CA2069365A1 - Video signal gradation corrector - Google Patents

Video signal gradation corrector

Info

Publication number
CA2069365A1
CA2069365A1 CA2069365A CA2069365A CA2069365A1 CA 2069365 A1 CA2069365 A1 CA 2069365A1 CA 2069365 A CA2069365 A CA 2069365A CA 2069365 A CA2069365 A CA 2069365A CA 2069365 A1 CA2069365 A1 CA 2069365A1
Authority
CA
Canada
Prior art keywords
luminance level
constant
circuit
gradation
output signal
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
CA2069365A
Other languages
French (fr)
Other versions
CA2069365C (en
Inventor
Toshiaki Tsuji
Atsuhisa Kageyama
Kiyoshi Imai
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.)
Panasonic Holdings Corp
Original Assignee
Individual
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
Priority claimed from JP3123648A external-priority patent/JP3021769B2/en
Priority claimed from JP3123647A external-priority patent/JPH04349784A/en
Application filed by Individual filed Critical Individual
Publication of CA2069365A1 publication Critical patent/CA2069365A1/en
Application granted granted Critical
Publication of CA2069365C publication Critical patent/CA2069365C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • G06T5/92—
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/20—Circuitry for controlling amplitude response
    • H04N5/202—Gamma control
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T5/00—Image enhancement or restoration
    • G06T5/40—Image enhancement or restoration by the use of histogram techniques
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/20—Circuitry for controlling amplitude response

Abstract

A video signal gradation corrector used in a television receiver or the like for preventing the destruction of the gradation of the black side and the floating of the luminance level of the black side and/or an excessive increase of the luminance level of the white side. The corrector can be realized with a small circuit scale. A histogram operating circuit includes an average luminance level detecting circuit. A constant is subtracted from an output signal of the average luminance level detecting circuit by a subtractor. The result of subtraction is multiplied by a constant by a constant-multiplication circuit. A lower-limit limiter circuit limits an output signal of the constant-multiplication circuit to a signal having a value not smaller than 0. An output signal of the lower-limit limiter circuit is provided as an accumulation start luminance level, thereby enabling a gradation correction in which the floating of the luminance level of the black side and the destruction of the gradation of the black side are prevented. Also, the average luminance level and a constant may be added by an adder. The result of addition is multiplied by a constant by a second constant-multiplication circuit, and is limited to a certain value by an upper-limit limiter circuit. An output signal of the upper-limit limiter circuit is provided as an accumulation stop luminance level, thereby enabling a gradation correction in which an excessive increase of the luminance level of the white side is prevented to suppress the blooming of a CRT.
CA002069365A 1991-05-28 1992-05-25 Video signal gradation corrector Expired - Fee Related CA2069365C (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP3123648A JP3021769B2 (en) 1991-05-28 1991-05-28 Gradation correction device
JP03-123647 1991-05-28
JP3123647A JPH04349784A (en) 1991-05-28 1991-05-28 Gradation correction device
JP03-123648 1991-05-28

Publications (2)

Publication Number Publication Date
CA2069365A1 true CA2069365A1 (en) 1992-11-29
CA2069365C CA2069365C (en) 1999-08-31

Family

ID=26460527

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002069365A Expired - Fee Related CA2069365C (en) 1991-05-28 1992-05-25 Video signal gradation corrector

Country Status (8)

Country Link
US (1) US5289282A (en)
EP (1) EP0516084B1 (en)
KR (1) KR960011974B1 (en)
CN (1) CN1026378C (en)
AU (1) AU641320B2 (en)
CA (1) CA2069365C (en)
DE (1) DE69224102T2 (en)
MY (1) MY108732A (en)

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JPH04271669A (en) * 1991-02-27 1992-09-28 Matsushita Electric Ind Co Ltd Gradation corrector
JPH0799862B2 (en) * 1991-03-22 1995-10-25 松下電器産業株式会社 Gradation correction device
JP2936791B2 (en) * 1991-05-28 1999-08-23 松下電器産業株式会社 Gradation correction device
EP0613294B1 (en) * 1993-02-24 1998-10-28 Matsushita Electric Industrial Co., Ltd. Gradation correction device and image sensing device therewith
JPH0773308A (en) * 1993-09-03 1995-03-17 Matsushita Electric Ind Co Ltd Digital image processor
BE1007777A3 (en) * 1993-11-23 1995-10-17 Philips Electronics Nv Non-linear signal.
KR0142290B1 (en) * 1993-11-24 1998-06-15 김광호 Image improving method and its circuits
US6002797A (en) 1994-06-22 1999-12-14 Hitachi, Ltd. Apparatus for detecting position of featuring region of picture, such as subtitle or imageless part
JPH0852638A (en) * 1994-08-15 1996-02-27 Toshiba Mach Co Ltd Interference check method, machining program check method and machining suitability check method
JP2795214B2 (en) * 1994-10-12 1998-09-10 日本電気株式会社 VDT disturbance mitigation method, image frequency attenuating device, and VDT adapter
TW373402B (en) * 1996-01-10 1999-11-01 Matsushita Electric Ind Co Ltd Television receiver
JP3130266B2 (en) * 1996-03-09 2001-01-31 三星電子株式会社 Image improvement method and circuit using average separation histogram equalization
DE69716803T2 (en) * 1996-04-10 2003-03-27 Samsung Electronics Co Ltd Image quality improvement method by histogram equalization with mean agreement and circuit therefor
JP3685575B2 (en) * 1997-01-30 2005-08-17 三菱電機株式会社 Display device
MY118136A (en) 1997-03-06 2004-09-30 Matsushita Electric Ind Co Ltd Image quality correction circuit for video signals
US6038341A (en) * 1997-03-06 2000-03-14 Matsushita Electric Industrial Co., Ltd. Histogram operating unit for video signals
MY118340A (en) * 1997-03-06 2004-10-30 Matsushita Electric Ind Co Ltd Histogram generator.
JP2951910B2 (en) * 1997-03-18 1999-09-20 松下電器産業株式会社 Gradation correction device and gradation correction method for imaging device
JP4257036B2 (en) * 1999-02-05 2009-04-22 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Histogram equalization method
JP3661168B2 (en) * 1999-11-25 2005-06-15 松下電器産業株式会社 Gradation correction apparatus, gradation correction method, and video display apparatus
TW518882B (en) * 2000-03-27 2003-01-21 Hitachi Ltd Liquid crystal display device for displaying video data
EP1164784A1 (en) * 2000-06-13 2001-12-19 Koninklijke Philips Electronics N.V. Preventing doming phenomena
JP4783985B2 (en) * 2001-02-28 2011-09-28 日本電気株式会社 Video processing apparatus, video display apparatus, video processing method used therefor, and program thereof
JP3992177B2 (en) * 2001-11-29 2007-10-17 株式会社リコー Image processing apparatus, image processing method, and computer program
KR20040040699A (en) * 2002-11-07 2004-05-13 삼성전자주식회사 Apparatus and Method for compansation contrast
US20040109091A1 (en) * 2002-12-03 2004-06-10 Samsung Electronics Co., Ltd. Apparatus and method for adaptive brightness control
JP4271978B2 (en) * 2003-04-18 2009-06-03 株式会社日立製作所 Video display device
JP2005130159A (en) * 2003-10-23 2005-05-19 Sony Corp Imaging apparatus and camera shake correcting method thereof
US7362290B2 (en) * 2003-10-29 2008-04-22 Seiko Epson Corporation Image signal correcting circuit, image processing method, electro-optical device and electronic apparatus
JP2005202159A (en) * 2004-01-15 2005-07-28 Seiko Epson Corp Electrooptical device and the driving circuit and method for driving the same, and electrooptical equipment
CN1305317C (en) * 2004-12-27 2007-03-14 北京中星微电子有限公司 Image brightness correcting method of video monitoring system
JP4419933B2 (en) * 2005-08-26 2010-02-24 ソニー株式会社 Image processing apparatus, image display apparatus, and image processing method
JP4921202B2 (en) * 2006-03-15 2012-04-25 キヤノン株式会社 Job history management system, control method therefor, program, and storage medium
KR100849845B1 (en) * 2006-09-05 2008-08-01 삼성전자주식회사 Method and apparatus for Image enhancement
JP4835525B2 (en) * 2007-07-04 2011-12-14 ソニー株式会社 Image processing apparatus, image processing method, and program
KR101132069B1 (en) * 2010-02-03 2012-04-02 삼성모바일디스플레이주식회사 organic light emitting display device and driving method thereof
US8736766B2 (en) * 2010-10-15 2014-05-27 Sharp Kabushiki Kaisha Image processing device, image processing method, image processing program, and recording medium, each capable of correcting luminance of image so that the local deterioration of grey scales is unlikely to occur
JP6241192B2 (en) * 2013-10-18 2017-12-06 株式会社リコー Image processing apparatus, image processing system, image processing method, program, and recording medium

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59125176A (en) * 1982-12-30 1984-07-19 インタ−ナシヨナル　ビジネス　マシ−ンズ　コ−ポレ−シヨン Device for correcting ageing effect in video image
US4731662A (en) * 1985-03-21 1988-03-15 Canon Kabushiki Kaisha Image processing method for processing an image signal differently depending on the range of an image characteristic thereof relative to the range within which an output device can reproduce the image characteristic
JPS63274281A (en) * 1987-04-30 1988-11-11 Nec Corp System for compressing picture signal band
US4786968A (en) * 1987-07-16 1988-11-22 Sony Corporation Gamma correction of digital video data by calculating linearly interpolated gamma correction values
JP2512562B2 (en) * 1989-10-12 1996-07-03 松下電器産業株式会社 Gradation correction device
JPH04271669A (en) * 1991-02-27 1992-09-28 Matsushita Electric Ind Co Ltd Gradation corrector
JPH0799862B2 (en) * 1991-03-22 1995-10-25 松下電器産業株式会社 Gradation correction device
JP2936791B2 (en) * 1991-05-28 1999-08-23 松下電器産業株式会社 Gradation correction device

Also Published As

Publication number Publication date
EP0516084B1 (en) 1998-01-21
EP0516084A3 (en) 1994-08-03
CN1067347A (en) 1992-12-23
KR920022879A (en) 1992-12-19
CA2069365C (en) 1999-08-31
AU641320B2 (en) 1993-09-16
EP0516084A2 (en) 1992-12-02
DE69224102T2 (en) 1998-07-23
US5289282A (en) 1994-02-22
MY108732A (en) 1996-11-30
AU1714092A (en) 1993-03-11
CN1026378C (en) 1994-10-26
DE69224102D1 (en) 1998-02-26
KR960011974B1 (en) 1996-09-06

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