CN104299565B - The low gray scale correction method and system of LED display - Google Patents
The low gray scale correction method and system of LED display Download PDFInfo
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Abstract
The present invention relates to the low gray scale correction method and system of LED display.Methods described includes step：A () control LED display shows the color of multiple GTGs and the color to multiple GTGs carries out data acquisition and distinguishes corresponding multiple brightness measurements at least to obtain multiple GTGs, wherein described color is same primary colours, and multiple GTGs are the part gray-scale being located in the corresponding all GTGs of the primary colours in low grey-scale range；And (b) obtains the corresponding multiple adjustment factors of multiple GTGs at least with the difference between the multiple brightness measurements for obtaining and multiple GTG corresponding brightness target values of difference, and multiple adjustment factors are uploaded to LED display so that LED display changes LED drive current so as to realize the correction to multiple GTGs when the multiple GTG is shown according to multiple adjustment factors.The present invention carries out calibration one by one by low GTG, is capable of achieving LED display current signal linear is responded when low GTG shows.
Description
Technical Field
The invention relates to the technical field of LED display, in particular to a low gray scale correction method and a low gray scale correction system of an LED display device.
Background
The gray level is a so-called gray level, which is a brightness level; in the LED display industry, the luminous brightness of each primary color is specified. The luminance of the primary colors is divided according to the intensity, namely, the gray level. The higher the grey scale level that can be produced by an LED display screen, the more colors and image levels are displayed. For digital display technology, gray scale is the determining factor for the number of colors displayed. Generally speaking, the higher the gray level is, the richer the displayed color is, and the finer the picture is, the more easily the rich details are expressed.
In a digitizing system, the ability to control gray scale is represented by the number of gray scales. The number of gray levels is how many gray levels can be controlled. For example, 16 levels of gray scale can be controlled, and the number of gray scale levels is 16. In digital circuits, 16 different numbers are represented by 4-bit binary numbers. It can be seen that the larger the number of bits used for gray level control, the larger the gray level that can be generated, and the finer the displayed image.
The gray scale level mainly depends on the digital-to-analog conversion bit number of the processing system, and of course, the video processing chip, the memory and the transmission system of the system all need to provide the support of the corresponding bit number. At present, the LED display screen mainly adopts: (a) an 8-bit processing system, i.e., 256 (8 th power of 2) gray levels, is simply understood to have 256 brightness variations from black to white; (b) a 10-bit processing system, namely 1024 (10 power of 2) gray levels, which is simply understood to have 1024 brightness changes from black to white; (c) a 12-bit processing system, i.e., 4096 (12 th power of 2) gray levels, is simply understood to have 4096 brightness changes from black to white; and (d) a 14-bit processing system, i.e., 16384 (power 14 of 2) gray levels, with a simple understanding that there are 16384 luminance variations from black to white.
In practice, LED displays are linear light emitting devices, but are not linear when the current pulse width is narrow (i.e., low gray). When the current pulse width is very narrow, the response of the driving chip for the LED display screen and the LED lamp to the current deviates from linearity. In addition, the dispersion of the LED lamp, the dispersion of the driving chip, the dispersion of the LED optical axis, the dispersion of the mask ink color, the nonuniformity of the heat distribution in the module and other factors influence the deviation of the response of the LED display screen to the current signal.
Disclosure of Invention
In order to overcome the defects and shortcomings of the prior art, the invention provides a low gray scale correction method and a low gray scale correction system of an LED display device, so that the LED display device linearly responds to a current signal when displaying low gray scale.
Specifically, the low gray scale correction method for the LED display device provided in the embodiment of the present invention includes the steps of: (S1) controlling an LED display device to display colors of a plurality of gray scales and carrying out data acquisition on the colors of the plurality of gray scales so as to at least obtain a plurality of brightness measurement values respectively corresponding to the plurality of gray scales, wherein the colors are the same primary color, and the plurality of gray scales are partial gray scales in a low gray scale range in all gray scales corresponding to the primary color; and (b) obtaining a plurality of adjusting coefficients corresponding to the plurality of gray scales at least by using the difference between the plurality of brightness measured values and a plurality of brightness target values corresponding to the plurality of gray scales, and uploading the plurality of adjusting coefficients to the LED display device so that the LED display device changes the LED driving current according to the plurality of adjusting coefficients when displaying the plurality of gray scales, thereby realizing the correction of the plurality of gray scales.
In an embodiment of the invention, the colors of the plurality of gray levels are sequentially displayed.
In an embodiment of the invention, the colors of the plurality of gray levels are displayed in a divisional manner.
In one embodiment of the present invention, the step (b) includes: a plurality of luminance correction coefficients are calculated as the plurality of adjustment coefficients, respectively, using differences between the plurality of luminance measurement values and the plurality of luminance target values, respectively.
In an embodiment of the present invention, the step (a) includes performing data acquisition on the colors of the gray scales to obtain a plurality of sets of luminance and chrominance measurement values corresponding to the gray scales, respectively, and the step (b) includes: calculating a plurality of luminance and chrominance correction coefficients respectively serving as the plurality of adjustment coefficients by using the difference between the plurality of groups of luminance and chrominance measurement values and a plurality of luminance and chrominance target values respectively corresponding to the plurality of gray scales; wherein, each bright chroma correction coefficient is a coefficient matrix.
In one embodiment of the present invention, the step (b) includes: calculating a plurality of brightness ratios respectively corresponding to the plurality of gray scales by respectively using the differences between the plurality of brightness measurement values and the plurality of brightness target values; and modifying a plurality of gamma values respectively corresponding to the plurality of gray scales by utilizing the plurality of brightness ratios respectively to obtain a plurality of target gamma values serving as the plurality of adjustment coefficients.
In one embodiment of the present invention, the step (b) includes: calculating a plurality of brightness ratios respectively corresponding to the plurality of gray scales by respectively using the differences between the plurality of brightness measurement values and the plurality of brightness target values; and modifying the corresponding OE width by using the plurality of brightness ratios to obtain a plurality of target OE widths as the plurality of adjustment coefficients.
In addition, an embodiment of the present invention provides a low gray scale correction system for an LED display device, including: the device comprises a display control module, a data acquisition module, an adjustment coefficient calculation module and an adjustment coefficient uploading module. Specifically, the display control module is configured to control the LED display device to display colors of a plurality of gray scales, where the colors are the same primary color, and the gray scales are partial gray scales located in a low gray scale range among all gray scales corresponding to the primary color. The data acquisition module is used for acquiring data of the colors of the gray scales so as to at least acquire a plurality of brightness measurement values corresponding to the gray scales respectively. The adjusting coefficient calculating module is used for obtaining a plurality of adjusting coefficients corresponding to the plurality of gray scales by using at least the difference between the plurality of brightness measured values and a plurality of brightness target values corresponding to the plurality of gray scales respectively. The adjusting coefficient uploading module is used for uploading the adjusting coefficients to the LED display device so that the LED display device can change the LED driving current according to the adjusting coefficients when displaying the gray scales, and therefore correction of the gray scales is achieved.
In an embodiment of the present invention, the adjustment coefficient calculating module is specifically configured to: a plurality of luminance correction coefficients are calculated as the plurality of adjustment coefficients, respectively, using differences between the plurality of luminance measurement values and the plurality of luminance target values, respectively. Or, the data acquisition module is specifically configured to perform data acquisition on the colors of the multiple gray scales to obtain multiple luminance and chrominance measurement values corresponding to the multiple gray scales, and the adjustment coefficient calculation module is specifically configured to: calculating a plurality of luminance and chrominance correction coefficients respectively serving as the plurality of adjustment coefficients by using the difference between the plurality of groups of luminance and chrominance measurement values and a plurality of groups of luminance and chrominance target values respectively corresponding to the plurality of gray scales; wherein, each bright chroma correction coefficient is a coefficient matrix.
In an embodiment of the present invention, the adjustment coefficient calculating module is specifically configured to: and respectively calculating a plurality of brightness ratios corresponding to the gray scales by using the differences between the plurality of brightness measured values and the plurality of brightness target values, and respectively modifying a plurality of gamma values corresponding to the gray scales by using the plurality of brightness ratios to obtain a plurality of target gamma values serving as the plurality of adjustment coefficients.
In an embodiment of the present invention, the adjustment coefficient calculating module is specifically configured to: and calculating a plurality of brightness ratios corresponding to the gray scales respectively by using the differences between the plurality of brightness measurement values and the plurality of brightness target values, and modifying OE widths corresponding to the bits of binary codes corresponding to the gray scales by using the brightness ratios to obtain a plurality of target OE widths as the plurality of adjustment coefficients.
According to the embodiment of the invention, the low gray scale is corrected one by one, so that the linear response of an LED display device such as an LED display screen to a current signal during low gray scale display can be realized, the definition and the fineness of a picture of the LED display screen during low gray scale display are improved, the problem that the response of a driving chip for the LED display screen and the response of an LED lamp to current deviate from linearity when the current pulse width is very narrow can be solved, and the problem that the response of the LED display screen to current deviates from linearity due to the influence of factors such as the dispersion of the LED lamp, the dispersion of the driving chip, the dispersion of an LED optical axis, the dispersion of the mask ink color, the nonuniformity of the heat distribution in a module and the like can be solved.
Other aspects and features of the present invention will become apparent from the following detailed description, which proceeds with reference to the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.
Drawings
The following detailed description of embodiments of the invention will be made with reference to the accompanying drawings.
Fig. 1A and 1B are schematic diagrams of two display modes of a plurality of low gray-scale colors in a low gray-scale correction method of an LED display device according to a first embodiment of the invention.
Fig. 2 is a waveform diagram illustrating a low gray level correction method of an LED display device according to a third embodiment of the present invention.
Fig. 3 is a block diagram of a low gray scale correction system of an LED display device according to a fourth embodiment of the present invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
[ first embodiment ] A method for manufacturing a semiconductor device
The technical scheme of the low gray scale correction method of the LED display device in the first embodiment of the invention mainly comprises two steps: firstly, a plurality of groups of luminance and chrominance measured values corresponding to the low gray scales are obtained, then a plurality of correction coefficients corresponding to the low gray scales are calculated and used as adjustment coefficients and are uploaded to the LED display screen, and therefore the LED display screen is linear in response to current signals when displaying the low gray scales. In this embodiment, the LED display panel includes, for example, an LED panel body and a display control system electrically connected to the LED panel body. Specifically, the method comprises the following steps:
in the process of obtaining a plurality of groups of brightness measurement values respectively corresponding to a plurality of low gray scales: firstly, controlling an LED display screen to display a plurality of low gray scale colors, wherein the display method can be that the whole screen displays a certain gray scale color and the low gray scale colors are displayed in sequence, for example, as shown in FIG. 1A; it is also possible to use the shape partition of the grid graph to display a plurality of low gray level colors at a time, for example, as shown in fig. 1B. After the LED display screen is controlled to display the colors of the low gray scales, data acquisition is carried out on the displayed colors of the low gray scales respectively to obtain a brightness and chrominance measured value Lxy corresponding to the color of each low gray scale. In this embodiment, the data acquisition method includes multiple methods: (1) the bright colorimetric value Lxy is measured by the light splitting colorimeter for one time, so that the precision is highest, but the efficiency is lower; (2) the bright chromatic value Lxy is obtained through the industrial camera with the XYZ filter, the precision is high, the efficiency is high, but the price of the industrial camera with the XYZ filter is high; (3) the bright chromatic value Lxy is obtained through a common color digital camera, the RGB numerical values of all LED lamp points are obtained through the color digital camera, then the RGB numerical values are converted into XYZ numerical values, and the bright chromatic value Lxy is obtained. The conversion method in the above method (3) may be: a model method, a Look-up Table (LUT), a neural network method, and the like. The model method is to realize linear or nonlinear transformation between RGB and XYZ by establishing a mathematical model. Such as an S-curve model, Masking model, GOG (Gain-Offset-Gamma) model, polynomial model, or the like. The table look-up method is to establish a one-dimensional or three-dimensional (3D-LUT) look-up table, which uses an interpolation or extrapolation algorithm to find out the corresponding relationship between RGB and XYZ, and points falling on the vertices of the sampling grid take the vertex value, and points not on the vertices are obtained by an interpolation algorithm using the nearest vertex values around. The neural network method is to establish a mapping relation of RGB to XYZ (forward network) by using the characteristic of nonlinear transformation of the artificial neural network, and to appropriately select the network structure and the spatial distribution of the training sample set, so as to obtain higher precision.
In the process of calculating a plurality of correction coefficients corresponding to a plurality of low gray scales respectively as adjustment coefficients and uploading the adjustment coefficients to the LED display screen: firstly, calculating correction coefficients corresponding to the low gray scales respectively, and then uploading the correction coefficients serving as adjustment coefficients to the LED display screen.
The calculation of the correction coefficient corresponding to each low gray scale can be divided into two types, namely luminance correction and chrominance correction:
luminance correction is the change of the luminance of only a single color LED lamp:
R_LEDout＝a11R_LEDin；
G_LEDout＝a22G_LEDin；
B_LEDout＝a33B_LEDin；
chromaticity correction is the correction of chromaticity by not only changing the luminance of a single-color LED lamp, but also by adding other single-color LED lamps, so the chromaticity correction is also commonly referred to as bright chromaticity correction:
in the above formula, R _ LEDin、G_LEDin、B_LEDinRespectively representing the luminance and chromaticity measurements of the tricolor (red, green, blue) LED lamp before correction, R _ LEDout、G_LEDout、B_LEDoutRespectively representing the desired brightness target value of the three primary LED lamps, a11、a22、a33In order to correct the coefficient for the brightness,the luminance correction coefficients are a matrix of coefficients.
As an example, for an LED display screen with 255 gray levels of each primary color, it needs to make a linear response to current in a low gray level, and 10 low gray levels are corrected one by one in the low gray level range, so as to meet the requirement; that is, the first embodiment of the present invention corrects the partial gray levels in the low gray level range among all the gray levels (255 gray levels) of the respective primary colors one by one. The specific correction method can be as follows: firstly, respectively measuring 10 brightness values Lxy respectively corresponding to low gray scales; secondly, calculating by using the difference between a brightness target value and a brightness measured value Lxy corresponding to each gray scale in the 10 low gray scales to obtain a brightness correction coefficient corresponding to each gray scale in the 10 low gray scales; and finally, uploading the calculated brightness and chrominance correction coefficients respectively corresponding to the 10 low gray scales to an LED display screen for storage. And then, when the low gray scale is displayed, the LED display screen displays a certain low gray scale, a brightness correction coefficient corresponding to the gray scale is extracted to correct the gray scale, and then the display is carried out to achieve the target brightness. In this example, it is understood that only the luminance correction coefficient may be calculated and the chrominance correction coefficient may be omitted, which may also achieve the purpose of low gray level correction. In this embodiment, the brightness correction coefficient or the brightness correction coefficient of each low gray scale is obtained one by one, which is substantially to change the LED driving current in the low gray scale display.
[ second embodiment ]
The technical scheme of the low gray scale correction method of the LED display device in the second embodiment of the invention mainly comprises two steps: firstly, a plurality of brightness measurement values corresponding to the low gray scales are obtained, then a plurality of target Gamma values corresponding to the low gray scales are obtained after partial Gamma values in a Gamma mapping table are modified and serve as adjusting coefficients, the adjusting coefficients are uploaded to an LED display screen to update the Gamma mapping table stored in the LED display screen, and therefore the LED display screen is linear in response to current signals during low gray scale display. In this embodiment, the LED display panel includes, for example, an LED panel body and a display control system electrically connected to the LED panel body. Specifically, the method comprises the following steps:
in the process of obtaining a plurality of luminance measurement values corresponding to a plurality of low gray levels respectively: firstly, the LED display screen is controlled to display a plurality of low gray scale colors, the display method can be that the whole screen displays a certain gray scale color and the low gray scale colors are displayed in sequence, or the grid graph shape is used for displaying the low gray scale colors in a partitioning mode at one time. After the LED display screen is controlled to display the colors of the low gray scales, data acquisition is carried out on the displayed colors of the low gray scales respectively to obtain a brightness and chrominance measured value Lxy corresponding to the color of each low gray scale. In this embodiment, the data acquisition method includes multiple methods: (1) the bright colorimetric value Lxy is measured by the light splitting colorimeter for one time, so that the precision is highest, but the efficiency is lower; (2) the bright chromatic value Lxy is obtained through the industrial camera with the XYZ filter, the precision is high, the efficiency is high, but the price of the industrial camera with the XYZ filter is high; (3) the bright chromatic value Lxy is obtained through a common color digital camera, the RGB numerical values of all LED lamp points are obtained through the color digital camera, then the RGB numerical values are converted into XYZ numerical values, and the bright chromatic value Lxy is obtained. The conversion method in the above method (3) may be: a model method, a Look-up Table (LUT), a neural network method, and the like. The model method is to realize linear or nonlinear transformation between RGB and XYZ by establishing a mathematical model. Such as an S-curve model, Masking model, GOG (Gain-Offset-Gamma) model, polynomial model, or the like. The table look-up method is to establish a one-dimensional or three-dimensional (3D-LUT) look-up table, which uses an interpolation or extrapolation algorithm to find out the corresponding relationship between RGB and XYZ, and points falling on the vertices of the sampling grid take the vertex value, and points not on the vertices are obtained by an interpolation algorithm using the nearest vertex values around. The neural network method is to establish a mapping relation of RGB to XYZ (forward network) by using the characteristic of nonlinear transformation of the artificial neural network, and to appropriately select the network structure and the spatial distribution of the training sample set, so as to obtain higher precision.
In the process of modifying the Gamma mapping table: firstly, the brightness ratio of the brightness measured value of each low gray scale to the brightness target value is calculated, then the gamma values corresponding to each low gray scale are respectively modified by using the calculated brightness ratio to obtain a plurality of target gamma values which are used as adjusting coefficients to be uploaded to the LED display screen.
Calculating the brightness ratio (or brightness difference) of a certain gray scale:
R_Lout＝ratioRR_Lin；
G_Lout＝ratioGG_Lin；
B_Lout＝ratioBB_Lin；
and modifying the Gamma value corresponding to the gray scale:
R_Gammaout＝ratioRR_Gammain；
G_Gammaout＝ratioGG_Gammain；
B_Gammaout＝ratioBB_Gammain；
in the above formula, R _ LEDin、G_LEDin、B_LEDinRespectively representing the luminance and chromaticity measurements of the tricolor (red, green, blue) LED lamp before correction, R _ LEDout、G_LEDout、B_LEDoutRespectively representing the target brightness and chromaticity values, ratio, of the three primary color LED lamps to be achievedR、ratioG、ratioBRespectively represent the brightness ratio of the three primary colors, R _ Gammain、G_Gammain、B_GammainRespectively representing the Gamma value, R _ Gamma, of the three primary colors before the gray scale correctionout、G_Gammaout、B_GammaoutRespectively representing the Gamma values of the three primary colors after the gray scale correction.
As an example, for an LED display screen with 255 gray levels of each primary color, it needs to make a linear response to current in a low gray level, and 10 low gray levels are corrected one by one in the low gray level range, so as to meet the requirement; that is, the second embodiment of the present invention corrects the partial gray levels in the low gray level range among all the gray levels (255 gray levels) of the respective primary colors one by one. The specific correction method can be as follows: firstly, respectively measuring brightness values L corresponding to 10 low gray scales; secondly, calculating to obtain a brightness ratio value corresponding to each gray scale in the 10 low gray scales by using the difference between the brightness target value corresponding to each gray scale in the 10 low gray scales and the brightness measured value L; and finally, modifying the corresponding Gamma values by utilizing the brightness ratios respectively corresponding to the 10 low gray scales obtained by calculation to obtain a plurality of target Gamma values which are used as adjusting coefficients to be uploaded to the LED display screen so as to update the Gamma mapping table stored in the LED display screen. And then, when the low gray scale is displayed, the LED display screen displays a certain low gray scale, the updated Gamma mapping table is utilized to correct the gray scale, and then the display is carried out to reach the target brightness. In this embodiment, the Gamma mapping table is updated to substantially change the LED driving current in the low gray scale display.
[ third embodiment ]
The technical scheme of the low gray scale correction method of the LED display device in the third embodiment of the invention mainly comprises two steps: firstly, a plurality of brightness measured values corresponding to the low gray scales are obtained, then OE widths corresponding to bits (Bit) of binary codes corresponding to the low gray scales are modified to obtain a plurality of target OE widths serving as adjusting coefficients and are uploaded to the LED display screen to update OE widths corresponding to the bits of the low gray scales stored in the LED display screen, and therefore the response of the LED display screen to current signals during low gray scale display is linear. In this embodiment, the LED display panel includes, for example, an LED panel body and a display control system electrically connected to the LED panel body. Specifically, the method comprises the following steps:
in the process of obtaining a plurality of luminance measurement values corresponding to a plurality of low gray levels respectively: firstly, controlling an LED display screen to display a plurality of low gray scale colors, wherein the display method can be that the whole screen displays a certain gray scale color and the low gray scale colors are displayed in sequence, for example, as shown in FIG. 1A; it is also possible to use the shape partition of the grid graph to display a plurality of low gray level colors at a time, for example, as shown in fig. 1B. After the LED display screen is controlled to display the colors of the low gray scales, data acquisition is carried out on the displayed colors of the low gray scales respectively to obtain a brightness and chrominance measured value Lxy corresponding to the color of each low gray scale. In this embodiment, the data acquisition method includes multiple methods: (1) the bright colorimetric value Lxy is measured by the light splitting colorimeter for one time, so that the precision is highest, but the efficiency is lower; (2) the bright chromatic value Lxy is obtained through the industrial camera with the XYZ filter, the precision is high, the efficiency is high, but the price of the industrial camera with the XYZ filter is high; (3) the bright chromatic value Lxy is obtained through a common color digital camera, the RGB numerical values of all LED lamp points are obtained through the color digital camera, then the RGB numerical values are converted into XYZ numerical values, and the bright chromatic value Lxy is obtained. The conversion method in the above method (3) may be: a model method, a Look-up Table (LUT), a neural network method, and the like. The model method is to realize linear or nonlinear transformation between RGB and XYZ by establishing a mathematical model. Such as an S-curve model, Masking model, GOG (Gain-Offset-Gamma) model, polynomial model, or the like. The table look-up method is to establish a one-dimensional or three-dimensional (3D-LUT) look-up table, which uses an interpolation or extrapolation algorithm to find out the corresponding relationship between RGB and XYZ, and points falling on the vertices of the sampling grid take the vertex value, and points not on the vertices are obtained by an interpolation algorithm using the nearest vertex values around. The neural network method is to establish a mapping relation of RGB to XYZ (forward network) by using the characteristic of nonlinear transformation of the artificial neural network, and to appropriately select the network structure and the spatial distribution of the training sample set, so as to obtain higher precision.
In the process of modifying the OE width corresponding to the Bit (Bit) of the binary code corresponding to each low gray scale: firstly, the brightness ratio of the brightness measured value of each low gray scale to the brightness target value is calculated, and then the OE widths corresponding to the bits of the binary code corresponding to each low gray scale are respectively modified by using the calculated brightness ratio to obtain a plurality of target OE widths which are used as adjusting coefficients to be uploaded to the LED display screen. The calculation method of the target OE width is the same as that of the target Gamma value, and is not described herein again.
For example, suppose the binary code corresponding to hardware with a certain low gray level is 0111, as shown in fig. 2. In fig. 2, the waveform P1 corresponds to the binary code 0100 (corresponding to gray level 4), the waveform P2 corresponds to the binary code 0010 (corresponding to gray level 2), and the waveform P3 corresponds to the binary code 0001 (corresponding to gray level 1).
After the measured brightness value of the low gray scale is measured, if the gray scale corresponding to a bit is not accurate, the OE width (the width of the waveform) corresponding to the bit can be modified by the brightness ratio, thereby changing the gray scale. Therefore, after the OE width corresponding to each bit is modified, the LED driving current output by the LED display screen during low-gray-scale display is correspondingly changed, so that the brightness of each low gray scale can be consistent with the target brightness.
[ fourth example ] A
Referring to fig. 3, a fourth embodiment of the invention provides a low gray scale correction system for an LED display device. As shown in fig. 3, the low gray scale correction system of the present embodiment includes: the device comprises a display control module 31, a data acquisition module 33, an adjustment coefficient calculation module 35 and an adjustment coefficient uploading module 37. Specifically, the display control module 31 is configured to control the LED display device (e.g., an LED display screen) to display a plurality of gray scales, where the color is a same primary color (e.g., red, green or blue), and the gray scales are partial gray scales in a low gray scale range among all gray scales corresponding to the primary color. The data acquisition module 33 is configured to perform data acquisition on the colors of the plurality of gray scales to at least obtain a plurality of luminance measurement values corresponding to the plurality of gray scales respectively. The adjusting coefficient calculating module 35 is configured to obtain a plurality of adjusting coefficients corresponding to the plurality of gray scales at least by using differences between the plurality of luminance measurement values and a plurality of luminance target values corresponding to the plurality of gray scales respectively. The adjustment coefficient uploading module 37 is configured to upload the plurality of adjustment coefficients to the LED display device, so that the LED display device changes the LED driving current according to the plurality of adjustment coefficients when displaying the plurality of gray scales, thereby implementing the correction of the plurality of gray scales. In addition, the low gray scale correction system according to the fourth embodiment of the present invention can be used to perform the low gray scale correction methods according to the first to third embodiments, and specific details can refer to the foregoing description, which is not repeated herein.
In summary, the embodiments of the present invention correct the low gray scales one by one, so as to achieve a linear response of the LED display device, such as the LED display screen, to the current signal during the low gray scale display, improve the definition and the fineness of the image of the LED display screen during the low gray scale display, solve the problem that the response of the LED display screen and the LED lamp to the current deviates from linearity when the current pulse width is very narrow, and solve the problem that the response of the LED display screen to the current deviates from linearity due to the influence of factors such as the dispersion of the LED lamp, the dispersion of the driving chip, the dispersion of the LED optical axis, the dispersion of the mask ink color, and the non-uniformity of the heat distribution inside the module.
So far, the principle and implementation of the low gray scale correction method and system of the LED display device according to the present invention are explained in the present document by applying specific examples, and the above description of the examples is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention, and the scope of the present invention should be subject to the appended claims.
Claims (9)
1. A low gray scale correction method of an LED display device, comprising the steps of:
(a) controlling an LED display device to display color pictures of a plurality of gray scales and carrying out data acquisition on the color pictures of the plurality of gray scales so as to at least obtain a plurality of brightness measurement values corresponding to the plurality of gray scales respectively, wherein the color pictures of the plurality of gray scales are color pictures of the same primary color, and the plurality of gray scales are partial gray scales in a low gray scale range in all the gray scales corresponding to the primary color; and
(b) obtaining a plurality of adjusting coefficients corresponding to the plurality of gray scales by using at least the difference between the plurality of luminance measured values and a plurality of luminance target values corresponding to the plurality of gray scales, and uploading the plurality of adjusting coefficients to the LED display device so that the LED display device changes the LED driving current according to the plurality of adjusting coefficients when displaying the plurality of gray scales, thereby realizing the correction of the plurality of gray scales; wherein,
the color pictures of the plurality of gray scales are a plurality of color pictures which are sequentially displayed and respectively correspond to the plurality of gray scales, each color picture in the plurality of color pictures which are sequentially displayed has a single gray scale, or the color pictures of the plurality of gray scales are the same color picture which is simultaneously displayed by the plurality of gray scale partitions.
2. The method of low gray scale correction of claim 1, wherein said step (b) comprises:
a plurality of luminance correction coefficients are calculated as the plurality of adjustment coefficients, respectively, using differences between the plurality of luminance measurement values and the plurality of luminance target values, respectively.
3. The method of claim 1, wherein the step (a) comprises collecting data of the color frames of the gray levels to obtain a plurality of sets of luminance and chrominance measurement values corresponding to the gray levels, respectively, and the step (b) comprises:
calculating a plurality of luminance and chrominance correction coefficients respectively serving as the plurality of adjustment coefficients by using the difference between the plurality of groups of luminance and chrominance measurement values and a plurality of groups of luminance and chrominance target values respectively corresponding to the plurality of gray scales; wherein, each bright chroma correction coefficient is a coefficient matrix.
4. The method of low gray scale correction of claim 1, wherein said step (b) comprises:
calculating a plurality of brightness ratios respectively corresponding to the plurality of gray scales by respectively using the differences between the plurality of brightness measurement values and the plurality of brightness target values; and
and modifying a plurality of gamma values respectively corresponding to the plurality of gray scales by utilizing the plurality of brightness ratios respectively to obtain a plurality of target gamma values serving as the plurality of adjustment coefficients.
5. The method of low gray scale correction of claim 1, wherein said step (b) comprises:
calculating a plurality of brightness ratios respectively corresponding to the plurality of gray scales by respectively using the differences between the plurality of brightness measurement values and the plurality of brightness target values; and
and modifying OE widths corresponding to the bits of the binary codes corresponding to the gray scales by using the brightness ratios to obtain target OE widths serving as the adjusting coefficients.
6. A low gray scale correction system for an LED display device, comprising:
the display control module is used for controlling the LED display device to display color pictures of a plurality of gray scales, wherein the color pictures of the plurality of gray scales are color pictures of the same primary color, and the plurality of gray scales are partial gray scales in a low gray scale range in all the gray scales corresponding to the primary color, wherein the color pictures of the plurality of gray scales are a plurality of color pictures which are sequentially displayed and respectively correspond to the plurality of gray scales, each color picture in the plurality of color pictures which are sequentially displayed has a single gray scale, or the color pictures of the plurality of gray scales are the same color picture which is simultaneously displayed by the plurality of gray scale partitions;
the data acquisition module is used for acquiring data of the colors of the gray scales so as to at least obtain a plurality of brightness measurement values corresponding to the gray scales respectively;
an adjustment coefficient calculation module, configured to obtain a plurality of adjustment coefficients corresponding to the plurality of gray scales at least by using differences between the plurality of luminance measurement values and a plurality of luminance target values corresponding to the plurality of gray scales, respectively; and
and the adjusting coefficient uploading module is used for uploading the adjusting coefficients to the LED display device so that the LED display device changes the LED driving current according to the adjusting coefficients when displaying the gray scales, thereby realizing the correction of the gray scales.
7. The low gray scale correction system of claim 6, wherein said adjustment coefficient calculation module is specifically configured to: calculating a plurality of luminance correction coefficients as the plurality of adjustment coefficients, respectively, using differences between the plurality of luminance measurement values and the plurality of luminance target values, respectively; or the data acquisition module is specifically configured to perform data acquisition on the color pictures of the multiple gray scales to obtain multiple sets of luminance and chrominance measurement values corresponding to the multiple gray scales, and the adjustment coefficient calculation module is specifically configured to: calculating a plurality of luminance and chrominance correction coefficients respectively serving as the plurality of adjustment coefficients by using the difference between the plurality of groups of luminance and chrominance measurement values and a plurality of groups of luminance and chrominance target values respectively corresponding to the plurality of gray scales; wherein, each bright chroma correction coefficient is a coefficient matrix.
8. The low gray scale correction system of claim 6, wherein said adjustment coefficient calculation module is specifically configured to: and respectively calculating a plurality of brightness ratios corresponding to the gray scales by using the differences between the plurality of brightness measured values and the plurality of brightness target values, and respectively modifying a plurality of gamma values corresponding to the gray scales by using the plurality of brightness ratios to obtain a plurality of target gamma values serving as the plurality of adjustment coefficients.
9. The low gray scale correction system of claim 6, wherein said adjustment coefficient calculation module is specifically configured to: and calculating a plurality of brightness ratios corresponding to the gray scales respectively by using the differences between the plurality of brightness measurement values and the plurality of brightness target values, and modifying OE widths corresponding to the bits of binary codes corresponding to the gray scales by using the brightness ratios to obtain a plurality of target OE widths as the plurality of adjustment coefficients.
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