CN100338959C - Automatic contrast control with masking out of interference signals - Google Patents
Automatic contrast control with masking out of interference signals Download PDFInfo
- Publication number
- CN100338959C CN100338959C CNB038235021A CN03823502A CN100338959C CN 100338959 C CN100338959 C CN 100338959C CN B038235021 A CNB038235021 A CN B038235021A CN 03823502 A CN03823502 A CN 03823502A CN 100338959 C CN100338959 C CN 100338959C
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- China
- Prior art keywords
- signal
- control
- color difference
- control device
- contrast
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- 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
- H04N9/68—Circuits for processing colour signals for controlling the amplitude of colour signals, e.g. automatic chroma control circuits
Abstract
On account of the 1H line delay of the PAL delay decoder (or SECAM decoder) and the subsequent dematrixing dictated addition of the color difference signals R - Y, G - Y, B - Y to the luminance signal Y, during an automatic contrast control in which the RGB signals are used as controlled variable, the controlled variable is increased if a color picture content of a picture line Hn-1 delayed in propagation-time-dictated fashion meets an achromatic picture content in the picture line Hn which follows at the line frequency, since the signal amplitude of the color picture content is added to the signal amplitude of the achromatic picture content, in principle, by the dematrixing. Therefore, the invention provides a circuit arrangement (3) for controlling the contrast control device (2) and for the signal monitoring of the luminance signal Y and the color difference signals R - Y, B - Y, which has a controllable switch (36), by means of which the control loop - formed by the control device (2) in the control of the contrast - can be interrupted practically immediately in the event of a luminance signal threshold value and a color difference signal threshold value being exceeded, so that an undesirably increased RGB signal amplitude is actually unable in the first place to pass to the signal input of the measurement and evaluation circuit (21, 22) of the contrast control device (2).
Description
Technical field
The present invention relates to a kind of device that is used to reproduce colour TV signal, relate in particular to and be used to use auto contrast (contrast) control to handle the circuit of vision signal.
Background technology
Many known, the residual carrier difference that causes at transmitter and/or receiver end and circuit tolerance and program domination dynamically poor---such as owing to write down to the studio or the change of so-called external broadcasting from lengthy motion picture (feature film)---may cause the contrast variation of bigger or less degree.
Therefore, in order to improve utilization by the modulation range of utilizing the picture tube in the advance TV machine accordingly for the luminous power of picture tube, useful is to come by means of control device to control automatically contrast by colour signal path R (redness), G (green) and the gain among the B (blueness) that improves or be reduced in the reconstruction of image on principle accordingly during the reconstruction of image.Under the cathode-driven situation of the current main color picture tube that uses, employed controlled variable is colour signal RGB---hereinafter referred to as rgb signal, these signals are fed into evaluation circuits via peak detector, so that therefrom obtain to be used for the control voltage that the correspondence gain of rgb signal is provided with.At for example US-A-5, the circuit that is used for such auto contrast's control has been described in 245,434.
But, compare with the device that does not have this control, use the control of such contrast principle, can demonstrate following not desired effects according to the television set of PAL or Secam method: supposition has identical contrast setting about the reproduction of black and white image, reproduction period at the coloured image of the device by having auto contrast's control unit, compare with the device that does not have auto contrast's control unit, contrast often is shown as reduction.
Summary of the invention
Therefore, the present invention relates to avoid the purpose of such contrast reduction.
The present invention is based on following experience:
Because postponing 1H wire delay and subsequently color difference signal R-Y, G-Y, the B-Y of decoder (or SECAM decoder), PAL arranges addition (dematrixing-dictatedaddition) to the dematrix of brightness signal Y, rgb signal is used as auto contrast's control period of controlled variable therein, if the image line H that the mode of arranging with the propagation time is delayed
N-1Color image content meet the image line H that follows on the online frequency
nIn colourless (achromatic) picture material, then increased described controlled variable, this be because the signal amplitude of color image content by dematrix on the signal amplitude that is added to described colourless picture material on the principle.
If during dematrix, the image line H that is postponed
N-1The blue image content of maximum saturation meet subsequently image line H
nColourless, maximum white image content, then by this way, the i.e. increase of the described controlled variable that takes place inevitably has maximum: under the situation that the rgb signal of correspondence changes, can obtain from following the establishing an equation for PAL and SECAM in essence aspect this---the line by having 75% saturated " blueness " and have 100% " white " for example, the line of following on the online frequency---maximum rgb signal amplitude or according to described example, signal amplitude B (blueness) from its controlled variable of can deriving reaches relative maximum in this case:
B=under the situation of PAL (1+0.89*0.75/2) * 100%=133% or
B=under the situation of SECAM (1+0.89*0.75) * 100%=167%, the control device that is used for auto contrast control is interpreted as the increase of rgb signal amplitude greater than 100%, promptly so-called " white excessively " is so that react for the minimizing of the control domination of the correspondence of rgb signal gain in view of the above.
Because the discharge time constant (amplitude level: several seconds) of the contrast flickering (flicker) that is used under situation about changing, avoiding possible in the picture material of the peak detector described in the introduction of auto contrast's control device, can't deny ground, this reduction of rgb signal gain often only is temporary transient under the situation that changes picture material, but remaining, this does not expect, because compare with the device that does not have this auto contrast's control unit, it has caused the image impression of low contrast, has therefore hindered the even high-contrast that is intended to.
Therefore, the present invention is based on such thought: reducing as wide as possible may be in the influence of vertical " colour/white signal is jumped " back rgb signal amplitude contingent, that improve by this way for auto contrast's control---hereinafter referred to as the rgb signal amplitude that increases undesirably.
Therefore, the invention provides a kind of circuit arrangement, the signal monitoring that is used to control contrast control spare and is used for brightness signal Y and color difference signal R-Y, B-Y, described circuit arrangement has a gate-controlled switch, by it, can be at the interruption controls loop immediately of reality under the situation that luminance signal threshold value and color difference signal threshold value are exceeded---in contrast control, forms, so that do not expect that in fact the rgb signal amplitude that increases can not at first not be sent to the measurement of contrast control spare and the signal of evaluation circuits is imported by control device.In this case, control described switch in a corresponding way by a control signal, described control signal is produced during the amplitude of signal monitoring brightness signal Y and color difference signal R-Y, B-Y by the assessment corresponding signal levels.
According to the threshold value that the present invention has been scheduled to be respectively applied to brightness signal Y and colour difference signal B-Y and R-Y, luminance signal threshold value is disposed near normal " white peak "---preferably being the 75%...85% of 100% normalized standard white level corresponding to quantity---and the maximum possible colour difference signal level of 75% saturated colour TV signal (with respect to the corresponding colour difference signal input for the treatment of the dematrix level of the corresponding circuits of vision signal) be provided for respectively the threshold value of the corresponding amplitude of colour difference signal B-Y and R-Y at the best 10%...20% in the PAL situation and the best 20%...40% in the SECAM situation. In this case, the present invention utilizes the fact valuably:statistically see, big luminance level like this is colourless or color is only arranged slightly, so that according to above-mentioned threshold value, the rgb signal amplitude that is increased undesirably can be used to control the described circuit arrangement identification of control device and signal monitoring brightness signal Y and color difference signal R-Y, B-Y, and can make a distinction with other brightness and colour signal constellation (constellation).
The invention enables might be to have the useful mode of maximum possible rgb signal gain---promptly, in fact at the cut-off point of their beam system separately with drive between their saturation point of RGB output amplifier level---operation display under than the situation of low contrast and under the situation of higher contrast vision signal, such as particularly color picture tube and TFT screen.
Other advantages of the present invention as can be seen from following explanation.
Description of drawings
Use illustration embodiment to illustrate in greater detail the present invention with reference to the accompanying drawings.
Fig. 1 is the schematic circuit according to the device of playback video signal of the present invention.
Embodiment
In the accompanying drawings, single accompanying drawing shows the block diagram of circuit 1, described circuit 1 uses control device 2 to handle vision signal, described control device 2 is used in conjunction with controlling contrast according to circuit arrangement 3 of the present invention, described circuit arrangement 3 is used to control control device 2 and signal monitoring brightness signal Y and color difference signal R-Y, B-Y, and described circuit arrangement 3 comprises circuit block 31-36 in fact.Suppose by be designed as video processor, know remaining circuit block 11-13 and 21-23 and function thereof from the integrated circuit STV 2161 of ST (SGS/Thomson).Therefore, only illustrate in necessary scope that they are to understand the present invention.
By threshold detector 31-33, circuit arrangement 3 monitors brightness signal Y and color difference signal R-Y, B-Y, and control control device 2 to depend on the mode that monitors the result, described control realizes by a switch, described switch is by described circuit arrangement 3 controls, and be disposed in the signal path of the control device 2 between combinational circuit 23 and the peak detector 22, described combinational circuit 23 makes and might detect corresponding maximum rgb signal level in the signal output of the circuit 1 that is used to handle vision signal.
For according to signal monitoring of the present invention, brightness signal Y and color difference signal R-Y, B-Y are fed into the signal input of threshold detector 31-33 by the respective signal carrying connecting line that is directed to circuit block 11.The circuit block that parts are set 11 that comprises the device setting that is used for contrast and colour saturation is also by feed-in control voltage U
Control---it obtains by control device 2---is to be used for controlling contrast during the reconstruction of image.In the path of further signal processing, there is circuit block 12 circuit block 11 back, and circuit block 12 comprises the circuit block that is used for recovering by dematrix color difference signal R-Y and B-Y rgb signal.Rgb signal R ', the G ' that is recovered, B ' are fed into the rgb signal output of the circuit 1 that is used to handle vision signal then via circuit block 13, described output is connected to the respective signal input of RGB output amplifier (not shown).Circuit block 13 has the parts that are provided with that are used for setting device brightness.Realize being provided with and being provided with via control bus 14 for the independent of contrast of installing and colour saturation for the independent of brightness.
Above-mentioned combinational circuit 23 makes might be by carrying out rgb signal or operate and detect its corresponding maximum level of exporting at the signal of the circuit 1 that is used to handle vision signal, except above-mentioned combinational circuit 23 and above-mentioned peak detector 22, control device 2 also comprises control amplifier 21, its signal input is connected to the signal output of peak detector 22, so that control contrast during the reconstruction of image.
Except being used to control the gate-controlled switch 36 and the threshold detector 31-33 of control device 2---by they via the assessment corresponding signal levels monitor brightness signal Y and color difference signal R-Y, B-Y---, comprise two gate circuits 34 and 35 in fact according to circuit arrangement 3 of the present invention, first gate circuit 34 is designed conduct or door, and second gate circuit 35 is designed conduct and door.The signal output of second gate circuit 35 is connected to the control input of gate-controlled switch 36, and second gate circuit 35 has two signal inputs.Its first signal input is connected to the signal output of the luminance signal threshold value detector 33 that is used for Y, and its secondary signal input is connected to the signal output of first gate circuit 34 that is designed conduct or door.First gate circuit 34 has two signal inputs equally, and each of these two signal inputs is connected to the signal output of the color difference signal threshold detector 31,32 that is assigned to it.
Be designed as a comparison that the operational amplifier of device can be used as threshold detector 31-33 valuably, the luminance signal threshold value that is used for corresponding color difference signal threshold value is used as benchmark.In this case, above-mentioned luminance signal threshold value is disposed near " white peak ", promptly is preferably in quantity and is the 75%...85% of 100% normalized standard white level.The maximum possible color difference signal level of 75% saturated colour TV signal, according to the 10%...20% under the situation of the colour signal of PAL method with in the threshold value that is used as corresponding color difference signal B-Y or R-Y according to the 20%...40% under the colour signal situation of SECAM method.
Illustrate method of operating according to the positive circuit logic according to circuit arrangement 3 of the present invention.
If for one of two color difference signal B-Y, R-Y, the threshold value of brightness signal Y threshold value and color difference signal is exceeded, and then the output in two relevant threshold detector 31,33 and 32,33 produces signal level corresponding to logical value H respectively in this case.Consequently also be designed to produce signal level corresponding to logical value H as signal output with second gate circuit 35 of door.By this signal level, gate-controlled switch 36 Be Controlled enter nonconducting state, as its result---shown in the position of the switch of switch 36---according to the control loop of the present invention's interruption with control device 2 formation, so that because the propagation delay of 1H and dematrix and in fact the rgb signal amplitude that improves undesirably can not at first be sent to the signal input of peak detector 22, described peak detector 22 forms the measurement and the evaluation circuits of control device 2 with control amplifier 21.
The circuit that being used to control can being integrated into valuably according to circuit arrangement 3 of the present invention of control device 2 is designed as video processor---type of for example above-mentioned STV 2161 from ST---.
Claims (6)
1. device according to PAL or SECAM method playback video signal, have color monitor and control device (2), described control device (2) is used for reproduced vision signal rgb signal (R, G, B) auto contrast's control, described rgb signal (R, G, B) be that (R-Y B-Y) obtains described rgb signal (R by utilizing luminance signal (Y) dematrix color difference signal, G, B) be used as controlled variable and be fed into the signal input of evaluation circuits (21,22), so that therefrom produce control voltage (U via combinational circuit (23)
Control), be used for controlling accordingly about the contrast of the vision signal reproduced and/or the signal gain of colour saturation, it is characterized in that: a kind of circuit arrangement (3) is provided, be used to control described control device (2) and be used for luminance signal (Y) and color difference signal (R-Y, B-Y) signal monitoring, described circuit arrangement (3) has a switch (36) that is connected among the control loop that is formed by control device (2) in contrast control, it can be according to the signal monitoring result and Be Controlled, but and under the situation that predetermined brightness signal threshold value and the color difference signal threshold value that can be scheduled to are exceeded, interrupt described control loop, the signal input feed-in that prevents the evaluation circuits (21,22) to control device thus is because the colour signal propagation delay of 1H and dematrix and the rgb signal amplitude of being amplified undesirably.
2. according to the device of claim 1, it is characterized in that: providing the quantity of " reference white " for luminance signal threshold value is the scope of the 75%-85% of 100% normalization level.
3. according to the device of claim 1, it is characterized in that, under the situation of PAL, be used for corresponding color difference signal (B-Y, R-Y) threshold value is disposed in the scope of 10%-20% of maximum possible color difference signal level of 75% saturated colour TV signal, under the SECAM situation, (B-Y, threshold value R-Y) is disposed in the scope of 20%-40% of the maximum possible color difference signal level of 75% saturated colour TV signal to be used for corresponding color difference signal.
4. according to each described device in the claim 1 to 3, it is characterized in that, be used for luminance signal (Y) and color difference signal (B-Y, the circuit arrangement of signal monitoring R-Y) (3) has and is used to treat supervisory signal (R-Y, B-Y, the threshold detector of each Y) (31-33), be used for corresponding color difference signal (R-Y, B-Y) threshold detector (31,32) output of signal via or door (34) and be connected to a signal input with door (35), its another signal input is connected to the signal output of the threshold detector (33) that is used for luminance signal (Y), produce control signal in signal output, be used for controlling the switch (36) of the signal path that is disposed in the control device (2) that is used for auto contrast's control with door (35).
5. one kind at the circuit of handling vision signal according to PAL or SECAM method reproduction period, has control device (2), described control device (2) is used for wanting reproduced vision signal rgb signal (R, G, B) auto contrast's control, described rgb signal (R, G, B) be that (R-Y B-Y) obtains described rgb signal (R by utilizing luminance signal (Y) dematrix color difference signal, G, B) be used as controlled variable and be fed into the signal input of evaluation circuits (21,22), so that produce control voltage (U from it via combinational circuit (23)
Control), be used for controlling accordingly about the contrast of the vision signal reproduced and/or the signal gain of colour saturation, it is characterized in that: a kind of circuit arrangement (3) is provided, be used to control described control device (2) and be used for luminance signal (Y) and color difference signal (R-Y, B-Y) signal monitoring, described circuit arrangement has a switch (36) that is connected among the control loop that is formed by control device (2) in contrast control, it can be according to the signal monitoring result and Be Controlled, but and under the situation that predetermined brightness signal threshold value and the color difference signal threshold value that can be scheduled to are exceeded, interrupt described control loop, the signal input feed-in that prevents the evaluation circuits (21,22) to control device thus is because the colour signal propagation delay of 1H and dematrix and the rgb signal amplitude of being amplified undesirably.
6. according to the circuit of claim 5, it is characterized in that, be used for luminance signal (Y) and color difference signal (B-Y, the circuit arrangement of signal monitoring R-Y) (3) has and is used to treat supervisory signal (R-Y, B-Y, the threshold detector of each Y) (31-33), be used for corresponding color difference signal (R-Y, B-Y) threshold detector (31,32) output of signal via or door (34) and be connected to a signal input with door (35), its another signal input is connected to the signal output of the threshold detector (33) that is used for luminance signal (Y), produce control signal in signal output, be used for controlling the switch (36) of the signal path that is disposed in the control device (2) that is used for auto contrast's control with door (35).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10246120.1 | 2002-10-01 | ||
| DE2002146120 DE10246120A1 (en) | 2002-10-01 | 2002-10-01 | Automatic contrast control with suppression of interference signals |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1685740A CN1685740A (en) | 2005-10-19 |
| CN100338959C true CN100338959C (en) | 2007-09-19 |
Family
ID=32038224
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB038235021A Expired - Fee Related CN100338959C (en) | 2002-10-01 | 2003-09-22 | Automatic contrast control with masking out of interference signals |
Country Status (4)
| Country | Link |
|---|---|
| CN (1) | CN100338959C (en) |
| AU (1) | AU2003270238A1 (en) |
| DE (1) | DE10246120A1 (en) |
| WO (1) | WO2004032525A1 (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1044796A (en) * | 1989-02-11 | 1990-08-22 | 顿涅茨克综合技术研究所 | The control monitor unit of lifting means brake system |
| EP0529522A2 (en) * | 1991-08-30 | 1993-03-03 | Thomson Consumer Electronics, Inc. | Video system including apparatus for deactivating an automatic control arrangement |
| CN1070783A (en) * | 1991-08-30 | 1993-04-07 | 汤姆森消费电子有限公司 | Comprise the video system that makes the inactive equipment of automatic control equipment |
| CN1082797A (en) * | 1992-05-22 | 1994-02-23 | 汤姆森消费电子有限公司 | Autopix circuit with vertical blanking of insertion |
| CN1175857A (en) * | 1996-08-08 | 1998-03-11 | 德国汤姆逊-布朗特公司 | Television receiver having line delay line in colour channel |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19632018A1 (en) * | 1996-08-08 | 1998-02-12 | Thomson Brandt Gmbh | Television receiver circuit with line delay line in colour channel |
-
2002
- 2002-10-01 DE DE2002146120 patent/DE10246120A1/en not_active Withdrawn
-
2003
- 2003-09-22 AU AU2003270238A patent/AU2003270238A1/en not_active Abandoned
- 2003-09-22 CN CNB038235021A patent/CN100338959C/en not_active Expired - Fee Related
- 2003-09-22 WO PCT/EP2003/010519 patent/WO2004032525A1/en not_active Application Discontinuation
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1044796A (en) * | 1989-02-11 | 1990-08-22 | 顿涅茨克综合技术研究所 | The control monitor unit of lifting means brake system |
| EP0529522A2 (en) * | 1991-08-30 | 1993-03-03 | Thomson Consumer Electronics, Inc. | Video system including apparatus for deactivating an automatic control arrangement |
| CN1070783A (en) * | 1991-08-30 | 1993-04-07 | 汤姆森消费电子有限公司 | Comprise the video system that makes the inactive equipment of automatic control equipment |
| CN1082797A (en) * | 1992-05-22 | 1994-02-23 | 汤姆森消费电子有限公司 | Autopix circuit with vertical blanking of insertion |
| CN1175857A (en) * | 1996-08-08 | 1998-03-11 | 德国汤姆逊-布朗特公司 | Television receiver having line delay line in colour channel |
Also Published As
| Publication number | Publication date |
|---|---|
| AU2003270238A1 (en) | 2004-04-23 |
| CN1685740A (en) | 2005-10-19 |
| DE10246120A1 (en) | 2004-04-22 |
| WO2004032525A1 (en) | 2004-04-15 |
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Granted publication date: 20070919 Termination date: 20120922 |