Title:
【発明の名称】ビデオカメラ用感度アップ回路
Document Type and Number:
Japanese Patent JP2807928
Kind Code:
B2
Abstract:
PURPOSE:To attain image pickup at a low illuminance and correction of rear light by converting the mode of a gain control amplifier in response to the illuminance. CONSTITUTION:A video signal whose low frequency noise is eliminated by a CDS circuit 4 is inputted to a diaphragm control circuit 5, which controls the diaphragm and inputted to a GCA 6 and the gain is controlled by an AGC circuit 7 to obtain a prescribed signal level. Then a signal processing circuit 8 and an encoder circuit 9 apply prescribed signal processing to obtain a composite video signal. With a BLC switch 10 closed, a control signal is fed to the diaphragm control circuit 5 and the AGC circuit 7 to widen the aperture of the diaphragm 2 and to increase the gain of the GCA 6. Furthermore, in the case of a low illuminance, an A/D converter 12 discriminates the low illuminance and a low illuminance signal is outputted and a characteristics of the GCA 6 is converted into the mode increase change characteristics based on an output from a D/A converter 15 via an AND gate 13. Thus, the image pickup at a low illuminance and at rear light is attained.
Inventors:
WATANABE MAKOTO
Application Number:
JP1353191A
Publication Date:
October 08, 1998
Filing Date:
February 04, 1991
Export Citation:
Assignee:
SHAAPU KK
International Classes:
H04N5/243; (IPC1-7): H04N5/243
Domestic Patent References:
| JP2128473U | ||||
| JP5794274U |
Attorney, Agent or Firm:
Toshio Morita (3 outside)