CN1033129C - Video system including apparatus for deactivating automatic control arrangement - Google Patents
Video system including apparatus for deactivating automatic control arrangement Download PDFInfo
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- CN1033129C CN1033129C CN92110193A CN92110193A CN1033129C CN 1033129 C CN1033129 C CN 1033129C CN 92110193 A CN92110193 A CN 92110193A CN 92110193 A CN92110193 A CN 92110193A CN 1033129 C CN1033129 C CN 1033129C
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- signal
- control
- contrast
- control signal
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/57—Control of contrast or brightness
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- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Television Receiver Circuits (AREA)
- Transforming Electric Information Into Light Information (AREA)
- Controls And Circuits For Display Device (AREA)
- Picture Signal Circuits (AREA)
Abstract
A projection television system includes an automatic contrast control section for controlling the amplitude of the luminance signal in response to the peak value of a luminance-representative image component signal in order to prevent white-spot blooming. Circuitry is provided for deactivating the automatic contrast control section when a user sets the contrast control level above a given threshold level, e.g., corresponding to the maximum contrast control level. As a result white-spot blooming is inhibited in order to ensure sharp images for a contrast control range below the given threshold level while allowing maximum white image components to be produced (at the expense of white spot blooming) when the contrast control level is set above the threshold level, depending on the preference of the user.
Description
The equipment that automatic control equipment is stopped using that the present invention relates to use in the television system more precisely, relates to the equipment of stopping using as the automatic control equipment of user's control setting function that makes.
In the advance TV receiver, preferably for example the contrast by automatic control representation image prevents " white point is fainted ".Generally, contrast is controlled by autoelectrinic bundle current limiting system, and this system detects electron beam current that picture tube attracts and reduce contrast when electron beam current surpasses predetermined line level.This system licenses to D.H.Willis on September 4th, 1979, be entitled as in the United States Patent (USP) 4167026 of " autoelectrinic bundle flow restricter " and describe.Contrast also can be by the control of automatic white peak control system, and this system detects the acrometron of vision signal, luminance signal for example, and when video amplitude surpasses intended threshold level, reduce contrast.When image comprised excessive white peak in corresponding to the zonule of for example information character or television stadio or the text that provides such as other signal source of VCR one class of band " on the screen " indicating characteristic, white peak response auto contrast control appliance forbade that luminous point faints.License in the United States Patent (USP) 4980756 that W.A.Lagoni is entitled as " control-signals generator of television system " in December 25 nineteen ninety and to have described this system.
Have recognized that the contrast decay can reduce the contrast and the brightness of representation image, more specifically get on very well, though having recognized that when the representation image comprises preferably provides the auto contrast to control the amplitude that reduces luminance signal when surpassing corresponding to the predetermined level of for example character white to peak value, the brightness amplitude of intermediate range also is lowered.This causes contrast and brightness decay.In order to overcome the problems referred to above, the nonlinear amplitude control section of known utilization and contrast control unit cascade coupled is with respect to dynamically emphasizing intermediate range amplitude intensity level as the intensity level significantly of luminance signal mean function.As a result, excessive white but for the low image of average brightness level for comprising to peak value, descend and the amplitude of intermediate range intensity level rises simultaneously to the amplitude of peak value in vain.Therefore, make " white luminous point is fainted " (and picture tube fluorescent material and driver saturated) minimum, form subjective sharp-pointed, bright image simultaneously.License in the United States Patent (USP) 5003394 that W.A.Lagoni is entitled as " comprise auto contrast and white extension process part dynamic video system " in December 25 nineteen ninety and to describe this system in detail.
Although above-mentioned dynamic video system is effectively forbidden fainting and excessive influence intermediate level luminance signal not owing to the luminous point of excessive peak white signal, in some cases, auto contrast's control appliance can be worked to limit the maximum obtainable operation of this system.For example, in projection television system, reduce the device of contrast automatically and under certain environment, can the mode opposite operate with the customer requirements that produces maximum light output in the maximum-contrast placement.It seems that from another point of view the user who buys optical projection system may not be concerned about especially that luminous point is fainted and replaced and be concerned about that the projection television system operation is to provide maximum light output when maximum-contrast is provided with.
According to one aspect of the present invention, in order to press the user's preferences operating TV system, provide equipment to be used for detecting the contrast control setting and on for example corresponding to the predetermined level of maximum-contrast setting or when surpassing this predetermined level auto contrast's control appliance is stopped using when it according to this setting.By this way, the maximum light output of display will not be subjected to the restriction of auto contrast's control section.
According to another aspect of the present invention, provide to be used for making the invalid circuit of automatic control equipment that resembles auto contrast's control appliance and so on.This circuit comprises the detecting element of the signal of the actual user's control level that is used to produce irrelevant contrast control level one class of expression such as the level that produces with the interaction of user's contrast control appliance and automatic control equipment, and is used to judge when user's control level representation signal reaches the comparing element of predetermined threshold.
During the manual control level size that the objective of the invention is to be equivalent to be scheduled to the work of control circuit is adjusted when a manual control signal.Described control circuit this manual control signal of response and an automatic control signal and work.
These aspects of the present invention and others are described in more detail below in conjunction with accompanying drawing.
Fig. 1 illustrates the block diagram that has wherein utilized a kind of canonical projection type television system of the present invention;
Fig. 2 illustrates the schematic diagram of the circuit enforcement of special some part be concerned about of the present invention in the expression television system shown in Figure 1; And
Fig. 3 illustrates the schematic diagram of the circuit enforcement of the special other part of being concerned about of the present invention in the expression television receiver shown in Figure 1.
In each accompanying drawing, same numeral is represented identical or like.
In television system shown in Figure 1, the independent brightness (Y that will derive from composite video signal by comb filter (not shown) for example
Go into) and colourity (C
Go into) signal component is coupled to for representation image and the respective input 1 and 3 of vision signal processing section that they are handled.
In the cascade brightness processed part that comprises " white expansion " part 5, pulse peaking part 7, contrast part 9 and brightness part 11, handle luminance input signal component (Y
Go into), handled luminance output signal (Y to produce
Go out).In brief, white expansion 5 provides the non-linear gain control function, the parts by a relatively large margin than the many mistakes of low amplitude part luminance signal of this function amplify brightness signal.In television system shown in Figure 1, luminance output signal (Y has been handled in response
Go out) average level dynamically control white spread function.Therefore, the luminance output signal Y that has handled by 6 responses of white expansion control unit
Go outProduce the white expansion control voltage of white expansion 5.In above-mentioned United States Patent (USP) 5003394, describe the function and the operation of white expansion 5 and white expansion control unit 6 in detail.Peaking, contrast and brightness part the 7,9, the 11st, conventional design and function, as known in field of television, they are controlled respectively corresponding to image and get over or the luminance output signal (Y of marginal definition
Go out) the high frequency composition, corresponding to the Y of image contrast
Go outAmplitude, and corresponding to the Y of image brightness
Go outThe DC component.
Be equipped with peaking, contrast and brightness user control unit 13,15 and 17 are to allow the individual features of user's manual adjustment flow graph elephant.Each user control unit 13,15 and 17 produces the DC control voltage of corresponding bright processing section, and can comprise a corresponding potentiometer under this application scenario.In addition, as more common in the advance TV system, each user control unit can comprise each D/A of being controlled by microprocessor, shown in Fig. 2 and 3.Microprocessor receives the order corresponding to image feature that the user is sent by keyboard.Keyboard can be installed on the remote control transmitter.
Handle chrominance input signal component (C by the color processing part 19 that comprises colour demodulator, saturation (amplitude) processing unit (not shown) and colourity or tone (phase place) processing unit (not shown)
Go into), to produce low level red, green and blue color difference signal (r-Y, g-Y and b-Y).In addition, color difference signal can be I and Q type.Saturation and colourity are handled available unshowned element and are controlled manual and/or automaticly.Color difference signal (r-Y, b-Y and g-Y), and the luminance output signal (Y that has handled
Go out) be coupled to matrix switch circuit 21 and make their combination results low level red, green and blue chrominance signals (r, g and b).
Such as contrast, brightness, color processing part 9,11 and 19 and the television system part of matrixer 21 1 classes can be included in the monolithic integrated circuit (IC) by frame 23 expressions.Represent each signal input and output side with small circle.
Amplify low level r, g and b colour signal by respective drive amplifier (DR) 25r, 25g and 25b and be suitable for being used for driving high level R, G and B colour signal such as the display 27 of projection arrangement one class that comprises each red, green and blue picture tube 29R, 29G and 29B, projection optical device's (not shown) and screen (not shown) with generation.Although described the present invention with reference to the projection type television system, it also can be applicable to the television system of direct viewing.Under the direct viewing situation, high level R.G and B colour signal are coupled to each negative electrode of public picture tube.
Though not shown for simplicity, this television system also comprises and is used to derive luminance input signal (Y
Go into) in the level that comprises and the Synchronous Processing part of vertical sync pulse.Lock-out pulse is handled by deflection and high voltage part 31, producing the defection signal of picture tube 29R, 29G and 29B, and the operating voltage of necessary high anode.Also lock-out pulse is handled with lead-out level and vertical blanking pulse, this level and vertical blanking pulse for example are inserted into each retrace interval of low level r, g and b signal within matrixer 21, therefore at level and vertical flyback interim display 24 with " blanking " from just avoiding producing visual return line.
As noted earlier, preferably limit electron beam current for fear of " white luminous point is fainted ".Generally, this is by detecting the average current that picture tube attracts from the high voltage source that links and producing the contrast that is used to reduce the representation image and the line control voltage of brightness one or both of is realized.In television system shown in Figure 1, this realizes by means of beam current limiter 33, and this electron beam current limliting device 33 can disclosed mode be provided with in the United States Patent (USP) 4167025 that D.H.Willis is entitled as " peak value electron beam flow restricter automatically " with licensing on September 4th, 1.Usually, the electron-beam limit flow operation is a kind of operation in tandem, at first reduces contrast, reduces brightness then, perhaps with contrast or independently.Determine the level that contrast and brightness descend by the diode 35 of Fig. 1 and the threshold value device of 37 expressions, described threshold value device is coupling between the corresponding contrast and brilliance control input of electron beam current limliting unit 33 and IC23.Diode 35 and 37 is normally non-conduction, and the line control voltage that produces when electron beam current limliting device 33 is when dropping to than low about 0.7 volt of contrast and brilliance control voltage respectively, and they transfer conducting to.In case one of diode 35 and 37 conducting, each image characteristics descends with the line control signal.
Except that the electron beam current limliting function that electron beam current limliting device 33 provides, the peak value drive level of picture tube 29R, 29G and 29B is restricted to predetermined value, because the electron-baem spot size is in big electron beam current amplitude non-linearity expansion.Especially, more describe in detail with reference to Fig. 3 as following, this is realized by auto contrast's control unit 39, this unit 39 detects by what peaking, contrast and the brightness processed part 7,9 of cascade and 11 produced and handles the instantaneous peak value amplitude that luminance output signal Y goes out, controls voltage to produce the auto contrast.Utilize and handled luminance output signal Y
Go outBut not undressed luminance input signal Y
Go into, because Y
Go outBe subjected to the influence of peaking, contrast and brightness user control.Such auto contrast control (can claim that also it is " automatic image (outo-pix) ") prevents the resolution detail loss in high brightness (white) district that brings because of fainting, allows the image of high-contrast (so subjectivity is bright) simultaneously when the threshold value of fainting is following when signal peak.This type auto contrast control device licenses in the United States Patent (USP) 4980756 that W.A.Lagoni is entitled as " the system control signal generator of TV " in above-mentioned December 25 nineteen ninety and is described in detail.
According to one aspect of the present invention, also provide and when the user is increased to the threshold value that surpasses corresponding to maximum-contrast with user's contrast control setting, make the invalid equipment of " automatic image " function.More particularly, television system shown in Figure 1 comprises the unit 41 that is coupling between user's contrast control unit 15 and the auto contrast's control unit 39, is used for making when customer requirements is provided with contrast control with maximum light output function television system auto contrast or " automatic image " function invalid or forbid.As mentioned above, in projection television system, for example as shown in Figure 1, no matter the user can find that projection television system is preferably in provides the output of maximum light and the possibility that defocuses of fainting and bringing because of luminous point under maximum user's contrast control setting.Certainly it is possible leaving out auto contrast's control appliance fully from projection television system, to guarantee producing maximum light output under the maximum-contrast control setting.Yet the anti-luminous point that this means auto contrast's control appliance benefit of fainting can not obtain on any contrast control set point.Therefore, for the image definition that keeps normal contrast to be provided with, best detection user's contrast control setting also makes as auto contrast's controlled function of user's control setting function inoperative selectively.Just as the skilled person will appreciate, the method that exists the multiple auto contrast's of making controlled function to stop using, wherein some is described with reference to Fig. 2 and 3.
In device shown in Figure 2, contrast control unit 15 comprises D/A (D/A) transducer that the responding digital control word produces the analog DC control signal.This D/A converter comprises the general control microprocessor 43 that is used to control the various functions that resemble peaking, contrast and brightness and so on.Comprise that the pulse signal of encoding with the pulse of expression contrast control setting in the mode of pulsewidth or binary rate modulation is produced by the switch element of switch 45 expressions under the control of microprocessor 43, and be coupled to the input of buffer amplifier 47.The low pass filter 49 by series resistance 51 and shunt capacitance 53 expressions is coupled in the output of buffer amplifier 47.The pulse signal filtering that filter 49 pair amplifiers 47 produce is to produce direct current user contrast control voltage.For illustrated embodiment, suppose and handle luminance output signal Y
Go outWhite be positive to part, increase the direct current contrast control signal corresponding to increasing gain, therefore increase contrast, and reduce contrast control signal and be equivalent to reduce gain and contrast.
As shown in Figure 2, auto contrast's control unit 39 comprises handling luminance output signal Y
Go outIn vain to the peak detector 55 of the peak detection of part.The VD of white peak wave detector 55 is coupled to an input of amplifier/comparator 57.Corresponding to the reference voltage V that has surpassed the peak level that image diffusion may take place
RPBe coupled to another input of amplifier/comparator 57.Peak detector 55 and amplifier/comparator 57 are set surpass reference voltage V at peak value
RPThe time reduce the contrast control voltage that the acrometron with luminance output signal becomes.
In the described layout of Fig. 2, as shown in Figure 1, autoelectrinic bundle flow restricter is coupled to contrast part 9 by diode 35.
The capacitor 53 of low pass filter 49 is shared filtering and storage respectively to control voltage by what user's contrast control unit 15, autoelectrinic bundle flow restricter 33 and auto contrast's control unit 39 produced.The control voltage that capacitor 53 two ends produce is the combination of control unit 15,33 and the 39 control voltages that produce.
As shown in Figure 2, make the auto contrast control inactive unit 41 and comprise another low pass filter 59, this low pass filter comprises series resistance 61 and the by-pass capacitor 63 that is coupled to buffer amplifier 47 outputs, is used to derive the actual manually dc voltage of setting corresponding to the user of contrast control setting.It should be noted that the contrast control voltage that capacitor 53 two ends of low pass filter 49 produce does not correspond to the actual manually contrast control setting that the user sets because it since user's contrast control unit 15 and auto contrast's control unit 39 and electron beam current limliting device 33 results of interaction produce.Buffer amplifier 47 is the low output impedance amplifier preferably, and for example the emitter follower amplifier is isolated low pass filter 59 and low pass filter 49 so that help.The direct voltage that filter 59 produces is coupled to an input of comparator 65.The reference voltage V that auto contrast's control unit 39 will be stopped using corresponding to the contrast control setting
RCBe coupled to another input of comparator 65.In most preferred embodiment of the present invention, reference voltage V
RCCorresponding to the maximum-contrast setting.The output of comparator 65 is coupled to the auto contrast controls single 39.Shown as with dashed lines among Fig. 2, the output of comparator 39 can be coupled to the different piece of auto contrast's control unit 39 to forbid its operation.Like this, for example the output of comparator 65 can be coupled to peak detection part 55 or amplifier/comparator part 57.
(the contrast control setting that the expression user wishes has surpassed reference voltage V when the output at low pass filter 59 produces dc voltage
RC) time comparator 65 produce the signal that auto contrast's control unit 39 is stopped using.If reference voltage V
RCCorresponding to the maximum-contrast setting, auto contrast's control unit 39 will be under an embargo in the maximum-contrast placement.If reference voltage V
RCCorresponding to being lower than the contrast setting that maximum-contrast is provided with, auto contrast's control unit 39 will be under an embargo than low level and corresponding to reference voltage V
RCAnd will obtain contrast control in the scope of the voltage difference between maximum user's contrast control voltage and nothing is controlled 39 interference from the auto contrast.By this way, television system will not have the white peak luminous point and work with fainting owing to the effect of auto contrast's control unit 39 on the first contrast control range, if and in surpassing second control range of the first contrast control range, regulated contrast, this television system could be operated and be produced prominent peak white picture component (not having the restriction owing to auto contrast's control unit 39).
As previously noted, available different ways is forbidden auto contrast's controlled function.A kind of mode is to prevent to handle luminance output signal (Y
Go out) be coupled to white peak wave detector 55.Another way is to change the reference voltage V that (raising) auto contrast controls comparator/amplifier 57
RPAn approach is to prevent that the control voltage of comparator/amplifier 57 outputs generation is coupled to the contrast part 9 of IC27 again.Also having an approach is to prevent that peak detector part 55 is coupled to comparator/amplifier 57.Fig. 3 shows the schematic diagram of the device of this technology of enforcement.
In device shown in Figure 3, the PNP transistor 67 and 69 that is configured to emitter follower amplifier is coupled to the corresponding output end of the white peak wave detector 55 and the comparator/amplifier 57 of auto contrast's control unit 39 as buffer.The comparator 65 of auto contrast's de-energisation unit 41 comprises PNP transistor 71, and this transistor base is coupled to the output of low pass filter 59, emitter be connected to the operating potential power supply (+Vcc), its collector electrode is connected to an end of resistor 73.The other end of resistor 73 is connected to the emitter of the emitter following structure PNP transistor 67 that links to each other with white peak wave detector 55 outputs of auto contrast's control unit 55.The collection of resistor 73 and transistor 71-emitter-base bandgap grading guiding path is as the emitter load impedance of emitter follower structure PNP transistor 67.
In operation, therefore transistor 71 common conductings form the emitter current path that emitter follower is constructed transistor 67.Therefore, transistor 67 conductings, the output signal of white peak wave detector 55 is coupled to comparator 57.When the voltage of transistor 71 base stages was approximately equal to emitter voltage, transistor 71 was non-conduction.In device shown in Figure 3, supply voltage+Vcc is approximate to be set corresponding to maximum-contrast control.When transistor 71 becomes when non-conduction, the emitter current path of the PNP transistor 67 of emitter follower structure interrupts, and the disconnection of the input of the output of white peak wave detector 55 and comparator/amplifier 57.Therefore the operation of auto contrast's control unit 39 is under an embargo.
In aforementioned description, pointed out the various remodeling of described embodiment at appropriate location, should understand those skilled in the art and also can make various other remodeling.For example, the control of user's contrast is set and can be determined by the numeric word of the contrast settings of storing in the expression microprocessor.And although the peak amplitude of the response of the auto contrast's control device among described embodiment vision signal, the present invention also can be applicable to other auto contrast's control device.In addition, though the video processing part of television system shown in Figure 1 is that white expansion, peaking, contrast and the brilliance control function of carrying out luminance signal is set, also the red, green, blue chrominance signal is carried out one or more of these functions separately.The available TA7730IC that buys from Toshiba company realizes contrast and the brightness function to the red, green and blue chrominance signal, and is applicable to above-mentioned purpose.TA7730IC also produces the brightness representation signal, and it is applicable to auto contrast's controlled function and white expansion controlled function to have handled the red, green and blue chrominance signal by combination.These and other remodeling is all in the scope of the invention that following claim limits.
Claims (6)
1. equipment of adjusting control device comprises:
Be used to handle the passage of the signal of carrying information, comprise in order to the combination that responds a manual control signal and an automatic control signal control device (9) with the characteristic of the signal of the described carrying information of continuous control;
Response user's the device (15) of manual adjustments to produce described manual control signal;
Respond the device (39) of signal to produce described automatic control signal of described carrying information; And
Described manual control signal and automatic control signal are coupled to device in the described control device (9);
It is characterized in that, also comprise
Be used for device (41) that the same predetermined manual control level of described manual control signal is compared; And
Described in order to the device (39) that produces automatic control signal when described manual control signal is equivalent to described predetermined manual control level size, respond described comparison means, carry out work in a kind of trained mode.
2. the equipment of adjustment control device as claimed in claim 1 is characterized in that:
When described manual control signal was equivalent to described predetermined manual control level, described comparison means (41) was stopped using described automatic control signal generation device (39).
3. the equipment of adjustment control device as claimed in claim 2, it is characterized in that: when the described work that is used to produce the device (39) of automatic control signal is under an embargo, the described device that is used to be coupled continues described manual control signal is coupled to described control device (9), so that described control device continues the described manual control signal of response.
4. the equipment of adjustment control device as claimed in claim 3 is characterized in that:
Described treatment channel is included in the television system, and the signal of described carrying information is a vision signal, the amplitude characteristic of the described vision signal of described control device (9) control.
5. the equipment of adjustment control device as claimed in claim 4 is characterized in that:
The peak amplitude of the described vision signal of described control device (9) control is so that respond the contrast-response characteristic that described vision signal is controlled the representation image;
Be used to produce the peak amplitude of the described vision signal of described device (39) response of described automatic control signal; And
The described device (15) that is used to produce described manual control signal comprises a manual contrast control device.
6. the equipment of adjustment control device as claimed in claim 5 is characterized in that:
Described predetermined manual control level is corresponding to the maximum-contrast control level.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US75181091A | 1991-08-30 | 1991-08-30 | |
| US751,810 | 1991-08-30 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1070783A CN1070783A (en) | 1993-04-07 |
| CN1033129C true CN1033129C (en) | 1996-10-23 |
Family
ID=25023580
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN92110193A Expired - Fee Related CN1033129C (en) | 1991-08-30 | 1992-08-28 | Video system including apparatus for deactivating automatic control arrangement |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPH05236385A (en) |
| KR (2) | KR930005462A (en) |
| CN (1) | CN1033129C (en) |
| MX (1) | MX9205002A (en) |
| MY (1) | MY111249A (en) |
| PL (1) | PL169171B1 (en) |
| TW (1) | TW248627B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10246120A1 (en) * | 2002-10-01 | 2004-04-22 | Deutsche Thomson-Brandt Gmbh | Automatic contrast control with suppression of interference signals |
-
1991
- 1991-09-04 KR KR1019910015439A patent/KR930005462A/en not_active Application Discontinuation
-
1992
- 1992-04-28 TW TW081103331A patent/TW248627B/en active
- 1992-08-10 MY MYPI92001432A patent/MY111249A/en unknown
- 1992-08-20 JP JP4262666A patent/JPH05236385A/en active Pending
- 1992-08-21 PL PL92295690A patent/PL169171B1/en unknown
- 1992-08-27 KR KR1019920015439A patent/KR100252723B1/en not_active IP Right Cessation
- 1992-08-28 CN CN92110193A patent/CN1033129C/en not_active Expired - Fee Related
- 1992-08-31 MX MX9205002A patent/MX9205002A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| MX9205002A (en) | 1993-04-01 |
| PL169171B1 (en) | 1996-06-28 |
| PL295690A1 (en) | 1993-03-08 |
| MY111249A (en) | 1999-10-30 |
| KR100252723B1 (en) | 2000-04-15 |
| JPH05236385A (en) | 1993-09-10 |
| CN1070783A (en) | 1993-04-07 |
| TW248627B (en) | 1995-06-01 |
| KR930005462A (en) | 1993-03-23 |
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