WO2006073569A1 - Convertisseur rvb vers yprpb - Google Patents

Convertisseur rvb vers yprpb Download PDF

Info

Publication number
WO2006073569A1
WO2006073569A1 PCT/US2005/041245 US2005041245W WO2006073569A1 WO 2006073569 A1 WO2006073569 A1 WO 2006073569A1 US 2005041245 W US2005041245 W US 2005041245W WO 2006073569 A1 WO2006073569 A1 WO 2006073569A1
Authority
WO
WIPO (PCT)
Prior art keywords
channel
converter
buffer
converter according
circuit
Prior art date
Application number
PCT/US2005/041245
Other languages
English (en)
Inventor
Richard Hugh Miller
Frank Melvin Koch
James Arthur Hutton
Richard William Collins
Richard Laverne Eyer
Original Assignee
Thomson Licensing
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 Thomson Licensing filed Critical Thomson Licensing
Publication of WO2006073569A1 publication Critical patent/WO2006073569A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/64—Circuits for processing colour signals
    • H04N9/67—Circuits for processing colour signals for matrixing

Definitions

  • the present invention relates to video devices (e.g., televisions) having RGB (video) to YPrPb (component video) converters for the same. More particularly, it relates to a simplified circuit design for an RGB to YPrPb converter.
  • HDTV High definition television
  • demand has prompted an increase in demand for larger aspect ratio, true flat screen displays having a shallower depth, increased deflection angle and improved visual resolution performance.
  • FIG. 1 illustrates the basic geometrical relationship between throw distance and deflection angle for a typical CRT. Increasing the deflection angle (A) reduces the throw distance, thus allowing for production of a shorter CRT and ultimately, a slimmer television set.
  • obliquity is defined as the effect of a beam intercepting the screen at an oblique angle, thereby causing an elongation of the spot.
  • the problem of obliquity becomes especially apparent in CRTs having a standard horizontal gun orientation, i.e., a CRT whose guns have a horizontal alignment along the major axis of the screen.
  • a spot having a generally circular shape at the center of the screen becomes oblong or elongated as the spot moves toward edges of the screen.
  • CRT's typically include a horizontal yoke that generates a pincushion shaped field and a vertical yoke that generates a barrel shaped field. These yoke fields cause the spot shape to become elongated. This elongation adds to the obliquity effect by further increasing spot distortion at the three-o'clock and nine o'clock positions (referred to as the "3/9" positions) and at corner positions on the screen.
  • U.S. Patent No. 5, 170,102 describes a CRT with a vertical electron gun orientation whose un- deflected beams appear parallel to the short axis of the display screen.
  • the deflection system described in this patent includes a signal generator for causing scanning of the display screen in a raster-scan fashion, thereby yielding a plurality of lines oriented along the short axis of the display screen.
  • the deflection system also comprises a first set of coils for generating a substantially pincushion- shaped deflection field for deflecting the beams in the direction of the short axis of the display screen.
  • a second set of coils generates a substantially barrel shaped deflection field for deflecting the beams in the direction in the long axis of the display screen.
  • the deflection system's coils generally distort spots by elongating them vertically. This vertical elongation compensates for obliquity effects, thereby reducing spot distortion at the 3/9 and corner positions on the screen.
  • the barrel shaped field required to achieve self convergence at 3/9 screen locations overcompensates for obliquity and vertically elongates the spot at the 3/9 and corner locations as shown in Figure 10 of the U.S. Patent No. 5, 170,102.
  • RGB to YPbPr converters may be disposed within the display electronics, or may be a stand along unit depending on the particular application.
  • size and space are always considerations.
  • RGB to YPrPb converter for use with high resolution display applications, for example, HDTV.
  • the RGB to YPrPb converter of the present principles includes a converter circuit having a first buffer stage for buffering the input R, G and B video signals, and a conversion stage connected to the buffer stage for converting the buffered R, G and B video signals to the Y, Pr, and Pb component video signals.
  • the circuit further includes scaling circuitry connected to the first buffer stage and the conversion stage for scaling the buffered R, G and B video signals, where the conversion stage sums the scaled R, G and B video signals to generate the Y component video signal.
  • a second buffer stage for buffers the generated Y component video signal for use by the conversion stage in obtaining the Pr and Pb component video signals.
  • the first buffer stage includes a transistor for each of the R, G and B inputs, where each of said transistors is configured in an emitter follower configuration.
  • the second buffer stage also includes a transistor configured in an emitter follower configuration.
  • the first buffer stage comprises an operational amplifier for each of the R, G and B signal inputs, while the second buffer stage also includes an operational amplifier.
  • the RGB to YPrPb converter circuit includes an input buffer stage for buffering the incoming R, G and B components of an input video signal, scaling means for scaling the buffered R, G and B video signals, and conversion means connected to the buffer stage and the scaling means for converting the R, G and B components of the video signals to the Y, Pr and Pb component video signals.
  • the RGB video to YPrPb component video converter circuit includes an R channel having a buffer circuit and a converter circuit, a G channel having a first buffer circuit, a converter circuit and a second buffer circuit, and a B channel having buffer circuit and a converter circuit.
  • the second buffer circuit of said G channel is connected to an input of the R channel converter circuit and to an input of the B channel converter circuit.
  • FIG. 1 is a schematic diagram of an RGB to YPrPb converter according to the prior art
  • FIG. 2 is a schematic diagram of the RGB to YPrPb converter according to the present principles
  • Figure 3 is a schematic diagram of the RGB to YPrPb converter according to an embodiment of the present principles
  • Figure 4 is a schematic diagram of the RGB to YPrPb converter according to yet another embodiment of the present principles.
  • RGB video information into a YPrPb signal is a common conversion that is defined by the following three (3) equations:
  • Figure 1 shows a prior art RGB to YPrPb converter having three (3) stages for each of the R, G and B channel.
  • the above equations are applied through the processing of the R, G and B signals through these three channels to provide the resultant YPrPb output.
  • the second stage for the R channel performs the "(R-Y)" portion of Equation 3, while the second stage for the B channel performs the "(B-Y)” operation of Equation 2.
  • FIG. 2 shows the simplified RGB to YPrPb circuit 200 according to the present principles.
  • this converter has removed the second stage of the prior art converters and allows a more streamlined and more efficient circuit design that does not require as much physical space as other known converters, while providing the same level of conversion without detrimental effects to the video signals.
  • the first stage of the circuit 200 includes a first stage for buffering each of the R, G and B channels. As shown in the exemplary circuit of Figure 2, the first stage is established by the initial op amps in each channel. These are Ul 1 IA, Ul 12 A, and Ul 13 A. They buffer the incoming signals (line receivers) to present a constant impedance to the source and a low impedance to drive the second stage or the load if the selector 2OA, 2OB, or 2OC is set to choose the buffered signal rather than the encoded Y, Pb,Pr from the second stage.
  • the Y component i.e., luminance
  • resistors R224 for the B component
  • R219 for the G component
  • R223 for the R component
  • These scaled R, G and B signal values are summed in_ accordance with Equation 1 to convert the incoming R, G and B signals into the Y component.
  • the converted Y component is input into op amp Ul 12B, which operates as a buffer for the same. Through the buffering of these values, the calculated (converted) Y component can be used in the corresponding Pb and Pr calculations in the R and B channels.
  • the buffering at the first stage isolates the feeds to the R and B channels to prevent crosstalk as well as providing a low impedance feed to the next stage, or line drive capability for the output if it the converter is used as a stand alone device.
  • the Pb component video output is obtained using simplified equation 4 and the corresponding circuitry to achieve the same.
  • resistors R218, R221 the video input B is scaled and input into op amp Ul 1 IB, while resistors R225 and R228 scale the Y signal and input the scaled Y signal into the op amp Ul 1 IB, where it is subtracted from the B component to produce the Pb component video signal output according to Equation 4 above.
  • op amp UlI lB acts as the "converter stage" for the Pb component output, as well as providing a low impedance drive for the next stage or line drive.
  • the Pr component video output is obtained using the simplified equation 5 and the corresponding circuitry to achieve the same.
  • the R and Y signals are processed through resistors which provide the appropriate gain to the same before performing the subtraction function.
  • the R signal is scaled by resistors R220 and R222 and input into op amp Ul 13B, and the Y signal component is scaled through resistors R226 and R227 and input to op amp Ul 13B.
  • Op amp Ul 13B performs the subtraction function (Eq. 5) and outputs the Pr component video signal output according to Equation 5 above.
  • op amp Ul 13B acts as the "converter stage" for the Pr component output, as well as providing a low impedance drive for the next stage or line drive.
  • circuit 200 includes jumpers 2OA, 2OB, 2OC corresponding to the B, G, R video inputs, respectively.
  • Jumpers 20 enable a change in the output depending on the desired application.
  • the circuit 200 acts as a pass through circuit and allows the RGB input to pass through the circuit to the outputs unmodified. This is useful if the incoming signal is already Y, Pb, Pr encoded.
  • the circuit's output is the modified RGB input according to Equations 1, 4 and 5 to YPrPb at the output according to the circuit design.
  • bypass jumpers 20 may be replaced with any suitable switching device without departing from the spirit of the present principles.
  • FIG. 3 shows a specific embodiment of the circuit 200 according to the present principles, hi this embodiment, the actual component values have been added to show one exemplary implementation of the RGB to YPrPB converter.
  • the circuit component values may be altered or modified without departing from the spirit of the present principles. Any such alterations or modifications require the maintenance of the relationships set forth in Equations 1, 4 and 5 above.
  • 1% resistors are used for professional signal generation equipment, and as such are chosen for the present implementation of circuit 200.
  • the use of 1% resistors provides the circuit with a more than acceptable range of tolerance and helps to reduce any potential for color errors.
  • resistors having tighter tolerances than the 1% resistors such as 0.5% or even 0.1% resistors, may be used, as well as resistors having looser tolerances (e.g., 2%, 5%, 10%) with improvement or degradation based on the selected tolerances.
  • FIG. 4 shows yet another embodiment of the RGB to YPrPb converter circuit 400 according to the present principles.
  • the entire buffering stage that is used to buffer the inputs and the Y signal have been replaced by transistors, thereby further simplifying the circuit 400.
  • transistors 40 R , 4O G and 40 B are configured to receive the corresponding inputs R, G and B, respectively at their base.
  • Each transistor 4O R , 4O G and 40 B is connected in an emitter follower configuration where the collector is tied to the +5V supply voltage, while the emitter is pulled through a resistor to the -5V supply voltage.
  • Transistor 42 continues to operate to buffer the Y signal and apply the same to the R and B channels for the conversion stages of op amps Ul 1 IB and Ul 13B.
  • This embodiment of the circuit 400 reduces the number of op amps required for the conversion to two (2), thus enabling the entire circuit to be implemented in one Integrated circuit package.
  • Those of skill in the art will clearly recognize the advantages of this yet simpler and more efficient circuit design for an RGB to YPrPb converter.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Processing Of Color Television Signals (AREA)

Abstract

Circuit de convertisseur RVB vers YPrPb étant simplifié en enlevant le second stade standard pour les trois canaux R, V et B. Le présent convertisseur reçoit les entrées R, V et B, et applique une mise à l’échelle et une mise en mémoire tampon des signaux afin d’obtenir la sortie YPrPb souhaitée. De cette façon, le convertisseur RVB vers YPrPb à trois stades standard est simplifié et réduit à un convertisseur RVB vers YPrPb à deux stades.
PCT/US2005/041245 2004-12-31 2005-11-15 Convertisseur rvb vers yprpb WO2006073569A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US64094504P 2004-12-31 2004-12-31
US60/640,945 2004-12-31

Publications (1)

Publication Number Publication Date
WO2006073569A1 true WO2006073569A1 (fr) 2006-07-13

Family

ID=35845956

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2005/041245 WO2006073569A1 (fr) 2004-12-31 2005-11-15 Convertisseur rvb vers yprpb

Country Status (1)

Country Link
WO (1) WO2006073569A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1985005718A1 (fr) * 1984-06-06 1985-12-19 Motorola, Inc. Circuit de regulation de la saturation des couleurs
US4743958A (en) * 1986-10-06 1988-05-10 The Grass Valley Group, Inc. Multiple television standards input selector and convertor
US5574506A (en) * 1989-09-07 1996-11-12 Advanced Television Test Center, Inc. Bi-directional television format digital signal converter with improved luminance signal-to-noise ratio
US5784050A (en) * 1995-11-28 1998-07-21 Cirrus Logic, Inc. System and method for converting video data between the RGB and YUV color spaces
US5995655A (en) * 1998-06-09 1999-11-30 Silicon Graphics, Inc. System and method for coding colors and storing compensation factors used in color space conversion
US6642962B1 (en) * 1999-09-01 2003-11-04 Neomagic Corp. Merged pipeline for color interpolation and edge enhancement of digital images

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1985005718A1 (fr) * 1984-06-06 1985-12-19 Motorola, Inc. Circuit de regulation de la saturation des couleurs
US4743958A (en) * 1986-10-06 1988-05-10 The Grass Valley Group, Inc. Multiple television standards input selector and convertor
US5574506A (en) * 1989-09-07 1996-11-12 Advanced Television Test Center, Inc. Bi-directional television format digital signal converter with improved luminance signal-to-noise ratio
US5784050A (en) * 1995-11-28 1998-07-21 Cirrus Logic, Inc. System and method for converting video data between the RGB and YUV color spaces
US5995655A (en) * 1998-06-09 1999-11-30 Silicon Graphics, Inc. System and method for coding colors and storing compensation factors used in color space conversion
US6642962B1 (en) * 1999-09-01 2003-11-04 Neomagic Corp. Merged pipeline for color interpolation and edge enhancement of digital images

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
"RGB to Component", SILICON CHIP, vol. 193, 8 October 2004 (2004-10-08), XP002370974, Retrieved from the Internet <URL:http://www.siliconchip.com.au/cms/A_102648/article.html> *
BILL BOUWDEN: "Operational Amplifier (Op Amp) Basics", 12 October 1999 (1999-10-12), XP002370976, Retrieved from the Internet <URL:http://web.archive.org/web/19991012040927/http://ourworld.compuserve.com/homepages/Bill_Bowden/opamp.htm> [retrieved on 19991012] *
JON RHEES: "Build Your Own RGB-to-YPrPb Transcoder", 24 July 2003 (2003-07-24), XP002370548, Retrieved from the Internet <URL:http://web.archive.org/web/20030724161647/http://www.keohi.com/keohihdtv/interfaces/diytranscoder_johrhees.html> [retrieved on 20030724] *
MOTOROLA: "Color Television RGB to PAL/NTSC Encoder", SEMICONDUCTOR TECHNICAL DATA, 1995, XP002370973, Retrieved from the Internet <URL:http://pdf1.alldatasheet.co.kr/datasheet-pdf/view/3507/MOTOROLA/MC1377.html> *
TOSHIBA: "RGB TO YUV/IQ HIGH-SPEED MATRIX IC", 13 May 1999 (1999-05-13), XP002370549, Retrieved from the Internet <URL:http://www.tranzistoare.ro/datasheets/700/489272_DS.pdf> *
WIKIPEDIA: "Operational amplifier", WIKIPEDIA, 3 July 2004 (2004-07-03), XP002370975, Retrieved from the Internet <URL:http://web.archive.org/web/20040703165421/http://en.wikipedia.org/wiki/Operational_amplifier> [retrieved on 20040703] *
WIKIPEDIA: "yuv", WIKIPEDIA, 10 November 2004 (2004-11-10), XP002370997, Retrieved from the Internet <URL:http://web.archive.org/web/20041110035720/http://en.wikipedia.org/wiki/YUV> [retrieved on 20041110] *

Similar Documents

Publication Publication Date Title
EP0326152B1 (fr) Dispositif numérique de correction de la convergence
JPS61238190A (ja) カラービデオモニター
US20090262263A1 (en) Multi-standard vertical scan crt system
US20020186225A1 (en) Method for implementing error diffusion on plasma display panel
WO2006073569A1 (fr) Convertisseur rvb vers yprpb
US7030936B2 (en) Pedestal level control circuit and method for controlling pedestal level
US20030098927A1 (en) Display apparatus having format converter
KR20000001754A (ko) 순차주사방식의 투사형 영상 디스플레이장치
US7236203B1 (en) Video circuitry for controlling signal gain and reference black level
CN1271851C (zh) 能够利用放大器校正会聚失调的图象失真校正装置
US6304235B1 (en) Impedance matching circuit and display device having the impedance matching circuit
US6215258B1 (en) Dynamic focus circuit suitable for use in a wide-angled cathode ray tube
US6215259B1 (en) Apparatus for compensating for corner focus and brightness in cathode ray tube
US20070262918A1 (en) Video displaying apparatus and method thereof
US5719476A (en) Apparatus for correcting distortion of an electron beam generated spot on a cathode ray tube screen
WO2006073792A1 (fr) Ecran cathodique a balayage vertical multistandard
JP3461634B2 (ja) コンバーゼンス補正装置
US5898466A (en) Apparatus for correcting vertical and optical distortions of images in projection TV sets
AU2001100380B4 (en) Entirely-D.S.P.-based correction for design-based distortion and outer pin-cushion mis-alignment in direct-view C.R.T&#39;s.
WO2006073733A1 (fr) Appareil et procede de balayage lent (horizontal) pour systemes d&#39;affichage a balayage transpose
CN1258293C (zh) 用于减少切换噪声影响的图像失聚校正装置
WO2006073855A1 (fr) Appareil et procede destines a generer des signaux focaux dynamiques pour des systemes d&#39;affichage de balayage transpose
JP2866721B2 (ja) 陰極線管駆動装置
US20090121972A1 (en) CRT display having a single plane sheath beam bender and video correction
WO2006036200A1 (fr) Tube cathodique de tvhd a balayage vertical et son procede d&#39;utilisation

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 05821267

Country of ref document: EP

Kind code of ref document: A1