JPS5480754A - Image quality adjusting circuit - Google Patents

Image quality adjusting circuit

Info

Publication number
JPS5480754A
JPS5480754A JP14896577A JP14896577A JPS5480754A JP S5480754 A JPS5480754 A JP S5480754A JP 14896577 A JP14896577 A JP 14896577A JP 14896577 A JP14896577 A JP 14896577A JP S5480754 A JPS5480754 A JP S5480754A
Authority
JP
Japan
Prior art keywords
video signals
level
image
voltage
circuit
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
JP14896577A
Other languages
Japanese (ja)
Other versions
JPS6135754B2 (en
Inventor
Yojiro Sato
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co 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
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP14896577A priority Critical patent/JPS5480754A/en
Publication of JPS5480754A publication Critical patent/JPS5480754A/en
Publication of JPS6135754B2 publication Critical patent/JPS6135754B2/ja
Granted legal-status Critical Current

Links

Landscapes

  • Facsimile Scanning Arrangements (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
  • Exposure Or Original Feeding In Electrophotography (AREA)
  • Projection-Type Copiers In General (AREA)
  • Television Receiver Circuits (AREA)

Abstract

PURPOSE: To intensify the black level in video signals and to improve the gradiation of an image by compressing the level of the video signals through an AGC circuit only when the video signals are higher or lower than a voltage of a preset width.
CONSTITUTION: Video signals are impressed upon a recording tube 49 through an amplifying transistor 12, a level adjusting circuit LV and amplifying transistors 26 and 29. If the resistance of a variable resistor 25 is adjusted, an AGC circuit CC is connected through a resistor 21 with the transistor 12. If the level of the video signals is higher than the voltage divided by resistors 17 and 18, a diode 22 is rendered conductive together with a diode 23, which is lower than the voltage divided by resistors 19 and 20, so that the level of the video signals to be impressed upon a recording tube 40 through the circuit CC is compressed when the video signals become higher or lower than a preset voltage. As a result, the image which is intensified in black and white levels is formed by the video signals, from which the unnecessary information such as the back ground or eging is eliminated, and the level of the video signals is controlled to fall within a preset range to produce an image having a satisfactory gradation.
COPYRIGHT: (C)1979,JPO&Japio
JP14896577A 1977-12-12 1977-12-12 Image quality adjusting circuit Granted JPS5480754A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP14896577A JPS5480754A (en) 1977-12-12 1977-12-12 Image quality adjusting circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14896577A JPS5480754A (en) 1977-12-12 1977-12-12 Image quality adjusting circuit

Publications (2)

Publication Number Publication Date
JPS5480754A true JPS5480754A (en) 1979-06-27
JPS6135754B2 JPS6135754B2 (en) 1986-08-14

Family

ID=15464615

Family Applications (1)

Application Number Title Priority Date Filing Date
JP14896577A Granted JPS5480754A (en) 1977-12-12 1977-12-12 Image quality adjusting circuit

Country Status (1)

Country Link
JP (1) JPS5480754A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6230480A (en) * 1985-08-01 1987-02-09 Agency Of Ind Science & Technol Automatic contrast converting system
JPS6230478A (en) * 1985-08-01 1987-02-09 Agency Of Ind Science & Technol Density gradation converting system
US5299008A (en) * 1991-02-28 1994-03-29 Matsushita Electric Industrial Co., Ltd. Video tone correction control circuit
US5307166A (en) * 1992-01-14 1994-04-26 Matsushita Electric Industrial Co., Ltd. Automatic image-tone control circuit and method for controlling brightness of image
US5391944A (en) * 1992-01-22 1995-02-21 Matsushita Electric Industrial Co., Ltd. Image-tone control circuit and gradient adjusting circuit therefor
KR100439544B1 (en) * 2002-03-25 2004-07-12 엘지전자 주식회사 Control apparatus for characteristic of video signal

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5136194A (en) * 1974-09-20 1976-03-26 Sanyo Jido Hanbaiki Kk

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5136194A (en) * 1974-09-20 1976-03-26 Sanyo Jido Hanbaiki Kk

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6230480A (en) * 1985-08-01 1987-02-09 Agency Of Ind Science & Technol Automatic contrast converting system
JPS6230478A (en) * 1985-08-01 1987-02-09 Agency Of Ind Science & Technol Density gradation converting system
US5299008A (en) * 1991-02-28 1994-03-29 Matsushita Electric Industrial Co., Ltd. Video tone correction control circuit
US5307166A (en) * 1992-01-14 1994-04-26 Matsushita Electric Industrial Co., Ltd. Automatic image-tone control circuit and method for controlling brightness of image
US5391944A (en) * 1992-01-22 1995-02-21 Matsushita Electric Industrial Co., Ltd. Image-tone control circuit and gradient adjusting circuit therefor
KR100439544B1 (en) * 2002-03-25 2004-07-12 엘지전자 주식회사 Control apparatus for characteristic of video signal

Also Published As

Publication number Publication date
JPS6135754B2 (en) 1986-08-14

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