Title:
GAMMA CORRECTION CIRCUIT
Document Type and Number:
Japanese Patent JPH01307369
Kind Code:
A
Abstract:
PURPOSE:To improve the picture quality with a few adjustment positions by correcting a sent video signal in a form of a quadratic curve in case of driving a projection type display device by the video signal subjected to gamma correction and sent for direct observation CRT for a conventional receiver. CONSTITUTION:The gamma correction circuit consists of a multiplier 5, a bias and setup adjustment device 8, a bias setting device 9 and a level adjustment device 10. The correction is implemented according to a quadratic curve of xX(ax+b)+c, where (x) is an input video signal and coefficients (a), (b), (c) are set respectively by the level adjustment device 10, the bias setting device 9 and the bias and setup adjustment device 8. Moreover, the correction may be implemented in a form of x+(ax<2>+(b-1)x+c). Thus, the picture quality is improved by a few adjustment positions.
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Inventors:
KANAZAWA MASARU
Application Number:
JP13748688A
Publication Date:
December 12, 1989
Filing Date:
June 06, 1988
Export Citation:
Assignee:
JAPAN BROADCASTING CORP
International Classes:
H04N5/202; (IPC1-7): H04N5/202
Attorney, Agent or Firm:
Akihide Sugimura (1 outside)