JPS62287790A - Automatic white balancing circuit for video camera - Google Patents

Automatic white balancing circuit for video camera

Info

Publication number
JPS62287790A
JPS62287790A JP13015486A JP13015486A JPS62287790A JP S62287790 A JPS62287790 A JP S62287790A JP 13015486 A JP13015486 A JP 13015486A JP 13015486 A JP13015486 A JP 13015486A JP S62287790 A JPS62287790 A JP S62287790A
Authority
JP
Grant status
Application
Patent type
Prior art keywords
value
automatic
control
automatic control
scope
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP13015486A
Inventor
Kazuteru Furuichi
Original Assignee
Hitachi Device Eng Co Ltd
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Abstract

PURPOSE: To prevent the erroneous adjustment of an automatic white balancing circuit by disconnecting a feedback loop for an automatic gain control and holding a white balancing control value immediately before the interruption of the feedback loop when the average value of a color difference signal is deviated to the outside of an automatic control scope.
CONSTITUTION: A reference voltage electric power source 14 sets the upper limit of an automatic control scope in cooperation to a reference voltage electric power source 13. A reference voltage electric power source 15 sets the lower limit of an automatic control scope. Comparators 16 and 18, when the output of respective low pass filters 9 and 10 is an automatic control scope upper limit voltage value or below, outputs '0' and when it is the value or above, outputs '1.' The output of low pass filters 11 and 12 determines the counting direction of respective up-down counters 22 and 23. D/A converters 24 and 25 convert the counting value output of respective up-down counters 22 and 23 to an analog value to control variable gain amplifiers 4 and 5. Thus, when the average value of the color difference signal is deviated to the outside of the automatic control scope, it is judged that the color of a photographing object is largely dislocated in a single direction, and the feedback loop for an automatic gain control is disconnected.
COPYRIGHT: (C)1987,JPO&Japio
JP13015486A 1986-06-06 1986-06-06 Automatic white balancing circuit for video camera Granted JPS62287790A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP13015486A JPS62287790A (en) 1986-06-06 1986-06-06 Automatic white balancing circuit for video camera

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP13015486A JPS62287790A (en) 1986-06-06 1986-06-06 Automatic white balancing circuit for video camera

Publications (1)

Publication Number Publication Date
JPS62287790A true true JPS62287790A (en) 1987-12-14

Family

ID=15027278

Family Applications (1)

Application Number Title Priority Date Filing Date
JP13015486A Granted JPS62287790A (en) 1986-06-06 1986-06-06 Automatic white balancing circuit for video camera

Country Status (1)

Country Link
JP (1) JPS62287790A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0322791A2 (en) * 1987-12-29 1989-07-05 Fuji Photo Film Co., Ltd. Method and apparatus for automatically adjusting white balance
JPH0263295A (en) * 1988-08-29 1990-03-02 Sony Corp White balance adjustment circuit
JPH0262184A (en) * 1988-08-29 1990-03-02 Matsushita Electric Ind Co Ltd Color image pickup device
EP0356711A2 (en) * 1988-08-30 1990-03-07 Fuji Photo Film Co., Ltd. Method and apparatus for adjusting chroma
JPH02295295A (en) * 1989-05-10 1990-12-06 Hitachi Ltd White balance device
JPH0478295A (en) * 1990-07-17 1992-03-12 Mitsubishi Electric Corp Automatic white balance adjustment device

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0322791A2 (en) * 1987-12-29 1989-07-05 Fuji Photo Film Co., Ltd. Method and apparatus for automatically adjusting white balance
JPH01264088A (en) * 1987-12-29 1989-10-20 Fuji Photo Film Co Ltd Method and apparatus for automatic adjustment of white balance
JPH0263295A (en) * 1988-08-29 1990-03-02 Sony Corp White balance adjustment circuit
JPH0262184A (en) * 1988-08-29 1990-03-02 Matsushita Electric Ind Co Ltd Color image pickup device
EP0356711A2 (en) * 1988-08-30 1990-03-07 Fuji Photo Film Co., Ltd. Method and apparatus for adjusting chroma
JPH02295295A (en) * 1989-05-10 1990-12-06 Hitachi Ltd White balance device
JPH0478295A (en) * 1990-07-17 1992-03-12 Mitsubishi Electric Corp Automatic white balance adjustment device

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