EP1258859A1 - Verfahren zur segmentierten invertierten Gammakorrektur für eine Plasmaanzeigetafel - Google Patents

Verfahren zur segmentierten invertierten Gammakorrektur für eine Plasmaanzeigetafel Download PDF

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Publication number
EP1258859A1
EP1258859A1 EP01112260A EP01112260A EP1258859A1 EP 1258859 A1 EP1258859 A1 EP 1258859A1 EP 01112260 A EP01112260 A EP 01112260A EP 01112260 A EP01112260 A EP 01112260A EP 1258859 A1 EP1258859 A1 EP 1258859A1
Authority
EP
European Patent Office
Prior art keywords
gray level
video signal
range
pdp
gamma
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
EP01112260A
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English (en)
French (fr)
Other versions
EP1258859B1 (de
Inventor
Kao Shiuh-Bin
Hsu Liang-Kuei
Chen Kuang-Lang
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.)
CPT Technology Group Co Ltd
Original Assignee
Chunghwa Picture Tubes Ltd
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Publication date
Application filed by Chunghwa Picture Tubes Ltd filed Critical Chunghwa Picture Tubes Ltd
Priority to EP01112260.3A priority Critical patent/EP1258859B1/de
Publication of EP1258859A1 publication Critical patent/EP1258859A1/de
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Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/2007—Display of intermediate tones
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0271—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0271—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
    • G09G2320/0276—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/28—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels

Definitions

  • the present invention relates to PDPs (plasma display panels) and more particularly to a method of effecting various anti compensation processes on segmented gray level of input image on PDP, thereby significantly improving image quality of PDP.
  • the relationship of input gray level (voltage) versus output brightness of color TV may be plotted as a curve (FIG. 1b).
  • a Gamma ( ⁇ ) compensation process (called compensation process hereinafter) is performed on the original video signal by utilizing above physical characteristic thereof. That is, a compensation process is performed with respect to ⁇ in equation (1).
  • the relationship of input brightness versus output gray level (voltage) of color TV may be plotted as a curve (FIG. 1a).
  • ⁇ 0.45 (i.e., obtained from 1/2.2)
  • the video signal received by color TV is converted into image for showing on screen of CRT of color TV.
  • the relationship of input brightness versus output brightness of color TV may be plotted as a straight line (FIG. 1c).
  • a high quality image is shown on the typical color TV without distortion.
  • brightness of respective discharge unit on panel thereof is controlled by discharge number.
  • brightness may be expressed in following equation (2) in terms of discharge number as below (i.e., a straight line):
  • the higher discharge number the brighter of PDP. This is similar to the effect that the larger input voltage the brighter of a typical color TV.
  • the relationship of input brightness versus output gray level (voltage) of PDP may be plotted as a curve (FIG. 2a).
  • the relationship of input gray level (voltage) versus output brightness of PDP may be plotted as a straight line (FIG. 2b).
  • video signal received by PDP is converted into image for showing on screen of PDP.
  • a distorted image with poor contrast is shown on PDP.
  • an anti compensation process is performed for solving above drawbacks.
  • the relationship of input gray level (voltage) versus output gray level may be plotted as a curve (FIG. 3b).
  • the relationship of input brightness versus output gray level (voltage) may be plotted as a curve (FIG. 3a).
  • the relationship of input gray level (voltage) versus output brightness of PDP may be plotted as a straight line (FIG. 3c).
  • FIGS. 3a, 3b and 3c By combining FIGS. 3a, 3b and 3c, in PDP the relationship of input brightness versus output brightness may be plotted as a straight line (FIG. 3d). In other words, a linear relationship exists between image shown on PDP and received video signal. As a result, a high quality image is shown on PDP without distortion.
  • gray level of PDP is expressed as a power of 2. For example, in PDP eight bits are needed for representing 256 gray levels.
  • an image is shown on PDP.
  • the previous improvement technique has a disadvantage. That is, a non-integer number (e.g., decimal) can not be expressed by a digital signal. Hence, the decimal has to be converted into an integer.
  • a smaller ⁇ is used in the anti compensation process with respect to the video signal in a range of low gray level for increasing the gray level in the range of low gray level.
  • a larger ⁇ is used in the anti compensation process with respect to the video signal in a range of high gray level for increasing a gradient in the range of high gray level , thereby obtaining a sharp contrast of image,, improving image quality, and rendering an enhanced image brightness.
  • FIGS. 4 to 6 where a method according to the invention is illustrated by respective graphs.
  • a processing is performed on the video signal for dividing it into at least two segments based on gray level thereof.
  • various anti compensation processes are performed on the video signal in respective segment so as to increase the number of gray level of video signal in the range of low gray level and increase gray level (or brightness) gradient of video signal in the range of high gray level.
  • image quality of PDP is greatly improved.
  • a false contour is not easily occurred in the range of low gray level. Consequently, a sharp contrast is occurred in the range of high gray level.
  • a difference between two gray levels in the range of high gray level is distinguishable visually, resulting in an enhanced image brightness.
  • the gray level of an image shown on a typical color TV may be varied depending on input voltage by utilizing the physical characteristic of CRT of color TV. Further, gray level of an output image is related to that of an input video signal.
  • an anti compensation process is performed on the received video signal for obtaining an improved image brightness on PDP.
  • brightness of an input image of PDP may be expressed in terms of an output gray level.
  • a plurality of ⁇ having values smaller than 2.2 e.g., 2.0, 1.8, and 1.6
  • ⁇ the higher the output gray level in the range of low gray level.
  • a maximum brightness of a PDP is 500 cd/m 2 if gray level thereof is 256.
  • a control circuit of PDP will be enabled to divide video signal into three segments based on gray level thereof.
  • a plurality of anti compensation processes are performed on the video signal in respective segment with respect to various ⁇ s.
  • the number of gray level in the range of low gray level is increased and gradient in the range of high gray level is also increased. As a result, a false contour is not easily occurred in the range of low gray level. Further, a sharp contrast of output image is obtained in the range of high gray level, thereby greatly improving the image quality of PDP.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Control Of Gas Discharge Display Tubes (AREA)
  • Picture Signal Circuits (AREA)
EP01112260.3A 2001-05-18 2001-05-18 Verfahren zur segmentierten invertierten Gammakorrektur für eine Plasmaanzeigetafel Expired - Lifetime EP1258859B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP01112260.3A EP1258859B1 (de) 2001-05-18 2001-05-18 Verfahren zur segmentierten invertierten Gammakorrektur für eine Plasmaanzeigetafel

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP01112260.3A EP1258859B1 (de) 2001-05-18 2001-05-18 Verfahren zur segmentierten invertierten Gammakorrektur für eine Plasmaanzeigetafel

Publications (2)

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EP1258859A1 true EP1258859A1 (de) 2002-11-20
EP1258859B1 EP1258859B1 (de) 2015-07-08

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005014296A1 (de) 2003-08-05 2005-02-17 Hueck Folien Gmbh & Co. Kg Bedruckte bahnförmge materialien, insbesondere für abdeckungen von behältern
CN101075428B (zh) * 2007-06-26 2010-07-21 四川长虹电器股份有限公司 多段Gamma曲线校正方法
CN101546509B (zh) * 2009-04-23 2011-08-10 北京德为视讯科技股份有限公司 显示器目标Gamma曲线的生成方法
CN110890058A (zh) * 2019-12-06 2020-03-17 长春希达电子技术有限公司 一种变换系数矩阵的逐点校正方法
CN114639346A (zh) * 2022-04-20 2022-06-17 武汉天马微电子有限公司 Mura补偿方法、装置、设备、存储介质和计算机程序产品

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06311394A (ja) 1993-04-21 1994-11-04 Fujitsu General Ltd ガンマ補正回路
JPH08317250A (ja) 1995-05-19 1996-11-29 Fujitsu General Ltd ダイナミック映像制御回路
EP0831643A2 (de) * 1996-09-18 1998-03-25 Matsushita Electric Industrial Co., Ltd. Plasmaanzeigetafel und Verfahren zur Helligkeitskontrolle
EP0947975A1 (de) * 1998-04-02 1999-10-06 Hitachi, Ltd. Gammakorrekturschaltung

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06311394A (ja) 1993-04-21 1994-11-04 Fujitsu General Ltd ガンマ補正回路
JPH08317250A (ja) 1995-05-19 1996-11-29 Fujitsu General Ltd ダイナミック映像制御回路
EP0831643A2 (de) * 1996-09-18 1998-03-25 Matsushita Electric Industrial Co., Ltd. Plasmaanzeigetafel und Verfahren zur Helligkeitskontrolle
EP0947975A1 (de) * 1998-04-02 1999-10-06 Hitachi, Ltd. Gammakorrekturschaltung

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005014296A1 (de) 2003-08-05 2005-02-17 Hueck Folien Gmbh & Co. Kg Bedruckte bahnförmge materialien, insbesondere für abdeckungen von behältern
CN101075428B (zh) * 2007-06-26 2010-07-21 四川长虹电器股份有限公司 多段Gamma曲线校正方法
CN101546509B (zh) * 2009-04-23 2011-08-10 北京德为视讯科技股份有限公司 显示器目标Gamma曲线的生成方法
CN110890058A (zh) * 2019-12-06 2020-03-17 长春希达电子技术有限公司 一种变换系数矩阵的逐点校正方法
CN114639346A (zh) * 2022-04-20 2022-06-17 武汉天马微电子有限公司 Mura补偿方法、装置、设备、存储介质和计算机程序产品
CN114639346B (zh) * 2022-04-20 2023-07-21 武汉天马微电子有限公司 Mura补偿方法、装置、设备、存储介质和计算机程序产品

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EP1258859B1 (de) 2015-07-08

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