CN103310765B - Backlight illumination compensation method and display device - Google Patents

Abstract

The invention discloses a kind of backlight illumination compensation method and display device, large for solving existing technology image fault, problems such as display effect difference and designing.Described backlight illumination compensation method comprises: receive and determine the original gray-scale of each pixel according to input picture; According to input picture determination backlight illumination; According to compensating factor f _comcarry out to original gray-scale the compensation GTG that linear compensation obtains each pixel, and judge whether the compensation GTG of each pixel is greater than the maximum gray of display device, if be not more than, then the display GTG of this pixel is described compensation GTG; If be greater than, then judge whether the pixel intensity that the original gray-scale of this pixel is corresponding is less than described backlight illumination, if so, then the display GTG of this pixel is described compensation GTG; If not, then the display GTG of this pixel is by foundation compensating factor f _comnonlinear compensation is carried out to original gray-scale and obtains GTG, have that image display effect is good, contrast is high, structure is simple and the advantage such as cost of manufacture is low.

Description

Backlight illumination compensation method and display device

Technical field

The present invention relates to display field, particularly relate to a kind of backlight illumination compensation method and display device.

Background technology

Display device, as liquid crystal display, generally includes display panel and provides the backlight of light for display panel.In order to the image coordinating display panel to show different brightness and color, backlight is divided into overall dimming backlight source and subregion dimming backlight source.If backlight is overall dimming backlight, then only can present bright and complete dark two states entirely, when the local showing image is lower GTG, backlight still presents complete bright state, cause display panel, present lower GTG local there is light leakage phenomena, improve display image local GTG, thus reduce display image contrast.

In order to solve the problem, existing display device, the brightness lower according to the given backlight of brightness of each pixel of display image, then the brightness of image is according to pixels compensated by display panel, as the driving voltage of the liquid crystal molecule at liquid crystal panel adjustment respective pixel place, thus improve the transmittance of respective pixel, thus realize backlight illumination compensation.Adopt the easy contrast that improve display image in this way, simultaneously backlight compensation cost low, realize easy; And the object reducing backlight power consumption is reached by the brightness reducing backlight, but there is following problem:

When showing that the major part of image presents lower GTG, a few pixels of local presents higher gray scale, the brightness of backlight is lower, display panel still adopts above-mentioned compensation method, its maximum gray that can show is exceeded by causing showing GTG needed for the partial pixel of display panel, and now this partial pixel of display device unification is shown as maximum gray, result in GTG and merge phenomenon.Concrete: when the grey exponent number as presented when display device is 256, may occur that the GTG that compensate for rearward point pixel needs show is greater than 255, then this partial pixel is unified to be shown as 255, which results in the distortion of image, what occurred that GTG merges cuts width phenomenon.

Summary of the invention

(1) goal of the invention

For the problems referred to above, the present invention aims to provide a kind of image display effect, and contrast is high, save backlight illumination compensation method and the display device of the energy.

(2) technical scheme

For reaching above-mentioned purpose, backlight illumination compensation method of the present invention comprises:

Receive and determine the original gray-scale of each pixel according to input picture;

According to input picture determination backlight illumination;

According to compensating factor f _comthe compensation GTG that linear compensation obtains each pixel is carried out to original gray-scale, and judges whether the compensation GTG of each pixel is greater than the maximum gray of display device,

If be not more than, then the display GTG of this pixel is described compensation GTG;

If be greater than, then judge whether the pixel intensity that the original gray-scale of this pixel is corresponding is less than described backlight illumination,

If so, then the display GTG of this pixel is described compensation GTG;

If not, then the display GTG of this pixel is by foundation compensating factor f _comnonlinear compensation is carried out to original gray-scale and obtains GTG.

Further, described backlight illumination is determined according to luminance histogram statistics.

Further, described backlight illumination equals the pixel intensity corresponding to GTG bl;

Described bl is determined by following formula statistics by brightness histogram:

$\mathrm{sum}=\underset{i=0}{\overset{M}{\mathrm{\Σ}}}f\left(i\right)$

$\frac{\mathrm{sum}\left(\mathrm{bl}\right)}{\mathrm{sum}}=T_m$

$\mathrm{sum}\left(\mathrm{bl}\right)=\underset{i=0}{\overset{\mathrm{bl}}{\mathrm{\Σ}}}f\left(i\right)$

Wherein, described f (i) is the i-th greyscale pixel number, and M is maximum gray, sum be number of pixels accumulative and;

T _mfor the statistical threshold factor, number of pixels when sum (bl) is for counting on GTG bl accumulative and.

Further, described compensating factor is by obtaining with step:

Step S1: judge whether backlight illumination is greater than backlight preset value;

If be greater than, then compensating factor f _compass through ask for,

If be not more than, then judge whether that the original gray-scale of pixel is greater than the first preset gray scale;

If nothing, then compensating factor f _compass through ask for;

If have, then judge whether the pixel that original gray-scale is greater than the second preset gray scale and the ratio accounting for total pixel are greater than default ratio,

If so, then compensating factor f _compass through ask for,

If not, then compensating factor f _compass through ask for;

Wherein, γ is correction factor; I _maxfor the maximum original gray-scale in input picture.

Further,

Described display GTG I ₂when being obtained by linear compensation, pass through I ₂=I ₀* f _comask for;

Described display GTG I ₂when being obtained by nonlinear compensation, pass through I ₂=(I ₀* f _com-bl) ^k+ bl asks for;

Wherein, described I ₀for carrying out the original gray-scale of nonlinear compensation pixel, penalty coefficient i ₀* f _commax is the maximal value of each pixel compensation GTG.

For reaching above-mentioned purpose, display device of the present invention, comprises backlight and is positioned at backlight light emission side and comprises the display panel of picture element matrix, also comprising:

Video Quality Metric unit, in order to receive input picture and to determine pixel original gray-scale;

Backlight illumination determining unit, in order to according to input picture determination backlight illumination;

Compensating unit, in order to foundation compensating factor f _comthe compensation GTG that linear compensation obtains each pixel is carried out to original gray-scale, and judges whether the compensation GTG of each pixel is greater than the maximum gray of display device,

If be not more than, then the display GTG of this pixel is described compensation GTG;

If be greater than, then judge whether the pixel intensity that this pixel original gray-scale is corresponding is less than described backlight illumination,

If so, then the display GTG of this pixel is described compensation GTG;

If not, then the display GTG of this pixel is by foundation compensating factor f _comnonlinear compensation is carried out to original gray-scale and obtains GTG;

Wherein,

Described backlight is connected with described backlight illumination determining unit, in order to provide light source according to described backlight illumination to described display panel;

Described display panel is in order to according to shown GTG output image.

Preferably, also comprise histogram statistical unit, in order to carry out luminance histogram statistics, to described backlight illumination unit input backlight illumination definition base.

Preferably, described backlight illumination equals the pixel intensity corresponding to GTG bl;

Described bl is determined by following formula by histogram statistical unit:

$\mathrm{sum}=\underset{i=0}{\overset{M}{\mathrm{\Σ}}}f\left(i\right)$

$\frac{\mathrm{sum}\left(\mathrm{bl}\right)}{\mathrm{sum}}=T_m$

$\mathrm{sum}\left(\mathrm{bl}\right)=\underset{i=0}{\overset{\mathrm{bl}}{\mathrm{\Σ}}}f\left(i\right)$

Wherein, described f (i) is the i-th greyscale pixel number, and M is maximum gray, sum be number of pixels accumulative and;

T _mfor the statistical threshold factor, number of pixels when sum (bl) is for counting on GTG bl accumulative and.

Preferably, described compensating unit comprises compensating factor determination module;

Described compensating factor determination module, in order to judge whether backlight illumination is greater than backlight preset value;

If be greater than, then compensating factor f _compass through ask for,

If be not more than, then judge whether that pixel original gray-scale is greater than the first preset gray scale;

If nothing, then compensating factor f _compass through ask for;

If have, then judge whether the pixel that original gray-scale is greater than the second preset gray scale and the ratio accounting for total pixel are greater than default ratio,

If so, then compensating factor f _compass through ask for,

If not, then compensating factor f _compass through ask for;

Wherein, γ is correction factor; I _maxfor the maximum original gray-scale in input picture.

Preferably, described compensating unit also comprises linear compensation module and nonlinearity compensation module;

Described linear compensation module, passes through I in order to carry out linear compensation ₂=I ₀* f _comask for display GTG I ₂

Described nonlinearity compensation module, in order to carry out nonlinear compensation, passes through I ₂=(I ₀* f _com-bl) ^k+ bl asks for display GTG;

Described I ₀for carrying out the original gray-scale of nonlinear compensation pixel, penalty coefficient i ₀* f _commax is the maximal value of each pixel compensation GTG.

(3) beneficial effect of backlight illumination compensation method of the present invention and display device

First: backlight illumination compensation method of the present invention and display device, compensation GTG after linear compensation is greater than display device maximum gray, and pixel intensity corresponding to original gray-scale is greater than the pixel of backlight illumination, adopt nonlinear compensation, realize backlight illumination and compensate.Adopt the display GTG after nonlinear compensation can not exceed the maximum gray of aobvious device, thus can not produce GTG merge cause cut width phenomenon, thus display image fault is little, display effect is good, existing simple and easy and display device structure is simple;

Second: adopt in the display device in subregion dimming backlight source in tradition, the contrast of the display device formed relative to the backlight of traditional overall light modulation owing to adopting the local backlight brilliance control of subregion light modulation is higher, display effect is better, but backlight has set up one or more driving circuit and drive source, cause the cost of backlight high.Backlight illumination compensation method of the present invention and display device, adopt the luminance compensation that linear compensation and nonlinear compensation combine, while making the display effect of image better than the display effect of the display device adopting subregion dimming backlight source, select the backlight of Jin You mono-road backlight drive circuit and drive source, thus cost is low;

3rd: backlight illumination compensation method of the present invention and display device, when carrying out backlight illumination and compensating, the pixel pixel intensity that original gray-scale is corresponding being greater than to backlight illumination adopts linear compensation or nonlinear compensation to carry out compensate for brightness, it can thus be appreciated that the pixel intensity of the corresponding maximum original gray-scale of backlight illumination is high in traditional method of not adopting of the backlight illumination of reality, brightness is low thus energy consumption is low, thus reduces the energy consumption of backlight.

Accompanying drawing explanation

Fig. 1 is the process flow diagram of backlight illumination compensation method described in the embodiment of the present invention one;

The original gray-scale that Fig. 2 is the backlight illumination compensation method described in the embodiment of the present invention one and traditional backlight luminance compensation method and display GTG mapping relations comparison diagram;

Fig. 3 is the structural representation of the display device described in the embodiment of the present invention two;

The process flow diagram that the image that Fig. 4 is display device described in Fig. 3 shows.

Embodiment

Embodiment one:

As shown in Figure 1, the compensation method of the present embodiment backlight illumination comprises:

Receive and determine the original gray-scale of each pixel according to input picture; Concrete as confirm respectively according to input picture R in each pixel G the original gray-scale of B tri-sub-pixel and corresponding pixel intensity;

According to input picture determination backlight illumination; The present embodiment is used in the display device of 0D backlight (overall dimming backlight), picture element matrix is contained in display device, pixel intensity desirable corresponding to different pixels original gray-scale is different, and 0D backlight only can provide uniform luminance, therefore need determine a backlight illumination; Backlight outwards exports light according to this backlight illumination;

According to compensating factor f _comthe compensation GTG that linear compensation obtains each pixel is carried out to original gray-scale, and judges whether the compensation GTG of each pixel is greater than the maximum gray of display device,

If be not more than, then the display GTG of this pixel is described compensation GTG;

If be greater than, then judge whether the pixel intensity that the original gray-scale of this pixel is corresponding is less than described backlight illumination,

If so, then the display GTG of this pixel is described compensation GTG;

If not, then the display GTG of this pixel is by foundation compensating factor f _comnonlinear compensation is carried out to original gray-scale and obtains GTG.

Described linear compensation is any in prior art linear compensation method, but all pixels of whole display device all adopt linear compensation that display GTG may be caused to be greater than the maximum gray of display device, cause GTG to merge to occur cutting width phenomenon, output image distortion is large, the problem that display effect is not good, therefore in the present embodiment, judge whether compensate GTG is greater than maximum gray.By judging to be compensated GTG and to be greater than display device maximum gray, and the pixel that desirable pixel intensity corresponding to original gray-scale is greater than maximum backlight illumination then needs to carry out nonlinear compensation; The principle acted on of described nonlinear compensation is, display GTG after compensation is less than or equal to the maximum gray of display device, thus can effectively overcome GTG in the middle of prior art merge cause cut width phenomenon, the display effect especially for high contrast images is especially good.

As the further improvement of the present embodiment, described backlight illumination is determined according to luminance histogram statistics.Adopt brightness histogram to provide definition base for backlight illumination, there is the multiple advantages such as deterministic process is simple, computation complexity is little, and calculated amount is little, and brightness histogram is the calculating of relative maturity, realizes simple and easy to do.

Further, described backlight illumination equals the pixel intensity corresponding to GTG bl;

Described bl is determined by following formula statistics by brightness histogram:

$\mathrm{sum}=\underset{i=0}{\overset{M}{\mathrm{\Σ}}}f\left(i\right)$

$\frac{\mathrm{sum}\left(\mathrm{bl}\right)}{\mathrm{sum}}=T_m$

$\mathrm{sum}\left(\mathrm{bl}\right)=\underset{i=0}{\overset{\mathrm{bl}}{\mathrm{\Σ}}}f\left(i\right)$

Wherein, described f (i) is the i-th greyscale pixel number, and M is maximum gray, sum be number of pixels accumulative and;

T _mfor the statistical threshold factor, number of pixels when sum (bl) is for counting on GTG bl accumulative and.In concrete implementation procedure, usual display device adopts light to mix the display that principle carries out image, therefore each pixel can be divided into again R G B tri-sub-pixel, the GTG that three sub-pixels are corresponding is different, corresponding brightness is different, when carrying out luminance histogram statistics in the present embodiment, the maximum gray of GTG corresponding to the original gray-scale of three sub-pixels in this pixel in pixel.When adding up, only adopt the pixel of high-high brightness in a pixel to add up, the sub-pixel all relative to statistics, statistic and calculated amount are all little, thus realize easier and quick; The pixel intensity that in R/G/B tri-sub-pixel, brightness maximum sub-pixel original gray-scale is corresponding is selected to be statistic at this on the other hand, minimum or the intermediate value of the pixel intensity corresponding relative to original gray-scale in employing three sub-pixel, remain the original image information of input picture to greatest extent, thus the information loss of input picture is little, image display effect is good.

M is the maximum gray of display device, and as the display device of 8bit passage, contain 256 GTGs, wherein maximum gray is 255, then M is 255.As the display device of 10bit passage, comprise 1024 GTGs, wherein maximum GTG is 1023, then M is 1023.

T _mthe statistical threshold factor be less than 1 decimal, concrete as 0.8,0.9 etc.The usual statistical threshold factor is less, the number then added up is fewer, and in the present embodiment, described statistics, from 0 GTG, namely add up from the GTG that required brightness is less, therefore the described statistical threshold factor is less, the bl that relative statistics obtains is also less, the backlight illumination then determined according to described bl is also lower, thus energy consumption is also lower, thus the described statistical threshold factor also can be thought for power saving factor.

Therefore due to the backlight compensation method described in the present embodiment, have that backlight power is low, the advantage of environmental protection.

Further, described compensating factor is by obtaining with step:

Step S1: judge whether backlight illumination is greater than backlight preset value; Described backlight preset value is prior predetermined set;

If be greater than, then compensating factor f _compass through ask for,

If be not more than, then judge whether that the original gray-scale of pixel is greater than the first preset gray scale;

If nothing, then compensating factor f _compass through ask for;

If have, then judge whether the pixel that original gray-scale is greater than the second preset gray scale and the ratio accounting for total pixel are greater than default ratio,

If so, then compensating factor f _compass through ask for,

If not, then compensating factor f _compass through ask for;

Wherein, γ is correction factor; I _maxfor the maximum original gray-scale in input picture.γ can be and pre-sets value, if described display device is liquid crystal indicator, then equal with the Gama regulation coefficient of liquid crystal display in liquid crystal indicator.

In concrete implementation process, described input picture can be divided into First Kind Graph picture, Equations of The Second Kind image and the 3rd class image; The GTG of First Kind Graph picture corresponding to backlight illumination, backlight illumination after determining according to described luminance histogram statistics is greater than backlight preset value, described Equations of The Second Kind image is that backlight brightness values is not more than backlight preset value, and the original gray-scale of all pixels is all not more than the first preset gray scale, the ratio that the number of pixels that simultaneously original gray-scale is greater than the second preset value accounts for view picture input image pixels sum is less than default ratio; Described 3rd class image is the image except First Kind Graph picture and Equations of The Second Kind image, is generally and adopts backlight illumination compensation method easily to occur the high contrast images that GTG merges.

Concrete is as follows, and described display device is the display device of 8bit, comprises 256 GTGs when wherein showing image; Described backlight preset value value is 60 or 80; Described first preset value is as 240, and described second preset value is 230, and what usually arranged by the grey decision-making of described first preset value is greater than the second preset value, and described default ratio is 0.0005 etc.Above-mentioned value within a particular process can according to display device pixel number, the display requirement of image effect and grey exponent number etc. arrange; Concrete as when as described in display device comprise 1024 GTGs time, described first preset value is arranged to 1004, and described second preset value is 984, and described default ratio is set to 0.001 etc.

Compensating factor described in the present embodiment, complexity in computation process is little, as calculating such as statistics and threshold decision, and described backlight preset value, first preset gray scale, the second preset gray scale can pre-set, manufacturer can adjust according to the demand of client, thus controls flexible and convenient.

Further, described display GTG I ₂when being obtained by linear compensation, pass through I ₂=I ₀* f _comask for;

Described display GTG I ₂when being obtained by nonlinear compensation, pass through I ₂=(I ₀* f _com-bl) ^k+ bl asks for;

Wherein, described I ₀for carrying out the original gray-scale of nonlinear compensation pixel, penalty coefficient i ₀* f _commax is the maximal value of each pixel compensation GTG.

In a display device, the brightness that beholder sees is the brightness of backlight and the product of image display brightness, therefore when described backlight illumination have dropped n doubly, if need display brightness to keep constant, then described brightness of image then needs to increase n doubly, and described compensating factor is determined according to backlight illumination, and described display GTG adjusts according to compensating factor, thus ensure that the brightness of output image equals the brightness required by input picture, therefore when adopting linear compensation, pass through I ₂=I ₀* f _comask for display GTG, therefore described linear compensation also can be described as compensating coefficient;

The GTG caused to make up linear compensation merges the image fault formed, by the pixel unified employing nonlinear compensation adopting linear compensation display GTG to exceed display device maximum gray, thus achieve display GTG all control in display device maximum gray, and still keep grey jump by the pixel that nonlinear compensation makes original gray-scale different, thus avoid GTG merging, thus improve the contrast of display image.

Concrete as Fig. 2 be the luminance compensation method mapping relations comparison diagram of the display device of 8bit, in diagram, dotted line AD is that original gray-scale is greater than backlight illumination part the display GTG adopting linear compensation method to calculate and the mapping compensating GTG, broken line ABC is the display GTG of classic method and the mapping of original gray-scale, from the known broken line BC section of diagram for there is the part that GTG merges, and the mapping that curve A C is the display GTG that adopts the nonlinear method described in this method and calculate and original gray-scale, from diagram, all display GTGs are all less than or equal to maximum gray 255, and the display GTG that different original gray-scale is corresponding different, therefore complete present grey jump, there is display effect good, the advantage that contrast is high.

Comprehensively above-mentioned, the backlight illumination compensation method described in the present embodiment, have that compensation effect is good, picture contrast is high, merge without GTG cut the advantages such as width phenomenon.

Embodiment two:

As Figure 3-Figure 4, the present embodiment display device, comprises backlight and is positioned at backlight light emission side and comprises the display panel 2 of picture element matrix, also comprising:

Video Quality Metric unit 6, in order to receive input picture and to determine pixel original gray-scale; Receive input picture, the pixel intensity that in conversion imaging prime matrix, each pixel is corresponding and the original gray-scale of display; Described Video Quality Metric unit 6 can be video conversion circuit or integrated video converter;

Backlight illumination determining unit 4, in order to according to input picture determination backlight illumination; By adjusting the brightness controlling backlight of described backlight illumination controlling value in concrete deterministic process; The concrete physical arrangement of backlight illumination determining unit can be concrete logical circuit, may also be the integration module being integrated with hardware and software;

Compensating unit 7, in order to foundation compensating factor f _comthe compensation GTG that linear compensation obtains each pixel is carried out to original gray-scale, and judge whether the compensation GTG of each pixel is greater than the maximum gray of display device, the maximum gray of display device is known, it is the hardware parameter of display device, directly determine after producing, concrete as 255 or 1023 etc.;

If be not more than, then the display GTG of this pixel is described compensation GTG;

If be greater than, then judge whether the pixel intensity that this pixel original gray-scale is corresponding is less than described backlight illumination,

If so, then the display GTG of this pixel is described compensation GTG;

If not, then the display GTG of this pixel is by foundation compensating factor f _comnonlinear compensation is carried out to original gray-scale and obtains GTG;

Wherein, described backlight 1 is connected with described backlight determining unit 4, in order to provide light source according to described backlight illumination to described display panel; Usual described backlight comprises backlight control circuit 3 and luminescence unit 2; Described backlight control circuit 3 can preferred pwm control circuit, and described luminescence unit comprises CCFL(cold-cathode tube) or LED(diode) etc.; And described backlight can be side entering type as shown in Figure 3 also can be the mixed structure of straight-down negative or side entering type and straight-down negative;

Described display panel, in order to according to shown GTG output image.Display panel described in concrete implementation process is undertaken driving by driving circuit, therefore between described display panel 2 and described compensating unit 7, be also provided with display panel drive 8, described display panel drives 8 to control the GTG of each pixel in display panel according to the display GTG of described compensating unit 7 output, then mixes by light the display that phenomenon realizes image by the effect of color film.

Display device described in the present embodiment, has that structure is simple, backlight power is low, and without cutting width phenomenon, display effect is good, contrast advantages of higher.

Preferably, the display device described in the present embodiment also comprises histogram statistical unit 5, in order to carry out luminance histogram statistics, to described backlight illumination unit input backlight illumination definition base.Described histogram statistical unit is statistics with histogram circuit, with R G maximum grey decision-making corresponding in B tri-sub-pixel add up, for backlight illumination is determined to provide foundation.Described histogram statistical unit hardware implementing is simple, cost is low.

Preferably, described backlight illumination equals the pixel intensity corresponding to GTG bl;

Described bl is determined by following formula by histogram statistical unit:

$\mathrm{sum}=\underset{i=0}{\overset{M}{\mathrm{\Σ}}}f\left(i\right)$

$\frac{\mathrm{sum}\left(\mathrm{bl}\right)}{\mathrm{sum}}=T_m$

$\mathrm{sum}\left(\mathrm{bl}\right)=\underset{i=0}{\overset{\mathrm{bl}}{\mathrm{\Σ}}}f\left(i\right)$

Wherein, described f (i) is the i-th grey decision-making number of pixels, and M is maximum gray, sum be number of pixels accumulative and;

T _mfor the statistical threshold factor, number of pixels when sum (bl) is for counting on GTG bl accumulative and.The size of M is determined by the parameter of of display device itself, and usual described M is 1023 or 255.The determination being backlight illumination by histogram statistical unit provides foundation, and realize simple and efficient, hardware cost is low.

Preferably, described compensating unit comprises compensating factor determination module;

Described compensating factor determination module, in order to judge whether backlight illumination is greater than backlight preset value;

If be greater than, then compensating factor f _compass through ask for,

If be not more than, then judge whether that pixel original gray-scale is greater than the first preset gray scale;

If nothing, then compensating factor f _compass through ask for;

If have, then judge whether the pixel that original gray-scale is greater than the second preset gray scale and the ratio accounting for total pixel are greater than default ratio,

If so, then compensating factor f _compass through ask for,

If not, then compensating factor f _compass through ask for;

Wherein, γ is that correction factor is normally preset; I _maxfor the maximum original gray-scale in input picture.By above-mentioned known, only have and be not more than backlight preset value at backlight illumination and have the original gray-scale of pixel to be greater than the first preset gray scale, and when the ratio that the pixel being greater than the second preset gray scale accounts for display device total pixel number is greater than default ratio, otherwise,

The maximum original gray-scale of different input picture is different, thus the compensating factor of trying to achieve is different, in concrete implementation procedure, and the I that general contrast is larger _maxlarger, thus the compensating factor obtained is also larger.

Preferably, described compensating unit also comprises linear compensation module and nonlinearity compensation module;

Described linear compensation module, passes through I in order to carry out linear compensation ₂=I ₀* f _comask for display GTG I ₂

Described nonlinearity compensation module, in order to carry out nonlinear compensation, passes through I ₂=(I ₀* f _com-bl) ^k+ bl asks for display GTG;

Described I ₀for carrying out the original gray-scale of nonlinear compensation pixel, penalty coefficient i ₀* f _commax is the maximal value of each pixel compensation GTG.

In concrete implementation procedure, described linear compensation modular approach and nonlinearity compensation module method all have multiple, originally implement as providing that a kind of algorithm complex is little, calculated amount is little is easy to realize and the good preferred module of display effect and method.The integrated module of linear compensation module and nonlinearity compensation module hardware implementing can be the logical circuit of pure hardware also can be electron device and software, concrete PLC programmable module or DSP digital signal processing module or MCU single chip processing module etc.

In concrete implementation process, described backlight illumination determining unit 4, described Video Quality Metric unit 6, described histogram statistical unit 5, backlight control circuit 3, described compensating unit 7, display panel drives 8 can be all the functional module be integrated in SOC; SOC (SystemOnChip) chip is System on Chip/SoC, has delicate structure, intelligent high advantage.It is liquid crystal LCD that described display device is preferably the display panel that namely liquid crystal indicator form described display device.

Above embodiment is only for illustration of the present invention; and be not limitation of the present invention; the those of ordinary skill of relevant technical field; without departing from the spirit and scope of the present invention; can also make a variety of changes and modification; therefore all equivalent technical schemes also belong to category of the present invention, and scope of patent protection of the present invention should be defined by the claims.

Claims (8)

1. a backlight illumination compensation method, is characterized in that, comprising:

Receive and determine the original gray-scale of each pixel according to input picture;

According to input picture determination backlight illumination;

According to compensating factor f _comthe compensation GTG that linear compensation obtains each pixel is carried out to original gray-scale, and judges whether the compensation GTG of each pixel is greater than the maximum gray of display device,

If be not more than, then the display GTG of this pixel is described compensation GTG;

If be greater than, then judge whether the pixel intensity that the original gray-scale of this pixel is corresponding is less than described backlight illumination,

If so, then the display GTG of this pixel is described compensation GTG;

If not, then the display GTG of this pixel is by foundation compensating factor f _comnonlinear compensation is carried out to original gray-scale and obtains GTG; Wherein,

Described display GTG I ₂when being obtained by linear compensation, pass through I ₂=I ₀* f _comask for;

Described display GTG I ₂when being obtained by nonlinear compensation, pass through I ₂=(I ₀* f _com-bl) ^k+ bl asks for;

Wherein, described I ₀for carrying out the original gray-scale of nonlinear compensation pixel, described bl is GTG, and the pixel intensity corresponding to described GTG bl equals described backlight illumination; Penalty coefficient i ₀* f _commax is the maximal value of each pixel compensation GTG.

2. backlight illumination compensation method according to claim 1, is characterized in that, described backlight illumination is determined according to luminance histogram statistics.

3. backlight illumination compensation method according to claim 2, is characterized in that, described backlight illumination equals the pixel intensity corresponding to GTG bl;

Described bl is determined by following formula statistics by brightness histogram:

$sum=\underset{i=0}{\overset{M}{\Σ}}f\left(i\right)$

$\frac{sum\left(bl\right)}{sum}=T_m$

$sum\left(bl\right)=\underset{i=0}{\overset{bl}{\Σ}}f\left(i\right)$

Wherein, described f (i) is the i-th greyscale pixel number, and M is maximum gray, sum be number of pixels accumulative and;

T _mfor the statistical threshold factor, number of pixels when sum (bl) is for counting on GTG bl accumulative and.

4. backlight illumination compensation method according to claim 3, is characterized in that, described compensating factor is by obtaining with step:

Step S1: judge whether backlight illumination is greater than backlight preset value;

If be greater than, then compensating factor f _compass through ask for,

If be not more than, then judge whether that the original gray-scale of pixel is greater than the first preset gray scale;

If nothing, then compensating factor f _compass through ask for;

If have, then judge whether the pixel that original gray-scale is greater than the second preset gray scale and the ratio accounting for total pixel are greater than default ratio,

If so, then compensating factor f _compass through ask for,

If not, then compensating factor f _compass through ask for;

Wherein, γ is correction factor; I _maxfor the maximum original gray-scale in input picture.

5. a display device, comprises backlight and is positioned at backlight light emission side and comprises the display panel of picture element matrix, it is characterized in that, also comprise:

Video Quality Metric unit, in order to receive input picture and to determine pixel original gray-scale;

Backlight illumination determining unit, in order to according to input picture determination backlight illumination;

Compensating unit, in order to foundation compensating factor f _comthe compensation GTG that linear compensation obtains each pixel is carried out to original gray-scale, and judges whether the compensation GTG of each pixel is greater than the maximum gray of display device,

If be not more than, then the display GTG of this pixel is described compensation GTG;

If be greater than, then judge whether the pixel intensity that this pixel original gray-scale is corresponding is less than described backlight illumination,

If so, then the display GTG of this pixel is described compensation GTG;

If not, then the display GTG of this pixel is by foundation compensating factor f _comnonlinear compensation is carried out to original gray-scale and obtains GTG;

Wherein,

Described backlight is connected with described backlight illumination determining unit, in order to provide light source according to described backlight illumination to described display panel;

Described display panel is in order to according to shown GTG output image; Wherein,

Described compensating unit also comprises linear compensation module and nonlinearity compensation module;

Described linear compensation module, passes through I in order to carry out linear compensation ₂=I ₀* f _comask for display GTG I ₂

Described nonlinearity compensation module, in order to carry out nonlinear compensation, passes through I ₂=(I ₀* f _com-bl) ^k+ bl asks for display GTG;

Described I ₀for carrying out the original gray-scale of nonlinear compensation pixel, described bl is GTG, and the pixel intensity corresponding to described GTG bl equals described backlight illumination; Penalty coefficient i ₀* f _commax is the maximal value of each pixel compensation GTG.

6. display device according to claim 5, is characterized in that, also comprises histogram statistical unit, in order to carry out luminance histogram statistics, to described backlight illumination unit input backlight illumination definition base.

7. display device according to claim 6, is characterized in that, described backlight illumination equals the pixel intensity corresponding to GTG bl;

Described bl is determined by following formula by histogram statistical unit:

$sum=\underset{i=0}{\overset{M}{\Σ}}f\left(i\right)$

$\frac{sum\left(bl\right)}{sum}=T_m$

$sum\left(bl\right)=\underset{i=0}{\overset{bl}{\Σ}}f\left(i\right)$

Wherein, described f (i) is the i-th greyscale pixel number, and M is maximum gray, sum be number of pixels accumulative and;

T _mfor the statistical threshold factor, number of pixels when sum (bl) is for counting on GTG bl accumulative and.

8. display device according to claim 7, is characterized in that, described compensating unit comprises compensating factor determination module;

Described compensating factor determination module, in order to judge whether backlight illumination is greater than backlight preset value;

If be greater than, then compensating factor f _compass through ask for,

If be not more than, then judge whether that pixel original gray-scale is greater than the first preset gray scale;

If nothing, then compensating factor f _compass through ask for;

If have, then judge whether the pixel that original gray-scale is greater than the second preset gray scale and the ratio accounting for total pixel are greater than default ratio,

If so, then compensating factor f _compass through ask for,

If not, then compensating factor f _comby asking for;

Wherein, γ is correction factor; I _maxfor the maximum original gray-scale in input picture.