Title:
NOISE REMOVING CIRCUIT FOR VIDEO CAMERA IN LOW ILLUMINANCE
Document Type and Number:
Japanese Patent JPH02228884
Kind Code:
A
Abstract:
PURPOSE:To obtain the picture of high picture quality even when illuminance is made low by inserting a noise removing part composed of attenuator for a low illuminance, frame memory and feedback attenuator. CONSTITUTION:An attenuator 13 to make a video signal (1-K)-fold, adding point 14 and frame memory 15 are serially provided in order and the output terminal of the memory 15 is connected through a K-fold feedback attenuator 17 to the adding point 14 and the noise removing part is provided to control a coefficient K in a control part 7. When the illuminance is made low, a switch 18 is changed over according to a light quantity detection signal by an iris gate 4 and the amplification factor of an AGC circuit 5 is increased. Then, sensitivity is improved and simultaneously, the degradation of an S/N due to a CCD is improved by adjusting the coefficient K of the noise removing part. Then, the amplification factor of the AGC circuit 5 is not changed but only the coefficient K is adjusted. Thus, even when the illuminance is made low, the S/N is suppressed and satisfactory photographing can be executed.
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Inventors:
MAKISHIMA SUGIO
Application Number:
JP4853789A
Publication Date:
September 11, 1990
Filing Date:
March 02, 1989
Export Citation:
Assignee:
FUJI PHOTO FILM CO LTD
International Classes:
H04N5/21; H04N5/217; H04N5/235; (IPC1-7): H04N5/21; H04N5/217; H04N5/235
Attorney, Agent or Firm:
Hidetoshi Mitsuishi (1 person outside)