit for a digital video signal includes a pair of moving average filters, one sampling pixels on a line basis and another sampling the pixel samples on a field basis to develop a moving digital average. The moving digital average is added to a constant to form a breakpoint value and supplied to a comparator along with the digital video signal. The output of the comparator controls a mutiplexer. The digital video signal is multiplied by a factor, algebraically summed with the breakpoint value and supplied as one input to the multiplexer with the digital video signal being supplied as the other input. The output of the multiplexer comprises a digital video signal that has portions below the breakpoint value expanded.