EP1679679A1 - Procédé et appareil pour le traitement d'images vidéo, en particulier pour la réduction de l'effet de scintillement et de l'effet de faux contour sur des surfaces de grandes dimensions - Google Patents

Procédé et appareil pour le traitement d'images vidéo, en particulier pour la réduction de l'effet de scintillement et de l'effet de faux contour sur des surfaces de grandes dimensions Download PDF

Info

Publication number
EP1679679A1
EP1679679A1 EP05112109A EP05112109A EP1679679A1 EP 1679679 A1 EP1679679 A1 EP 1679679A1 EP 05112109 A EP05112109 A EP 05112109A EP 05112109 A EP05112109 A EP 05112109A EP 1679679 A1 EP1679679 A1 EP 1679679A1
Authority
EP
European Patent Office
Prior art keywords
sub
level
code word
pixel
field
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.)
Ceased
Application number
EP05112109A
Other languages
German (de)
English (en)
Inventor
Cédric Thebault
Carlos Correa
Rainer Zwing
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.)
Thomson Licensing SAS
Original Assignee
Thomson Licensing SAS
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 EP05290036A external-priority patent/EP1679680A1/fr
Application filed by Thomson Licensing SAS filed Critical Thomson Licensing SAS
Priority to EP05112109A priority Critical patent/EP1679679A1/fr
Publication of EP1679679A1 publication Critical patent/EP1679679A1/fr
Ceased legal-status Critical Current

Links

Images

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
    • G09G3/2018—Display of intermediate tones by time modulation using two or more time intervals
    • G09G3/2022—Display of intermediate tones by time modulation using two or more time intervals using sub-frames
    • G09G3/2029—Display of intermediate tones by time modulation using two or more time intervals using sub-frames the sub-frames having non-binary weights
    • 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
    • G09G2320/0247—Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
    • 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
    • G09G2320/0266—Reduction of sub-frame artefacts
    • 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
    • G09G3/2044—Display of intermediate tones using dithering

Definitions

  • the invention relates to a method and apparatus for processing video pictures, in particular for large area flicker effect reduction and false effect contours.
  • the invention is closely related to a kind of video processing for improving the picture quality of pictures which are displayed on matrix displays like plasma display panels (PDP), display devices with digital micro mirror arrays (DMD) and all kind of displays based on the principle of duty cycle modulation (pulse width modulation) of light emission.
  • PDP plasma display panels
  • DMD digital micro mirror arrays
  • plasma display panels are known for many years, plasma displays are encountering a growing interest from TV manufacturers. Indeed, this technology now makes it possible to achieve flat colour panels of large size and with limited depths without any viewing angle constraints.
  • the size of the displays may be much larger than the classical CRT picture tubes would have ever been allowed.
  • a plasma display panel utilises a matrix array of discharge cells, which could only be switched ON or OFF. Also unlike a CRT or LCD in which grey levels are expressed by analogue control of the light emission, in a PDP the grey level is controlled by modulating the number of light pulses per frame. The eye will integrate this time-modulation over a period corresponding to the eye time response.
  • this time-modulation repeats itself, with a base frequency equal to the frame frequency of the displayed video norm.
  • a light emission with base frequency of 50 Hz introduces large area flicker, which can be eliminated by field repetition in 100Hz CRT TV receivers.
  • the duty cycle of light emission in PDPs is ⁇ 50% for middle grey. This reduces the amplitude of the 50Hz frequency component in the spectrum, and thus large area flicker artefact, but due to the larger size of PDPs, with a larger viewing angle, even a reduced large area flicker becomes objectionable in terms of picture quality.
  • the present trend of increasing size and brightness of PDPs will also contribute to aggravate this problem in the future.
  • This object is achieved by a method for processing video pictures consisting of pixels, the pixels being digitally coded, the digital code word determining the length of the time period during which the corresponding pixel of a display is activated, wherein to each bit of a digital code word a certain activation duration is assigned, hereinafter called sub-field, the sum of the duration of the sub-fields according to a given code word determining the length of the time period during which the corresponding pixel is activated, the sub-fields of a pixel being organised in two consecutive groups such that to a value of a pixel a code word is assigned which distributes the active sub-field periods equally over the two sub-field groups.
  • substantially all the sub-fields of the two groups have different activation durations and, for all pixel values apart from exceptions in the low pixel value range up to a first predetermined limit and/or in the high pixel value range from a second limit on, the pixel value is split into first and second substantially equal values, said first and second values being encoded into first and second code words, said first code word being the part of the code word assigned to one of the two sub-field groups and said second code word being the part of the code word assigned to the other sub-field group.
  • a dithering step can be possibly applied to said first and second values before being encoded into first and second code words.
  • the pixel values of the even pictures of the sequence will be encoded with the sub-fields of one of the sub-field groups and the pixel values of the odd pictures of the sequence with the sub-fields of the other sub-field group.
  • the invention concerns also an apparatus for processing video pictures consisting of pixels, the pixels being digitally coded, the digital code word determining the length of the time period during which the corresponding pixel of a display is activated, wherein to each bit of a digital code word a certain activation duration is assigned, hereinafter called sub-field, the sum of the duration of the sub-fields according to a given code word determining the length of the time period during which the corresponding pixel is activated, the sub-fields of a pixel being organised in two consecutive groups such that to a value of a pixel a code word is assigned which distributes the active sub-field periods equally over the two sub-field groups.
  • substantially all the sub-fields of the two groups have different activation durations and encoding means are provided for splitting, for all pixel values apart from exceptions in the low pixel value range up to a first predetermined limit and/or the in the high pixel value range from a second limit on, each of said pixel values into first and second substantially equal values and encoding said first and second values into first and second code words, said first code word being the part of the code word assigned to one of the two sub-field groups and said second code word being the part of the code word assigned to the other sub-field group.
  • the apparatus can further comprise dithering means for processing said first and second values.
  • the encoding means encode the pixel values of the even pictures of the sequence with the sub-fields of one of the two sub-field groups and the pixel values of the odd pictures of the sequence with the sub-fields of the other sub-field group.
  • the invention can be used with any number of sub-fields. It will be illustrated by a Parallel Peak Coding with 15 sub-fields. Considering a frame comprising 15 sub-fields with the following weights : 1-2-3-5-7-9-11-14-17-20-24-28-33-38-43
  • these sub-fields are organized in two consecutive groups. A part of a sub-field code word is assigned to each group. These two groups of subfields are used for generating the two packets of light.
  • the odd sub-fields are grouped in a first group, called G1, and the even sub-fields are grouped in a second group called G2.
  • G1 1 - 3 - 7 - 11 - 17 - 24 - 33 - 43
  • G2 2 - 5 - 9 - 14 - 20 - 28 - 38
  • the distribution of the sub-fields between the two groups can be carried out differently.
  • the only condition is that the two groups should comprise sub-fields of different weights.
  • the sub-fields of the group G1 could be put before or after the sub-fields of the group G2.
  • a different coding is selected for each group of sub-fields.
  • the level of false contour and the dithering noise obtained with the Parallel Peak Code are then depending directly on the level of false contour and dithering noise for each of the two packets of light.
  • the following encoding tables can be used : - forthe group G1 (1-3-7-11-17-24-33-43) level 0: 00000000 level 72: 11111010 level 1: 10000000 level 75: 00110110 level 3: 01000000 level 76: 10110110 level 4: 11000000 level 78: 01110110 level 7: 00100000 level 79: 11110110 level 8: 10100000 level 81: 00101110 level 10: 01100000 level 82: 10101110 level 11: 11100000 level 84: 01101110 level 14: 01010000 level 85: 11101110 level 15: 11010000 level 86: 10011110 level 18: 00110000 level 88: 01011110 level 19: 10110000 level 89: 11011110 level 21: 01110000 level 92: 00111110 level 22: 11110000 level 93: 10111110 level 24: 00101000 level 95: 01111110 level 25: 10101000 level 96: 11111110 level 27: 01101000 level 98: 010
  • the same light energy should be emitted during the two packets of light. It is not always possible, for example for the video levels greater than 232 in the present example. Furthermore, for the lowest video levels, the sub-fields of only one sub-field group are preferably used in order to reduce the dithering noise. The low video levels will have only one packet of light but it is not so important since these levels do not generate any flicker.
  • a the value of the part of code word assigned to the first packet of light, and b the value of the part of code word assigned to the second packet of light can be determined as follows:
  • FIG 1 a block diagram of a possible circuit implementation for encoding the video levels into sub-field code word as described above is illustrated.
  • These means comprise for example two Look-Up Tables (LUTs), one for delivering the value a and one for delivering the value b.
  • the value a (respectively b) is then advantageously transmitted to a dithering block 11 (resp. 21) for generating, if need be, values encodable by the subfield group G1 (resp. G2).
  • the dithered value is then forwarded to a subfield coding block 12 (resp.22) for outputting the corresponding subfield code word.
  • This subfield code word will be used by the display panel for driving the lighting period of the cells of the panel.
  • Count is a 1-bit counter, which is incremented at each frame. Depending on its value (0 or 1), the video is encoded with sub-field group G1 and the encoding table assigned to this first group (case 0) or with sub-field group G2 and the encoding table assigned to this second group (case 1).

Landscapes

  • 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)
EP05112109A 2005-01-06 2005-12-14 Procédé et appareil pour le traitement d'images vidéo, en particulier pour la réduction de l'effet de scintillement et de l'effet de faux contour sur des surfaces de grandes dimensions Ceased EP1679679A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP05112109A EP1679679A1 (fr) 2005-01-06 2005-12-14 Procédé et appareil pour le traitement d'images vidéo, en particulier pour la réduction de l'effet de scintillement et de l'effet de faux contour sur des surfaces de grandes dimensions

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP05290036A EP1679680A1 (fr) 2005-01-06 2005-01-06 Procédé et dispositif pour la réduction du scintellement de grande surface d'images vidéo
EP05112109A EP1679679A1 (fr) 2005-01-06 2005-12-14 Procédé et appareil pour le traitement d'images vidéo, en particulier pour la réduction de l'effet de scintillement et de l'effet de faux contour sur des surfaces de grandes dimensions

Publications (1)

Publication Number Publication Date
EP1679679A1 true EP1679679A1 (fr) 2006-07-12

Family

ID=36569846

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05112109A Ceased EP1679679A1 (fr) 2005-01-06 2005-12-14 Procédé et appareil pour le traitement d'images vidéo, en particulier pour la réduction de l'effet de scintillement et de l'effet de faux contour sur des surfaces de grandes dimensions

Country Status (1)

Country Link
EP (1) EP1679679A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1918902A1 (fr) 2006-11-03 2008-05-07 Lg Electronics Inc. Appareil d'affichage à plasma

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0982708A1 (fr) * 1998-08-19 2000-03-01 Deutsche Thomson-Brandt Gmbh Méthode et appareil de traitement d'images vidéo, en particulier pour la réduction du scintillement de grande surface
EP1326223A1 (fr) * 2000-11-30 2003-07-09 THOMSON multimedia S.A. Procedé et dispositif pour commander un dispositif d'affichage
US20040145543A1 (en) * 2001-05-29 2004-07-29 Roel Van Woudenberg Display driving unit for method of displaying pixels and image display apparatus comprising such a display driving unit
US20040160527A1 (en) * 1998-08-19 2004-08-19 Carlos Correa Method and apparatus for processing video pictures, in particular for large area flicker effect reduction

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0982708A1 (fr) * 1998-08-19 2000-03-01 Deutsche Thomson-Brandt Gmbh Méthode et appareil de traitement d'images vidéo, en particulier pour la réduction du scintillement de grande surface
US20040160527A1 (en) * 1998-08-19 2004-08-19 Carlos Correa Method and apparatus for processing video pictures, in particular for large area flicker effect reduction
EP1326223A1 (fr) * 2000-11-30 2003-07-09 THOMSON multimedia S.A. Procedé et dispositif pour commander un dispositif d'affichage
US20040145543A1 (en) * 2001-05-29 2004-07-29 Roel Van Woudenberg Display driving unit for method of displaying pixels and image display apparatus comprising such a display driving unit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1918902A1 (fr) 2006-11-03 2008-05-07 Lg Electronics Inc. Appareil d'affichage à plasma

Similar Documents

Publication Publication Date Title
US7227581B2 (en) Method and apparatus for processing video pictures, in particular for large area flicker effect reduction
US6894664B2 (en) Method and apparatus for processing video pictures
JP4517046B2 (ja) プラズマディスプレイ用の動き補正されたアップコンバージョン
US7773161B2 (en) Method and apparatus for controlling a display device
US20040263541A1 (en) Display apparatus and display driving method for effectively eliminating the occurrence of a moving image false contour
EP0982708B1 (fr) Méthode et appareil de traitement d'images vidéo, en particulier pour la réduction du scintillement de grande surface
KR100799746B1 (ko) 디스플레이 디바이스 상에 디스플레이하기 위한 비디오화상 처리 방법 및 비디오 화상 처리 장치
KR100482326B1 (ko) 플라즈마 디스플레이 패널 및 그 구동방법
US7609235B2 (en) Multiscan display on a plasma display panel
EP1679679A1 (fr) Procédé et appareil pour le traitement d'images vidéo, en particulier pour la réduction de l'effet de scintillement et de l'effet de faux contour sur des surfaces de grandes dimensions
US20070159469A1 (en) Method and apparatus for processing video pictures, in particular for large area flicker effect reduction
EP1679680A1 (fr) Procédé et dispositif pour la réduction du scintellement de grande surface d'images vidéo
EP1359564B1 (fr) Affichage à balayage multiple sur un panneau d'affichage à plasma
JP2007514972A (ja) 特にフィルム・モード系列内のビデオ・ピクチャを処理する方法及び装置
JP2004258069A (ja) 画像表示装置
KR20070049524A (ko) 플라즈마 디스플레이 패널의 화상처리 장치 및 화상처리방법

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA HR MK YU

17P Request for examination filed

Effective date: 20061219

AKX Designation fees paid

Designated state(s): DE FR GB

17Q First examination report despatched

Effective date: 20070604

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: THOMSON LICENSING SA

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED

18R Application refused

Effective date: 20130926