CN1791231A - Chromatic display unit white field homogeneity testing method and system - Google Patents

Abstract

The invention discloses a homogeneity test method for homogeneity of color display, which comprises: collecting image with image collector, filtering with mean value average filter device, partitioning image with image partition device, calculating lightness and colority and homogeneity of white field by opposite device. This invention decides the homogeneity of white field for whole screen with uniform standard instead of manual decision to avoid test error and ensure consistency.

Description

Chromatic display unit white field homogeneity testing method and system

Technical field

The present invention relates to the detection range of chromatic display,, relate to a kind of method and system of chromatic display unit white field homogeneity test with specifically.

Background technology

The unit white field homogeneity of color monitor is an important parameter of estimating the chromatic display quality, and it comprises the evaluation of color and brightness uniformity, and majority adopts single probe colorimeter pointwise test methods at present, or with the naked eye judges by experienced test man.These two kinds of determination methods all exist defective.Wherein single probe colorimeter pointwise test method can only be tested a point at every turn, therefore can't make integrally the performance of whole screen and estimating, and all there is error in the method for employing artificial judgment because everyone naked eyes are judged, therefore can't form unified standard.

So, just need a kind of method and system that can judge to the unit white field homogeneity of whole screen, can not rely on artificial judgment, avoided the test error that difference caused, thereby guaranteed the consistency of criterion owing to everyone visual characteristic.

Summary of the invention

The purpose of this invention is to provide a kind of chromatic display unit white field homogeneity testing method and system, the method and system that it can judge the unit white field homogeneity of whole screen according to unified standard.

According to an aspect of the present invention, provide a kind of chromatic display unit white field homogeneity testing method, this method may further comprise the steps:

Image acquisition step images in coloured image on the photodetector, by figure capture card images acquired, obtains R, G, the B value of the full frame white field picture of chromatic display;

Filter step adopts intermediate value average filter method that R, G, the B value of the image that obtains gathered are carried out filtering, and R, G, the B value of each frame sorted, and deleting after the minimum and maximum part adds up remaining value, and to make arithmetic average;

The image block step, image block that will be after above-mentioned steps is handled;

Calculate the step of brightness and colourity, to each above-mentioned image block, calculate its brightness, colourity with and x, y value, obtain brightness and colourity relation and distribution on the whole screen;

Calculate the step of unit white field homogeneity,, calculate the unit white field homogeneity of described chromatic display according to the brightness on the screen that obtains and colourity relation and distribution.

According to a further aspect in the invention, provide a kind of chromatic display unit white field homogeneity test macro, it is characterized in that, comprising:

Image collecting device is connected in chromatic display, and the image of gathering described chromatic display obtains R, the G of the full frame white field picture of chromatic display, B value;

Intermediate value average filter device, link to each other with the output of described image collecting device, adopt intermediate value average filter method that R, G, the B value of the image that obtains gathered are carried out filtering, R, G, the B value of each frame sorted, deleting after the minimum and maximum part adds up remaining value, and to make arithmetic average;

The image block device links to each other with the output of described intermediate value average filter device, with the image block of intermediate value average filter device output;

Calculate the device of brightness and colourity, link to each other with described image block device, to each above-mentioned image block, calculate its brightness, colourity with and x, y value, obtain the brightness on the whole screen and colourity concerns and distribution;

Calculate the device of unit white field homogeneity,, calculate the unit white field homogeneity of described chromatic display according to the brightness on the screen that obtains and colourity relation and distribution.

Adopted after the above-mentioned technical scheme, chromatic display unit white field homogeneity testing method of the present invention and system can not rely on artificial judgment and judge according to the unit white field homogeneity of unified standard to whole screen, thereby avoided the test error that difference caused, to guarantee the consistency of criterion owing to everyone visual characteristic.

Description of drawings

Above-mentioned feature and the advantage with other of the present invention will be below becomes more obvious after in conjunction with the accompanying drawings and embodiments the description, and identical in the accompanying drawings Reference numeral is represented identical feature all the time, wherein:

Fig. 1 is the flow chart of chromatic display unit white field homogeneity testing method of the present invention;

Fig. 2 is the figure of chromoscope under white field signal;

Fig. 3 is a test result data;

Fig. 4 is a brightness uniformity distribution graphics;

The Yc graphics of Fig. 5 for only considering that uniformity of chromaticity distributes;

Fig. 6 is for not only considering brightness but also consider the CLD graphics that uniformity of chromaticity distributes;

Fig. 7 is for not only considering brightness but also considering the color difference analysis Δ E graphics of colourity;

Fig. 8 is the block diagram of chromatic display unit white field homogeneity test macro of the present invention.

Embodiment

Further specify technical scheme of the present invention below in conjunction with drawings and Examples.

Fig. 1 is the flow chart of chromatic display unit white field homogeneity testing method of the present invention.With reference to figure 1, chromatic display unit white field homogeneity testing method of the present invention comprises following step:

S11. image acquisition step images in coloured image on the photodetector, by figure capture card images acquired, obtains R, G, the B value of the full frame white field picture of chromatic display.Generally speaking, utilize photodetector (CCD) that display image is intactly collected continuous acquisition 5 two field pictures at least.The form of the image that collects as shown in Figure 2, an example of the figure that this figure is a chromoscope under white field signal.

S12. filter step adopts intermediate value average filter method that R, G, the B value of the image that obtains gathered are carried out filtering, and R, G, the B value of each frame sorted, and deleting after the minimum and maximum part adds up remaining value, and to make arithmetic average.Owing to can run into the spike interference phenomenon, adopt intermediate value average filter method to eliminate the interference of this spike in the method for the present invention.

S13. image block step, image block that will be after above-mentioned steps is handled.The quantity minimum of the image block of cutting apart is 3 * 3, is 100 * 100 to the maximum, and the quantity of image block can be adjusted according to the size of real image.

S14. calculate the step of brightness and colourity, to each above-mentioned image block, calculate its brightness, colourity with and x, y value, obtain brightness and the colourity relation on the whole screen and distribute.In this embodiment, also comprise according to brightness, colourity with and x, y value produce the distribution map of colourity and relative brightness.Shown in Figure 4 is an example of brightness uniformity distribution graphics, and it is that coordinate figure according to brightness value and x, y generates.

S15. calculate the step of unit white field homogeneity,, calculate the unit white field homogeneity of described chromatic display according to the brightness on the screen that obtains and colourity relation and distribution.What embody unit white field homogeneity mainly is three parameters, Δ E, Yc and CLD, and in this embodiment, above-mentioned three parameters are to calculate according to following formula:

Calculate Δ E:

$L^{*}=116f\left(\frac{Y}{Y_0}\right)-16;$

u ^*＝13L ^*(u′-u ₀′)；

v ^*＝13L ^*(v′-v ₀′)；(3)

Wherein

$f\left(x\right)=\left\{\begin{array}{cc}{x}^{1/3}& x>0.008856\\ 7.787x+16/116& \mathrm{otherwise}\end{array}\right.;---\left(4\right)$

$u^{\′}=\frac{4X}{X+15Y+3Z}{,v}^{\′}=\frac{9Y}{X+15Y+3Z}$

${u_0}^{\′}=\frac{4X_0}{X_0+15Y_0+3Z_0},{v_0}^{\′}=\frac{9Y_0}{X_0+15Y_0+3Z_0}---\left(5\right)$

(X wherein ₀, Y ₀, Z ₀) be with reference to white point (white point), L ^*Represent the luminance signal coordinate, it and u ^*And v ^*Coordinate is mutually orthogonal, in the CIELUV space, and two color (L ₁ ^*, u ₁ ^*, v ₁ ^*) and (L ₂ ^*, u ₂ ^*, v ₂ ^*) between difference can represent with Euclidean distance,

${\mathrm{\ΔE}}_{\mathrm{Luv}}=\sqrt{{\left({\mathrm{\ΔL}}^{*}\right)}^2+{\left({\mathrm{\Δu}}^{*}\right)}^2+{\left({\mathrm{\Δv}}^{*}\right)}^2}---\left(6\right)$

Δ L wherein ^*=L ^* ₁-L ^* ₂Δ u ^*With Δ v ^*Similar.In image processing, color difference amount Δ E _LuvBe widely used for weighing two difference between the color.

Calculate the formula of Yc:

$Y_c=\frac{\sqrt[2]{{(u_c-u_m)}^2+{(v_c-v_m)}^2}}{0.00384}$ The JND of unit (7)

Wherein,

$u_c=\frac{{4x}_c}{{-2x}_c+{12y}_c+3}$

$u_m=\frac{{4x}_m}{{-2x}_m+{12y}_m+3}$

$v_c=\frac{{6y}_c}{{-2x}_c+{12y}_c+3}$

$v_m=\frac{{6y}_m}{{-2x}_m+{12y}_m+3}---\left(8\right)$

Calculate the formula of CLD:

$\mathrm{CLD}=\sqrt{{1.56\mathrm{\&Delta;x}}^2-1.2\mathrm{\&Delta;x\&Delta;y}+{0.44\mathrm{\&Delta;<figure-callout\; id="2"\; label="y"\; filenames="A20041009317500142.png"\; state="\{\{state\}\}">y</figure-callout>}}^2+500{(\mathrm{\&Delta;Y}/Y_0)}^2}$

In the formula: Δ x, Δ y are test point and central point colour difference; Δ Y is the luminance difference of test point and central point, and Y ₀Be central point brightness.

After above-mentioned method acquisition test result, the present invention more provides the multiple mode that shows test results, and the first is utilized the form of chart, and as shown in Figure 3, Fig. 3 shows the form of test result data with chart.Another kind of mode is the three-dimensional distribution map that produces the unit white field homogeneity parameter.For example in this embodiment, can produce as shown in Figure 5 only consider Yc graphics that uniformity of chromaticity distributes, not only considering brightness but also considering CLD graphics that uniformity of chromaticity distributes and not only considering brightness but also considering the color difference analysis Δ E graphics of colourity as shown in Figure 7 as shown in Figure 6.

The present invention also provides a kind of chromatic display unit white field homogeneity test macro 100, and as shown in Figure 8, this system comprises:

Image collecting device 104 is connected in chromatic display 102, and the image of gathering chromatic display 102 obtains R, G, the B value of the full frame white field picture of chromatic display.In this embodiment, image collecting device 104 comprises two parts, photodetector 106 and figure capture card 108.Wherein photodetector 106 is connected in chromatic display 102, and the coloured image of chromatic display 102 images on the photodetector 106.Figure capture card 108 is connected in photodetector 106, is used for images acquired.And in this embodiment, image collecting device 104 is gathered 5 continuous two field pictures at least.

Intermediate value average filter device 110, link to each other with the output of image collecting device 104, adopt intermediate value average filter method that R, G, the B value of the image that obtains gathered are carried out filtering, R, G, the B value of each frame sorted, deleting after the minimum and maximum part adds up remaining value, and to make arithmetic average.The effect of intermediate value average filter device 110 is to eliminate the spike interference phenomenon that runs into.

Image block device 112 links to each other with the output of intermediate value average filter device 110, with the image block of intermediate value average filter device 110 outputs.According to this embodiment, the quantity minimum of image block device 112 split image pieces is 3 * 3, is 100 * 100 to the maximum.

Calculate the device 114 of brightness and colourity, link to each other with image block device 112, to each above-mentioned image block, calculate its brightness, colourity with and x, y value, obtain the brightness on the whole screen and colourity concerns and distribution.According to this embodiment, also comprise the first distribution map generation device 116 in the device 114 of this calculating brightness and colourity, its according to brightness, colourity with and x, y value produce the distribution map of colourity and relative brightness.The example of figure can be with reference to above-mentioned Fig. 4.

Calculate the device 118 of unit white field homogeneity,, calculate the unit white field homogeneity of described chromatic display according to the brightness on the screen that obtains and colourity relation and distribution.What embody unit white field homogeneity mainly is three parameters, Δ E, Yc and CLD, adopt to calculate the device 122 of Δ E among this embodiment respectively, the device 126 that calculates the device 124 of Yc and calculate CLD calculates three above-mentioned parameters, the computing formula that adopts in these three devices can be with reference to described in the above-mentioned step S15.According to this embodiment, the device 118 that calculates unit white field homogeneity also comprises the second distribution map generation device 120, produces the three-dimensional distribution map of unit white field homogeneity parameter.The example of figure can be with reference to above-mentioned Fig. 5,6,7.

During the system that states in the use, carry out under the environment of darkroom when preferably requiring test, the testing lens putting position be that assurance camera lens visual angle is less than 2 ° from display screen diagonal distance more than 3 times.This system present colourity measuring accuracy average out to ± about 0.004, luminance test precision average out to ± about 5.0%.

Adopted after the above-mentioned technical scheme, chromatic display unit white field homogeneity testing method of the present invention and system can not rely on artificial judgment and judge according to the unit white field homogeneity of unified standard to whole screen, thereby avoided the test error that difference caused, to guarantee the consistency of criterion owing to everyone visual characteristic.

The foregoing description provides to being familiar with the person in the art and realizes or use of the present invention; those skilled in the art can be under the situation that does not break away from invention thought of the present invention; the foregoing description is made various modifications or variation; thereby protection scope of the present invention do not limit by the foregoing description, and should be the maximum magnitude that meets the inventive features that claims mention.

Claims (10)

1. chromatic display unit white field homogeneity testing method may further comprise the steps:

Image acquisition step images in coloured image on the photodetector, by figure capture card images acquired, obtains R, G, the B value of the full frame white field picture of chromatic display;

Filter step adopts intermediate value average filter method that R, G, the B value of the image that obtains gathered are carried out filtering, and R, G, the B value of each frame sorted, and deleting after the minimum and maximum part adds up remaining value, and to make arithmetic average;

The image block step, image block that will be after above-mentioned steps is handled;

Calculate the step of brightness and colourity, to each above-mentioned image block, calculate its brightness, colourity with and x, y value, obtain brightness and colourity relation and distribution on the whole screen;

Calculate the step of unit white field homogeneity,, calculate the unit white field homogeneity of described chromatic display according to the brightness on the screen that obtains and colourity relation and distribution.

2. the method for claim 1 is characterized in that, continuous acquisition 5 two field pictures at least in the described image acquisition step.

3. the method for claim 1 is characterized in that, the quantity minimum of image block is 3 * 3 in the described image block step, is 100 * 100 to the maximum.

4. the method for claim 1 is characterized in that,

The step of described calculating brightness and colourity also comprise according to brightness, colourity with and x, y value produce the distribution map of colourity and relative brightness;

Also comprise the three-dimensional distribution map that produces the unit white field homogeneity parameter in the step of described calculating unit white field homogeneity.

5. the method for claim 1 is characterized in that, in the step of described calculating unit white field homogeneity, specifically adopts following formula:

Calculate Δ E:

$L^{*}=116f\left(\frac{Y}{Y_0}\right)-16;$

u ^*＝13L*(u′-u ₀′)； (3)

v ^*＝13L*(v′-v ₀′)；

Wherein

$f\left(x\right)=\left\{\begin{array}{cc}{x}^{1/3}& x>0.008856\\ 7.787x+16/116& \mathrm{otherwise}\end{array}\right.;$ (4)

$u^{\&prime;}=\frac{4X}{X+15Y+3Z}$ $v^{\&prime;}=\frac{9Y}{X+15Y+3Z}$

${u_0}^{\&prime;}=\frac{{4X}_0}{X_0+15Y_0+3Z_0}$ ${v_0}^{\&prime;}=\frac{9Y_0}{X_0+15Y_0+3Z_0};$ (5)

(X wherein ₀, Y ₀, Z ₀) be that reference is from point (white point), L ^*Represent the luminance signal coordinate, it and u ^*And v ^*Coordinate is mutually orthogonal, in the CIELUV space, and two color (L ₁ ^*, u ₁ ^*, v ₁ ^*) and (L ₂ ^*, u ₂ ^*, v ₂ ^*) between difference can represent with Euclidean distance,

$\mathrm{\&Delta;}{E}_{\mathrm{Luv}}=\sqrt{{\left(\mathrm{\&Delta;}{L}^{*}\right)}^2+{\left(\mathrm{\&Delta;}{u}^{*}\right)}^2+{\left(\mathrm{\&Delta;}{v}^{*}\right)}^2}$ (6)

Δ L wherein ^*=L ^* ₁-L ^* ₂

Calculate the formula of Yc:

$Y_c=\frac{2\sqrt{{(u_c-u_m)}^2+{(v_c-v_m)}^2}}{0.00384},$ The JND of unit (7)

Wherein,

$u_c=\frac{4x_c}{-2x_c+12y_c+3}$

$u_m=\frac{4x_m}{-2x_m+12y_m+3}$

$v_c=\frac{6y_c}{-2x_c+12y_c+3}$

$v_m=\frac{6y_m}{-2x_m+12y_m+3}$ (8)

Calculate the formula of CLD:

$\mathrm{CLD}=\sqrt{{1.56\mathrm{\&Delta;x}}^2-1.2\mathrm{\&Delta;x\&Delta;y}+0.44\mathrm{\&Delta;}{y}^2+500{(\mathrm{\&Delta;Y}/Y_0)}^2}$

In the formula: Δ x, Δ y are test point and central point colour difference; Δ Y is the luminance difference of test point and central point, and Y ₀Be central point brightness.

6. a chromatic display unit white field homogeneity test macro is characterized in that, comprising:

Image collecting device is connected in chromatic display, and the image of gathering described chromatic display obtains R, the G of the full frame white field picture of chromatic display, B value;

Intermediate value average filter device, link to each other with the output of described image collecting device, adopt intermediate value average filter method that R, G, the B value of the image that obtains gathered are carried out filtering, R, G, the B value of each frame sorted, deleting after the minimum and maximum part adds up remaining value, and to make arithmetic average;

The image block device links to each other with the output of described intermediate value average filter device, with the image block of intermediate value average filter device output;

Calculate the device of brightness and colourity, link to each other with described image block device, to each above-mentioned image block, calculate its brightness, colourity with and x, y value, obtain the brightness on the whole screen and colourity concerns and distribution;

Calculate the device of unit white field homogeneity,, calculate the unit white field homogeneity of described chromatic display according to the brightness on the screen that obtains and colourity relation and distribution.

7. system as claimed in claim 6 is characterized in that, described image collecting device comprises:

Photodetector is connected in chromatic display, and the coloured image of described chromatic display images on the photodetector;

The figure capture card is connected in described photodetector, is used for images acquired; And

Described image collecting device is gathered 5 continuous two field pictures at least.

8. system as claimed in claim 6 is characterized in that, the quantity minimum of described image block device split image piece is 3 * 3, is 100 * 100 to the maximum.

9. system as claimed in claim 6 is characterized in that,

The device of described calculating brightness and colourity also comprises the first distribution map generation device, according to brightness, colourity with and x, y value produce the distribution map of colourity and relative brightness;

The device of described calculating unit white field homogeneity also comprises the second distribution map generation device, produces the three-dimensional distribution map of unit white field homogeneity parameter.

10. system as claimed in claim 6 is characterized in that, the device of described calculating unit white field homogeneity further comprises:

Calculate the device of Δ E, this device calculates Δ E according to following formula:

$L^{*}=116f\left(\frac{Y}{Y_0}\right)-16;$

u ^*＝13L*(u′-u ₀′)； (3)

v ^*＝13L*(v′-v ₀′)；

Wherein

$f\left(x\right)=\left\{\begin{array}{cc}{x}^{1/3}& x>0.008856\\ 7.787x+16/116& \mathrm{otherwise}\end{array}\right.;$ (4)

$u^{\&prime;}=\frac{4X}{X+15Y+3Z}$ $v^{\&prime;}=\frac{9Y}{X+15Y+3Z}$

${u_0}^{\&prime;}=\frac{{4X}_0}{X_0+15Y_0+3Z_0}$ ${v_0}^{\&prime;}=\frac{9Y_0}{X_0+15Y_0+3Z_0};$ (5)

(X wherein ₀, Y ₀, Z ₀) be with reference to white point (white point), L ^*Represent the luminance signal coordinate, it and u ^*And v ^*Coordinate is mutually orthogonal, in the CIELUV space, and two color (L ₁ ^*, u ₁ ^*, v ₁ ^*) and (L ₂ ^*, u ₂ ^*, v ₂ ^*) between difference can represent with Euclidean distance,

$\mathrm{\&Delta;}{E}_{\mathrm{Luv}}=\sqrt{{\left(\mathrm{\&Delta;}{L}^{*}\right)}^2+{\left(\mathrm{\&Delta;}{u}^{*}\right)}^2+{\left(\mathrm{\&Delta;}{v}^{*}\right)}^2}$ (6)

Δ L wherein ^*=L ^* ₁-L ^* ₂

Calculate the device of Yc, this device calculates Yc according to following formula:

$Y_c=\frac{2\sqrt{{(u_c-u_m)}^2+{(v_c-v_m)}^2}}{0.00384},$ The JND of unit (7)

Wherein,

$u_c=\frac{4x_c}{-2x_c+12y_c+3}$

$u_m=\frac{4x_m}{-2x_m+12y_m+3}$

$v_c=\frac{6y_c}{-2x_c+12y_c+3}$

$v_m=\frac{6y_m}{-2x_m+12y_m+3}$ (8)

Calculate the device of CLD, this device calculates CLD according to following formula:

$\mathrm{CLD}=\sqrt{{1.56\mathrm{\&Delta;x}}^2-1.2\mathrm{\&Delta;x\&Delta;y}+0.44\mathrm{\&Delta;}{y}^2+500{(\mathrm{\&Delta;Y}/Y_0)}^2}$

In the formula: Δ x, Δ y are test point and central point colour difference; Δ Y is the luminance difference of test point and central point, and Y ₀Be central point brightness.

Images