CN104036717B - A kind of method for correcting image improving EED display quality - Google Patents

Abstract

The invention discloses a kind of EED display brightness uniformity and method realizing field emission display gray scale gamma correction improved.Described luminance uniformity correction method can be improved the brightness causing display screen each pixel I/V characteristic curve to there is difference owing to the electron emission characteristic of electron source each in cold-cathode electron source array is inconsistent and to cause and show unbalanced, the method is that static shift correction combines with dynamic calibration, be conducive to obtaining preferable homogeneity correction effect, and image can be kept to keep clear.Described gray scale non-linear correction method, makes the luminosity of display device follow applied gradation of image signal voltage linear, to show Well-recovered image.

Description

A kind of method for correcting image improving EED display quality

Technical field

The present invention relates to a kind of method for correcting image, a kind of figure improving EED display quality As bearing calibration.

Background technology

Existing flat-panel monitor is of a great variety, and (Liquid Crystal Display is called for short mainly liquid crystal display LCD), plasma display panel (Plasma Display Panel is called for short PDP), electro-luminescence display device (Electroluminescent Display is called for short ELD), EED (Field Emission Display, It is called for short FED) etc..Field Emission Display is the emerging flat panel display technology of similar tradition CRT (cathode-ray tube display), nothing Need the scanning of electron beam, its structure slimming can be made, it is achieved low energy consumption, fine definition, high stability giant-screen plane show, but Filed emission cathode material there is also in performance, preparation and processing technology many still need solve problem, the appearance of CNT Open the new upsurge of research CNT-Field Emission Display (CNT-FED).Owing to EED possesses flat board The advantages such as change, low-power consumption, high-contrast, high brightness, high dynamic definition, wide viewing angle, can be made as high-quality, giant-screen high definition Clear degree display, it is achieved image shows it is practical inevitable approach.

In field emission display, the electric current that display brightness is launched with cold-cathode electron source is linear, and cold the moon Pole electron source emission current is non-linear relation with the relation of its driving voltage or electric field.It is illustrated in figure 1 typical cold cathode Electron source field emission characteristic, the electric current of transmitting increases, therefore with the relation of the voltage journey approximation index driving cold-cathode electron source In non-linear relation between field emission display display brightness and driving voltage.Owing to machining process exists dispersiveness, Cause the electron emission characteristic of each electron source in cold-cathode electron source array inconsistent, the fluorescent material thickness of each pixel of fluorescent screen Deviation causes the inconsistent of luminous efficiency, or the reason such as inconsistent of gate electron absorptivity, all can cause brightness display inequality Even.

Above-mentioned showing, there is gray scale and shows that non-linear, brightness shows that the image such as uneven shows in EED Quality problems, will reach to apply requirement, be the problem faced by researcher needs.The present invention proposes a kind of EED Image display bearing calibration, in conjunction with the display characteristic of FED screen itself, is shown gray scale by digital image processing techniques Show that non-linear, brightness shows uneven being corrected, to improve image displaying quality, novel flat-plate Display Technique research is had a mind to Justice.

Summary of the invention

In order to overcome the deficiencies in the prior art, it is uniform that the present invention provides one to improve EED display brightness Property and the method that realizes field emission display gray scale gamma correction.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of method for correcting image improving EED display quality, comprises the following steps, and its feature exists In:

Step one:

For 2ⁿThe display screen of level gray scale, makes each pixel on display screen apply 0 to 2 successivelyⁿThe display data of-1, obtain The each pixel of display screen corresponding to gray values at different levels luminosity f (i, j), to the luminosity of pixel each on display screen and Gradation data matched curve is:

$f(i,j)=a(i,j)+b(i,j){\left(\frac{G}{2^n-1}\right)}^2\exp (c(i,j)/\frac{G}{2^n-1})---\left(1\right)$

In above-mentioned relation formula, (i, j), (i, j), (i, j) is the parameter of each pixel of display to c to b to a, reflects display Relation between luminosity and signal level；G is gradation data；I and j is pixel place row and column on a display screen respectively Position,

Step 2:

By the c in step one, (i j) averages, formula (1) is modified to:

$f_1(i,j)=a(i,j)+b(i,j){\left(\frac{G}{2^n-1}\right)}^2\exp (\stackrel{\‾}{c}/\frac{G}{2^n-1})---\left(2\right)$

Order $\frac{\mathrm{Go}}{2^n-1}={\left(\frac{G}{2^n-1}\right)}^2\exp (\stackrel{\‾}{c}/\frac{G}{2^n-1})$

Can be obtained by formula (2):

$f_1(i,j)=a(i,j)+b(i,j)\frac{G_o}{2^n-1}---\left(3\right)$

Wherein G_oFor gradation data；

Step 3:

To a in step 2 formula (3), (i, j) (i j) averages with bWith, obtain a new gamma correction Matrix:

$f_2(i,j)=\stackrel{\‾}{a}+\stackrel{\‾}{b}\frac{G_i}{2^n-1}---\left(4\right)$

Wherein G_iFor input gray level data；

Step 4:

Make f₁(i, j)=f₂(i, j)

By formula (3) and formula (4), can obtain $G_O=\frac{\stackrel{\‾}{a}-a(i,j)}{b(i,j)}+\frac{\stackrel{\‾}{b}}{b(i,j)}{G}_i---\left(5\right)$

Order $\mathrm{\α}(i,j)=\frac{\stackrel{\‾}{a}-a(i,j)}{b(i,j)},{\mathrm{\α}}^{\′}(i,j)=\frac{\stackrel{\‾}{b}}{b(i,j)},$

G can be obtained_o=α (i, j)+α ' (i, j) G_i (6)

α (i, j) and α ' (i, j) is stored in the nonvolatile memory, as luminance uniformity correction parameter,

Step 5:

Utilize step 4 gained brightness correction parameter matrix α (i, j) and α ' (i, j) to display received image signal enter Row correction, with G_iFor for input picture gradation data, with G_OFor the display data after correction, formula (6) is utilized to be corrected.School Picture signal G after just_O, make each pixel display brightness under identical received image signal reach unanimity,

Step 6:

To G_OCarry out gray scale non-linear correction processing, obtain view data G, wherein G and G_OThere is following relation:

$\frac{\mathrm{Go}}{2^n-1}={\left(\frac{G}{2^n-1}\right)}^2\exp (\stackrel{\‾}{c}/\frac{G}{2^n-1})---\left(7\right)$

Step 7:

According to formula (7) in above-mentioned steps six, make G_OIt is followed successively by 0 to 2ⁿ-1, calculate view data G after correction, round numbers Value, is compiled into a correction parameter look-up table, and storage is in the nonvolatile memory；

Step 8:

Utilize the correction parameter look-up table of step 7 gained, display received image signal is carried out the non-linear school of gray scale Just, with view data G_OAs address, from correction lookup table memories, take out view data G after correction, as FED device Driving signal data.

When in described step 5, received image signal to certain pixel is corrected processing, with this pixel at display screen On position be address, table look-up obtain this pixel corrected parameter α (i, j) and α ' (i, j), calculate correction gradation data, right Input picture gradation data G_iIt is modified, display data G after being corrected_O, and G_ORound numbers.

When in described step 7, received image signal to certain pixel is corrected processing, for ensureing the gray scale after correction It is worth without departing from display tonal range, for realizing 2ⁿThe gray scale of level shows, revised gray value G is more than 2ⁿWhen-1, with 2ⁿ-1 makees Display for this pixel drives picture signal.

The invention has the beneficial effects as follows:

1, the luminance uniformity correction described in step 4, its bearing calibration is that static shift correction combines with dynamic calibration, has It is beneficial to obtain preferable homogeneity correction effect, and image can be kept to keep clear.

2, the luminance uniformity correction described in step 4 can improve due to electron source each in cold-cathode electron source array The inconsistent brightness display inequality causing display screen each pixel I/V characteristic curve to there is difference and to cause of electron emission characteristic Weighing apparatus.

3, step 5 carries out gray scale gamma correction to the grey scale signal of input picture, make the luminosity of display device with Linear with the gradation of image signal voltage applied, to show Well-recovered image.

4, combine the display characteristic of FED screen itself, by circuit and digital image processing techniques, be effectively improved Flied emission image displaying quality, to novel flat-plate Display Technique research and practical significant.

Accompanying drawing explanation

Fig. 1 is typical FED display cold-cathode electron source field emission characteristic curve map；

Fig. 2 is EED image correction process system schematic.

Detailed description of the invention

The present invention is further described with embodiment below in conjunction with the accompanying drawings.

As in figure 2 it is shown, be image correction system schematic diagram block diagram of the present invention, by the memory 1 of luminance uniformity correction, ash Degree nonlinear lookup table memory 2, microprocessor and control circuit composition.G_iFor deriving from the input picture gray scale of vision facilities Data, after image correction system processes, display data G after being corrected, drive FED display.

Below in conjunction with Fig. 2 method for correcting image detailed description of the invention of the present invention is described:

Step one:

For 2ⁿThe display screen of level gray scale, makes each pixel on display screen apply 0 to 2 successivelyⁿThe display data of-1, obtain The each pixel of display screen corresponding to gray values at different levels luminosity f (i, j), to the luminosity of pixel each on display screen and Gradation data matched curve is:

$f(i,j)=a(i,j)+b(i,j){\left(\frac{G}{2^n-1}\right)}^2\exp (c(i,j)/\frac{G}{2^n-1})---\left(1\right)$

In above-mentioned relation formula, (i, j), (i, j), (i, j) is the parameter of each pixel of display to c to b to a, reflects display Relation between luminosity and signal level；G is gradation data；I and j is pixel place row and column on a display screen respectively Position；

Step 2:

To the c in step one, (i j) averagesFormula (1) is modified to:

$f_1(i,j)=a(i,j)+b(i,j){\left(\frac{G}{2^n-1}\right)}^2\exp (\stackrel{\‾}{c}/\frac{G}{2^n-1})---\left(2\right)$

Order $\frac{\mathrm{Go}}{2^n-1}={\left(\frac{G}{2^n-1}\right)}^2\exp (\stackrel{\‾}{c}/\frac{G}{2^n-1})$

Can be obtained by formula (2):

$f_1(i,j)=a(i,j)+b(i,j)\frac{G_o}{2^n-1}---\left(3\right)$

Wherein G_oFor gradation data；

Step 3:

To a in step 2 formula (3), (i, j) (i j) averages with bWithObtain a new gamma correction square Battle array:

$f_2(i,j)=\stackrel{\‾}{a}+\stackrel{\‾}{b}\frac{G_i}{2^n-1}---\left(4\right)$

Wherein G_iFor input gray level data；

Step 4:

Make f₁(i, j)=f₂(i, j)

By formula (3) and formula (4), can obtain $G_O=\frac{\stackrel{\‾}{a}-a(i,j)}{b(i,j)}+\frac{\stackrel{\‾}{b}}{b(i,j)}{G}_i---\left(5\right)$

Order $\mathrm{\α}(i,j)=\frac{\stackrel{\‾}{a}-a(i,j)}{b(i,j)},{\mathrm{\α}}^{\′}(i,j)=\frac{\stackrel{\‾}{b}}{b(i,j)},$

G can be obtained_O=α (i, j)+α ' (i, j) G_i (6)

α, (i, j) (i, j) is stored in memory 1, and memory 1 is in nonvolatile memory, equal as brightness with α ' Even property correction parameter.

Step 5:

As in figure 2 it is shown, with G_iFor input picture gradation data, microprocessor and control circuit with this pixel at display screen On position be address, from memory 1 take out luminance uniformity correction parameter, to display received image signal G_iCarry out school Just, each pixel display brightness under identical received image signal is made to reach unanimity.

Step 6:

To G_OCarry out gray scale non-linear correction processing, obtain view data G, wherein G and G_OThere is following relation:

$\frac{\mathrm{Go}}{2^n-1}={\left(\frac{G}{2^n-1}\right)}^2\exp (\stackrel{\‾}{c}/\frac{G}{2^n-1})---\left(7\right)$

According to formula (7), make G_OIt is followed successively by 0 to 2ⁿ-1, calculate view data G after correction, round numerical value, be compiled into one Individual correction parameter look-up table, is stored in memory 2, and memory 2 is in nonvolatile memory；

Step 7:

As in figure 2 it is shown, the correction data that microprocessor and control circuit obtain with step 5 is as address, from memory 2 Read gray scale gamma correction look-up table, table look-up and obtain view data G, as the driving signal data of FED device.

When received image signal to certain pixel described in above-mentioned steps five is corrected processing, right according to formula (6) Input picture gradation data G_iIt is modified, display data G after being corrected_O, and G_ORound numbers.

When received image signal to certain pixel described in above-mentioned steps six is corrected processing, after ensureing correction Gray value is without departing from display tonal range, for realizing 2ⁿThe gray scale of level shows, if revised gray value G is more than 2ⁿWhen-1, With 2ⁿ-1 as this pixel display drive picture signal.

A kind of image rectification improving EED the display quality above embodiment of the present invention provided Method, is described in detail, and principle and the embodiment of the present invention are set forth by specific case used herein, with The explanation of upper embodiment is only intended to help to understand method and the core concept thereof of the present invention；General simultaneously for this area Technical staff, according to the thought of the present invention, the most all will change, in sum, This specification content should not be construed as limitation of the present invention.

Claims (3)

1. improve a method for correcting image for EED display quality, comprise the following steps, it is characterised in that:

Step one:

For 2ⁿThe display screen of level gray scale, makes each pixel on display screen apply 0 to 2 successivelyⁿThe display data of-1, obtain display Shield each pixel corresponding to gray values at different levels luminosity f (i, j), luminosity and the gray scale to pixel each on display screen Data matched curve is:

$f(i,j)=a(i,j)+b(i,j){\left(\frac{G}{2^n-1}\right)}^2\exp \left(c\right(i,j)/\frac{G}{2^n-1})---\left(1\right)$

In above-mentioned relation formula, (i, j), (i, j), (i, j) is the parameter of each pixel of display to c to b to a, reflects display lighting Relation between brightness and signal level；G is gradation data；I and j is the position of pixel place row and column on a display screen respectively Put,

Step 2:

By the c in step one, (i j) averagesFormula (1) is modified to:

$f_1(i,j)=a(i,j)+b(i,j){\left(\frac{G}{2^n-1}\right)}^2\exp (\stackrel{\‾}{c}/\frac{G}{2^n-1})---\left(2\right)$

Order

Can be obtained by formula (2):

$f_1(i,j)=a(i,j)+b(i,j)\frac{G_o}{2^n-1}---\left(3\right)$

Wherein G_OFor gradation data；

Step 3:

To a in step 2 formula (3), (i, j) (i j) averages with bWithObtain a new gamma correction matrix:

$f_2(i,j)=\stackrel{\‾}{a}+\stackrel{\‾}{b}\frac{G_i}{2^n-1}---\left(4\right)$

Wherein G_iFor input gray level data；

Step 4:

Make f₁(i, j)=f₂(i,j)

By formula (3) and formula (4), can obtainOrder

G can be obtained_O=α (i, j)+α ' (i, j) G_i (6)

α (i, j) and α ' (i, j) is stored in the nonvolatile memory, as luminance uniformity correction parameter,

Step 5:

Utilize step 4 gained brightness correction parameter matrix α (i, j) and α ' (i, j) to display received image signal carry out school Just, with G_iFor input picture gradation data, with G_OFor the display data after correction, formula (6) is utilized to be corrected, after correction Picture signal G_O, make each pixel display brightness under identical received image signal reach unanimity；

Step 6:

To G_OCarry out gray scale non-linear correction processing, obtain view data G, wherein G and G_OThere is following relation:

$\frac{Go}{2^n-1}={\left(\frac{G}{2^n-1}\right)}^2\exp (\stackrel{\‾}{c}/\frac{G}{2^n-1})---\left(7\right)$

Step 7:

According to formula (7) in above-mentioned steps six, make G_OIt is followed successively by 0 to 2ⁿ-1, calculate view data G after correction, round numerical value, Being compiled into a correction parameter look-up table, storage is in the nonvolatile memory；

Step 8:

Utilize the correction parameter look-up table of step 7 gained, display received image signal is carried out gray scale gamma correction, with View data G_OAs address, from correction lookup table memories, take out view data G after correction, as driving of FED device Dynamic signal data.

A kind of method for correcting image improving EED display quality the most according to claim 1, it is special Levy and be: when received image signal to certain pixel is corrected processing in described step 5, with this pixel at display screen On position be address, table look-up obtain this pixel corrected parameter α (i, j) and α ' (i, j), calculate correction gradation data, right Input picture gradation data G_iIt is modified, display data G after being corrected_O, and G_ORound numbers.

A kind of method for correcting image improving EED display quality the most according to claim 1, it is special Levy and be: when received image signal to certain pixel is corrected processing in described step 7, for ensureing the gray scale after correction It is worth without departing from display tonal range, for realizing 2ⁿThe gray scale of level shows, revised gray value G is more than 2ⁿWhen-1, with 2ⁿ-1 Display as this pixel drives picture signal.