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:
Dec. 08, 1992
Filed:
Jan. 17, 1991
Yasushi Takagi, Yokohama, JP;
Takuya Imaide, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Operational amplifiers detect deviations from white in pictures picked up based on color-difference signals and generate white balance control signals, respectively. The data that correspond to the generated white balance control signals are held at counters. The data that should be held at the counters are updated successively according to a synchronization signal which is applied successively to the counters. Gains of variable gain amplifiers (3r, 3b) that amplify red and blue color signals are controlled, respectively, based on the data held at the counters. A color temperature detection circuit detects a difference between a level of white balance control signal and a level expressed by the data held at the counter and generates a color temperature variation detection signal when the difference exceeding a predetermined level exists. In the event the color temperature variation detection signal is generated, a synchronization signal whose cycle is shorter than a cycle of synchronization signal that has been applied until that time is applied to the counters for a predetermined amount of time to accelerate the speed of updating data that should be held at the counters.