CN112666731B - Visual angle evaluation method of display screen - Google Patents
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Abstract
The invention discloses a visual angle assessment method of a display screen, and belongs to the technical field of display. The evaluation method comprises the following steps: acquiring a plurality of brightness values and/or a plurality of chromaticity values of at least one test picture on a display screen when a plurality of test angles are displayed; obtaining at least one of a saturation viewing angle, a hue viewing angle, a white field brightness viewing angle, a gray field brightness viewing angle, and a black field brightness viewing angle of a display screen based on the plurality of luminance values and/or the plurality of chrominance values; the visibility of the display screen is evaluated based on at least one of a saturation visibility, a hue visibility, a white field luminance visibility, a gray field luminance visibility, and a black field luminance visibility of the display screen. By adopting the technical scheme of the invention, the change of the picture of the display screen perceived by human eyes along with the viewing angle can be reflected more objectively and more accurately from the dimensions of saturation, tone, white field brightness, gray field brightness, black field brightness and the like, so that the visual angle of the display screen is estimated correctly.
Description
Technical Field
The invention relates to the technical field of display, in particular to a visual angle assessment method of a display screen.
Background
The brightness of a typical screen display decreases with increasing viewing angle, and the brightness and color effect are best seen from the front of the screen, and the brightness and color effect gradually decrease no matter in the vertical direction or in the horizontal direction, and the brightness and color effect decrease to an unacceptable degree for users due to the overlarge viewing angle. The viewing angle may be defined as an angle at which a user can clearly observe all contents on a screen from different directions.
However, in the related art, the visual angle evaluation method of the display device such as the liquid crystal is mainly considered from two dimensions of color and white field brightness, and the evaluation is inaccurate.
Disclosure of Invention
The invention mainly aims to provide a visual angle assessment method of a display screen, which aims to solve the technical problem that the visual angle assessment method of the display screen in the prior art cannot accurately assess the visual angle of the display screen.
In order to achieve the above object, the present invention provides a method for evaluating a viewing angle of a display screen, comprising:
acquiring a plurality of brightness values and/or a plurality of chromaticity values of a test picture on a display screen when a plurality of test angles are displayed;
obtaining at least one of a saturation viewing angle, a hue viewing angle, a white field brightness viewing angle, a gray field brightness viewing angle, and a black field brightness viewing angle of a display screen based on the plurality of luminance values and/or the plurality of chrominance values;
the visibility of the display screen is evaluated based on at least one of a saturation visibility, a hue visibility, a white field luminance visibility, a gray field luminance visibility, and a black field luminance visibility of the display screen.
Optionally, the test pictures comprise a red test picture, a green test picture and a blue test picture which are displayed in sequence;
a step of obtaining a saturation viewing angle and a hue viewing angle of a display screen based on a plurality of luminance values and/or a plurality of chrominance values, comprising:
generating a saturation value and a hue value of the test picture in the LCH color space diagram at any angle according to the brightness value and the chromaticity value obtained at any test angle;
screening a plurality of qualified saturation values from the plurality of saturation values according to a preset qualified saturation value, and screening a plurality of qualified tone values from the plurality of saturation values according to a preset qualified tone value;
the maximum angle of a plurality of test angles corresponding to the plurality of qualified saturation values is set as the saturation viewing angle of the display screen, and the maximum angle of a plurality of test angles corresponding to the plurality of qualified tone values is set as the tone value viewing angle of the display screen.
Optionally, the red test picture, the green test picture and the blue test picture are displayed in a partial area of the display screen.
Optionally, the step of generating the saturation value and the hue value of the test picture in the LCH color space diagram at any angle according to the luminance value and the chrominance value obtained at any test angle includes:
converting a brightness value and a chromaticity value obtained at any test angle to obtain a tristimulus value of the test picture at any angle;
converting the tristimulus values of the test picture at any angle to obtain Lab values;
and converting to obtain the saturation value and the tone value of the test picture in the LCH color space diagram at any angle according to the Lab value.
Optionally, the test picture is a full black picture, and the test picture is displayed on the display screen in a full screen;
the step of obtaining a black field luminance viewing angle of the display screen based on the plurality of luminance values includes:
taking a brightness value obtained when the test angle is 0 DEG as a first brightness value;
screening a second brightness value from the plurality of brightness values, wherein a first preset condition is met between the value of the second brightness value and the value of the first brightness value;
and taking the test angle corresponding to the second brightness value as a black field brightness visual angle of the display screen.
Optionally, the first preset condition is:
the second luminance value has a value twice the value of the first luminance value.
Optionally, the test picture is a full-white picture, and the test picture is displayed on the display screen in a full screen;
the step of obtaining a white field luminance viewing angle of the display screen based on the plurality of luminance values includes:
taking a brightness value obtained when the test angle is 0 DEG as a third brightness value;
screening a fourth brightness value from the brightness values, wherein a second preset condition is met between the value of the fourth brightness value and the value of the third brightness value;
and taking the test angle corresponding to the third brightness value as a white brightness visual angle of the display screen.
Optionally, the second preset condition is:
the value of the fourth luminance value is 75% of the value of the third luminance value.
Optionally, the test pictures comprise gray pictures with different gray scales, wherein gray scale values of the gray pictures are in an arithmetic progression, and the test pictures are displayed on a display screen in full screen in sequence;
the step of obtaining gray field luminance visibility angles of the display screen based on the plurality of luminance values includes:
any gray picture in the gray pictures with different gray scales is determined to be an ideal test picture;
screening a plurality of first ideal brightness values obtained by displaying an ideal test picture when the test angle is 0 DEG from the plurality of brightness values, and screening a plurality of second ideal brightness values obtained by displaying the rest pictures in the plurality of different gray-scale pictures when the test angle is 0 DEG;
calculating a plurality of theoretical brightness values of the residual pictures when the residual pictures are displayed at a plurality of test angles based on the first ideal brightness value and the second ideal brightness value;
screening out a target brightness value from the rest brightness values in the brightness values, wherein a fourth preset condition is met between the target brightness value and the corresponding theoretical brightness value;
and taking the minimum angle in a plurality of test angles corresponding to the target brightness value as the gray field brightness visual angle of the display screen.
Optionally, the fourth preset condition is:
the deviation value between the target brightness value and the theoretical brightness value is more than or equal to 3%.
According to the technical scheme, the luminance value and/or the chromaticity value obtained by the test picture are processed to obtain at least one of the saturation visual angle, the tone visual angle, the white field visual angle, the gray field visual angle and the black field visual angle, so that the change of a picture of the display screen perceived by human eyes along with the viewing angle can be more objectively and accurately reflected through at least one dimension of the saturation, the tone, the white field visual angle, the gray field visual angle, the black field visual angle and the like, and the visual angle and the display effect of the display screen can be more accurately estimated.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a visibility measuring device for a method for evaluating visibility of a display screen according to the present invention;
FIG. 2 is a schematic diagram illustrating deflection of an embodiment of a visibility measuring device required for a visibility evaluation method of a display screen of the present invention;
FIG. 3 is a flowchart illustrating a first embodiment of a visibility evaluation method for a display screen according to the present invention;
FIG. 4 is a flowchart illustrating a visibility evaluation method according to a second embodiment of the present invention;
FIG. 5 is a flowchart illustrating a third embodiment of a visibility evaluation method for a display screen according to the present invention;
FIG. 6 is a flowchart of a fourth embodiment of a visibility evaluation method for a display screen according to the present invention;
FIG. 7 is a flowchart of a fifth embodiment of a visibility evaluation method for a display screen according to the present invention;
FIG. 8 is a schematic diagram illustrating the deflection of another embodiment of the visibility measuring device required for the visibility evaluation method of a display screen according to the present invention.
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.
In addition, if there is a description of "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.
In the related art, the viewing angle of a display device is generally characterized by color and white brightness. The current color angle measurement is established in the CIE1931 xy color or CIE 1976uv color space. The CIE1931 color space is not a uniform color space and changes in xy coordinates do not adequately describe changes in subjective perception by the human eye. The CIE 1976uv color space, although a uniform color space, Δu 'v' does not accurately describe the change in color. And besides color, brightness should be an important criterion for viewing angle determination. The luminance viewing angle herein does not refer to just a white luminance viewing angle, but only one of them. However, the ability of the display device to display black and gray fields can also be important, and after all, white fields are not always displayed when the display device is in use.
Therefore, the embodiment of the invention provides a visual angle evaluation method of a display screen, which is used for measuring the change of a picture of the display screen perceived by human eyes along with the viewing angle through multiple dimensions of saturation, tone, white field brightness, gray field brightness, black field brightness and the like, so that the visual angle of the display screen can be evaluated more scientifically and reasonably, and the display effect of the display screen can be evaluated.
The inventive concepts of the present application are further described below in conjunction with some of the drawings and specific embodiments.
Referring to fig. 3, fig. 3 is a flowchart illustrating a first embodiment of a method for evaluating a viewing angle of a display screen according to an embodiment of the invention.
The method provided by the invention is suitable for liquid crystal display screens, laser display screens, OLED (organic light emitting diode) screens and other screens, but is not limited to the display equipment.
In this embodiment, the evaluation method includes the following steps;
step S100, a plurality of brightness values and/or a plurality of chromaticity values of at least one test picture on a display screen when a plurality of test angles are displayed are obtained.
Specifically, in this step, the display screen is a display interface of the display device, and the test picture may be different pictures, for example, a full black picture, a full white picture, or a gray picture with different gray scales, or may be a R, G or B monochrome picture, according to different scenes. And the measurement picture can be displayed in a full screen mode, and can also be displayed in the central part of the display screen in a window mode.
The obtained luminance value and/or chromaticity value can be obtained in a visual angle measurement experiment. For ease of understanding, a specific embodiment is shown:
referring to fig. 1, the viewing angle measuring apparatus for a display screen includes a mounting platform 100 and a measuring platform 200, wherein the mounting platform 100 is used for mounting a display device 300 to be tested, and the measuring platform 200 is used for mounting a measuring device 400 such as a spectrometer and/or a colorimeter. The spectrometer is used for measuring brightness data, namely a brightness value L, when the test picture is displayed on the display device, and the colorimeter is used for measuring the number of colorimetry values when the test picture is displayed on the display device, wherein the colorimeter outputs an x value and a y value in a CIE1931 xy color space.
And either the mounting platform 100 or the measuring platform 200 may be rotated on a horizontal plane with the center of the display screen as a center of circle. For example, referring to fig. 2, the mounting platform 100 remains stationary and the measurement platform 200 rotates on a horizontal plane centered at the center of the display screen. Alternatively, in another embodiment, the mounting platform 100 rotates while the measuring platform 200 is stationary, and referring to fig. 8, after the display device 300 is fixedly mounted to the mounting platform 100, the center of the display screen is located on the rotation axis of the rotation of the mounting platform 100. Further description will be given below taking an example in which the mounting platform 100 is kept stationary and the measuring platform 200 is rotated.
And the spacing between the measurement platform 200 and the mounting platform 100 is adjustable. Alternatively, the spacing is generally determined according to the size of the display screen, for example, the spacing may be 1.5 times the diagonal size of the display screen. The spectrometers and colorimeters on the measurement platform 200 are all aligned to the very center of the display screen. .
Referring to fig. 2, in the case of performing the visual angle measurement of the display device, first, the measurement device such as a spectrometer and a colorimeter is placed in front of the display device and aligned with the S in the center of the display screen 0 The position, where the state of the display device 300 is measured and recorded, is kept stationary, where the measurement angle is 0 °. The measuring platform 200 and the measuring device 400 are horizontally deflected to the left to S by taking the display screen as the center of a circle 1 Position or deflection to the right by one step to S 2 The position, step size per step is 1 °. If the measuring platform deflects from 0 deg. to the right to the +1 deg. position, the state at this time is measured and recorded. The measuring platform is then deflected further to the right, the state at this time is measured and recorded until it reaches +90°, and then the measurement is continued from 0 ° to-90 °. I.e. a plurality of measurement angles lying between-90 deg. and +90 deg., with adjacent measurement angles differing by 1 deg..
It is worth mentioning that all devices require 10-20min of ambient temperature ageing before measurement to ensure that the machine is in a stable state during measurement. More particularly, the self-luminous display device of the OLED needs to be aged after each switching of the test picture.
Step S200, obtaining at least one of a saturation viewing angle, a hue viewing angle, a white field luminance viewing angle, a gray field luminance viewing angle, and a black field luminance viewing angle of the display screen based on the plurality of luminance values and/or the plurality of chrominance values.
In this step, at least one of a saturation viewing angle, a hue viewing angle, a white field luminance viewing angle, a gray field luminance viewing angle, and a black field luminance viewing angle of the display screen can be obtained by further processing the obtained luminance value and chromaticity value.
Step S300, the visual angle of the display screen is evaluated based on at least one of the saturation visual angle, the tone visual angle, the white field brightness visual angle, the gray field brightness visual angle and the black field brightness visual angle of the display screen.
The step of evaluating the display effect of the display screen according to the obtained saturation viewing angle, hue viewing angle, white field brightness viewing angle, gray field brightness viewing angle and black field brightness viewing angle may be whether the viewing angle of the display device meets the relevant standard, and whether the viewing angle of the display screen meets the variation of the human eye feeling along with the variation of the viewing angle.
In this embodiment, the change of the picture of the display screen perceived by the human eye along with the viewing angle can be more objectively and more accurately reflected from at least one dimension such as saturation, hue, white field brightness, gray field brightness, black field brightness and the like, and further can be used as a reference standard for improving the display effect and user experience of the display device. And when multiple dimensions are evaluated at the same time, the embodiment can also evaluate the change condition of the picture of the display screen perceived by human eyes along with the viewing angle more comprehensively, thereby improving the user experience.
Based on the first embodiment of the present invention, a second embodiment of the evaluation method of the present invention is presented. Referring to fig. 4, fig. 4 is a flow chart of the present embodiment.
In this embodiment, the evaluation method evaluates the visual angle of the display screen from the saturation and tone 2 dimensions. The test pictures comprise three test pictures of R (191,0,0), G (0, 191,0) and B (0, 191). And outputting signals of the three test pictures on a display screen in sequence on a measuring device, and measuring to obtain corresponding brightness values and chromaticity values in sequence.
And optionally, the red test picture, the green test picture and the blue test picture are all displayed in a partial area of the display screen. I.e., R (191,0,0), G (0, 191,0), and B (0, 191) are shown in a window form on the midpoint of the display screen, instead of being shown in full screen. And the window is located at the midpoint of the display screen.
In this embodiment, step S200 of the evaluation method includes the steps of:
step S211, generating a saturation value and a hue value of the test picture in the LCH color space diagram at any angle according to the brightness value L and the chromaticity values x and y obtained at any test angle.
Specifically, the luminance value L and the chrominance values x and y measured at any one test angle may be converted into the saturation value C and the hue value h of the test picture in the LCH color space map in the following manner. At this time, step S201 includes the steps of:
(a) The luminance value L and the chromaticity values x and y obtained at any one test angle are converted to tristimulus values X, Y, Z of the test picture at any one angle.
Wherein, the tristimulus values are X, Y, Z values under CIE1931 color space, and can be obtained by the following formulas:
X＝x×L/y；
Y＝L；
Z＝(1-x-y)×L/y。
(b) And converting the tristimulus values of the test picture at any angle to obtain Lab values.
This step converts the tristimulus values to Lab values. Lab values in Lab color space include L * For brightness, a * And b * Is two color channels, which can be obtained by the following formulas:
wherein, let theOr->The parameter in the above 3 formulas +.>And +.>The function f (x) is involved to satisfy the following condition:
when x > 0.008856;
when x < 0.008856.
And when the field angle of the measuring instrument (the field range of the measuring equipment) is less than or equal to 4 DEG, X n ＝95.04，Y n ＝100.00，Z n = 108.88. When the field angle of the test instrument is larger than 4 DEG, X n ＝94.81，Y n ＝100.00，Z n ＝107.32。
(c) Converting to obtain a saturation value c of the test picture in the LCH color space diagram at any angle according to the Lab value * And a hue value h.
Wherein the saturation value c * And the hue value h can be respectively determined byThe formula is:
wherein, when a * > 0 and b * At > 0, Δ=0;
when a is * When < 0, Δ=180;
when a is * > 0 and b * When < 0, Δ=360.
In this step, the saturation value c corresponding to the luminance value and the chrominance value measured at each test angle of 1 ° at each interval in-90 ° to 90 ° of each test picture can be obtained * And a hue value h.
Step S212, screening a plurality of qualified saturation values from the plurality of saturation values according to a preset qualified saturation value, and screening a plurality of qualified tone values from the plurality of saturation values according to a preset qualified tone value.
In this step, the preset acceptable saturation value may be determined to be 80%, so that all the saturation values c converted from step S201 * And screening all qualified saturation values with the saturation of more than 80% from the hue value h.
And determines the preset qualified hue value to be 3 deg., thereby converting all the saturation values c obtained in step S201 * And screening all qualified tone values with tone values smaller than 80% from the tone values h.
Step S213, setting the maximum angle of the plurality of test angles corresponding to the plurality of qualified saturation values as the saturation viewing angle of the display screen, and setting the maximum angle of the plurality of test angles corresponding to the plurality of qualified tone values as the tone value viewing angle of the display screen.
After screening out all the qualified saturation values, the corresponding measurement angles can be obtained, and as the plurality of measurement angles capable of obtaining the qualified saturation values are provided, the maximum angle in the measurement angles can be set as the saturation view angle of the display screen. And it is easy to understand that the measurement angle is-90 ° to +90°, and in the rectangular coordinate system, the sign of the angle indicates only the rotation direction of the side, and cannot indicate the size. Thus, the maximum angle may be positive or negative. And the visual angle of the display screen is generally symmetric left and right, so that only one maximum angle is obtained.
It should be noted that, in the present embodiment, both the hue angle view and the saturation angle view may be the same or different.
The saturation visibility angle represents the variation of the shade of color with the viewing angle. A device with a high saturation viewing angle may ensure that the color seen by the viewer at both high and low angles is dark or light, such as positive red when viewed from the side or positive red rather than pale red. The hue angle of visibility represents the relationship of color to viewing angle. A device with a large tonal viewing angle can ensure that the colors seen by the viewer at large and small angles are the same color, such as positive red when viewed from the side or positive red instead of pink or purple.
In this embodiment, three R (191,0,0) G (0, 191,0) B (0, 191) test pictures are obtained by measurement, and the luminance values and the chrominance values of a plurality of measurement angles in-90 ° to +90°, and the color visibility angle is evaluated from two dimensions of saturation and hue on the basis of Lch color space, so as to more accurately reflect or measure the change of the human eye perceived picture along with the viewing angle.
Based on the first embodiment of the present invention, a third embodiment of the evaluation method of the present invention is proposed. Referring to fig. 5, fig. 5 is a flow chart of the evaluation method of the present invention.
In this embodiment, the evaluation method evaluates the viewing angle of the display screen from the dimension of black field luminance. Wherein, the test picture is a full black picture. And outputting the signal of the full-black test picture on the display screen in a full screen mode, and measuring to obtain a corresponding brightness value.
Step S200 includes:
step S222, taking the brightness value obtained when the test angle is 0 DEG as a first brightness value L 0 。
Step S223, screening a second brightness value L' from the plurality of brightness values, wherein the value of the second brightness value and the value of the first brightness value meet a first preset condition.
Alternatively, as an option of this embodiment, the first preset condition is: the second luminance value has a value twice the value of the first luminance value. I.e. L' =2l 0 。
Step S224, the test angle corresponding to the second brightness value is used as the black field brightness visual angle of the display screen.
In the present embodiment, the luminance value at the test angle of 0 ° is used as the reference, i.e., the first luminance value L 0 Then the measuring device deflects leftwards or rightwards by one step, and the deflection is continued after the brightness value is obtained by measurement. In this process, the brightness of the display screen displayed by the full black screen gradually increases, and when the brightness of the black field is doubled, the measured brightness value is the second brightness value L', and the measurement angle at this time is the black field brightness visual angle. And the viewing angle of the display screen is generally bilateral symmetry, so that the black field brightness viewing angle can select brightness value data from 0 degree to 90 degrees or brightness value data from 0 degree to-90 degrees.
In this embodiment, the viewing angle of the black field is used to describe the viewing angle capability of the display device to display the black field. And unlike the contrast of the display screen, the contrast measures the ability to display black when in front view. The black field luminance viewing angle can more accurately reflect the black field condition seen by the observer from a large angle.
Based on the first to second embodiments of the present invention, a fourth embodiment of the evaluation method of the present invention is presented. Referring to fig. 6, fig. 6 is a flow chart of the evaluation method of the present invention.
In this embodiment, the evaluation method evaluates the visual angle of the display screen from the dimension of white field luminance. Wherein, the test picture is a full white picture. And outputting the signal of the full-white test picture on the display screen in a full screen mode, and measuring to obtain a corresponding brightness value.
Step S200 includes:
step S231, setting the test angle to 0 DEGThe luminance value obtained at that time is taken as a third luminance value L 1 。
Step S231, screening the fourth luminance value L 'from the plurality of luminance values, wherein the value of the fourth luminance value L' is equal to the third luminance value L 1 The values of (2) satisfy a second preset condition.
Alternatively, as an option of this embodiment, the second preset condition is: the value of the fourth luminance value is 75% of the value of the third luminance value. I.e. L "=0.75l 1 。
Step S231, taking the test angle corresponding to the third brightness value as the white field brightness visual angle of the display screen.
In the present embodiment, the luminance value at the test angle of 0 ° is used as the reference, i.e., the third luminance value L 1 Then the measuring device deflects leftwards or rightwards by one step, and the deflection is continued after the brightness value is obtained by measurement. In this process, the brightness of the display screen of the white field display gradually decreases, when the white field brightness decreases to L 1 When 75% of the brightness value is measured as a fourth brightness value L', the measurement angle is the white field brightness visual angle. And the viewing angle of the display screen is generally bilateral symmetry, so that the white brightness viewing angle can select the brightness value data from 0 degree to 90 degrees or the brightness value data from 0 degree to-90 degrees.
Due to the directionality of the screen, the brightness of the image may vary with the change in viewing angle. In this embodiment, the effect of the brightness variation of the display device on the human eye perception is described by the white field brightness viewing angle.
Based on the first to fourth embodiments of the present invention, a fifth embodiment of the evaluation method of the present invention is proposed. Referring to fig. 7, fig. 7 is a flowchart of a fifth embodiment of the evaluation method according to the present invention.
In this embodiment, the evaluation method evaluates the viewing angle of the display screen from the dimension of gray-scale luminance. The test pictures comprise a plurality of gray pictures with different gray scales, wherein the gray scale values of the gray pictures are in an arithmetic progression, and the test pictures are displayed on a display screen in full screen in sequence. In this embodiment, the five test pictures can be sequentially output and displayed at a test angle of 0 ° to obtain a brightness value by measurement, then the measurement platform continues to deflect by 1 °, and the five test pictures are sequentially output and displayed again until the measurement angle is completely measured from-90 ° to 90 °.
As an option of this embodiment, the test pictures include five total: 0% gray scale picture (full white), 20% gray scale picture, 40% gray scale picture, 60% gray scale picture, 80% gray scale picture.
In this embodiment, step S200 includes:
step S241, any gray picture in the gray pictures with different gray scales is determined as an ideal test picture.
Since gray-scale luminance viewing angle is a measure of luminance viewing angle at different gray scales, the degree of offset between the Gamma curve at different gray scales and the ideal Gamma curve is described. Therefore, any gray picture in the gray pictures with different gray scales is determined as an ideal test picture, and the gray scale loading state measured by the ideal test picture when the measurement angle is 0 DEG is the ideal Gamma curve of the display screen.
As an alternative to this embodiment, the ideal test picture may be a 0% gray scale picture.
Step S242, a plurality of first ideal brightness values obtained when the test angle is 0 degree are screened out from the ideal test pictures, and a plurality of second ideal brightness values obtained when the test angle is 0 degree are screened out from the rest pictures in the plurality of different gray-scale pictures.
For example, the luminance value of the 0% gray-scale picture measured at 0 ° may be selected, where the luminance value is the first ideal luminance value, and the luminance values of the 20% gray-scale picture, the 40% gray-scale picture, the 60% gray-scale picture, and the 80% gray-scale picture at 0 ° are the second ideal luminance values. Namely, the brightness data of the full gray display screen, which is measured by the measuring device when the full gray display screen is opposite to the display screen, are displayed in different gray scales.
Step 243, calculating a plurality of theoretical brightness values of the remaining pictures when the plurality of test angles are displayed based on the first ideal brightness value and the second ideal brightness value.
In this step, since one skilled in the art knows that gray scale is proportional to brightness, the theoretical brightness of different gray scales can be calculated according to any one. Therefore, theoretical brightness values which are measured in theory when the residual pictures are displayed at a plurality of test angles can be calculated based on the first ideal brightness value and the second ideal brightness value. For example, after obtaining the luminance values of the 0% gray-scale picture at 0 ° and the respective luminance values of the 20% gray-scale picture, the 40% gray-scale picture, the 60% gray-scale picture, and the 80% gray-scale picture at 0 °, the theoretical luminance values of the 20% gray-scale picture, the 40% gray-scale picture, the 60% gray-scale picture, and the 80% gray-scale picture at any measurement angle between 0 ° and 90 °, or between 0 ° and-90 °, can be calculated.
Step S244, a target brightness value is screened from the rest brightness values in the brightness values, and a fourth preset condition is met between the target brightness value and the corresponding theoretical brightness value.
As an option of this embodiment, the fourth preset condition is: the deviation value between the target brightness value and the theoretical brightness value is more than or equal to 3%.
The target brightness values meeting the preset conditions, namely the deviation of the target brightness values is 3%, can be screened out by comparing a plurality of brightness values obtained through actual measurement with corresponding theoretical values, namely the theoretical brightness values.
Step S245, the minimum angle among a plurality of testing angles corresponding to the target brightness value is used as the gray field brightness visual angle of the display screen.
The viewing angle of the display screen is generally symmetric left and right, so that the gray field brightness viewing angle can select brightness value data from 0 degree to 90 degrees or brightness value data from 0 degree to-90 degrees. Thus, it is possible to start the measurement from 0 ° at the time of the test by the measuring platform and then to step the deflection one step to the left and then to measure again until-90 °. Therefore, the minimum angle in a plurality of test angles corresponding to the target brightness value can be used as the gray-field brightness visual angle of the display screen, namely, the angle which is the earliest 3% of deflection, and the angle is the gray-field brightness visual angle. In this embodiment, the gray field visual angle is a measure for the brightness visual angle under different gray scales, and describes the offset degree between the Gamma curve under different gray scales and the ideal Gamma curve. The gray brightness visual angle is obtained by using the angle when the actual Gamma curve deviates from the ideal Gamma curve by 3%, so that the visual angle of the display screen can be estimated more comprehensively and accurately in the dimension of gray brightness.
The foregoing description is only of the optional embodiments of the present invention, and is not intended to limit the scope of the invention, and all the equivalent structural changes made by the description of the present invention and the accompanying drawings or the direct/indirect application in other related technical fields are included in the scope of the invention.
Claims (4)
1. A viewing angle assessment method for a display screen, comprising:
acquiring a plurality of brightness values and/or a plurality of chromaticity values of at least one test picture on a display screen when a plurality of test angles are displayed;
obtaining a saturation viewing angle and a hue viewing angle of the display screen based on a plurality of the luminance values and/or a plurality of the chromaticity values, or obtaining a gray-scale luminance viewing angle of the display screen based on a plurality of the luminance values;
evaluating the visibility of the display screen based on the saturation visibility and the hue visibility of the display screen or based on the gray field luminance visibility;
the step of obtaining a saturation viewing angle and a hue viewing angle of the display screen based on a plurality of the luminance values and/or a plurality of the chrominance values includes:
generating a saturation value and a hue value of the test picture in an LCH color space diagram when any test angle is generated according to the brightness value and the chromaticity value obtained by any test angle; the test pictures comprise a red test picture, a green test picture and a blue test picture which are displayed in sequence;
screening a plurality of qualified saturation values from the plurality of saturation values according to a preset qualified saturation value, and screening a plurality of qualified hue values from the plurality of saturation values according to a preset qualified hue value;
setting the maximum angle of a plurality of test angles corresponding to the qualified saturation values as the saturation viewing angle of the display screen, and setting the maximum angle of a plurality of test angles corresponding to the qualified tone values as the tone value viewing angle of the display screen;
the step of obtaining gray field luminance visibility angles of the display screen based on the plurality of luminance values includes:
any gray picture in the gray pictures with different gray scales is determined to be an ideal test picture; the test pictures comprise a plurality of gray pictures with different gray scales, wherein gray scale values of the gray pictures are in an arithmetic progression, and the test pictures are displayed on the display screen in full screen in sequence;
screening out a first ideal brightness value obtained when the test angle of the ideal test picture is 0 DEG from a plurality of brightness values, and screening out a plurality of second ideal brightness values obtained when the test angle of the rest pictures in a plurality of different gray-scale pictures is 0 DEG;
calculating a plurality of theoretical brightness values of the residual picture when the residual picture is displayed at a plurality of test angles based on the first ideal brightness value and the second ideal brightness value;
screening out a target brightness value from the rest brightness values in the brightness values, wherein a fourth preset condition is met between the target brightness value and the corresponding theoretical brightness value;
and taking the minimum angle of a plurality of test angles corresponding to the target brightness value as the gray field brightness visual angle of the display screen.
2. The method of evaluating according to claim 1, wherein,
the red test picture, the green test picture and the blue test picture are all displayed in a partial area of the display screen.
3. The evaluation method according to claim 1, wherein the step of generating the saturation value and the hue value of the test picture in the LCH color space map at any one test angle from the luminance value and the chromaticity value obtained from the any one test angle includes:
converting the brightness value and the chromaticity value obtained at any test angle to obtain a tristimulus value of the test picture at any test angle;
converting the tristimulus values of the test pictures under any test angle to obtain Lab values;
and according to the Lab value, converting to obtain a saturation value and a tone value of the test picture in the LCH color space diagram at any test angle.
4. The evaluation method according to claim 1, wherein the fourth preset condition is:
and the deviation value between the target brightness value and the theoretical brightness value is more than or equal to 3%.
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