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. 24, 1992
Filed:
Oct. 20, 1989
Takahiro Fuse, Akigawa, JP;
Hideo Takizawa, Fuchu, JP;
Casio Computer Co., Ltd., Tokyo, JP;
Abstract
A contrast control circuit for processing a video signal comprises a digital video-signal processing circuit which detects a mean value of a digital luminance signal of the digital video signal and subtracts the detected mean value from the digital luminance signal in order to obtain a difference signal, and a limiter circuit which receives and limits the difference signal to a range defined by predetermined upper and lower limits. And a digital video-signal processing circuit including amplifier means for amplifying a digital luminance signal, obtains a mean value of one field of the digital luminance signal or of one field of the digital luminance signal amplified by the amplifier means, calculates deviations of the digital luminance signal or of the digital luminance signal amplified by the amplifier means from the obtained mean value, accumulates the deviations calculated for the period of one field in order to obtain a contrast value, and controls the gain of the amplifier means on the basis of the obtained contrast value.