CN1291841A - Correction method for uniform bright field of CRT projection TV - Google Patents
Correction method for uniform bright field of CRT projection TV Download PDFInfo
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- CN1291841A CN1291841A CN 00134020 CN00134020A CN1291841A CN 1291841 A CN1291841 A CN 1291841A CN 00134020 CN00134020 CN 00134020 CN 00134020 A CN00134020 A CN 00134020A CN 1291841 A CN1291841 A CN 1291841A
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Abstract
A calibration method for the uniform brightness field of projection TV set with CRT includes full-screen brightness calibration to the amplifiers of R, G and B video signals, finding a calibration voltage whose variation rule is consistant to the distortion rule of brightness on screen in horizontal and vertical directions, calibrating the brightness of R, G and B video signals by positive or negative addition, and controlling the gains of R, G and B amplifying channels. Said method can raise the overall working efficiency and is suitable for the whole machine design with high integration and multisignal interface.
Description
The invention belongs to TV tech and application, specially refer to a kind of correction method for uniform bright field of CRT projection TV.
Since adopt cathode ray tube type shadow casting technique and relevant optic technology improve constantly and perfect, the projection TV of this mode especially rear-projection TV with its higher performance and practical value as a kind of large screen display device, popularly enter various public arenas and family gradually.But,, thereby greatly reduce the subjective vision effect of integral image because the restriction of himself working method of this kind projection TV exists the inconsistent defective of brightness in display screen center and peripheral part.
In the CN1149230A patent disclosure a kind of technology, this technology adopt on projection screen, increase again a slice therein heart part have the method for the luminance compensation film of different light transmittances with the marginal portion, can realize that the screen of back projection TV reaches the demonstration of equal uniform brightness.But this kind method is to be cost with the brightness of sacrificing the higher part of screen intensity, exists shortcomings such as luminance compensation film processing difficulties, cost of manufacture height, integral image brightness reduce greatly simultaneously.
Disclose another technology in the CN1205602A patent, this technology produces brightness and contrast's control level with numeral of row field signal control or analog circuit, controls the complete machine brightness and contrast respectively, and is even with the bright field that reaches screen display.But because the development of circuit engineering and large scale integrated circuit technology, the luminance signal processing circuit of image generally is integrated in the specialized large scale integrated circuit inside of carrying out signal processing, the central processing unit of complete machine carries out brightness and contrast's control by digitized control bus to the luminance signal processing circuit of specialized large scale integrated circuit inside, thereby can't adopt this kind method to go luminance signal processing circuit to inside to carry out the brightness and contrast in the outside of specialized large scale integrated circuit with a control level and control.In addition, in order to be connected with multiple signal source, large-curtain projecting TV set has often required R, G, B three primary colors video signal input interface, can both realize the gamma correction of full screen in the time of can not reaching the variety of way input signal by the method for utilizing a control level that the luminance signal treatment channel is controlled, so there is actual not exploitativeness in this kind technical scheme.
Purpose of the present invention, be to overcome in the prior art and use the luminance compensation film to realize that even bright method reduces integral image brightness greatly and cost of manufacture height and the method that can not can both utilize a control level that the luminance signal treatment channel is controlled realize outside the deficiencies such as gamma correction of full screen when various mode input signal, and provide a kind of and needn't sacrifice integral image brightness, adopt cost of manufacture low, a kind of technical method that when various input pattern signal, can both effectively proofread and correct the brightness of full screen.
The present invention relies on following technical scheme to realize, the CRT projection TV correction method for uniform bright field, it is characterized in that, respectively R, G, B three primary colors vision signal amplifying circuit are carried out the gamma correction of full screen, aligning step is: 1) seek one on image level direction and vertical direction by with the consistent correction voltage that changes of the rugged change rule of screen intensity; 2) carrying out forward or backwards to R, G, B three primary colors vision signal according to primary video signal polarity respectively with this correction voltage, the mode of superposition realizes gamma correction; 3) also can carry out gamma correction with the mode that the screen grid voltage superposition of R, G, B three primary colors projection tube is modulated respectively with this correction voltage; 4) the mode degree of comparing of controlling the gain of R, G, B three primary colors vision signal processing and amplifying passage respectively with this correction voltage is proofreaied and correct.
About on image level direction and vertical direction according to the generation of the consistent correction voltage that changes of the rugged change rule of screen intensity, can adopt the Waveform Synthesis Technology of analog form and the data access D/A switch technology of digital form to realize.
The major advantage of the technology of the present invention is, not to adopt sacrificing luminance Signal Processing mode to control but adopts the gamma correction that respectively R, G, B three primary colors vision signal amplifying circuit is carried out full screen, perhaps adopt respectively the mode of modulating to carry out gamma correction with the screen grid voltage superposition of R, G, B three primary colors projection tube.Thereby improved overall operating efficiency, the effective correction that full screen brightness has been carried out, and go for the entire machine design of high integrationization and multiple signaling interface.
Below in conjunction with accompanying drawing, with regard to several preferred embodiments, the invention will be further described:
Description of drawings:
Fig. 1 is one of the embodiments of the invention block diagram;
Fig. 2 is two block diagrams of embodiments of the invention;
Fig. 3 is three block diagrams of embodiments of the invention;
Fig. 4 is the cubic block diagram of embodiments of the invention;
Fig. 5 is five block diagrams of embodiments of the invention;
Fig. 6 is brightness and contrast's correction voltage waveform of the present invention;
Fig. 7 is the partial enlarged drawing of correction voltage waveform among Fig. 6.
In each figure, 1 is video switch switch and decoding circuit, 2,3,4 is the electronic attenuator circuit, 5 is the correction wave form generator of numeral or analog form, and 6,7,8 are the simulation adder circuit, and 9,10,11 is last line video amplifier circuit, 12,13,14 is the primary colours projection tube, 15 is the high pressure mixing circuit, and 16 is the level change component consistent with the luminance distortion situation of screen vertical direction, and 17 is the level change component consistent with the luminance distortion situation of screen level direction.
Fig. 1 provides a kind of embodiment that is suitable under the general application scenario.
As shown in block diagram, composite video signal (VIDEO) from the outside input, brightness and chrominance separation signal (Y, C), brightness and chrominance component signal (Y, Cr, Cb), primary colour signal (R, G, B, H, V) etc. the input signal of various different modes is converted into tristimulus signals R1 after via video switch switch and decoding circuit 1, G1, B1, the correction wave form generator 5 of numeral or analog form is brightness and contrast's correction signal Va that benchmark produces waveform shown in (Fig. 6) with line synchronizing signal H1 and field sync signal V1, with Va is that control voltage is controlled electronic attenuator circuit 2 respectively, 3,4 attenuation, control the amplitude of three primary colors vision signal by the size of controlling this attenuation, thereby control the size of contrast.In simulation adder circuit 6,7,8, Va and the three primary colors vision signal R2, G2, the B2 that handle through contrast correction are carried out superposition, thereby change the luminance reference level of three primary colors vision signal, realize correction brightness.The three primary colors vision signal R3, G3, the B3 that proofread and correct through the brightness and contrast amplify tristimulus signals R, G, the B that the back obtains by final stage video amplifier circuit 9,10,11, are used to drive projection tube.System's control microprocessor of complete machine is by the waveform adjustment of system's control bus (SCL, SDA) realization to Va, thereby realization is adjusted the full screen calibration result.The characteristics of present embodiment are to carry out the brightness and contrast to proofread and correct and utilize special correcting circuit (2,3,4,6,7,8) to carry out, can not produce additional dark balance of three primary colors or bright balance distortion in the central authorities and the marginal portion of screen, overall brightness is obtained calibration result preferably.
Fig. 2 provides second embodiment, and it is suitable for the occasion that correction accuracy is had relatively high expectations.Shown in block diagram, composite video signal (VIDEO) from the outside input, brightness and chrominance separation signal (Y, C), brightness and chrominance component signal (Y, Cr, Cb), primary colour signal (R, G, B, H, V) etc. the input signal of various different modes is converted into tristimulus signals R1 after via video switch switch and decoding circuit 1, G1, B1, the correction wave form generator 5 of numeral or analog form is gamma correction signal Va and the contrast correction signal Vb that benchmark produces waveform shown in (Fig. 6) with line synchronizing signal H1 and field sync signal V1, with Vb is that control voltage is controlled electronic attenuator circuit 2 respectively, 3,4 attenuation, control the amplitude of three primary colors vision signal by the size of controlling this attenuation, thereby control the size of contrast.In simulation adder circuit and 6,7,8, gamma correction signal Vb and the three primary colors vision signal R2, G2, the B2 that handle through contrast correction are carried out superposition, thereby change the luminance reference level of three primary colors vision signal, realize correction brightness.The three primary colors vision signal R3, G3, the B3 that proofread and correct through luminance contrast are used to drive projection tube by tristimulus signals R, G, the B that final stage video amplifier circuit 9,10,11 amplifies the back acquisition.System's control microprocessor of complete machine is by the waveform adjustment of system's control bus (SCL, SDA) realization to Va, Vb, thereby realization is to the adjustment of full screen mode calibration result.Present embodiment is except the characteristics of last example, also have gamma correction and contrast to proofread and correct and separately carry out, can transfer to the characteristics of calibration result the best respectively by control bus (SCL, SDA) by the machine system control microprocessor, be applicable to the occasion that correction accuracy is had relatively high expectations.
Fig. 3 provides the 3rd embodiment, and it is applicable to the occasion that correction accuracy is had relatively high expectations.As block representation, composite video signal (VIDEO) from the outside input, brightness and chrominance separation signal (Y, C), brightness and chrominance component signal (Y, Cr, Cb), primary colour signal (R, G, B, H, V) etc. the input signal of various different modes is converted into tristimulus signals R1 after via video switch switch and decoding circuit 1, G1, B1, the correction wave form generator 5 of numeral or analog form is the gamma correction signal Var that benchmark produces waveform shown in (Fig. 6) with line synchronizing signal H1 and field sync signal V1, Vag, Vab and contrast correction signal Vb, with Vb is that control voltage is controlled electronic attenuator circuit 2 respectively, 3,4 attenuation, control the amplitude of three primary colors vision signal by the size of controlling this attenuation, thereby control the size of contrast.Three primary colors vision signal R2, G2, B2 through contrast correction are added to final stage video amplifier circuit 9,10,11, R2, G2, B2 and Var, Vag, Vab are carried out superposition in 9,10,11, to realize the gamma correction of three primary colors respectively, be used to drive projection tube by 9,10,11 tristimulus signals R, G, the B that amplify the back acquisition.System's control microprocessor of complete machine is by the waveform adjustment of system's control bus (SCL, SDA) realization to Vb, thereby realize adjustment to full screen contrast correction effect, realize the waveform of Var, Vag, Vab is adjusted respectively by system's control bus (SCL, SDA), thereby realize the adjustment of full screen brightness calibration result and realize owing to carry out the compensation adjustment that three primary colors that gamma correction brings are added dark balance and bright balance distortion.Present embodiment except example one and example two characteristics owing to omitted the simulation adder, circuit is comparatively simple.But, owing in the final stage video amplifier circuit, carry out gamma correction and bring dark balance of additional three primary colors and bright balance distortion, so need system's control microprocessor of complete machine respectively the waveform of Var, Vag, Vad to be adjusted the compensation that realizes this kind distortion respectively by system's control bus (CSL, SDA).So the present embodiment hardware circuit is comparatively simple, circuit cost is lower, but the machine system Control Software is complicated, is applicable to the occasion that correction accuracy is had relatively high expectations.
Fig. 4 provides the 4th embodiment, it is suitable for alignment requirements is not very high, do not need the occasion of accurately proofreading and correct, shown in block diagram, composite video signal (IDEO) from the outside input, brightness and chrominance separation signal (Y, C), brightness and chrominance component signal (Y, Cr, Cb), primary colour signal (R, G, B, H, V) etc. the input signal of various different modes is converted into tristimulus signals R1 after via video switch switch and decoding circuit 1, G1, B1, the correction wave form generator 5 of numeral or analog form is the gamma correction signal Var that benchmark produces waveform shown in (Fig. 6) with line synchronizing signal H1 and field sync signal V1, Vag, Vab, R1, G1, B1 is added to final stage video amplifier circuit 9,10,11, with R1, G1, B1 and Var, Vag, Vab is 9,10, carry out superposition in 11, to realize the gamma correction of three primary colors respectively, by 9,10,11 amplify the tristimulus signals R that the back obtains, G, B is used to drive projection tube.The system control processor of complete machine is realized the waveform of Var, Vag, Vab is adjusted respectively by system's control bus (SCL, SDA), thereby realizes the adjustment of full screen brightness calibration result and realize owing to carry out the additional dark balance of three primary colors that gamma correction brings and the compensation adjustment of bright balance distortion.Present embodiment is because omitted the contrast correction circuit, so have the circuit characteristic of simple, also three the same with embodiment simultaneously, having needs the system of complete machine control microprocessor respectively the waveform adjustment of Var, Vag, Vab to be realized characteristics to the compensation of this kind distortion by system's control bus (SCL, SDA).Present embodiment is applicable to less demanding, does not need the occasion of accurately proofreading and correct.
Fig. 5 provides the 5th embodiment, it is suitable for the not high occasion that only needs simple and easy correction of alignment requirements, by block representation, three primary colors vision signal R1, G1, B1 is through final stage video amplifier circuit 9,10, the three primary colors vision signal R that obtains after 11 amplifications, G, B is used to drive three kinds of primary colours projection tubes 12,13,14, the correction wave form generator 5 of numeral or analog form is that benchmark produces the gamma correction signal Va of waveform as shown in Figure 6 with line synchronizing signal H1 and field sync signal V1, amplify and high pressure mixing circuit 15 in be added to the screen grid of three kinds of primary colours projection tubes after Va amplified again behind the screen grid voltage Vs mixing superposition with certain ratio and three kinds of primary colours projection tubes, realization to full screen brightness from dynamic(al) correction.The characteristics of present embodiment are to have omitted contrast correction, and do not need to carry out embodiment four in system's control microprocessor of necessary complete machine by system's control bus (SCL, SDA) to the adjustment of full screen brightness calibration result and to owing to carry out the additional dark balance of three primary colors that gamma correction brings and the compensation adjustment of bright balance distortion, be applicable to require different simple and easy correction occasions.
Fig. 6 represents that waveform (a) is line synchronizing signal H1, waveform (b) is field sync signal V1, waveform (c) is that field sync signal V1 and line synchronizing signal H1 are gamma correction Va and the contrast correction signal Vb that benchmark produced, waveform (b) is made up of 16 and 17 two component superpositions again, the level of component 16 changes consistent with the luminance distortion situation of screen vertical direction, and its cycle and phase place are that benchmark carries out synchronously with V1.
Claims (3)
1, CRT projection TV correction method for uniform bright field, it is characterized in that, respectively R, G, B three primary colors vision signal amplifying circuit are carried out the gamma correction of full screen, the step of correction is: 1) seek one on image level direction and vertical direction by with the consistent correction voltage that changes of the rugged change rule of screen intensity; 2) carrying out forward or backwards to R, G, B three primary colors vision signal according to primary video signal polarity respectively with this correction voltage, the mode of superposition realizes gamma correction; 3) also can carry out gamma correction with the mode that the screen grid voltage superposition of R, G, B three primary colors projection tube is modulated respectively with this correction voltage; 4) the mode degree of comparing of controlling the gain of R, G, B three primary colors vision signal processing and amplifying passage respectively with this correction voltage is proofreaied and correct.
2, bearing calibration according to claim 1, it is characterized in that, described correction voltage, its producing method can adopt the technology that waveform is synthesized of signal imitation mode, also can adopt the data access D/A switch technology of digital processing mode to realize.
3, bearing calibration according to claim 1 is characterized in that, this bearing calibration is suitable for the entire machine design field of highly integrated circuit scope and multiple signaling interface.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 00134020 CN1127263C (en) | 2000-12-07 | 2000-12-07 | Correction method for uniform bright field of CRT projection TV |
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| CN 00134020 CN1127263C (en) | 2000-12-07 | 2000-12-07 | Correction method for uniform bright field of CRT projection TV |
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| CN1291841A true CN1291841A (en) | 2001-04-18 |
| CN1127263C CN1127263C (en) | 2003-11-05 |
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| CN 00134020 Expired - Fee Related CN1127263C (en) | 2000-12-07 | 2000-12-07 | Correction method for uniform bright field of CRT projection TV |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100417185C (en) * | 2001-03-01 | 2008-09-03 | 深圳Tcl新技术有限公司 | Brightness compensation method for digital dynamic-nonlinear CRT projection system |
| CN102256086A (en) * | 2010-05-20 | 2011-11-23 | 北京创毅视讯科技有限公司 | Image adjusting method and device for television broadcast technology |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100442333C (en) * | 2004-09-14 | 2008-12-10 | 佳能株式会社 | Display apparatus and display method |
| JP5127121B2 (en) | 2004-09-14 | 2013-01-23 | キヤノン株式会社 | Display device and display method |
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2000
- 2000-12-07 CN CN 00134020 patent/CN1127263C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100417185C (en) * | 2001-03-01 | 2008-09-03 | 深圳Tcl新技术有限公司 | Brightness compensation method for digital dynamic-nonlinear CRT projection system |
| CN102256086A (en) * | 2010-05-20 | 2011-11-23 | 北京创毅视讯科技有限公司 | Image adjusting method and device for television broadcast technology |
| CN102256086B (en) * | 2010-05-20 | 2013-01-02 | 北京创毅视讯科技有限公司 | Image adjusting method and device for television broadcast technology |
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| CN1127263C (en) | 2003-11-05 |
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Granted publication date: 20031105 Termination date: 20131207 |