Title:
VIDEO CAMERA FOR DOCUMENT PHOTOGRAPHING
Document Type and Number:
Japanese Patent JPH01196978
Kind Code:
A
Abstract:
PURPOSE:To obtain a sufficient contrast even in the case of photographing of black/white document material by selecting one of gamma(gamma) correction values of two kinds of discrete values in response to the pickup object from a gamma correction means applying gamma correction to a video signal. CONSTITUTION:Gamma correction circuits 50, 56 apply gamma correction to a green signal GS(Gs), a red signal RS(Rs) and a blue signal BS(Bs) so that the gamma of the entire picture display system comprising a conventional TV, etc., is always the unity. That is, the gamma correction circuits 50, 56 apply gamma of each color signal to nearly 0.45 because the gamma of a cathode ray tube of a TV set is nearly 2.2. This is applied to a picture of a general object of a positive picture or a negative picture and in the case of white/black document material as the pickup object of an image sensor 2, the gamma of each color signal is corrected to a value larger than 0.45. Thus, black/white contrast on the monitor television screen is increased.
Inventors:
SAWACHI YOICHI
Application Number:
JP2077088A
Publication Date:
August 08, 1989
Filing Date:
January 30, 1988
Export Citation:
Assignee:
FUJI PHOTO FILM CO LTD
International Classes:
H04N1/407; H04N5/202; H04N5/222; H04N9/04; (IPC1-7): H04N5/202; H04N5/222; H04N9/04
Attorney, Agent or Firm:
Kenzo Matsuura