CN101917561A - Method for processing TV nonstandard signal - Google Patents
Method for processing TV nonstandard signal Download PDFInfo
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- CN101917561A CN101917561A CN 201010227149 CN201010227149A CN101917561A CN 101917561 A CN101917561 A CN 101917561A CN 201010227149 CN201010227149 CN 201010227149 CN 201010227149 A CN201010227149 A CN 201010227149A CN 101917561 A CN101917561 A CN 101917561A
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Abstract
The invention discloses a method for processing a TV nonstandard signal, which comprises the following steps of: detecting the amplitude of a synchronous head of an input signal, and obtaining the detected amplitude of the synchronous head of the input signal by reading the size of automatic gain control (AGC), wherein the size of the AGC can be read in a register directly; and correspondingly adjusting the amplitude of a white level peak or black level size according to the obtained size of the synchronous head to realize the control of brightness of an image signal. By detecting the amplitude of the synchronous head of the input signal and setting the brightness of the image signal according to the amplitude of the synchronous head, the invention ensures that the viewing effect of the image is not affected and effectively solves the problem of image brightness change because a synchronous signal is changed by interference.
Description
Technical field
The invention belongs to the digital television techniques field, relate in particular to a kind of processing method of TV nonstandard signal.
Background technology
Although the digital television techniques development rapidly, simulated television is still at transmission and demonstration field dominate.TV signal is mostly based on anolog TV signals at present, and at the transmitting terminal of TV signal, the picture signal of collection and audio signal are through ovennodulation, and be synthetic, zooms into the RF signal, through the antenna emission.At receiving terminal, the high-frequency signal that antenna receives becomes intermediate-freuqncy signal after tuner amplification and mixing.Intermediate frequency carrier extracts the video signal that is modulated on the carrier wave, on TV reproduced image and acoustic information through amplifying and synchronous detection.Signal for the RF transmission, noise is common problem, add characteristic impedance and damped expoential that transmission medium self exists, can there be certain loss in the signal of transmission, these factors all can cause the signal quality variation, and influence the detection of terminal equipment to signal, extract, for terminal TV equipment, some severe attrition, be subjected to the interference signals can't be by correct extraction, can cause when these signals show on TV eclipsed, the shake, audio distortions or the like problem, serious words even can't show on TV that these signals that are badly damaged are exactly nonstandard signal.Nonstandard signal divides various situation, and wherein have a kind of nonstandard signal to be: signal is interfered in transmission course, causes the changes in amplitude of synchronizing signal and image signal amplitude is constant.Because the rear end Video processing is to decide the multiplication factor of signal according to the size of synchronous head, so when the synchronous head amplitude diminished, the rear end multiplication factor will become greatly, causes picture signal to be turned white; Otherwise if the synchronous head amplitude diminishes, the multiplication factor of rear end will diminish, and the image deepening influences normal image effect.Therefore, be necessary that research provides a kind of scheme, to handle at so a kind of nonstandard signal, when making the synchronous head changes in amplitude, the viewing effect of image is unaffected.
Summary of the invention
The purpose of the embodiment of the invention is to provide a kind of processing method of TV nonstandard signal, TV nonstandard signal is handled, when making the synchronous head changes in amplitude, the viewing effect of image is unaffected, can solve the image brightness variation issue that caused by interference variations because of synchronizing signal effectively.
The embodiment of the invention is achieved in that a kind of processing method of TV nonstandard signal, comprises the steps:
Detect the synchronous head amplitude size of input signal, obtain the synchronous head amplitude size that detects input signal by reading automatic gain control (AGC) size, automatic gain control (AGC) value size can directly read in register;
According to the synchronous head sizes values of obtaining, corresponding adjusting white peak amplitude or black level size are to realize the bright dark control to picture signal.
In embodiments of the present invention, by detecting the synchronous head amplitude size of input signal, according to synchronous head amplitude size the bright dark of picture signal is set, makes that the viewing effect of image is unaffected, imitate ground and solve the image brightness variation issue that caused by interference variations because of synchronizing signal.
Description of drawings
Fig. 1 is a flow process diagram of the present invention.
Embodiment
In order to make purpose of the present invention, technical scheme and advantage clearer,, the present invention is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
With reference to shown in Figure 1, the processing method of TV nonstandard signal of the present invention is by detecting the synchronous head amplitude size of input signal, according to synchronous head amplitude size the bright dark of picture signal is set, its software program adds in the real-time detecting system that is implanted in TV software, detection signal synchronous head amplitude size variation ceaselessly, in case monitor unusually, will handle accordingly.
The synchronous head amplitude size of described detection input signal is obtained by reading automatic gain control (AGC) size, and automatic gain control (AGC) value size can directly read in register.In actual applications, because the influence that reception environment difference or external interference and device aging etc. produce can cause the power of receiving end signal to change, and cause serious distortion: when the signal grow, to make post-amplifier enter saturation region and cut-off region, the image saturation distortion; Otherwise when signal weaker, image brightness and contrast can diminish, poor definition and unstable synchronously.So at receiving terminal design automatic gain control (AGC) circuit, it is according to the characteristics of synchronous head amplitude maximum in the vision signal, from output, obtain vision signal with the AGC feedback loop, through the detection rectification, make it to become the direct-current control voltage that the power with vision signal changes, this Voltage Feedback is to video amplifier circuit, thereby control its gain, to reach the purpose of stable output, improve input signal amplitude, improve the adaptive capacity of whole system.AGC voltage is with the peak change of synchronous signal, and is irrelevant with the content of image, avoided the influence of picture material to AGC voltage.Automatic gain (AGC) size is to become certain proportionate relationship with a signal Synchronization peak value size, and the synchronous amplitude size of input signal can directly be fed back by the AGC size, and when the synchronous head of input signal was standard state, corresponding A GC value was exactly a benchmark AGC value; When synchronizing signal diminished, it is big that AGC value relative datum AGC value can become, and when synchronizing signal became big, AGC value relative datum AGC value can diminish.
According to the synchronous head sizes values of obtaining, corresponding adjusting white peak amplitude or black level size are to realize the bright dark control to picture signal.Black level refers on the display unit through certain calibration, the video level that does not have delegation's light output, just define the signal level that view data is 0 o'clock correspondence, regulating black level does not influence the multiplication factor of signal, and only be that signal is carried out upper and lower translation: if to the adjusted black level, image will be just dark, will brighten if regulate the black level image downwards.Black level is 0 o'clock, and the following level of corresponding 0V all is converted to view data 0, and the above level of 0V is then changed according to the multiplication factor of gain definitions.White level is exactly the highest white peak signal, and in color TV, the level value of white signal is the highest, regulates the multiplication factor that the white peak size also can not influence signal, only can influence the brightest level amplitude of image.
When detecting nonstandard signal, compared to standard synchronous head amplitude, the synchronous head signal amplitude diminishes, corresponding AGC value becomes big, and the integral image multiplication factor increases, and picture brightens, reduce the high-high brightness signal by the maximum of regulating white peak, constant with the highest brightness value that guarantees image; Otherwise when input signal synchronous head amplitude becomes big, corresponding AGC value diminishes, and the whole multiplication factor of image reduces, and the image deepening by increase black level amplitude, promotes the brightness of whole picture.Because signal changes constantly, so algorithm software is added in the real-time detecting system that is implanted in TV software, the detection signal synchronous head amplitude size variation of not stopping, in case monitor unusual, will handle accordingly, return to normal amplitude if detect synchronous head, original initial black level and white peak parameter can be set back automatically.
The above only is preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of being done within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.
Claims (3)
1. the processing method of a TV nonstandard signal is characterized in that, comprises the steps:
Detect the synchronous head amplitude size of input signal, obtain the synchronous head amplitude size that detects input signal by reading automatic gain control (AGC) size, automatic gain control (AGC) value size can directly read in register;
According to the synchronous head sizes values of obtaining, corresponding adjusting white peak amplitude or black level size are to realize the bright dark control to picture signal.
2. the processing method of TV nonstandard signal as claimed in claim 1 is characterized in that: add in the real-time detecting system of TV software and plant software program, ceaselessly detection signal synchronous head amplitude size variation.
3. the processing method of TV nonstandard signal as claimed in claim 2, it is characterized in that: when the synchronous head of input signal was standard state, corresponding A GC value was exactly a benchmark AGC value; When synchronizing signal diminished, it is big that AGC value relative datum AGC value can become, and when synchronizing signal became big, AGC value relative datum AGC value can diminish.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102271495A CN101917561B (en) | 2010-07-14 | 2010-07-14 | Method for processing TV nonstandard signal |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2010102271495A CN101917561B (en) | 2010-07-14 | 2010-07-14 | Method for processing TV nonstandard signal |
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| CN101917561A true CN101917561A (en) | 2010-12-15 |
| CN101917561B CN101917561B (en) | 2012-11-14 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102567959A (en) * | 2010-12-31 | 2012-07-11 | 新奥特（北京）视频技术有限公司 | Multi-way image grey adjusting method |
| CN105812763A (en) * | 2014-12-30 | 2016-07-27 | 深圳艾科创新微电子有限公司 | Automatic gain control method and device for CVBS (Composite Video Broadcast Signal) |
| CN108337444A (en) * | 2018-02-06 | 2018-07-27 | 青岛大学 | The extraction system and method for invisible video image under high brightness and dark lightness environment |
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| US3569620A (en) * | 1969-03-21 | 1971-03-09 | Rca Corp | Automatic video signal gain controlling apparatus |
| CN1060566A (en) * | 1990-10-04 | 1992-04-22 | 汤姆森消费电子有限公司 | The method and apparatus of defeating operation of IC built-in noise inverter |
| JP3470043B2 (en) * | 1998-06-03 | 2003-11-25 | シャープ株式会社 | Automatic gain control circuit and satellite broadcast receiving tuner |
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| CN201369773Y (en) * | 2009-03-27 | 2009-12-23 | 上虞市宇恒电子有限公司 | Twisted Pair Video Automatic Gain Control Receiver |
| CN101753898A (en) * | 2008-12-05 | 2010-06-23 | 索尼株式会社 | Receiving device, reception method, and program |
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2010
- 2010-07-14 CN CN2010102271495A patent/CN101917561B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3569620A (en) * | 1969-03-21 | 1971-03-09 | Rca Corp | Automatic video signal gain controlling apparatus |
| CN1060566A (en) * | 1990-10-04 | 1992-04-22 | 汤姆森消费电子有限公司 | The method and apparatus of defeating operation of IC built-in noise inverter |
| JP3470043B2 (en) * | 1998-06-03 | 2003-11-25 | シャープ株式会社 | Automatic gain control circuit and satellite broadcast receiving tuner |
| CN101409805A (en) * | 2007-10-11 | 2009-04-15 | 三洋电机株式会社 | Automatic gain control circuit in video signal processing device |
| CN101753898A (en) * | 2008-12-05 | 2010-06-23 | 索尼株式会社 | Receiving device, reception method, and program |
| CN201369773Y (en) * | 2009-03-27 | 2009-12-23 | 上虞市宇恒电子有限公司 | Twisted Pair Video Automatic Gain Control Receiver |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102567959A (en) * | 2010-12-31 | 2012-07-11 | 新奥特（北京）视频技术有限公司 | Multi-way image grey adjusting method |
| CN102567959B (en) * | 2010-12-31 | 2016-10-19 | 新奥特（北京）视频技术有限公司 | A kind of multimode gradation of image method of adjustment |
| CN105812763A (en) * | 2014-12-30 | 2016-07-27 | 深圳艾科创新微电子有限公司 | Automatic gain control method and device for CVBS (Composite Video Broadcast Signal) |
| CN105812763B (en) * | 2014-12-30 | 2018-12-28 | 深圳开阳电子股份有限公司 | A kind of CVBS signal automatic gain control method and device |
| CN108337444A (en) * | 2018-02-06 | 2018-07-27 | 青岛大学 | The extraction system and method for invisible video image under high brightness and dark lightness environment |
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| CN101917561B (en) | 2012-11-14 |
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