CN100542236C - Brightness adjusting method of LCD TV backlight - Google Patents
Brightness adjusting method of LCD TV backlight Download PDFInfo
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- CN100542236C CN100542236C CNB2006100615302A CN200610061530A CN100542236C CN 100542236 C CN100542236 C CN 100542236C CN B2006100615302 A CNB2006100615302 A CN B2006100615302A CN 200610061530 A CN200610061530 A CN 200610061530A CN 100542236 C CN100542236 C CN 100542236C
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- relative peak
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Abstract
The present invention relates to a kind of brightness adjusting method of LCD TV backlight, this method is by setting up one average picture level-relative peak illuminometer, and read in the RGB data of a frame video signal, calculate the average picture level of a described frame picture, then according to described average picture level, from average picture level-relative peak illuminometer, find corresponding relative peak brightness, and according to described relative peak brightness calculation duty ratio, described duty ratio is imported the pulse width modulator of described control LCD TV backlight unit, backlight illumination to LCD TV is adjusted, at last image is carried out reverse control, increase luminance signals.Technical scheme of the present invention has reached LCD TV and reduced the purpose of picture peak brightness when mean picture brightness increases, thereby has strengthened the contrast of television image, has improved the comfortableness of watching, and can reduce power consumption simultaneously.
Description
[technical field]
The present invention relates to a kind of brightness adjusting method of LCD TV backlight, particularly a kind of method of carrying out LCD TV backlight brightness adjustment according to television image brightness automatically.
[background technology]
Recently, along with the development of Display Technique, the purposes of LCD (LCD) becomes more and more widely.Owing to compare with traditional C RT (cathode ray tube) TV, LCD TV (LCD-TV) has advantages such as light weight, volume are little, environmental protection and energy saving, and beginning is subjected to consumer's favor gradually.
When playing television image, the peak brightness of CRT TV can be along with average picture level (AveragePicture Level, increase APL) and reducing.Promptly when large tracts of land high brightness picture occurring, the peak brightness of whole television image also can decrease, and can not cause bigger stimulation to user's eyes.But because the mechanism of production difference of image frame, the LCD TV of constant backlight brightness is when playing image, backlight illumination can not change with the variation of picture brightness, so its peak brightness is constant, when playing large tracts of land high brightness picture, still keep constant peak brightness.This characteristic makes LCD TV when playing big dynamic menu, and is bigger to the stimulation of human eye, and the comfortableness of watching is not as the CRT television set.Simultaneously, because invariable backlight illumination also can bring bigger power consumption.
Existing LCD backlight adjustment mode mainly contain manual type and with photo resistance as two kinds of backlight control apparatus assemblies.Manual type adjustment meeting brings very burden to the user, obviously and be not suitable for adopting on LCD TV; And for the mode that adopts photo resistance, generally be to change resistance value according to background luminance, produce one group of pulse signal corresponding to resistance, microprocessor produces pulse duration adjustment signal according to the frequency of pulse signal, and backlight drive circuit is adjusted the signal controlling backlight illumination according to this pulse duration.But owing to reasons such as photo resistance photobehaviors, existence is the situation of sensing background luminance correctly, is difficult to carry out correct adjustment backlight.
[summary of the invention]
Technical problem to be solved by this invention is to provide a kind of brightness adjusting method of LCD TV backlight, particularly a kind of method of carrying out LCD TV backlight brightness adjustment according to television image brightness automatically.
For solving the problems of the technologies described above, the technical solution adopted in the present invention is: a kind of brightness adjusting method of LCD TV backlight, this method is by setting up one average picture level-relative peak illuminometer, and read in the RGB data of a frame video signal, calculate the average picture level of a described frame picture, then according to described average picture level, from average picture level-relative peak illuminometer, find corresponding relative peak brightness, and according to described relative peak brightness calculation duty ratio, described duty ratio is imported the pulse width modulator of described control LCD TV backlight unit, backlight illumination to LCD TV is adjusted, at last image is carried out reverse control, increase luminance signals, wherein, from average picture level-relative peak illuminometer, find corresponding relative peak brightness, and be specially: the R that finds out all pixels in the described frame video signal according to the step of described relative peak brightness calculation duty ratio, G, one of maximum value P in the B value
MAX, find out the full amplitude F of vision signal R, G, B component, and according to following formula
K＝P
MAX/F
Obtain COEFFICIENT K;
According to following formula
Duty ratio=relative peak brightness * K
Obtain duty ratio;
Image is carried out reverse control, and the step that increases luminance signals is specially: read the RGB data of next frame, each pixel is carried out computing and output: R ' one by one
N=R
N/ K, G '
N=G
N/ K, B '
N=B
N/ K, wherein, R
N, G
N, B
NBe illustrated in the red, green, blue component value of N pixel in the frame signal.
Technical scheme of the present invention has reached LCD TV and reduced the purpose of picture peak brightness when mean picture brightness increases, thereby has strengthened the contrast of television image, has improved the comfortableness of watching, and can reduce power consumption simultaneously.
[description of drawings]
Fig. 1 is the APL-peak brightness curve chart of existing CRT TV.
Fig. 2 is the LCD TV APL-relative peak brightness curve figure that the present invention simulates generation.
Fig. 3 is the APL-relative peak illuminometer of setting up according to Fig. 2.
Fig. 4 is fast acquisition of digital video signals of the present invention and the flow chart of adjusting backlight illumination.
[embodiment]
The invention will be further described below in conjunction with accompanying drawing.
See also Fig. 1, be the APL-peak brightness curve of certain model C RT TV.Therefrom the peak brightness of CRT TV can reduce along with the increase of average picture level as can be seen.Therefore, by dynamically controlling backlight and the correction image signal amplitude, the above-mentioned characteristic with simulation CRT TV just can reach the enhancing picture contrast, improves and watches comfortableness, reduces the purpose of power consumption simultaneously on LCD TV.
See also Fig. 2 and Fig. 3, at first will be converted to relative peak brightness to the peak brightness of LCD TV, can simulate its APL-relative peak brightness curve.Curve among Fig. 2 can utilize fitting function to realize, also can be by tabling look-up and the interpolation method realization.Fig. 3 is the APL-relative peak illuminometer of setting up according to Fig. 2.
Because The present invention be directed to LCD TV carries out adjustment backlight, so what handle usually is digital video signal, realization of the present invention system mainly is made up of an integrated digital signal processing chip and necessary memory element, receive the digital video signal of input, the digital video signal after output backlight illumination control signal and the processing.
In the following description, some symbols are defined as follows:
R, G, B: be respectively red, green, blue component and component value thereof in the digital video signal;
R
N, G
N, B
N: be illustrated in the frame signal red, green, blue component and the component value thereof of N pixel;
APL: average picture level;
F: the full amplitude of digital video signal R, G, B component is a constant.Such as for 8 signals, F=255;
P
MAX: in the frame signal in the R of all pixels, G, the B value maximum one, i.e. P
MAX=MAX (R
1, G
1, B
1..., R
N, G
N, B
N...);
K a: coefficient, K=P
MAX/ F;
BR: relative peak brightness.Refer to the peak brightness value when peak brightness was maximum with respect to backlight illumination when adjustment was backlight, promptly
Peak brightness when relative peak brightness=peak brightness/backlight illumination is maximum
See also Fig. 4, to fast acquisition of digital video signals and to adjust process description backlight as follows:
1. according to Fig. 2, in read-only memory (ROM), set up an APL-relative peak illuminometer.
2. read in the RGB data of a frame by pixel, calculate APL and find out P
MAXWith the RGB brightness of each pixel with divided by the maximum 255 of whole all pixels of screen, take advantage of 3 to take advantage of N.
3. calculating K=P
MAX/ F.If K=0.1 (this moment, the K value was too small, showed dark images, was similar to blank screen, did not have the necessity of adjustment) is then got in K＜0.1.
4. according to APL, from APL-relative peak illuminometer, find relative peak brightness BR.And with following formula computed duty cycle D:
D=BR*K formula (1)
Remove to control back light unit with duty ratio D output PWM (pulse-width modulation) waveform then and adjust backlight illumination.
When APL increased, system can check in a BR value that reduces according to APL-relative peak illuminometer, and by formula (1) as can be known, this moment, the D value reduced.Its duty ratio of PWM controller that promptly drives back light unit reduces, and duty ratio reduces to make the brightness deterioration of back light unit output, thereby reaches the purpose that reduces the picture peak brightness.
5. last, need carry out reverse control, increase luminance signals.Promptly read the RGB data of next frame, each pixel carried out computing and output one by one:
R’
N＝R
N/K，G’
N＝G
N/K，B’
N＝B
N/K
In sum, technical scheme of the present invention can reach the characteristic of simulation CRT TV, reduces the purpose of picture peak brightness when mean picture brightness increases, thereby has strengthened the contrast of television image, improves and watches comfortableness, reduces power consumption simultaneously.
Claims (3)
1, a kind of brightness adjusting method of LCD TV backlight is characterized in that, said method comprising the steps of:
A. set up one average picture level-relative peak illuminometer;
B. read in the RGB data of a frame video signal, calculate the average picture level of a described frame picture;
C. according to described average picture level, from average picture level-relative peak illuminometer, find corresponding relative peak brightness, and according to described relative peak brightness calculation duty ratio;
D. with the pulse width modulator of described duty ratio input control LCD TV backlight unit, backlight illumination is adjusted;
E. image is carried out reverse control, increase luminance signals;
Wherein, step c is specially: find out a maximum value P in R, G, the B value of all pixels in the described frame video signal
MAX, find out the full amplitude F of vision signal R, G, B component, and according to following formula
K＝P
MAX/F
Obtain COEFFICIENT K;
According to following formula
Duty ratio=relative peak brightness * K
Obtain duty ratio;
Step e is specially: read the RGB data of next frame, each pixel is carried out computing and output: R ' one by one
N=R
N/ K, G '
N=G
N/ K, B '
N=B
N/ K, wherein, R
N, G
N, B
NBe illustrated in the red, green, blue component value of N pixel in the frame signal.
2, brightness adjusting method of LCD TV backlight as claimed in claim 1 is characterized in that average picture level among the step a-relative peak illuminometer is the display characteristic foundation of simulation CRT TV.
3, brightness adjusting method of LCD TV backlight as claimed in claim 1, it is characterized in that when described K value less than 0.1 the time, described television image is not adjusted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100615302A CN100542236C (en) | 2006-07-03 | 2006-07-03 | Brightness adjusting method of LCD TV backlight |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100615302A CN100542236C (en) | 2006-07-03 | 2006-07-03 | Brightness adjusting method of LCD TV backlight |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101102437A CN101102437A (en) | 2008-01-09 |
| CN100542236C true CN100542236C (en) | 2009-09-16 |
Family
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006100615302A Expired - Fee Related CN100542236C (en) | 2006-07-03 | 2006-07-03 | Brightness adjusting method of LCD TV backlight |
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Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009089686A1 (en) * | 2008-01-14 | 2009-07-23 | Hong Kong Applied Science and Technology Research Institute Co. Ltd | Method of determining luminance values for a backlight of an lcd panel displaying an image |
| CN101609650B (en) * | 2008-06-19 | 2011-12-07 | 群康科技(深圳)有限公司 | LCD and driving method thereof |
| TWI410936B (en) * | 2008-06-27 | 2013-10-01 | Innolux Corp | Liquid crystal display and method for driving same |
| CN101686590B (en) * | 2008-09-27 | 2013-01-30 | 比亚迪股份有限公司 | LED dynamic backlight source control algorithm |
| CN102270928A (en) * | 2010-06-07 | 2011-12-07 | 联咏科技股份有限公司 | power conversion device and power conversion method |
| CN102377956B (en) * | 2010-08-09 | 2014-03-12 | 厦门华侨电子股份有限公司 | Dynamic backlight regulation method of LCD (liquid crystal display) television |
| CN102355561B (en) * | 2011-09-20 | 2013-05-22 | 青岛海信电器股份有限公司 | Method and device for improving image contrast, LCD TV (liquid crystal display television) set |
| KR102083299B1 (en) * | 2013-09-02 | 2020-03-03 | 엘지전자 주식회사 | Display device and luminance control method thereof |
| CN105070251A (en) * | 2015-07-22 | 2015-11-18 | Tcl海外电子（惠州）有限公司 | Backlight control method and device |
| CN105374323B (en) * | 2015-12-18 | 2018-02-13 | 深圳Tcl数字技术有限公司 | Dot matrix backlight drive method, device and system |
| CN105448248B (en) * | 2016-01-15 | 2018-05-08 | 深圳市华星光电技术有限公司 | Power conditioning circuitry and liquid crystal display device |
| CN106057861B (en) * | 2016-08-08 | 2019-03-12 | 深圳市华星光电技术有限公司 | OLED display and the method for reducing OLED display power consumption |
| TWI671732B (en) * | 2018-08-07 | 2019-09-11 | 緯創資通股份有限公司 | Brightness adjusted method and related driving device |
| CN113380202A (en) * | 2018-12-28 | 2021-09-10 | 海信视像科技股份有限公司 | Liquid crystal display device and backlight brightness adjusting method |
| CN110599967B (en) * | 2019-09-19 | 2021-06-08 | 深圳市万普拉斯科技有限公司 | Image display method and device, electronic equipment and readable storage medium |
| CN113554973B (en) * | 2020-04-08 | 2022-11-22 | 华为技术有限公司 | Display brightness adjusting method and related device |
| CN112689107B (en) * | 2020-12-16 | 2022-02-08 | 四川长虹电器股份有限公司 | Method for dynamically adjusting backlight |
| CN113270064B (en) * | 2021-05-28 | 2022-09-27 | 深圳市华星光电半导体显示技术有限公司 | Driving method and driving device of display panel and electronic equipment |
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- 2006-07-03 CN CNB2006100615302A patent/CN100542236C/en not_active Expired - Fee Related
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|---|---|
| CN101102437A (en) | 2008-01-09 |
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