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:
Mar. 07, 1989
Filed:
May. 16, 1988
Yasuo Yagi, Ohta, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A black level correction circuit includes an extraction circuit for extracting a black signal from a video signal as a signal whose level is lower than a reference level, and a black level expanding circuit for expanding in level of the black signal for that peak level of the black signal equals a normal black level. The circuit further includes a level adjusting circuit which adjusts the reference level for extracting the black signal on the basis of at least one of an average value of a luminance signal portion the video signal, and a beam current value of a cathode-ray tube to which the video signal is supplied. With the variable reference level, contrast is improved for pictures having high luminance levels or low luminance levels on the whole.