CN117409734A - Color temperature correction method and device of display equipment, display equipment and medium - Google Patents

Color temperature correction method and device of display equipment, display equipment and medium Download PDF

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Publication number
CN117409734A
CN117409734A CN202311435767.2A CN202311435767A CN117409734A CN 117409734 A CN117409734 A CN 117409734A CN 202311435767 A CN202311435767 A CN 202311435767A CN 117409734 A CN117409734 A CN 117409734A
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China
Prior art keywords
backlight
pixel
display
partition
color temperature
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CN202311435767.2A
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Chinese (zh)
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吴聪睿
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BOE Technology Group Co Ltd
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BOE Technology Group Co Ltd
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Priority to CN202311435767.2A priority Critical patent/CN117409734A/en
Publication of CN117409734A publication Critical patent/CN117409734A/en
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0666—Adjustment of display parameters for control of colour parameters, e.g. colour temperature

Abstract

The invention provides a color temperature correction method and device of display equipment, the display equipment and a medium, and relates to the field of image processing. According to the embodiment of the invention, the gray scale of each backlight partition is determined according to the display image on the display panel; according to the gray scale of each backlight partition, determining the backlight brightness of the pixel corresponding to each pixel in the display partition; the pixel value of each pixel is corrected according to a color temperature correction coefficient that is associated in advance with the pixel backlight luminance. By correcting the pixel value of each pixel, the color temperature of each region is uniform when the display panel displays images, so that the screen display effect is improved.

Description

Color temperature correction method and device of display equipment, display equipment and medium
Technical Field
The present invention relates to the field of image processing, and in particular, to a color temperature correction method and apparatus for a display device, and a medium.
Background
In a display device using a sub-millimeter light emitting diode (Mini Light Emitting Diode, miniLED) as a backlight module, a MiniLED backlight source generally adopts a blue LED, and then converts blue light into white light through a blue-to-white light conversion film material, such as a fluorescent powder film material, a quantum dot film material, and the like, so as to realize backlight for a liquid crystal display device (Liquid Crystal Display, LCD). Taking Quantum Dot (QD) film as an example, the principle is that the QD film is excited by blue light energy to excite red and green Quantum dots under the excitation of a blue light source, thereby generating red light and green light, and the red light and the green light are mixed with blue light penetrating through the film to form white light which can be observed by human eyes. Based on the principle, the white light with the required color temperature can be formed by controlling the components of the red-green quantum dot material and the transmittance of blue light in the film material by controlling the mixing of red light, green light and blue light with fixed proportion.
However, when the brightness of the MiniLED blue light bead changes, the energy proportion of the red, green and blue spectrums in the white light excited by the QD film material changes slightly, so that the color temperature of the mixed white light changes. Along with the rise of the brightness of the blue light LED, the increment of the blue light transmitted by the QD film material is larger than the increment of the excited red-green light, so that the color temperature of the mixed white light becomes high, and the blue-emitting trend is shown. Due to the abnormal color temperature phenomenon in the process of turning blue into white of the QD film material, the color temperature of the mixed white light is different between the high brightness and the low brightness, and the difference causes the difference of the backlight color temperatures of all backlight partitions in the backlight partition control, so that the abnormal image color display is further caused.
Disclosure of Invention
The invention provides a color temperature correction method and device of a display device, the display device and a medium, which are used for solving the defects in the related art.
According to a first aspect of an embodiment of the present invention, there is provided a color temperature correction method of a display device, where the display device includes a display panel and a backlight module, the backlight module includes a plurality of backlight partitions, and the display panel includes display partitions corresponding to the plurality of backlight partitions one by one, and the method includes: determining the gray scale of each backlight partition according to the display image on the display panel; according to the gray scale of each backlight partition, determining the pixel backlight brightness of each pixel in the display partition, wherein the pixel backlight brightness refers to the brightness provided for the pixel by a plurality of backlight partitions corresponding to the pixel in a set range; acquiring a color temperature correction coefficient corresponding to the pixel backlight brightness of each pixel from a pre-constructed mapping relation table for each pixel, wherein the mapping relation table is constructed when the display color temperature of the display equipment reaches a target color temperature by adjusting the pixel value of the pixel under the condition that all backlight partitions synchronously display different gray scales; and correcting the pixel value of the pixel according to the color temperature correction coefficient.
In some embodiments, the method further comprises: controlling a display panel to display a designated image, and acquiring a reference pixel value according to the designated image; under each gray level, adjusting the pixel value of the pixel in the appointed image until the display color temperature of the display equipment reaches the target color temperature, and acquiring a first pixel value; determining a color temperature correction coefficient according to the first pixel value and the reference pixel value; determining the pixel backlight brightness of each pixel according to the gray scale of each backlight partition; and establishing a mapping relation between the brightness of the pixel backlight and the color temperature correction coefficient.
In some embodiments, when the display color temperature of the display device reaches the target color temperature, the display color coordinates of the display device are reference color coordinates;
the adjusting the pixel value of the pixel, obtaining a first pixel value when the display color temperature of the display device reaches the target color temperature, includes:
acquiring display color coordinates of a display panel under the current backlight brightness; if the display color coordinates are inconsistent with the reference color coordinates, adjusting pixel values of pixels until the display color coordinates are consistent with the reference color coordinates; and acquiring a first pixel value when the display color coordinates are consistent with the reference color coordinates.
In some embodiments, determining the pixel backlight brightness of each pixel in the display section according to the gray scale of each backlight section includes: determining the backlight brightness of the backlight subarea according to the gray level of the backlight subarea and a pre-constructed optical diffusion model, wherein the optical diffusion model is used for indicating the influence degree of other surrounding backlight subareas on the backlight subarea; and determining the pixel backlight brightness of each pixel in the display partition according to the backlight brightness of a plurality of target backlight partitions, wherein the target backlight partitions are backlight partitions with the distances from the pixels meeting the set conditions.
In some embodiments, the determining the backlight brightness of the backlight partition according to the gray scale of the backlight partition and a pre-constructed optical diffusion model includes:
and determining the backlight brightness of the backlight subarea according to the gray scale of the backlight subarea and the influence coefficients of other backlight subareas around the backlight subarea.
In some embodiments, determining the pixel backlight brightness of each pixel in the display partition based on the backlight brightness of the plurality of target backlight partitions includes:
for each target pixel in a display partition, acquiring four target backlight partitions, wherein the distance between the four target backlight partitions and the target pixel accords with a set condition; and obtaining the pixel backlight brightness corresponding to the target pixel according to the backlight brightness of each target backlight partition and the normalized distance between the target pixel and the center of each target backlight partition.
In some embodiments, the determining the gray scale of each backlight partition according to the display image on the display panel includes: and determining the gray scale of each backlight partition according to the pixel value of each pixel in the display partition corresponding to each backlight partition.
In some embodiments, the determining the gray level of each backlight partition according to the pixel value of each pixel in the display partition corresponding to each backlight partition includes: obtaining the maximum pixel value in the display partition and the pixel sum of all pixels according to the pixel value of each pixel in the display partition; determining the pixel average value according to the pixel sum; determining a basic backlight of a backlight partition corresponding to the display partition according to the maximum pixel value, the pixel average value and the respective weights; and filtering the basic backlight of the backlight partition to obtain the gray scale of the backlight partition.
According to a second aspect of an embodiment of the present invention, there is provided a color temperature correction apparatus for a display device, where the display device includes a display panel and a backlight module, the backlight module includes a plurality of backlight partitions, the display panel includes display partitions corresponding to the plurality of backlight partitions one by one, and the apparatus includes:
A determining unit for determining the gray scale of each backlight partition according to the display image on the display panel; determining the pixel backlight brightness of each pixel in the display partition according to the gray scale of each backlight partition, wherein the pixel backlight brightness refers to the brightness provided by the backlight partition in a set range corresponding to the pixel for the pixel;
an obtaining unit, configured to obtain, for each pixel, a color temperature correction coefficient corresponding to a pixel backlight luminance of the pixel from a mapping relation table that is previously constructed, where the mapping relation table is constructed when a display color temperature of a display device reaches a target color temperature by adjusting a pixel value of the pixel under a condition that all backlight partitions synchronously display different gray scales;
and the correction unit is used for correcting the pixel value of the pixel according to the color temperature correction coefficient.
According to a third aspect of an embodiment of the present invention, there is provided a display apparatus including: a display panel and a backlight module; the image to be displayed on the display panel is pixel corrected by the method of any one of the above.
According to a fourth aspect of embodiments of the present invention, there is provided a storage medium storing computer instructions for causing a computer to perform the method of any one of the above.
As can be seen from the above embodiments, the gray scale of each backlight partition is determined according to the display image on the display panel; according to the gray scale of each backlight partition, determining the backlight brightness of the pixel corresponding to each pixel in the display partition; the pixel value of each pixel is corrected according to a color temperature correction coefficient that is associated in advance with the pixel backlight luminance. By correcting the pixel value of each pixel, the color temperature of each region is uniform when the display panel displays images, so that the screen display effect is improved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.
Fig. 1 is a schematic diagram showing a display apparatus displaying an image according to an embodiment of the present invention.
Fig. 2 is a flowchart illustrating a color temperature correction method of a display device according to an embodiment of the present invention.
Fig. 3 is a frame diagram illustrating a color temperature correction method of a display device according to an embodiment of the present invention.
Fig. 4 is a schematic diagram showing a process of calculating a backlight partition gray scale according to an embodiment of the present invention.
Fig. 5 is a schematic diagram showing a process of determining brightness of a pixel backlight according to an embodiment of the present invention.
Fig. 6a is a schematic diagram of an optical diffusion model according to an embodiment of the present invention.
Fig. 6b is a schematic diagram showing a determination of backlight brightness according to an embodiment of the present invention.
Fig. 7 is a schematic diagram showing a determination of pixel back brightness according to an embodiment of the present invention.
Fig. 8 is a schematic diagram showing a process of correcting pixel values according to an embodiment of the present invention.
FIG. 9 is a schematic diagram illustrating a testing environment according to an embodiment of the present invention.
Fig. 10 is a schematic flow chart of constructing a mapping relation table according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the invention. Rather, they are merely examples of apparatus and methods consistent with aspects of the invention as detailed in the accompanying claims.
In a MiniLED backlight display system, the backlight source is usually a blue LED, and the blue LED is excited into light with three spectrums of red, green and blue after passing through the QD film material, and the light is mixed to form white light. However, when the light intensity of the backlight MiniLED changes, the proportion of RGB spectrum energy passing through the QD film changes, and the color temperature of the backlight correspondingly changes, so that the color temperature index of the image display is abnormal. That is, as the brightness of the blue LED increases, the blue light transmitted by the QD film is increased more than the red-green light excited, resulting in a higher color temperature of the mixed white light, and a blue-emitting trend is exhibited.
This phenomenon can cause significant negative effects in a MiniLED segmented backlight display system. In the hardware design of the MiniLED partition backlight display system, miniLED backlight in display equipment is divided into tens to thousands of backlight partitions, and independent brightness control is carried out on the backlight partitions by adopting a partition light control algorithm, so that the effects of increasing contrast ratio and improving display image quality are realized. The partition light control algorithm can calculate the lighting brightness of each backlight partition MiniLED lamp according to the video image displayed in real time, so as to obtain a frame of backlight image, and the MiniLED backlight is lighted according to the backlight image. However, due to the abnormal color temperature phenomenon of the quantum dot film material in the process of changing blue into white, the color temperature of the mixed white light is different between the high brightness and the low brightness, namely, the color temperature of the backlight of each backlight partition of the backlight module is different, so that the color abnormality phenomenon of an image displayed on the display panel is caused, and the phenomenon is obvious in certain scenes.
For ease of understanding, the following embodiment will explain the cause of occurrence of the bad display phenomenon with reference to fig. 1.
In fig. 1, the backlight module includes a first backlight partition, a second backlight partition, and a third backlight partition, and the display panel includes a first display partition corresponding to the first backlight partition, a second display partition corresponding to the second backlight partition, and a third display partition corresponding to the third backlight partition. As shown in fig. 1, for convenience of description, the image where the white lines in the image are located is referred to as a sub-image a, the other low-dark gray-scale images displayed in the second display section except for the sub-image a are referred to as sub-images B, and the low-dark gray-scale images displayed in the first and third display sections in the image are referred to as sub-images C. And determining the backlight brightness of the first backlight partition by utilizing a partition light control algorithm, namely determining the backlight brightness of the second backlight partition according to the sub-image A and the sub-image B displayed in the first display partition, and determining the backlight brightness of the third backlight partition according to the sub-image C displayed in the third display partition. Since the sub-image C is displayed in both the first display section and the third display section, the backlight brightness of the first backlight section and the third backlight section is the same according to the low-brightness gray-scale pixels in the sub-image C, and the first backlight section and the third backlight section are low-brightness backlight sections relative to the second backlight section. In the second display partition, the existence of the sub-image A causes the backlight brightness of the second backlight partition to be higher than that of the first backlight partition and the third backlight partition, so that the second backlight partition is a highlight backlight area.
Because the backlight brightness is different, the white light color temperature of the low-brightness backlight area is different from the white light color temperature of the high-brightness backlight area, so that the backlight color temperature of the second backlight partition is high, and the backlight color temperatures of the first and third backlight partitions are low. Because the image pixels of the sub-image BC are of the same gray scale, the corresponding colors and the brightness are displayed consistently, but the display colors and the brightness of the region where the sub-image B is positioned and the region where the sub-image C is positioned are different due to the difference of the color temperatures of the backlight, and the phenomenon of a display boundary occurs.
In summary, in the MiniLED backlight display system applying the partition light control algorithm, due to the brightness difference of different backlight partitions, a deviation phenomenon occurs in the display color temperature of the image pixels.
In view of the above, the present invention provides a color temperature correction method for a display device, where the display device includes a display module, the display module includes a display panel and a backlight module, the backlight module includes a plurality of backlight partitions, the display panel includes a plurality of display partitions corresponding to the backlight partitions one by one, pixel backlight brightness of each pixel in the display partition corresponding to the backlight partitions is counted, a color temperature correction coefficient corresponding to the pixel backlight brightness is obtained, and a pixel value of the pixel is corrected by using the color temperature correction coefficient. The invention can automatically correct the pixel value of each pixel according to the backlight gray level, and the color temperature index accords with the user's expectations after the corrected pixel value is lightened on the display module. That is, the invention can adjust the color temperature value measured after the display image is displayed on the display module to the target color temperature, thereby realizing pixel display correction and improving the display effect of screen color.
The invention can be applied to a MiniLED backlight display system to improve the color temperature deviation phenomenon caused by inconsistent backlight brightness of different backlight partitions, so that the color temperature of each region is uniform and consistent when different images are displayed on a screen, and the screen display effect is improved.
The following examples will illustrate the invention with reference to the accompanying drawings.
Fig. 2 is a flowchart of a color temperature correction method of a display device according to an embodiment of the present invention, and as shown in fig. 2, a color temperature correction method of a display device includes the following steps 201 to 203.
In step 201, the gray scale of each backlight partition is determined according to the display image on the display panel.
The display image may be a specific image, such as a white image, or may be a custom other image. The gray level of a backlight partition may be determined from the pixel maximum and/or pixel average of all pixels in the display partition corresponding to the backlight partition.
In step 202, the pixel backlight brightness of each pixel in the display section is determined based on the gray scale of each backlight section.
The pixel backlight brightness refers to the brightness provided for the pixel by a plurality of backlight partitions corresponding to the pixel in a set range. The pixel backlight brightness is also understood to be the brightness provided by the pixel by the backlight partition within a set range below the pixel.
In order to solve the problem that the display color temperature does not reach the standard when the display panel displays images from the pixel angle, the invention determines the pixel backlight brightness of each pixel through a conversion relation after determining the backlight brightness of each backlight partition, namely, simulates that a virtual backlight source for providing the backlight brightness for each pixel exists below the pixel.
In step 203, a color temperature correction coefficient corresponding to the pixel backlight luminance of each pixel is acquired from a mapping relation table constructed in advance for each pixel.
The mapping relation table is constructed when the display color temperature of the display device reaches the target color temperature by adjusting the pixel value of the pixel under the condition that all backlight partitions synchronously display different gray scales.
When the mapping relation table is constructed, all backlight partitions can be regarded as a whole, namely, all backlight partitions are synchronously driven according to different gray scales. The pixel value of the display image is referred to as a reference pixel value, the pixel value of the pixel may be continuously adjusted in order to make the display color temperature of the display device reach the target color temperature under different backlight gray scales, the pixel value when the display color temperature of the display device reaches the target color temperature is referred to as a first pixel value, and the color temperature correction coefficient may be determined according to the first pixel value and the reference pixel value. That is, at each gradation, a color temperature correction coefficient is determined from the first pixel value and the reference pixel value corresponding to the target color temperature. And converting the gray scale into the pixel backlight brightness, and constructing the mapping relation between the pixel backlight brightness and the color temperature correction coefficient.
In step 204, the pixel values of the pixels are corrected according to the color temperature correction coefficients.
And obtaining corrected pixel values according to the product of the pixel values of the pixels and the color temperature correction coefficients. The display panel is controlled to display the corrected pixel value of each pixel, namely, a time sequence control signal and a data signal for driving the display panel are generated according to the corrected pixel value.
According to the display image on the display panel, the gray scale of each backlight partition is determined; determining the pixel backlight brightness of each pixel on the display panel according to the gray scale of each backlight partition; the pixel value of each pixel is corrected according to a color temperature correction coefficient that is associated in advance with the pixel backlight luminance. The invention can automatically adjust the pixel value of the pixel according to the backlight brightness, and restore the real image display effect.
The color temperature correction method provided by the invention can be used for correcting the display equipment before leaving the factory, and the display equipment with different models is usually produced in batch, but for different display equipment with the same model, the display effect of each display equipment is different due to various factors, so that the color temperature correction can be carried out on each display equipment through the invention. After the color temperature correction coefficient of each pixel is stored after the correction is finished by using the invention, when the display equipment displays an image, the color temperature correction coefficient of each pixel can be used for correcting the pixel value of each pixel and controlling the display panel to display the corrected pixel value, thereby avoiding the phenomenon that the display color temperature of the image pixel is deviated due to the brightness difference of different backlight partitions. In addition, in order to improve the correction efficiency, a map may be constructed in advance, and a required color temperature correction coefficient is obtained from the map at the time of correction, and a process of specifically constructing the map will be specifically described in the following embodiments.
The following embodiment will describe the implementation concept of the present invention with reference to fig. 3.
Fig. 3 is a frame diagram of a color temperature correction method of a display device according to an embodiment of the present invention, and the present invention includes three parts of backlight calculation, backlight-color temperature mapping, and color temperature adjustment, as shown in fig. 3.
In the backlight calculation section, the display image is subjected to partition calculation according to the physical backlight partitions, and the gray scale of each backlight partition, which is also called as the backlight gray scale, is obtained.
And in the backlight-color temperature mapping part, performing optical diffusion simulation on the backlight subareas to determine the actual backlight brightness of each backlight subarea, then, for each pixel, determining the pixel backlight brightness of the pixel, and then, acquiring a color temperature correction coefficient corresponding to the pixel backlight brightness from a backlight-color temperature mapping relation table.
In the color temperature adjusting section, the RGB values of the pixel are corrected based on a color temperature correction coefficient corresponding to the backlight luminance of the pixel, thereby completing the abnormality correction. When the corrected RGB values are displayed, the color temperature of the display device can reach the target color temperature, namely the color temperature of the D65 color, namely the color temperature index of the corrected display panel meets the requirement.
In some embodiments, determining the gray scale of each backlight partition from the display image on the display panel may include: and determining the gray scale of each backlight partition according to the pixel value of each pixel in the display partition corresponding to each backlight partition.
In this embodiment, the backlight value of each backlight partition may be determined according to an average method and/or a maximum method.
In some embodiments, a maximum and average weighted algorithm may be used, which may adjust the duty cycle of the maximum and average in the output base backlight by a weighting factor, and may smooth the backlight value after obtaining the base backlight, so as to make the backlight transition more uniform.
That is, determining the gradation of each backlight section based on the pixel value of each pixel in the display section corresponding to each backlight section may include: obtaining the maximum pixel value in the display partition and the pixel sum of all pixels according to the pixel value of each pixel in the display partition; determining the pixel average value according to the pixel sum; determining a basic backlight of a backlight partition corresponding to the display partition according to the maximum pixel value, the pixel average value and the respective weights; and filtering the basic backlight of the backlight partition to obtain the gray scale of the backlight partition.
FIG. 4 is a schematic diagram of a process for calculating the gray scale of a backlight partition according to an embodiment of the present invention, where, as shown in FIG. 4, the partition statistics is performed on the display image by using an average value method and a maximum value method, so as to obtain a maximum pixel value and a pixel average value; obtaining basic backlight of the backlight partition by adopting a gray feature weighting statistical method; and the gray level is smoothed by adopting the smoothing filtering of the adjacent area, so that the partition splitting phenomenon is reduced. When the method is realized, the gray value is converted into the backlight driving data according to the conversion relation between the gray and the backlight driving data, and the backlight driving data is output.
In the present invention, the color temperature difference of the backlight partition is neutralized by correction of the pixels, and therefore, the pixel backlight luminance of each pixel can be determined by the following examples.
In this embodiment, determining the pixel backlight brightness of each pixel in the display section according to the gray scale of each backlight section may include: determining the backlight brightness of the backlight subarea according to the gray level of the backlight subarea and a pre-constructed optical diffusion model, wherein the optical diffusion model is used for indicating the influence degree of diffusion of other surrounding backlight subareas on the backlight subarea; and determining the pixel backlight brightness of each pixel in the display partition according to the backlight brightness of a plurality of target backlight partitions, wherein the target backlight partitions are backlight partitions with the distances from the pixels meeting the set conditions.
The backlight source (i.e. lamp beads) in the backlight module emits light under the drive of the backlight driving data, and the backlight brightness of the backlight partition is affected by other surrounding backlight partitions based on the diffusion characteristic of light. In other words, the actual backlight brightness of a backlight partition should overlap the diffused brightness of other backlight partitions surrounding the backlight partition.
FIG. 5 is a schematic diagram showing a process for determining the brightness of a pixel backlight according to an embodiment of the present invention, and as shown in FIG. 5, the actual brightness L' of each backlight partition after brightness superposition is calculated according to an actually measured optical diffusion model; after determining the actual backlight brightness of each backlight partition, the pixel backlight brightness L of each pixel can be obtained by interpolation calculation p 。
All the lamp beads in one backlight partition are regarded as a whole, and the backlight partition emits light and diffuses under the drive of backlight driving data. The backlight brightness of each backlight partition is affected by diffusion of other surrounding backlight partitions, but the distances and the affected degrees are different. Typical optical diffusion models are of specifications 7*7, 9*9, 11 x 11. As shown in FIG. 6a, for a 7x7 optical diffusion model, mu is calculated 0,0 The backlight partition at the location is called backlight partition a, and the value in the model represents the influence coefficient of the backlight partition a by the backlight partition at the location of the value.
In some embodiments, the determining the backlight brightness of the backlight partition according to the gray scale of the backlight partition and a pre-constructed optical diffusion model includes: and determining the backlight brightness of the backlight subarea according to the gray scale of the backlight subarea and the influence coefficients of other backlight subareas around the backlight subarea.
FIG. 6b is a schematic diagram showing a determination of backlight brightness according to an embodiment of the present invention, shown in FIG. 6b, BL ij For the center of the 7x7 backlight area, BL is calculated from the 7x7 optical diffusion model ij And overlapping the backlight brightness after the diffusion of other surrounding backlight partitions. With BL ij For example, select BL ij A 7x7 backlight rectangle as the center, BL was calculated according to the following equation 1 ij And superposing the diffused backlight brightness.
In equation 1, BL_spin ij For BL ij Superposing the diffused backlight brightness; BL (bit line) i+m,j+n Backlight gray scale of backlight partition of the ith row and the jth column and the nth column; mu (mu) m,n For the ith+m row, the backlight brightness of the backlight partition of the jth+n column is diffused and then the backlight partition BL is divided ij Is used for the influence coefficient of the (c).
In some embodiments, bilinear interpolation may be used to obtain the pixel backlight brightness for each pixel in the display partition. That is, the determining the pixel backlight brightness of each pixel in the display partition according to the backlight brightness of the plurality of target backlight partitions may include: for each target pixel in a display partition, acquiring four target backlight partitions, wherein the distance between the four target backlight partitions and the target pixel accords with a set condition; and obtaining the pixel backlight brightness corresponding to the target pixel according to the backlight brightness of each target backlight partition and the normalized distance between the target pixel and the center of each target backlight partition.
The four target backlight partitions whose distances from the target pixels meet the set condition may also be understood as four target backlight partitions adjacent to the target pixels.
FIG. 7 is a schematic diagram illustrating a determination of pixel back brightness, shown in FIG. 7, bl according to an embodiment of the present invention 1 、Bl 2 、Bl 3 、Bl 4 Is to be with the target pixel L p The backlight brightness of the adjacent four target backlight partitions is the backlight brightness after superposition and diffusion. a. (1-a), b, (1-b) are the target pixels L, respectively p And normalization near the center of four target backlight partitionsDistance. The target pixel L may be determined using equation 2 p Is used for the brightness of the pixel backlight.
L p ＝
b×(a×Bl 1 +(1-a)×Bl 2 )+(1-b)×(a×Bl 3 +(1-a)×Bl 4 ) Equation 2
For example, for an 8K display device, there are 64×36 backlight partitions, each including 120×120 pixels, and the pixel backlight brightness of each pixel may be determined according to the backlight brightness of each backlight partition by the above embodiment.
In the case of obtaining the pixel backlight luminance of a pixel, a color temperature correction coefficient corresponding to the pixel backlight luminance may be acquired from the map table according to a map table constructed in advance, and then the pixel value of the pixel may be corrected based on the color temperature correction coefficient.
FIG. 8 is a schematic diagram showing a process of correcting pixel values according to an embodiment of the present invention, wherein the pixel brightness backlight value L is found from the mapping relation table as shown in FIG. 8 p Corresponding target color temperature correction coefficient (μ) r ,μ g ,μ b ). And carrying out gray scale adjustment on the pixel value rgb of the current pixel according to a linear adjustment formula shown in a formula 3.
In formula 3, (r ', g ', b ') is an adjusted pixel by which it is possible to achieve that the display color temperature of all areas of the image is adjusted to the target color temperature.
The above embodiments introduce that the display color temperature of the display device reaches the target color temperature by correcting the pixel values of the pixels on the display panel, so as to solve the problem that the display color temperature of the display device does not reach the standard due to the color temperature difference of each backlight partition. The correction process is implemented based on a map table constructed in advance, and the following embodiment will explain the process of constructing a map.
In order to realize color temperature correction, the color temperature correction coefficient of any pixel needs to be obtained under the backlight brightness of any pixel, and therefore, a mapping relation table between brightness and color temperature correction coefficients needs to be constructed. In the construction process, the RGB value of each pixel is regulated to a new RGB value according to each backlight gray level, so that the display color temperature can be equal to the target color temperature when the display module displays the regulated RGB value, and the color temperature correction coefficient is determined according to the ratio of the new RGB value to the initial RGB value.
In some embodiments, the process of building the mapping relationship includes: controlling a display panel to display a designated image, and acquiring a reference pixel value according to the designated image; under each gray level, adjusting the pixel value of the pixel in the appointed image until the display color temperature of the display equipment reaches the target color temperature, and acquiring a first pixel value; determining a color temperature correction coefficient according to the first pixel value and the reference pixel value; determining the pixel backlight brightness of each pixel according to the gray scale of each backlight partition; and establishing a mapping relation between the brightness of the pixel backlight and the color temperature correction coefficient. Wherein the specified image is a specified white image.
Fig. 9 is a schematic diagram of a test environment according to an embodiment of the present invention, in which the measurement environment shown in fig. 9 is constructed, and a measurement initial state is set.
Firstly, determining basic specifications of a display module and establishing an adjusted target value, selecting a configured display module (a backlight module, an LCD, a QD film and the like), enabling the LCD to display a color temperature D65 meeting a target under a set standard brightness of 1000nit, obtaining (x 0, y 0) as (0.3127,0.329) by measuring with a spectrometer, wherein the coordinate is a D65 white color coordinate under a CIE standard chromaticity system, and setting the gray level L0 of a backlight MiniLED at the moment (namely in the standard state).
In the present embodiment, the white screen of (r 0, g0, b 0) = (255 ) is lit up by using the individually driven lighting values of the LCD panel pixels and the MiniLED backlight in the display module, respectively, and the MiniLED backlight is lit up according to the backlight gray level L0, which is set to the measurement initial state.
Fig. 10 is a schematic flow chart of a mapping table construction process according to an embodiment of the present invention, and as shown in fig. 10, the construction process includes steps 1001 to 1003.
In step 1001, a test environment is built.
In step 1002, a measurement initial state is entered.
The LCD panel was lit (r 0, g0, b 0) = (255 ) on a white screen, and the MiniLED backlight lit the backlight gray scale L0 of the display module at standard luminance.
In step 1003, the display color coordinates (x 1, y 1) of the current display module measured by the spectrometer are acquired.
In measuring the display color coordinates of the display module, the spectrometer typically selects a particular measurement point on the screen and then records the spectral data at that point with a detector. Using these spectral data, the color coordinates at the point can be calculated to describe the color that the point displays. In this embodiment, the display color coordinates of the central area of the screen are measured by the spectrometer, considering that the points of the central area are most comprehensively diffused by the surrounding backlight partitions.
In the initial measurement state, the display color coordinates should be the reference color coordinates (x 0, y 0) which are the set initial values.
In step 1004, it is determined whether or not the display color coordinates (x 1, y 1) match the reference color coordinates (x 0, y 0), if so, step 1005 is executed, and if not, step 1006 is executed.
A first pixel value is acquired when a display color temperature of the display device reaches a target color temperature. And determining a pixel color temperature correction coefficient according to the reference pixel value and the first pixel value.
In the measurement initial state, the first pixel value is (255 ), and therefore, the pixel color temperature correction coefficient (μr0, μg0, μb0) = (1, 1), that is, (μr0, μg0, μb0) = (R0/255, G0/255, B0/255) corresponding to the initial backlight luminance.
In step 1005, a mapping relationship is established at the current backlight brightness.
According to the backlight diffusion and pixel backlight interpolation algorithm described in the foregoing embodiments, the pixel backlight brightness corresponding to the current backlight gray level can be obtained, and the mapping relationship between the pixel backlight brightness and the color temperature correction coefficient can be established.
Determining the pixel backlight brightness Lp0 corresponding to the initial backlight gray level L0, and establishing a mapping relation between the pixel backlight brightness and a color temperature correction coefficient in a standard state: lp0→ (μR0, μG0, μB0).
In step 1006, the pixel value of the pixel is adjusted, and step 1003 is performed.
In step 1007, the backlight gray level is adjusted downward according to the preset step value, if the adjusted backlight gray level is greater than or equal to 0, the backlight module is driven based on the adjusted backlight gray level, and step 1003 is performed, and if the adjusted backlight gray level is less than 0, step 1008 is performed.
In this embodiment, the measurement of the low backlight brightness interval is performed first, the gray scale of the MiniLED backlight is reduced to L1 according to the preset step value Lstep, the display color coordinates (x 1, y 1) of the current module are measured by using a spectrometer, and whether the values of the reference color coordinates (x 0, y 0) are equal to the values of the target color temperature D65 or not is determined, if not, the rgb value is continuously adjusted until a new set of pixel values (r 1, g1, b 1), namely, the first pixel value, is obtained, so that the display color coordinates measured by the spectrometer are (x 0, y 0). The current adjustment coefficients (μr1, μg1, μb1) are recorded μr1=r1/255, μg1=g1/255, μb1=b1/255.
According to the backlight diffusion and pixel backlight interpolation algorithm, calculating the corresponding pixel backlight brightness Lp1 when the backlight gray level of the backlight partition is L1, and constructing the mapping relation Lp1→ (mu R1, mu G1, mu B1) of the pixel backlight brightness Lp1 and the color temperature correction coefficient.
And (3) cycling the steps, gradually reducing the backlight gray level according to the step value Lstep until the backlight gray level is 0, recording the current backlight gray level as Li when each reduction is performed, and adjusting the (ri, gi, bi) value to enable the display color coordinate measured by the spectrometer to be the D65 color coordinate (x 0, y 0) when each reduction is performed. And obtaining a color temperature adjustment coefficient (muRi, muGi, muBi) under the current backlight gray scale according to the adjusted pixel values (muRi=ri/255, muGi=gi/255 and muBi=bi/255). And calculating the corresponding pixel backlight brightness Lpi according to each backlight gray scale Li, thereby establishing a mapping table LUTa of the pixel backlight brightness and the color temperature correction coefficient in the low backlight gray scale interval, namely Lpi- (muRi, muGi, muBi).
In step 1008, the backlight gray level is adjusted upwards according to the preset step value based on the initial backlight gray level, if the adjusted backlight gray level is less than or equal to the maximum backlight gray level, the backlight module is determined based on the adjusted backlight gray level, and step 1003 is performed, if the adjusted backlight gray level is greater than the maximum backlight gray level, the construction process is completed.
After the mapping relation of the low backlight gray scale interval is built, high backlight gray scale interval measurement is carried out, and the backlight gray scale is gradually increased from the L0 initial state according to the step value Lstep until the backlight gray scale is the maximum backlight gray scale Lm of the display module. In the same manner, a map table LUTb: lpj → (μRj, μGj, μBj) between pixel backlight luminance and color temperature correction coefficients in a high backlight gray scale region is constructed.
And combining the mapping relation table of the low backlight gray scale interval and the mapping relation table of the high backlight gray scale interval to obtain the mapping relation table LUT between the pixel backlight brightness and the color temperature correction coefficient of the display module in the whole interval, wherein the LUT is Lp- (mu R, mu G and mu B).
The embodiment also provides a color temperature correction device of a display device, the display device includes a display panel and a backlight module, the backlight module includes a plurality of backlight partitions, the display panel includes a display partition corresponding to the backlight partitions one to one, the device includes:
a determining unit for determining the gray scale of each backlight partition according to the display image on the display panel; determining the pixel backlight brightness of each pixel in the display partition according to the gray scale of each backlight partition, wherein the pixel backlight brightness refers to the brightness provided by the backlight partition in a set range corresponding to the pixel for the pixel;
an obtaining unit, configured to obtain, for each pixel, a color temperature correction coefficient corresponding to a pixel backlight luminance of the pixel from a mapping relation table that is previously constructed, where the mapping relation table is constructed when a display color temperature of a display device reaches a target color temperature by adjusting a pixel value of the pixel under a condition that all backlight partitions synchronously display different gray scales;
And the correction unit is used for correcting the pixel value of the pixel according to the color temperature correction coefficient.
The specific implementation process of each unit in the above apparatus may refer to the foregoing embodiment, and will not be described herein.
The display device in this embodiment may be: electronic paper, mobile phone, tablet computer, television, notebook computer, digital photo frame, navigator and any other products or components with display function.
It is noted that in the drawings, the size of layers and regions may be exaggerated for clarity of illustration. Moreover, it will be understood that when an element or layer is referred to as being "on" another element or layer, it can be directly on the other element or intervening layers may be present. In addition, it will be understood that when an element or layer is referred to as being "under" another element or layer, it can be directly under the other element or intervening layers or elements may be present. In addition, it will be understood that when a layer or element is referred to as being "between" two layers or elements, it can be the only layer between the two layers or elements, or more than one intervening layer or element may also be present. Like reference numerals refer to like elements throughout.
In the present invention, the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The term "plurality" refers to two or more, unless explicitly defined otherwise.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
It is to be understood that the invention is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims (11)

1. The color temperature correction method of the display device is characterized in that the display device comprises a display panel and a backlight module, the backlight module comprises a plurality of backlight partitions, the display panel comprises display partitions which are in one-to-one correspondence with the backlight partitions, and the method comprises the following steps:
Determining the gray scale of each backlight partition according to the display image on the display panel;
according to the gray scale of each backlight partition, determining the pixel backlight brightness of each pixel in the display partition, wherein the pixel backlight brightness refers to the brightness provided for the pixel by a plurality of backlight partitions corresponding to the pixel in a set range;
acquiring a color temperature correction coefficient corresponding to the pixel backlight brightness of each pixel from a pre-constructed mapping relation table for each pixel, wherein the mapping relation table is constructed when the display color temperature of the display equipment reaches a target color temperature by adjusting the pixel value of the pixel under the condition that all backlight partitions synchronously display different gray scales;
and correcting the pixel value of the pixel according to the color temperature correction coefficient.
2. The method according to claim 1, wherein the method further comprises:
controlling a display panel to display a designated image, and acquiring a reference pixel value according to the designated image;
under each gray level, adjusting the pixel value of the pixel in the appointed image until the display color temperature of the display equipment reaches the target color temperature, and acquiring a first pixel value;
determining a color temperature correction coefficient according to the first pixel value and the reference pixel value;
Determining the pixel backlight brightness of each pixel according to the gray scale of each backlight partition;
and establishing a mapping relation between the brightness of the pixel backlight and the color temperature correction coefficient.
3. The method according to claim 2, wherein the display color coordinates of the display device are reference color coordinates when the display color temperature of the display device reaches a target color temperature;
the adjusting the pixel value of the pixel, obtaining a first pixel value when the display color temperature of the display device reaches the target color temperature, includes:
acquiring display color coordinates of a display panel under the current backlight brightness;
if the display color coordinates are inconsistent with the reference color coordinates, adjusting pixel values of pixels until the display color coordinates are consistent with the reference color coordinates;
and acquiring a first pixel value when the display color coordinates are consistent with the reference color coordinates.
4. The method of claim 1, wherein determining the pixel backlight brightness of each pixel in the display section based on the gray scale of each backlight section comprises:
determining the backlight brightness of the backlight subarea according to the gray level of the backlight subarea and a pre-constructed optical diffusion model, wherein the optical diffusion model is used for indicating the influence degree of other surrounding backlight subareas on the backlight subarea;
And determining the pixel backlight brightness of each pixel in the display partition according to the backlight brightness of a plurality of target backlight partitions, wherein the target backlight partitions are backlight partitions with the distances from the pixels meeting the set conditions.
5. The method of claim 4, wherein determining the backlight brightness of the backlight partition based on the gray scale of the backlight partition and a pre-constructed optical diffusion model comprises:
and determining the backlight brightness of the backlight subarea according to the gray scale of the backlight subarea and the influence coefficients of other backlight subareas around the backlight subarea.
6. The method of claim 4, wherein determining the pixel backlight brightness for each pixel in the display partition based on the backlight brightness for the plurality of target backlight partitions comprises:
for each target pixel in a display partition, acquiring four target backlight partitions, wherein the distance between the four target backlight partitions and the target pixel accords with a set condition;
and obtaining the pixel backlight brightness corresponding to the target pixel according to the backlight brightness of each target backlight partition and the normalized distance between the target pixel and the center of each target backlight partition.
7. The method of claim 1, wherein determining the gray level of each backlight partition from the display image on the display panel comprises:
And determining the gray scale of each backlight partition according to the pixel value of each pixel in the display partition corresponding to each backlight partition.
8. The method of claim 7, wherein determining the gray level of each backlight partition based on the pixel value of each pixel in the display partition corresponding to each backlight partition comprises:
obtaining the maximum pixel value in the display partition and the pixel sum of all pixels according to the pixel value of each pixel in the display partition;
determining the pixel average value according to the pixel sum;
determining a basic backlight of a backlight partition corresponding to the display partition according to the maximum pixel value, the pixel average value and the respective weights;
and filtering the basic backlight of the backlight partition to obtain the gray scale of the backlight partition.
9. The utility model provides a colour temperature correcting unit of display device, its characterized in that, display device includes display panel and backlight unit, include a plurality of backlight subregions in the backlight unit, include in the display panel with a plurality of backlight subregions one-to-one show subregion, the device includes:
a determining unit for determining the gray scale of each backlight partition according to the display image on the display panel; determining the pixel backlight brightness of each pixel in the display partition according to the gray scale of each backlight partition, wherein the pixel backlight brightness refers to the brightness provided by the backlight partition in a set range corresponding to the pixel for the pixel;
An obtaining unit, configured to obtain, for each pixel, a color temperature correction coefficient corresponding to a pixel backlight luminance of the pixel from a mapping relation table that is previously constructed, where the mapping relation table is constructed when a display color temperature of a display device reaches a target color temperature by adjusting a pixel value of the pixel under a condition that all backlight partitions synchronously display different gray scales;
and the correction unit is used for correcting the pixel value of the pixel according to the color temperature correction coefficient.
10. A display device, characterized by comprising:
a display panel and a backlight module;
an image to be displayed on the display panel is pixel corrected by the method of any one of claims 1 to 8.
11. A storage medium having stored thereon computer instructions for causing a computer to perform the method of any one of claims 1 to 8.
CN202311435767.2A 2023-10-31 2023-10-31 Color temperature correction method and device of display equipment, display equipment and medium Pending CN117409734A (en)

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