WO2019214449A1 - 屏幕亮度的控制方法、装置及终端设备 - Google Patents
屏幕亮度的控制方法、装置及终端设备 Download PDFInfo
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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
- G09G3/22—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 using controlled light sources
- G09G3/30—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 using controlled light sources using electroluminescent panels
- G09G3/32—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3258—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the voltage across the light-emitting element
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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
- G09G3/22—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 using controlled light sources
- G09G3/30—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 using controlled light sources using electroluminescent panels
- G09G3/32—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
- G09G5/10—Intensity circuits
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0233—Improving the luminance or brightness uniformity across the screen
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0271—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
- G09G2320/0276—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0285—Improving the quality of display appearance using tables for spatial correction of display data
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- G09G2320/0606—Manual adjustment
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- G09G2320/0626—Adjustment of display parameters for control of overall brightness
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- 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
- G09G2320/0673—Adjustment of display parameters for control of gamma adjustment, e.g. selecting another gamma curve
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- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2340/00—Aspects of display data processing
- G09G2340/16—Determination of a pixel data signal depending on the signal applied in the previous frame
Definitions
- the present application relates to the field of display display, and in particular, to a method, device and terminal device for controlling screen brightness.
- the organic light emitting diode display device has the advantages of self-luminous, thin thickness, high contrast, large viewing angle, and the like, and is the main development direction of the next generation mobile phone panel.
- the active-matrix organic light emitting diode (AMOLED) has a focus on development because of its good flexibility.
- the brightness adjustment range of the screen is divided into a plurality of different brightness adjustment points, and each brightness adjustment point is configured with an independent correspondence, and the corresponding relationship can represent the original display input of the screen.
- the mapping relationship between the data and the display input data corresponding to the brightness of the segment is typically stored in the form of a lookup table.
- the lookup table for each brightness adjustment point can be viewed as a separate memory or register.
- each existing correspondence needs to be obtained through an independent measurement process, and multiple correspondences require multiple memories for storage, and the cost is high; and if the current brightness of the screen is not located in the existing When the brightness adjustment point is on, it is also necessary to obtain corresponding display input data through linear interpolation, etc., resulting in inaccurate brightness display of the panel.
- the present application provides a method, a device and a terminal device for controlling the brightness of a screen, which can perform correct brightness display during brightness adjustment, and occupy less hardware resources.
- the present application provides a method for controlling screen brightness, which includes first determining a first brightness value corresponding to a screen in a current gear position of a brightness adjustment; and then determining, according to a preset gamma correction lookup table, a first brightness value.
- the first input grayscale value, the gamma correction lookup table is a gamma correction relationship of the brightness value of the screen and the initial input grayscale value of the screen under the specified gear position of the brightness adjustment; finally, the screen is controlled according to the first input grayscale value.
- the brightness value is displayed.
- the correspondence between the brightness value and the input gray level value of the other gears of the brightness adjustment is obtained by the Gamma correction relationship between the brightness value and the input gray level value in the specified gear position of the brightness adjustment.
- the relationship can be based on the Gamma correction relationship under the specified gear position to achieve the gamma correction for the brightness of the screen display under the other gears of the brightness adjustment, without storing the gamma correction relationship under other gear positions, effectively saving hardware resources.
- the screen includes a non-uniform Mura region, and if the pixel values of the pixels in the initial brightness adjustment are corresponding to the second brightness value, determining that the screen corresponds to the first gear in the current gear position of the brightness adjustment.
- the method further includes: first determining, according to the preset gamma correction lookup table, a second input grayscale value corresponding to the second brightness value before performing the Demura on the screen; and then controlling according to the second input grayscale value according to the second input grayscale value The brightness value of each pixel of the screen.
- Gamma correction is performed on the screen containing the Mura area before Demura is performed on the screen, and Gamma correction is performed on the screen subjected to Demura operation during the brightness adjustment, which ensures the uniformity of the screen and the brightness adjustment of the screen.
- the correct brightness display is always achieved during the process.
- Demura's previous Gamma correction is based on the same Gamma correction lookup table during the brightness adjustment process, which can achieve better hardware integration, save storage space and reduce hardware cost. .
- the gamma correction lookup table includes any one of the following: a plurality of discrete grayscale values and a plurality of display luminance values, the number of grayscale values is equal to the number of display luminance values, and the grayscale value corresponds to the display luminance value.
- the number of discrete grayscale values is equal to the total order of grayscale values of the screen; or, multiple discrete grayscale values and multiple display luminance values, the number of grayscale values is equal to the number of displayed luminance values, grayscale values Corresponding to the display brightness value, the number of discrete gray scale values is less than the total order of the gray scale values of the screen.
- the current hardware can be used to store and express the correspondence between the finite integer gray scale values and the corresponding display luminance values, which can accurately represent the correspondence between the input gray scale values and the display luminance values. It also saves hardware resources such as memory space or processing power.
- the two-dimensional coordinate points formed by the display luminance values corresponding to the gray scale values of the discrete gray scale values and the discrete gray scale values are all located on a Gamma curve, wherein the abscissa of the Gamma curve represents the gray scale value.
- the ordinate of the Gamma curve represents the brightness value of the display.
- the preset condition is met between the current brightness value of the screen under the current gear position and the previous brightness value of the previous gear position of the brightness adjustment, wherein the current brightness value corresponds to the same input gray level value as the previous brightness value.
- the preset condition is that the ratio of the difference between the brightness value of the adjacent gear position and the previous brightness value satisfies Weber's law.
- the luminance value difference is a difference between the current luminance value and the previous luminance value. In this way, when the brightness adjustment is implemented, the brightness and darkness of the screen can be evenly transitioned, which makes the human eye more adaptable.
- the maximum brightness value supported by the screen in the specified gear position is greater than the maximum brightness value supported by the screen in the current gear position of the brightness adjustment.
- the corresponding brightness value of the pixel point in the gear position will be included in the screen to display the brightness value and the input gray scale value of the pixel in the specified gear position.
- the specified gear position is the maximum gear position supported when the screen brightness is adjusted.
- determining, according to the preset gamma correction lookup table, the input grayscale value corresponding to the brightness value comprises: first determining that the brightness value of the screen display is an initial input corresponding to the screen when the brightness value of the current gear position of the brightness adjustment is corresponding. Grayscale value; then the initial input grayscale value is replaced with the input grayscale value determined based on the Gamma corrected lookup table as the input grayscale value corresponding to the luminance value.
- the correspondence between the plurality of grayscale values and the plurality of display luminance values in the gamma correction lookup table conforms to a Gamma correction formula, wherein the display luminance value is an input of a Gamma correction formula, and the grayscale value is an output of a Gamma correction formula.
- determining, according to the preset gamma correction lookup table, the input grayscale value corresponding to the brightness value specifically: calculating a plurality of grayscale values corresponding to the plurality of display luminance values one by one based on the plurality of display luminance values and the gamma correction formula .
- f is the grayscale value corresponding to the first brightness value in the current gear position of the normalized brightness adjustment
- ⁇ is the gamma value in the preset gamma correction lookup table
- N is the total number of gray levels .
- determining, according to the preset gamma correction lookup table, the first input gray level value corresponding to the first brightness value includes : first obtaining the display brightness value of the first brightness value in the current gear position closest to the brightness adjustment in the Gamma correction lookup table; and then graying out the display brightness value corresponding to the first brightness value in the current gear position closest to the brightness adjustment
- the order value is the first input gray level value corresponding to the first brightness value.
- the method further includes rounding the calculated grayscale value, and using the rounded result as the first input grayscale corresponding to the displayed first luminance value. value.
- determining the input gray level value corresponding to the screen brightness value based on the preset gamma correction lookup table specifically includes: Determining two display brightness values directly adjacent to the first brightness value under the current gear position of the brightness adjustment based on the Gamma correction lookup table; and establishing linear interpolation based on the directly adjacent two display brightness values and their corresponding gray level values Equation; finally, the first input grayscale value corresponding to the first brightness value is obtained according to the linear interpolation equation and the first brightness value under the current gear position of the brightness adjustment.
- the lookup table includes only a correspondence between a limited number of input grayscale values and display luminance values, and other correspondences included in the preset gamma correction lookup table are obtained by simple linear interpolation operations.
- the method before determining the first brightness value displayed by the screen under the current gear position of the brightness adjustment, the method further includes receiving a brightness adjustment signal, the brightness adjustment signal is used to indicate that the display brightness of the screen is adjusted to the current gear position of the brightness adjustment. .
- the present application further provides a screen brightness control apparatus, including: a brightness determining module, configured to determine a first brightness value corresponding to a screen in a brightness adjustment current gear position; a first gamma gamma correction module, Determining, according to a preset gamma correction lookup table, a first input grayscale value corresponding to the first brightness value, the gamma correction lookup table is a brightness value of the screen and an initial input grayscale value of the screen under the specified gear position of the brightness adjustment a gamma correction relationship; and a brightness adjustment module for controlling a display brightness value of the screen according to the first input gray level value.
- a brightness determining module configured to determine a first brightness value corresponding to a screen in a brightness adjustment current gear position
- a first gamma gamma correction module Determining, according to a preset gamma correction lookup table, a first input grayscale value corresponding to the first brightness value, the gamma correction lookup table is a brightness
- the correspondence between the brightness value and the input gray level value of the other gears of the brightness adjustment is obtained by the Gamma correction relationship between the brightness value and the input gray level value in the specified gear position of the brightness adjustment.
- the relationship can be based on the Gamma correction relationship under the specified gear position, and the Gamma correction is performed on the brightness of the screen display under other gear positions of the brightness adjustment, and the gamma correction relationship under other gear positions does not need to be stored, thereby effectively saving hardware resources.
- the screen includes a non-uniform Mura region.
- the device further includes: a second gamma correction module, configured to Before the screen is performed by Demura, the second gamma value corresponding to the brightness value displayed when the screen is displayed in the initial gear position is determined based on the preset gamma correction lookup table; the second gamma correction module is further used according to the The two input gray scale values control the display brightness of each pixel of the screen; in addition, the device further includes a Mura correction module for performing Demura on the screen.
- the gamma correction lookup table includes any one of the following: a plurality of discrete grayscale values and a plurality of display luminance values, the number of grayscale values is equal to the number of display luminance values, and the grayscale value corresponds to the display luminance value.
- the number of discrete grayscale values is equal to the total order of grayscale values of the screen; or, multiple discrete grayscale values and multiple display luminance values, the number of grayscale values is equal to the number of displayed luminance values, grayscale values Corresponding to the display brightness value, the number of discrete gray scale values is less than the total order of the gray scale values of the screen.
- the current hardware can be used to store and express the correspondence between the finite integer gray scale values and the corresponding display luminance values, which can accurately represent the correspondence between the input gray scale values and the display luminance values. It also saves hardware resources such as memory space or processing power.
- the two-dimensional coordinate points formed by the display luminance values corresponding to any of the gray scale values and the discrete gray scale values are located on a Gamma curve, wherein the abscissa of the Gamma curve represents the gray scale value.
- the ordinate of the Gamma curve represents the brightness value of the display.
- a preset condition is met between a current brightness value of the screen under the current gear position and a previous brightness value of the previous gear position of the brightness adjustment, wherein the current brightness value corresponds to the same input gray level as the previous brightness value.
- the value is preset as follows: the ratio of the luminance value difference of the adjacent gear position to the previous luminance value satisfies Weber's law, wherein the luminance value difference is the difference between the current luminance value and the previous luminance value.
- the maximum brightness value supported by the screen in the specified gear position is greater than the maximum brightness value supported by the screen in the current gear position of the brightness adjustment.
- the corresponding brightness value of the pixel point in the gear position will be included in the screen to display the brightness value and the input gray scale value of the pixel in the specified gear position.
- the specified gear position is the maximum gear position supported during brightness adjustment.
- the first gamma module is specifically configured to: first determine that the brightness value of the screen display is an initial input grayscale value corresponding to the screen when the first brightness value corresponding to the current gear position of the brightness adjustment is adjusted; and further use the Gamma-based correction lookup table.
- the determined input grayscale value replaces the initial input grayscale value as the first input grayscale value corresponding to the first luminance value.
- the correspondence between the plurality of grayscale values and the plurality of display luminance values in the gamma correction lookup table conforms to a Gamma correction formula, wherein the display luminance value is an input of a Gamma correction formula, and the grayscale value is an output of a Gamma correction formula.
- the control device further includes: a gamma correction lookup table acquisition module, configured to calculate a plurality of grayscale values corresponding to the plurality of display luminance values in one-to-one based on the plurality of display luminance values and the correction formula.
- the first gamma correction module is further configured to: first obtain the current file closest to the brightness adjustment in the gamma correction lookup table. a display brightness value of the first brightness value under the bit; then the gray level value corresponding to the display brightness value of the first brightness value under the current gear position closest to the brightness adjustment is used as the first input gray level corresponding to the first brightness value value.
- the first gamma correction module is specifically configured to: first determine the current gear position with the brightness adjustment based on the gamma correction lookup table.
- the first first brightness value is directly adjacent to the two display brightness values; then a linear interpolation equation is established based on the directly adjacent two display brightness values and their corresponding gray level values; finally, the current file is adjusted according to the linear interpolation equation and the brightness
- the first luminance value under the bit acquires a first input grayscale value corresponding to the first luminance value.
- the current hardware can be used to store and express the correspondence between the finite integer gray scale values and the corresponding display luminance values, which can accurately represent the correspondence between the input gray scale values and the display luminance values. It also saves hardware resources such as memory space or processing power.
- the application provides a terminal device, where the terminal device includes: a processor, a first gamma selector, a first gamma correction controller, and a screen.
- the processor is configured to determine a first brightness value corresponding to the screen in the current brightness adjusted gear position.
- the first gamma selector is configured to determine a first input grayscale value corresponding to the first brightness value based on the preset gamma correction lookup table, and the gamma correction lookup table is the brightness value of the screen and the screen under the specified gear position of the brightness adjustment The gamma correction relationship of the initial input grayscale value.
- the first gamma correction controller is configured to control the display brightness value of the screen according to the first input grayscale value.
- the gamma correction relationship between the brightness value and the input gray level value in the specified gear position determined by the brightness adjustment is used to obtain the correspondence between the brightness value and the input gray level value of the other gear positions of the brightness adjustment.
- the relationship can be based on the Gamma correction relationship under the specified gear position, and the Gamma correction is performed on the brightness of the screen display under other gear positions of the brightness adjustment, and the gamma correction relationship under other gear positions does not need to be stored, thereby effectively saving hardware resources.
- the screen includes a non-uniform Mura region, and if the pixel values of the pixels in the initial position of the brightness adjustment are corresponding to the second brightness value, the terminal device further includes a second gamma selector and a second gamma correction.
- a controller a second gamma selector, configured to determine a second input grayscale value corresponding to the second brightness value based on the preset gamma correction lookup table before performing Demura on the screen; the second gamma correction controller is further used to The display brightness value of each pixel of the screen is controlled according to the second input grayscale value.
- the terminal device further includes a memory for storing a preset gamma correction lookup table.
- the gamma correction controller comprises: a voltage generator and a brightness controller, a voltage generator for generating a reference voltage according to the input grayscale value; and a brightness controller for controlling the screen display and the input gray based on the reference voltage The display brightness value corresponding to the order value.
- FIG. 1 is a schematic flow chart of a method for controlling screen brightness according to an embodiment of the present application
- FIG. 2 is a schematic diagram of a Gamma curve at different gear positions of brightness adjustment
- FIG. 3 is a schematic flowchart of determining a first input grayscale value corresponding to a first brightness value in a current gear position of a brightness adjustment according to an embodiment of the present application
- FIG. 4 is a schematic diagram of a Gamma curve corresponding to a Gamma correction lookup table in a method for controlling screen brightness according to an embodiment of the present application;
- FIG. 5 is a schematic flowchart diagram of another method for controlling screen brightness according to an embodiment of the present application.
- FIG. 6 is a schematic structural diagram of a screen brightness control apparatus according to an embodiment of the present application.
- FIG. 7 is a schematic structural diagram of another apparatus for controlling brightness of a screen according to an embodiment of the present application.
- FIG. 8 is a schematic structural diagram of hardware of a terminal device according to an embodiment of the present disclosure.
- FIG. 9 is a schematic structural diagram of hardware of another terminal device according to an embodiment of the present disclosure.
- the brightness of the image displayed on the screen is usually inconsistent with the original brightness of the original input image, but there is Certain deviation.
- the image outputted by the screen is distorted compared with the input image, resulting in a large difference in color between the screen display color and the input image, or the screen is too bright or too dark for the image to be displayed.
- the color of the screen display changes from black to white
- the grayscale value of the input of the screen also changes, but the change is not linear.
- the physical characteristics of the screen display determine if the grayscale value of the input is linear.
- the output brightness value is not linear.
- the gamma correction process is performed on the screen. It shows the desired brightness.
- the gamma correction of the screen can make the relationship between the grayscale value of the screen input and the brightness of the output satisfy a corresponding relationship curve, and the curve is a Gamma curve.
- the screen can display the preset brightness and color.
- FIG. 1 is a schematic flow chart of a method for controlling screen brightness according to Embodiment 1 of the present application. As shown in FIG. 1 , the method for controlling the brightness of the screen provided in this embodiment may specifically include the following steps:
- the screen may have multiple different gear positions for adjusting the brightness, and the range of brightness values that can be displayed on the screen in different brightness adjusted gear positions is different.
- the brightness adjustment of the screen is exemplified.
- the maximum brightness value that the screen itself can display is 500 nits. If the screen has 5 different brightness adjustment positions, the first brightness adjustment position, the next The range of brightness values that can be displayed on the screen is 0-100nit. Under the second brightness adjustment position, the range of brightness values that can be displayed on the screen is 0-200nit,..., the screen of the fifth brightness adjustment can be displayed.
- the brightness value ranges from 0 to 500 nit.
- the five brightness adjustment positions of the screen can correspond to five scales on the brightness bar of the screen.
- the rightmost scale on the screen brightness bar corresponds to the fifth one.
- the brightness adjusted gear position shifts one scale to the left corresponding to the fourth brightness adjustment gear position, and so on, the leftmost scale on the screen brightness bar corresponds to the first brightness adjusted gear position (ie, the brightness range that can be displayed) Small, brightness of the screen is also the darkest).
- the brightness value corresponding to the area of the same brightness level will also change. It should be understood that the above-listed data is merely illustrative of the gears for adjusting the brightness of the screen, and does not limit the range of brightness adjustments of the screen and the range of corresponding displayable brightness values.
- the pixels on the screen will remain the same.
- the light-dark ratio is such that the entire display image can maintain the original picture features such as texture and pattern when the reference brightness value is changed.
- the brightness value displayed by each pixel point under the gear position will also change along with the change of the gear position.
- the screen There is a positive correlation between the brightness-adjusted gear position and the brightness value displayed at each pixel point, so that the image can be adjusted to the overall brightness without damaging the image's own pattern and texture details. Therefore, when the brightness is adjusted to the current gear position, the corresponding first brightness value of each pixel of the screen in the current gear position can be determined.
- each pixel on the screen Since the pixels on the screen are independent of each other, the brightness values of each pixel are also independent of each other, and only change with the change of the position of the brightness of the screen. Therefore, when the screen is in a certain brightness adjustment position, for example, the current gear position of the brightness adjustment, each pixel on the screen will have an independent first brightness value, and each pixel point is displayed when the screen displays different images.
- the brightness values can be the same or different. Specifically, when the same image is displayed, if the brightness adjustment of the screen is adjusted, the brightness value displayed when the grayscale value of the screen input is maximum may be determined first, and determined according to a specific ratio or other positive correlation. Each pixel is a display brightness value that is adjusted to display other grayscale values.
- the first brightness value displayed by each pixel point and the brightness adjustment position of the screen can be positively correlated, that is, the first brightness value will change direction with the display brightness of the screen.
- the gear position of the screen is changed from the gear position indicating the darker picture to the reference indicating the brighter picture
- the first brightness value of each pixel point becomes correspondingly larger
- the gear position of the bright picture becomes the gear position of the darker picture
- the first brightness value of each pixel point will become smaller accordingly.
- S102 Determine a first input grayscale value corresponding to the first brightness value based on a preset gamma correction lookup table.
- the gamma correction lookup table is a brightness value of the screen and an initial input grayscale of the screen under the specified gear position of the brightness adjustment. The value of the gamma correction relationship.
- a certain gray scale value is input to the pixel
- a certain brightness value is displayed correspondingly by applying different driving voltages and the like, thereby displaying the image normally on the screen.
- the screen is displayed, because of the sensitivity of the human eye or the photoelectric characteristics of the screen itself, there will be distortion between the image outputted by the screen and the input image, for example, the color difference between the screen display color and the input image is large. Or the brightness of the screen display is different from the original brightness of the input image.
- the grayscale value input of the screen can be changed by changing the voltage input by the screen, optionally By correcting the voltage input by the screen, the brightness value of the image displayed on the screen is equal to or linear with the brightness value of the actually input image.
- Gamma correction may be performed on the relationship between the output luminance value of the screen display and the input grayscale value of the screen, thereby adjusting the response curve between the screen input and output. To correct the deviation of the brightness of the image actually displayed on the screen.
- the gamma correction relationship between the brightness value displayed by any pixel of the screen and the input gray scale value may be continuous or discrete.
- the correspondence between the brightness value displayed by any pixel point and the input gray level value will follow the same response curve, that is, the Gamma curve.
- the gamma curve represents a correspondence relationship between the luminance value displayed by the pixel point and the input grayscale value under the gear position, thereby forming a gamma correction relationship between the luminance value and the input grayscale value.
- the abscissa of the Gamma curve can represent the grayscale value of the input
- the ordinate of the Gamma curve can represent the brightness value of the display.
- the corresponding input grayscale value can be found on the Gamma curve.
- the brightness value displayed by the pixel and the corresponding input gray level value are continuous and uninterrupted.
- the corresponding accurate input gray level value can be found.
- the grayscale value input on the screen panel is usually a discrete positive integer, so the correspondence between the brightness value of the screen pixel point and the input grayscale value is often not A continuous curve, but some discrete points on the Gamma curve. Therefore, under a certain brightness adjustment gear position, the correspondence between the brightness value displayed by the pixel point and the input gray scale value is represented by a set of discrete data.
- each luminance value and its corresponding input grayscale value can be characterized as a discrete point on the above Gamma curve, that is, a discrete grayscale value and a display luminance value corresponding to the grayscale value are formed.
- the two-dimensional coordinate points are all above the Gamma curve.
- the gray scale value can still be used as the abscissa of the Gamma curve, and the displayed brightness value is taken as the ordinate of the Gamma curve.
- the number of discrete points in the set of data may be the total number of grayscale values that can be displayed on the screen.
- the screen when the screen is 8-bit (8-bit) gray-scale input, the screen can display a grayscale value of 0-255. There are 256 integers in the interval. In this case, 256 sets of discrete data can be stored in the preset correspondence, corresponding to 256 discrete points on the Gamma curve, and the screen is 10 bits (10bit) grayscale input, the screen
- the grayscale value that can be displayed is 1,204 of any integer within 0-1023.
- 1024 sets of discrete data can be stored in the preset gamma correction relationship, corresponding to 1024 discrete points on the Gamma curve.
- the data format in the preset gamma correction relationship may be (Code0, Lum), where Code0 is the grayscale value of the pixel input, corresponding to the abscissa of the Gamma curve, and Lum is the grayscale value of the pixel input.
- the brightness value displayed when Code0 corresponds to the ordinate of the Gamma curve.
- the grayscale value of the input corresponding to the known luminance value can be obtained according to the gamma correction relationship, or the corresponding display luminance value or the like can be obtained according to the known grayscale value.
- the number of grayscale values becomes a finite value, and thus the luminance value displayed under a certain brightness adjusted gear position and the input grayscale value are
- the number of correspondences between the two will also be limited, for example, 256 (corresponding to 8 bits) or 1024 (corresponding to 10 bits), etc.; thus, the current hardware can be used for a limited number of integer grayscale values and corresponding display luminance values.
- the correspondence between the two is stored and expressed, and the correspondence between the input grayscale value and the display luminance value can be accurately represented, and hardware resources such as memory space or processing capability can be saved.
- the preset gamma correction relationship includes only a part of the grayscale values of the grayscale values that the screen can display and the corresponding luminance values, for example, for an 8-bit screen, in a preset gamma correction relationship.
- the gamma correction relationship may be included in only 30 sets of gray scale values and display brightness values, and other gray scale values and corresponding brightness values other than the 30 sets may utilize the existing brightness values and gray scale values in the set of data.
- the gamma correction relationship is obtained, and specifically, the remaining part of the Gamma correction relationship can be obtained by interpolation calculation or the like.
- a Gamma correction lookup table may be utilized to determine a Gamma correction relationship between the screen output brightness and the input grayscale value.
- the gamma correction lookup table usually stores the initial input grayscale value of the screen and the corresponding screen luminance value, which is actually a mapping table between the screen initial input grayscale value and the corresponding screen luminance value, when a specific screen luminance value needs to be acquired.
- the corresponding input grayscale value, or the brightness value that can be output by acquiring a specific grayscale value, can be searched and obtained through the Gamma correction lookup table.
- the Gamma correction lookup table can usually be obtained by taking the form of on-site measurement on the production line. Specifically, in the measuring station of the production line, an external device such as an image generator is used to input a certain preset input gray scale value, and the sampling device is used to sample and measure the brightness value corresponding to the screen, and so on.
- Different input gray scale values and corresponding display brightness values are used to establish a one-to-one correspondence between the input gray scale values and the display brightness values one by one, and the obtained correspondence relationship is written into a register or a memory, and Arranged in a list in a certain order, that is, a Gamma correction lookup table.
- a Gamma correction lookup table When performing gamma correction, the desired input grayscale value or display luminance value can be obtained in the gamma correction lookup table.
- the grayscale values input by the screen have different grayscale levels.
- the input grayscale value may be any value from 0 to 255.
- each different grayscale input corresponds to one luminance. output value.
- the gamma correction lookup table can store the relationship between all the input grayscale values of the screen and the corresponding output luminance values.
- the grayscale value of the screen may be a different number of digits, such as 8 bits (8 bits) or 10 bits (10 bits), etc.
- the gray scale value of the pixel point input may be any integer within 0-1023.
- the gamma correction lookup table can store the gamma correction relationship between different input grayscale values and output luminance values, thereby finding the grayscale input of the pixel points according to different brightness output values, and further performing the Adjustment of parameters such as the voltage of the pixel.
- the gamma correction lookup table generally only includes a gamma correction between the initial input grayscale value of the screen and the brightness value displayed on the screen under the screen of one brightness adjustment. relationship.
- the gamma correction lookup table may be a gamma correction relationship of the brightness value of the screen and the initial input grayscale value of the screen under the specified gear position of the brightness adjustment.
- the brightness adjustment gear position mainly means that when the screen is in the gear position, the initial input gray scale value of the screen has a certain correspondence with the pre-specified brightness value, so that the screen as a whole is maintained within a certain brightness level range.
- the same initial input gray level value corresponding to the pixel point will display different brightness values under the new brightness adjustment gear position. This allows the screen to display the same picture in different brightness states.
- the gamma correction lookup table may include two sets of data, and each of the first set of data has a corresponding data in the second set of data, so that the first set of data is a screen.
- the grayscale value entered, and the second set of data is the corresponding display brightness value
- the corresponding display brightness value can be found according to the input grayscale value through the Gamma correction lookup table, or the corresponding input can be found according to the display brightness value.
- Grayscale value
- a uniform solid image is an image with the same pixel value for all pixels, and each pixel in the screen displays the same brightness value. That is, the brightness displayed by each pixel is the same; correspondingly, the initial input grayscale value of each pixel is the same.
- different pixels in the screen when a non-uniform image is displayed on the screen, different pixels in the screen usually have different grayscale value inputs, thereby presenting a light and dark texture of the image. At this time, different grayscales The values will also display different brightness values, so that different pixels on the screen have different brightness.
- the non-uniform image is an image with more than one color. Alternatively, the non-uniform image may have Rich texture features.
- a uniform solid color image is displayed on the screen, for example, a uniform pure white image
- the input gray scale value corresponding to the brightness value of the screen in the specified gear position of the brightness adjustment is determined based on the preset gamma gamma correction lookup table.
- the general process is explained. Exemplarily, it is assumed that the brightness value currently displayed on the screen is the brightness value corresponding to the maximum grayscale value that can be displayed on the screen.
- the screen display is uniform, all the pixels on the screen will input the same grayscale value, and
- the brightness value displayed by each pixel on the screen is also equal to the brightness value corresponding to the maximum gray level value, and the brightness bar on the screen for adjusting the brightness of the screen is located at the maximum scale (for example, may be located at the far right of the brightness bar). Therefore, in the gamma correction lookup table, the corresponding grayscale value input is determined when the pixel point displays the brightness value, and the grayscale value found is used as the grayscale value actually input by each pixel of the screen, that is, each pixel on the screen is displayed.
- the brightness value displayed by each pixel of the screen is ideally equal; and the ideal output is determined in the Gamma correction lookup table.
- the luminance value corresponds to an initial input grayscale value, and the grayscale value is used as an input of each pixel point, so that the actual luminance value displayed on the screen is equal to the luminance value in the ideal case.
- the grayscale value input of each pixel point can be adjusted by changing the voltage value for driving the illumination of each pixel of the screen, for example, the input voltage of the screen can be increased or decreased to increase or decrease.
- the grayscale value of the pixel input can be adjusted by changing the voltage value for driving the illumination of each pixel of the screen, for example, the input voltage of the screen can be increased or decreased to increase or decrease.
- the screen displayed on the screen can be prevented from appearing too dark, too bright, or uneven brightness.
- the corresponding grayscale value input is also different.
- the brightness that is desired to be displayed for each pixel in the screen is determined, and the grayscale value input corresponding to the desired displayed brightness value of each pixel is searched in the gamma correction lookup table, and the search is performed.
- the grayscale value input is used as the grayscale value of the actual input of the screen.
- the grayscale value of the screen input is the grayscale value found in the Gamma correction lookup table.
- the brightness value displayed by each pixel of the screen is the same as the brightness value of the input image, and the brightness value deviation does not occur, for example, the displayed picture appears too dark, too bright or bright. Uneven phenomenon.
- the current brightness value of the screen under the current gear position of the brightness adjustment and the previous brightness value of the previous gear position of the brightness adjustment generally need to meet certain preset conditions.
- the current brightness value corresponds to the same input gray level value as the previous brightness value.
- the brightness of the screen is changed to achieve a uniform transition effect.
- the ratio of the luminance value difference of the adjacent gears to the previous luminance value satisfies Web-Fechner Law.
- the luminance value difference is a difference between the current luminance value and the previous luminance value.
- the brightness of the screen can be changed within a certain brightness adjustment range.
- the brightness adjustment range is equally divided into several brightness adjustment points, each brightness adjustment point corresponds to an independent brightness value, and the screen adjustment will The brightness adjustment points are sequentially passed, and the brightness of the screen is sequentially displayed as the brightness values corresponding to the different brightness adjustment points.
- the gear position of the brightness adjustment of the screen is adjusted from the original brightness adjustment position, that is, the gear position before the brightness adjustment to the current gear position of the brightness adjustment, the corresponding correspondence of the screen under two different gear positions
- the brightness value of the same input gray scale value that is, the current brightness value of the current gear position and the previous brightness value of the previous gear position may be the brightness values of the adjacent two brightness adjustment points, so that if the screen is in two If the difference between the brightness values of the different brightness adjustment positions is too large, the difference between the brightness values will be too large when the screen is adjusted between the two adjacent brightness adjustment points, so that the brightness of the screen exhibits a jump effect. , seriously affecting the user's visual experience.
- the difference threshold of human eye perception changes with the amount of original stimulus. Therefore, in order to avoid the phenomenon of flickering of the screen during brightness adjustment, the amount of change in brightness between two adjacent brightness adjustment points needs to be reduced to such an extent that the human eye does not feel drastic changes, that is, the difference in brightness values is required, that is, The difference between the current brightness value and the previous brightness value and the previous brightness value of the screen in the previous gear of the brightness adjustment is less than a certain threshold. At this time, the magnitude of the luminance value difference between the luminance values under the two different brightness adjustment gear positions of the screen changes with the magnitude of the luminance value as the same grayscale value corresponding to the pre-adjustment gear position.
- the brightness value of the screen When the brightness value of the screen is large, the brightness of the screen is brighter. Even if the brightness changes greatly, it is not easy for the naked eye to feel; when the screen brightness value is small, the screen is in a darker brightness. At this time, the naked eye It is sensitive to changes in brightness and therefore requires a small difference in luminance values.
- the current brightness value and the previous brightness value are generally the corresponding maximum brightness of the screen under the gear position of the brightness adjustment.
- the threshold may be 0.017, that is, when the screen is adjusted in brightness, the difference between the brightness values of the adjacent two brightness adjustment points and the screen is in the previous gear position of the brightness adjustment.
- the ratio between the previous brightness values is less than or equal to 0.017, which allows the screen to achieve a smoother brightness change process when making brightness adjustments, making it difficult for the naked eye to perceive a jump in the amount of change in unit brightness.
- the maximum brightness value corresponding to the gear position before the brightness adjustment is L
- the ratio ⁇ L/L ⁇ 0.017 between the brightness value difference ⁇ L and L, and the changed brightness value L' L- ⁇ L ⁇ 0.983.
- the difference in brightness value between each adjacent two brightness adjustment points should be
- the gear position before the brightness adjustment is less than or equal to 0.017 times the brightness value of the same preset gray level value, that is, L N - L N-1 ⁇ 0.017 * L N , so that the brightness change between each two brightness adjustment points It is not easy for the human eye to feel the degree of dramatic changes, so that the screen is adjusted from the initial brightness to the desired brightness. The human eye does not easily feel the dramatic change of the screen brightness, thus ensuring the user's visual experience.
- the brightness of each pixel on the screen changes accordingly.
- the maximum brightness value that can be displayed on the screen in the current position of the brightness adjustment is 0.983 times.
- the other brightness values that can be displayed on the screen are also 0.983 times the brightness value corresponding to the gear position before the brightness adjustment.
- the gamma correction relationship at a specified gear position of the brightness adjustment or the gamma correction look-up table may be used to determine the brightness of the pixel display.
- the maximum brightness value supported by the screen in the specified gear position can be greater than the maximum brightness value that the screen can display under the current gear position of the brightness adjustment.
- the designated gear position can be the maximum gear position supported by the brightness adjustment, so that the maximum brightness value supported by the screen under the specified gear position reflects the maximum brightness value that the screen can reach, regardless of the brightness of the screen.
- the adjusted gear position is adjusted to which gear position, and the corresponding brightness value of the pixel point in the gear position is included in the gamma correction relationship between the pixel display brightness value and the input gray scale value of the screen under the specified gear position.
- the same screen hardware is always used for display before and after the brightness adjustment, so the screen is displayed based on the inconsistency of the human eye on different brightness or the photoelectric characteristics of the screen itself.
- the non-linear variation between the brightness and the input brightness of the original image ie, the grayscale value of the pixel
- the Gamma curve after the brightness adjustment of the gear position change is not the same as the Gamma curve before the brightness adjustment.
- the solid line is the Gamma curve before the brightness adjustment of the gear position change.
- the dotted line is the Gamma curve after the brightness adjustment of the gear position is changed. It can be concluded from Fig. 2 that the same gray scale value (i.e., the x coordinate is the same) of the pixel point input will correspond to different brightness values (corresponding to different y coordinates) on different gamma curves. However, when theoretically inputting the same grayscale value, only the same luminance value can be displayed on the same screen hardware. Therefore, it is necessary to correct the Gamma correction relationship of the grayscale value and the displayed luminance value of each pixel input on the screen.
- the gamma correction relationship between the grayscale value input under the different brightness adjustment gear positions and the displayed brightness value always conforms to the gamma curve, that is, when the pixel points on the screen input the same initial grayscale value, the brightness adjustment is performed at different brightness adjustments.
- Different brightness values will be displayed under the gear position. Exemplarily, if the gray point value of the pixel input is 1023, the brightness value of the pixel displayed in the original brightness adjustment position is 500 nit (the corresponding y coordinate is 500 in the solid line), and the brightness adjustment of the screen is changed. After the gear position, the grayscale value of the same input in the adjusted gear position of the brightness adjustment needs to be adjusted accordingly, so that the input grayscale value and the display brightness value can also be adjusted under the adjusted benchmark.
- the gamma curve (corresponding to the dotted line in Fig. 2), in an optional case, the adjusted brightness value is 0.983 times the original brightness value, and the brightness value displayed when the input gray level value is 1023 is 491.5 nit. (The corresponding y coordinate in the dotted line is 491.5).
- the Gamma curve corresponding to the grayscale value input by the screen pixel point of the specified gear position of a certain brightness adjustment and the displayed brightness value may be measured, and other gear positions of the brightness adjustment are calculated based on the curve. Enter the gray level value and the Gamma curve corresponding to the display brightness value, which saves the production line measurement resources and hardware storage resources.
- the gear position corresponding to the maximum brightness value that can be displayed on the screen can be selected as the specified gear position for the brightness adjustment, and the grayscale value and the displayed brightness input to the screen in the brightness adjusted gear position. The value of the gamma correction relationship is measured to obtain a set of gamma curves.
- the gamma curve contains all the brightness values from the minimum brightness value to the maximum brightness value. After adjusting the gear position, the brightness value displayed on the screen will be less than the brightness adjustment. The brightness value under the specified gear position, so the brightness value displayed on the screen and the corresponding input gray level value can still be found in the gamma curve, so the gamma curve under the brightness adjusted gear position corresponding to the maximum brightness value can be pre-stored. In the memory or the register, after the change of the brightness adjusted gear position, the Gamma curve of the input gray scale value and the displayed brightness value under the other brightness adjusted gear positions is calculated based on the pre-stored Gamma curve, so as to realize other files. The correspondence between the input grayscale value under the bit and the displayed luminance value is corrected.
- the correspondence between the brightness value displayed on any pixel of the screen and the input gray level value may be continuous or discrete. Therefore, under a certain brightness adjustment position, the correspondence between the brightness value displayed by any pixel point and the input gray level value can follow the same curve, that is, the above gamma curve, and at this time, it can be utilized.
- the gamma curve represents a Gamma correction relationship between the brightness value displayed by the pixel point and the gray scale value of the output in the brightness adjusted gear position. At this time, regardless of which brightness is displayed on the pixel, the corresponding input grayscale value can be found on the Gamma curve.
- the gamma correction relationship between the brightness value of the screen pixel point and the input gray scale value is limited by hardware and other constraints and cannot be expressed by a continuous curve, it is also possible to adjust the brightness of the certain brightness position under the pixel.
- the gamma correction lookup table between the brightness value displayed by the point and the gray level value entered is represented by discrete data. Wherein, each luminance value and its corresponding input grayscale value can represent a discrete point on the above Gamma curve.
- the gamma correction lookup table may include a plurality of discrete grayscale values and a plurality of display luminance values, wherein the number of grayscale values is equal to the number of display luminance values, and the grayscale values are in one-to-one correspondence with the display luminance values, and are discrete.
- the number of grayscale values is equal to the total order of the grayscale values of the screen.
- the existing brightness value and the gray level value may be utilized, and the input gray level value corresponding to the brightness value may be obtained by means of interpolation calculation or the like.
- the Gamma correction lookup table also includes a plurality of discrete grayscale values and a plurality of display luminance values.
- the grayscale values and the display luminance values are equal and one-to-one correspondence, but the number of discrete grayscale values is smaller than the grayscale value of the screen.
- the remaining correspondence can be obtained by means of interpolation calculation or the like.
- the partial Gamma correction relationship included in the set of discrete data is usually discrete points arranged at equal intervals on the Gamma curve.
- FIG. 2 is still taken as an example for explanation.
- the solid line is the Gamma curve corresponding to the input brightness value and the display brightness value under the specified gear position of the brightness adjustment measured on the production line.
- the maximum brightness value that the screen can display is 500 nit
- the gear position corresponding to the brightness adjustment of 500 nit is selected as the specified gear position for brightness adjustment, and since the maximum brightness value of the screen corresponds to the input maximum gray level value, for example, the gray scale value 1023, the brightness adjustment is specified at this time.
- the Gamma curve under the gear position will satisfy the gamma correction relationship between the above gray scale value 1023 and the brightness value 500 nit.
- the maximum brightness value that the screen can display becomes 491.5 nit.
- the initial input gray scale value and the gamma correction relationship of the display brightness value should conform to the Gamma curve shown in the dotted line of FIG. 2, however The gamma curve shown by this dotted line does not actually exist (that is, there is no actual measurement and is not stored in the memory or register).
- the observation is available, and the brightness value after adjustment of the brightness adjustment is 491.5 nit in the solid line.
- the corresponding input grayscale value can be found in the representative gamma curve, so it can be found in the solid line how much the grayscale value of the display luminance value 491.5nit needs to be input. In the solid line of FIG.
- the input gray scale value corresponding to the display luminance value of 491.5 nit should be 1015, and the 1015 found as the gray input value of the real input pixel of the initial input gray scale value of 1023, that is, 1023 Replace with 1015 to make the brightness value displayed under the adjusted gear position 491.5nit.
- the Gamma curve after the brightness adjustment of the gear position change is not actually measured, nor is it stored in the memory, but is obtained by a series of operations.
- the relationship is some discrete points on the Gamma curve.
- the initial input gray scale value of 1023 does not make the displayed brightness value 491.5nit, for example, the original input image source is a picture of a giant panda, the giant panda white hair area
- the input gray scale value is 1023.
- the white area of the initial input grayscale value of 1023 before the brightness adjustment shift position is displayed with a brightness value of 500 nit.
- the initial input gray scale value is 1023.
- the brightness value displayed in the white area should be changed to 491.5 nit.
- the white area with the initial input grayscale value of 1023 can not display the brightness of 491.5nit, and the gray level value of the output of 491.5nit needs to be input based on the Gamma curve corresponding to the solid line.
- 1015 is input as the actual grayscale value of the white region in the image source to the pixel of the screen, so that the luminance value of the region with the grayscale value of 1023 in the image source is 491.5 nit.
- 1023 is the initial input grayscale value of the white area in the image source, and 1015 is the grayscale value actually input by the white area.
- the initial input grayscale value is Code0
- the actual input gray is If the order value is Code1
- the grayscale value Code0 of the original input of the image source is the grayscale value Code0 of the original input of the image source
- the ordinate is the luminance value Lum of the display
- the correspondence between the initial input grayscale value and the displayed luminance value can be used.
- the gray level value Code1 that should be input when the brightness value is Lum is displayed, and Code1 is used as the gray value of the actual input of the pixel corresponding to Code0. That is, the first input gray scale value, the brightness value displayed by the pixel point is Lum, that is, the first brightness value corresponding to the first input gray scale value.
- the pixel point displays the first brightness value corresponding to the current gear position of the brightness adjustment
- the corresponding first gray level value of the input should be the actual pixel point.
- the grayscale value that should be entered which is Code1. Since different input gray scale values correspond to different driving voltages, different brightnesses are also displayed on the screen, and accordingly, the voltage used to drive the pixel is not the voltage value corresponding to Code0, but Code1 The corresponding voltage value.
- the brightness values displayed on each pixel of the screen are the same and are equal to the maximum brightness value of the screen in the specified gear position of the brightness adjustment, that is, the pixel point.
- the display brightness is 500 nit
- the gray level value of the corresponding input is the maximum gray level value 1023.
- the difference between the brightness value of the screen when the screen is changed from the specified gear position of the brightness adjustment to the current gear position is a fixed value, for example, the fixed value can take the maximum brightness before the gear position change of the brightness adjustment.
- the maximum brightness value of the screen will change from 500nit to 491.5nit.
- the initial input grayscale value Code0 of the screen does not change, and the actual corresponding input grayscale value Code1 needs to be changed to other grayscale values to display the corresponding luminance value. .
- the gamma correction relationship may be a gamma correction lookup table.
- the gamma correction lookup table may be a continuous gamma curve or a partially discrete point located on the gamma curve, so when the screen is the current gear position of the brightness adjustment, in order to find each pixel point.
- the preset gamma correction lookup table may also be used to obtain the corresponding position of each pixel on the screen for the display brightness adjustment.
- the first input grayscale value required for the first luminance value may be used.
- the grayscale value can be used as the corresponding pixel on the screen for display in the current gear of the brightness adjustment.
- the first brightness value, and the actual input gray level value that is, the first input gray level value, and when displaying, replace the original gray level value of each pixel point in the source image with the actual gray level value,
- the screen display output of the screen under the current gear position of the brightness adjustment can be obtained.
- each pixel on the screen can be changed as the overall brightness of the screen changes.
- the new brightness value is displayed so that the screen displays the normal picture image at the new overall brightness.
- the input gray scale value corresponding to the pixel point when the new brightness value is displayed may be found based on the previously preset gamma correction lookup table, and the input gray scale value is used to replace the screen.
- the initial grayscale value of the source image is used to achieve a change in the overall brightness of the image while maintaining features such as texture and pattern of the source image.
- the same gamma correction lookup table used for the gamma correction process is always used.
- the corresponding gamma correction lookup table is retrieved for comparison with the gamma correction process.
- the method for controlling the brightness of the screen in this embodiment can significantly reduce the hardware storage space, thereby reducing the manufacturing cost.
- the method of the screen brightness in this embodiment is adjusted to which brightness the screen is adjusted to.
- the adjusted gear position can be calculated by the preset Gamma correction look-up table to obtain the corresponding input, thus having higher correction precision.
- the method for controlling the brightness of the screen includes first determining a brightness value corresponding to the current gear position of the brightness adjustment; and determining an input gray level value corresponding to the brightness value based on the preset gamma gamma correction lookup table, Gamma
- the calibration lookup table is a gamma correction relationship of the brightness value of the screen and the initial input grayscale value of the screen under the specified gear position of the brightness adjustment; finally, the brightness of the screen is controlled according to the input grayscale value.
- the correspondence between the brightness value and the input gray level value of the other gears of the brightness adjustment can be obtained by the Gamma correction relationship between the brightness value and the input gray level value in the specified gear position of the brightness adjustment, which can be based on the Gamma under the specified gear position.
- Correction relationship Gamma correction for the brightness of the screen display under other gear positions of brightness adjustment without storing the gamma correction relationship under other gear positions, effectively saving hardware resources.
- each display brightness value of the screen pixel and the input gray level value is usually represented by a series of discrete points.
- the number of discrete points used to represent the correspondence between the display brightness value and the input gray level value may be 1024, and each discrete point corresponds to a gray scale value of 0.
- the Gamma correction lookup table can be used to indicate the correspondence between the display luminance value and the input grayscale value, that is, the Gamma correction lookup table can include a plurality of discrete grayscale values and a plurality of display luminance values, wherein the number of grayscale values It is equal to the number of display brightness values, and the gray scale value corresponds to the display brightness value one by one, and the number of discrete gray scale values is equal to the total order of the gray scale values of the screen.
- the first input grayscale value corresponding to the first brightness value corresponding to the current gear position of the brightness adjustment may be determined based on the preset gamma gamma correction lookup table.
- the gamma correction relationship represented by the discrete points is used to obtain a first input grayscale value corresponding to the first luminance value under the current gear of the brightness adjustment.
- the correspondence between the plurality of grayscale values and the plurality of display luminance values in the gamma correction lookup table may conform to a Gamma correction formula, wherein the display luminance value is an input of a Gamma correction formula, and the grayscale value is a Gamma correction formula.
- the step of determining the first input grayscale value corresponding to the first brightness value corresponding to the current gear position of the brightness adjustment based on the preset gamma correction lookup table may specifically include the following steps. :
- a plurality of grayscale values corresponding to the plurality of display luminance values are calculated based on the plurality of display luminance values and the gamma correction formula.
- the gamma correction formula corresponding to the gamma curve can be calculated to obtain the grayscale value corresponding to the display luminance value.
- the Gamma correction formula corresponding to the Gamma curve is usually a power function.
- the screen will have different brightness adjustment ranges; for example, the brightness value of the screen may be up to 500 nit or 800 nit, and thus the corresponding actual input gray scale is obtained by using the brightness value displayed by the pixel points.
- the brightness value of the screen may be up to 500 nit or 800 nit, and thus the corresponding actual input gray scale is obtained by using the brightness value displayed by the pixel points.
- the value generally can try to eliminate the dimension of each brightness value, for example, the maximum brightness value of the screen under the specified gear position of the brightness adjustment and the maximum brightness value of the screen in the current gear position of the brightness adjustment, and the corresponding brightness of the pixel point.
- the absolute value relationship between the adjusted first brightness value under the current gear position and the brightness value displayed under the specified gear position of the brightness adjustment is converted into a relative value relationship, thereby eliminating the influence of different dimensions and simplifying the calculation Process and improve the accuracy of the results.
- the brightness adjustment position of the screen can be adjusted for the brightness of any pixel in each pixel after adjusting from the specified gear position of the brightness adjustment to the current gear position of the brightness adjustment.
- the corresponding first brightness value under the current gear position is normalized.
- the normalized brightness value is a dimensionless value, so it can be directly substituted, so that the first brightness value of the pixel point in the current gear position of the brightness adjustment and the brightness value under the specified gear position are obtained. Relative proportional relationship.
- the normalized brightness value may be obtained according to formula (1).
- F 2 is a first brightness value corresponding to the current gear position after the normalized brightness adjustment
- F 1 is a corresponding brightness value under the specified gear position of the normalized brightness adjustment
- B 2 For the corresponding maximum brightness value of the screen under the current gear position of the brightness adjustment, B 1 is the corresponding maximum brightness value of the screen under the specified gear position of the brightness adjustment.
- the normalized brightness value of the specified gear position of the brightness adjustment can usually be reduced to a dimensionless pure number for subsequent calculation.
- the screen can display a solid color image.
- the screen is in the specified gear position of the brightness adjustment, and the brightness value displayed on each pixel on the screen is the maximum brightness value of the screen under the specified gear position of the brightness adjustment.
- the maximum brightness value of the screen and the brightness value of each pixel is 500 nit
- the brightness value is normalized, and the normalized brightness adjustment is specified.
- the maximum brightness value of the screen under the current gear position of the brightness adjustment may be 491.5 nit, according to the above formula (1)
- the grayscale value corresponding to the first brightness value corresponding to the current gear position of the normalized brightness adjustment may be determined as the first input gray level corresponding to any one of the pixel points based on the preset gamma correction lookup table. value.
- the first brightness value of any one of the pixels in the current gear position of the brightness adjustment is obtained, and normalized, thereby obtaining the current gear position of the brightness adjustment after the normalization process.
- the grayscale value corresponding to the dimensionless value is calculated according to the preset gamma correction lookup table, that is, when the screen is in the current gear position of the brightness adjustment, the pixel The point is the corresponding actual input gray level value that should be displayed corresponding to the corresponding first brightness value, that is, the first input gray level value.
- the input gray scale value in the Gamma correction lookup table is taken as the abscissa, and the corresponding output luminance value is taken as the ordinate, and a response curve between the input gray scale value and the output luminance value is obtained.
- Y (X+e) ⁇ , where Y is the output luminance value, X is the input gray scale value, e is the compensation coefficient, and ⁇ is the power value of the curve, also called the gamma value.
- This curve is the gamma curve corresponding to the gamma correction lookup table.
- the relationship between all grayscale values and luminance values in the preset gamma correction lookup table satisfies the power function relationship.
- the grayscale value corresponding to the second preset luminance value can be obtained by the power function relationship in the gamma correction lookup table.
- the curve corresponding to the Gamma correction lookup table is shown in Figure 2.
- the horizontal axis in FIG. 2 is the input grayscale value
- the vertical axis is the output luminance value
- the gamma correction curve is shown by the solid line in FIG.
- the step of determining, according to the preset gamma correction lookup table, the first input grayscale value corresponding to the first luminance value in the current gear position of the normalized brightness adjustment may be A first input grayscale value corresponding to the first luminance value in the current gear position of the normalized brightness adjustment is obtained according to formula (2).
- f is the first input grayscale value corresponding to the first luminance value in the current gear position of the normalized brightness adjustment
- ⁇ is the Gamma value in the preset Gamma correction lookup table
- N is a grayscale The total number of.
- f can be determined as the input grayscale value corresponding to any one of the pixel points.
- the Gamma value in the preset gamma correction lookup table is the gamma value of the response curve.
- the total number of gray scales indicates how many gray scale values exist from gray to white (corresponding to binary numbers from 0 to 1). For example, when the gray scale value of the input is 8 bits, there are 256 gray scales. The value is 0-255, where the grayscale value is 0 corresponding to black, the grayscale value is 255 when it corresponds to white; when the input grayscale value is 10bit, there are 1024 grayscale values, where the grayscale value is 0. Black, grayscale value corresponding to white when taken 1023.
- N 1024 gray scales
- the result obtained by the gamma correction formula may be a decimal, and the grayscale values stored in the gamma correction lookup table are integers.
- the step of determining the first input gray level value corresponding to the first brightness value based on the preset gamma correction lookup table may specifically The method includes: first obtaining a display brightness value of a first brightness value in a current gear position closest to the brightness adjustment in the gamma correction lookup table; and then using the gray level value corresponding to the display brightness value closest to the preset brightness value as the first brightness The first input grayscale value corresponding to the value.
- (1024-1) 1015.06
- the value contains a decimal
- the grayscale value of each discrete point is Integer, so the result is not included in the default gamma correction lookup table.
- the integer closest to the calculation result may be taken as the corresponding grayscale value
- the display luminance corresponding to the point having the grayscale value may be approximated as the corresponding luminance value in the current gear of the brightness adjustment.
- the integer 1015 closest to the f value can be taken, which is the first input gray corresponding to the first brightness value in the current gear position after the normalized brightness adjustment.
- the order value, and the point representing the gray level value 1015 among all the discrete points, approximates the first brightness value under the current gear position of the brightness adjustment.
- the grayscale value result obtained by the discrete points is obtained. It is closer to the input grayscale value required for the brightness value under the current gear position of the actual display brightness adjustment.
- the calculated gray scale value 1015 and the first input gray scale value 1015.06 of the first brightness value under the current gear position of the actual display brightness adjustment have only a small error (0.06), That is, less than an integer grayscale value, and when the preset gamma correction lookup table has a large number of grayscale values (for example, a 10-bit screen has 1024 different grayscale values), the adjacent two grayscale values correspond to the display. There is only a small difference between the luminance values, and thus it is possible to more accurately represent the correspondence between the input grayscale value and the display luminance value while saving hardware resources such as memory space or processing capability.
- the screen is displayed under the specified gear position of the brightness adjustment.
- the maximum brightness value of the screen is 500 nit.
- the input gray scale value corresponding to the pixel point with the brightness value of 500 nit is 1023, and the input gray scale value corresponding to the other brightness value of the pixel point in the gear position can be obtained according to the Gamma curve under the gear position, exemplary.
- the specified gear position of the brightness adjustment of the screen is the maximum brightness value corresponding to the gear position of 500 nit
- the corresponding Gamma curve may be a Gamma curve as shown by the solid line in FIG. 2 .
- the ordinate of the point b on the gamma curve is the brightness value F1 of the specified gear position of the brightness adjustment of a certain pixel point, and is assumed to be the same as the maximum brightness value of the screen under the specified gear position of the brightness adjustment. It is 500 nit, and the abscissa of point a is the gray scale value corresponding to the luminance value F1 of the pixel at the specified gear position of the brightness adjustment, which is easily understood as 1023, as indicated by the arrow 1.
- the maximum brightness value is adjusted from 500 nit under the specified gear position of the brightness adjustment to 491.5 under the current gear position of the brightness adjustment.
- the Gamma curve corresponding to the screen at this time may be a Gamma curve indicated by a broken line; it should be understood that when the position of the brightness adjustment of the screen is changed, the Gamma curve corresponding to the pixel value of the pixel input gray scale value and the displayed brightness value is also Will change, that is, different benchmarks correspond to different Gamma curves. In the embodiment of the present application, there is only one set of gamma curves.
- the gamma curve of other reference brightness is obtained based on the unique set of gamma curves, and each corresponding gear position is obtained.
- the brightness value of the pixel also changes, and becomes the brightness value F2 under the current gear position of the brightness adjustment, as indicated by an arrow 2 in FIG.
- the brightness value F2 under the current gear position of the brightness adjustment is the same as the maximum brightness value of the screen under the current gear position of the brightness adjustment, both being 491.5 nit.
- the screen adjusts the current gear position of the brightness adjustment, its maximum brightness value becomes 491.5nit, and the corresponding brightness value is 491.5nit when the input gray level value is 1023.
- the maximum brightness value is 491.5nit.
- the gamma curve corresponding to the bit does not actually exist, so the specified gear position based on the brightness adjustment, that is, the gamma curve corresponding to the maximum brightness value of 500 nit, that is, the solid line obtained in FIG. 2 is displayed as 491.5 nit.
- the corresponding input grayscale value should be actually, and replace the initial input grayscale value of the source image on the screen with the actual input grayscale value, so that the pixel of the screen is normal under the current gear of the brightness adjustment. Brightness display.
- the brightness value F2 in the current gear position of the current brightness adjustment needs to be adjusted in the original screen brightness.
- the corresponding point on the gamma correction curve under the bit that is, the point a in the figure, as shown by the arrow 3.
- the ordinate of the point a is the brightness value F2 under the current gear position of the brightness adjustment, and the maximum brightness value of the screen under the current gear position of the brightness adjustment is 491.5 nit, and the abscissa of the point a is
- the pixel point corresponds to the grayscale value f when the brightness value under the current gear position of the brightness adjustment is displayed, so that the abscissa of the point a can be obtained by the position of the point a on the gamma correction curve, for example, 1015. That is, the pixel point displays the grayscale value f corresponding to the brightness value under the current gear position of the brightness adjustment, as indicated by the arrow 4.
- 1015 can be used as the actual input grayscale value when a pixel is displayed at 491.5 nit.
- the maximum brightness value of the screen is 491.5 brightness adjustment
- the other pixel points on the screen are the first brightness levels corresponding to the first brightness values respectively displayed in the current gear position of the brightness adjustment. Values can also be determined in the same way.
- the grayscale value of each pixel of the screen usually has a range, that is, it will be less than or equal to a maximum grayscale value, so that the points on the curve will be located on the horizontal axis with the maximum grayscale value max.
- the maximum grayscale value is usually the grayscale value entered when the screen displays a full white screen.
- the correspondence between the input grayscale value of the screen and the displayed luminance value is always consistent with the gamma curve, and the grayscale of the screen display brightness is prevented during the adjustment process. Color shift.
- the method only needs a set of discrete values to represent the correspondence between the input gray scale value and the display brightness value, and based on the set of discrete values, the screen is determined to display the brightness after the brightness adjustment of the gear position is changed.
- the actual input gray scale value should save the storage space and reduce the hardware cost; and because the discrete values of the group include all the integer gray scale values and the corresponding relationship between the display brightness values, the determined input gray
- the accuracy of the order value is higher, and the accuracy of the screen brightness adjustment is also higher.
- a preset gamma correction lookup table usually stores a limited number of discrete values, for example, only the correspondence between 30 typical input grayscale values and the displayed luminance values can be measured.
- the preset correspondence is 30 sets of discrete points, and the 30 sets of discrete points are all located on the same gamma curve.
- the preset correspondence may be referred to as a gamma correction lookup table.
- the 30 sets of discrete points can be equally spaced on the Gamma curve.
- the gamma correction lookup table stores a plurality of grayscale values and corresponding display luminance values, the number of grayscale values is less than the total number of grayscale values that the screen can display.
- the brightness value displayed by each pixel on the screen under the current gear position of the brightness adjustment may not be stored in the current gear position.
- the step S102 of the method for controlling the screen brightness of the first embodiment is executed, that is, when the input gray scale value corresponding to the brightness value of the current gear position of the brightness adjustment is determined based on the preset gamma correction lookup table, it may also be adopted.
- the linear interpolation method performs the calculation of the grayscale value.
- FIG. 3 is a schematic flowchart of determining a first input grayscale value corresponding to a first luminance value in a current gear position of a brightness adjustment according to an embodiment of the present application.
- a step of determining an input grayscale value corresponding to a luminance value of a current gear position of the brightness adjustment is determined according to a preset gamma correction lookup table, specifically The steps can be included:
- the interpolation method obtains a grayscale value approximate to the first input grayscale value corresponding to the first luminance value in the current gear position of the brightness adjustment, and uses the approximate grayscale value as the actual input grayscale value of the screen, so that the screen is A normal brightness display at the current gear position of the brightness adjustment can be achieved.
- a known correspondence between a plurality of sets of suitable luminance values and grayscale values may be selected in the gamma correction lookup table.
- a correspondence between two sets of output luminance values and input grayscale values may be selected. Linear interpolation calculations are performed based on these correspondences.
- two display brightness values directly adjacent to the first brightness value under the current gear position of the brightness adjustment may be selected. Since the two display brightness values and the first brightness value under the current gear position of the brightness adjustment are directly adjacent, the first brightness value under the current gear position of the brightness adjustment is located between the two display brightness values, and the two The display brightness value is a brightness value adjacent to the first brightness value in the current gear position of the brightness adjustment in the Gamma correction lookup table.
- an approximate arc in the Gamma curve can be established according to the two display brightness values and the corresponding gray level values.
- the linear interpolation equation of the segment is, for example, a straight line equation.
- the linear equation is a one-dimensional equation, and the number of variables and dependent variables is only one.
- the line equation can also approximate the relationship between the first brightness value under the current gear position and the corresponding first input gray level value, which can be used as linear interpolation.
- the equation is used, for example, when the screen is adjusted from the specified gear position to the current gear position of the brightness adjustment, the linear interpolation equation can be established according to the two adjacent display brightness values and the corresponding gray level values.
- one of the luminance value and the grayscale value may be used as a variable of the equation, and the other as a dependent variable of the equation, thereby including the maximum luminance value of the screen under the specified gear position of the brightness adjustment and the corresponding grayscale value.
- a plurality of corresponding correspondences are substituted into the linear interpolation equation, thereby deriving a specific expression of the linear interpolation equation.
- the maximum brightness value of the screen under the specified gear position is one of two directly adjacent display brightness values
- the maximum brightness value of the screen under the specified gear position and the corresponding gray level value may be used as the first group.
- FIG. 4 is a schematic diagram of a Gamma curve corresponding to a Gamma correction lookup table in a method for controlling screen brightness according to an embodiment of the present application. As shown in FIG.
- point B Since the first luminance value of the screen pixel at the current gear of the brightness adjustment is between two directly adjacent display luminance values, point B is also located between point A and point C. Thus, if a line is made through points A and C, then point B is also approximately on the line, so that the equation expression of the line can be obtained from the coordinates of point A and point C, and it is used as a linear interpolation equation. The point coordinates are obtained.
- Y 1 is the maximum brightness value of the screen under the specified gear position of the brightness adjustment
- X 1 is the gray level value corresponding to the maximum brightness value of the screen in the specified gear position of the brightness adjustment
- Y 2 is the brightness value of the C point
- X 2 is the gray scale value corresponding to point C.
- the linear interpolation equation is a linear equation expression
- a and b After obtaining the specific values of a and b in the previous step, let a denote the slope of the straight line represented by the linear interpolation equation, and b be the intercept of the straight line represented by the linear interpolation equation on the vertical axis, and thus The actual values of a and b establish a linear interpolation equation.
- the straight line represented by the linear interpolation equation approximates the arc between the A and C points of the Gamma curve.
- the first luminance value of the current position of the brightness adjustment of any one of the pixels may be used as a variable.
- the obtained equation dependent variable can be approximately equal to the first input grayscale value corresponding to the first brightness value of the pixel point in the current gear position of the display brightness adjustment, as in step S303. Show.
- the first input grayscale value that should be input for each pixel point when the current gear position of the screen is adjusted for brightness is obtained.
- a linear interpolation formula can also be established according to other linear interpolation algorithms, and a specific expression of the linear interpolation formula is determined by using a relationship between the input gray scale value and the displayed luminance value in the preset gamma correction lookup table, and the linear interpolation is used.
- the formula obtains the first input grayscale value corresponding to the first brightness value in the current gear position of the brightness adjustment, and corresponds to the first brightness value of each pixel point in the current gear position of the display brightness adjustment.
- the first input grayscale value is obtained by performing the above processing on each pixel on the screen, the first input grayscale value that should be input for each pixel point when the current gear position of the screen is adjusted for brightness.
- the input gray scale value of the screen and the displayed brightness value are always consistent with the gamma curve, and the gray scale color shift of the screen display brightness is prevented during the adjustment process.
- the brightness is flickering; at the same time, the method only needs to specify the gamma correction relationship under the gear position, and then the screen can be determined that the screen is gamma corrected for the brightness of the screen display in other gear positions of the brightness adjustment, and the gamma correction relationship under other gear positions is not needed, saving
- the storage space reduces the hardware cost; and the preset gamma correction lookup table used includes only a correspondence between a limited number of input grayscale values and display luminance values, and the others are included in the preset gamma correction lookup table. The corresponding relationship in the middle is obtained by a simple linear interpolation operation. While achieving high gray-scale value input precision, the operation speed is faster and the processor overhead is small.
- the screen is a screen such as AMOLED
- the luminescence characteristics of the individual pixel points may change due to process reasons (for example, vapor deposition uniformity of the entire surface and film thickness control, etc.).
- the driving voltages of the individual pixels are the same, the magnitude of the current flowing through them will be different, which will cause uneven brightness (Mura) when individual pixels on the screen are displayed.
- the screen In order to correct the Mura phenomenon of the screen, the screen also needs to compensate for the Mura phenomenon, that is, the Demura step. Therefore, on the basis of the foregoing embodiment, a step for eliminating the Mura phenomenon can be added to the method of controlling the screen brightness.
- FIG. 5 is a schematic flowchart diagram of another method for controlling screen brightness according to an embodiment of the present application.
- the screen brightness control method provided by this embodiment is provided.
- the following steps may be included:
- the pixel points of the screen may be gamma-compensated by using a preset gamma correction lookup table to obtain a brightness value displayed by each pixel point in the specified gear position.
- the input gray scale value corresponding to each pixel point can correct the deviation of the brightness of the image actually displayed on the screen.
- the screen is a uniform color picture display.
- the second input grayscale value corresponding to the maximum brightness value displayed by the pixel point when the screen is in the initial brightness adjustment position is determined.
- the input grayscale value of each pixel point can be determined as the second input grayscale value, so that the pixel of the screen should display the second corresponding to the second input grayscale value.
- the brightness value, so that the display brightness of each pixel can be controlled according to the second input gray level value, so that the screen is displayed.
- the screen includes a Mura region, that is, each pixel includes a pixel point whose luminance value is not uniform, and thus Demura adjustment is required to keep all the pixels to maintain uniform brightness when displaying the screen.
- the Demura step is required to allow the input of the same grayscale value of each pixel on the screen to output the same brightness value. Since the mura compensation is based on the gamma-corrected luminance data, the compensation step needs to perform gamma correction on the initial pixel of the screen according to the preset gamma correction lookup table, so that the screen outputs the luminance value and the input grayscale value. After following the steps of following the gamma curve.
- the pixel value is usually obtained when the specified gray scale value is input, and the actual brightness value corresponding to the second input gray scale value is displayed, or the pixel point is outputting a certain brightness value, and exemplary.
- the pixel point corresponds to the input gray level value, and compensates according to the relationship between the gray level value and the brightness value of the pixel point, so that each pixel point on the screen The input and output characteristics are consistent.
- the compensation data may include a coordinate of the pixel point to be compensated in the screen and a corresponding relationship of the grayscale values before and after the compensation when the pixel point displays the uniform brightness.
- the brightness value of each pixel in the screen may be the maximum brightness value corresponding to the screen in the initial brightness adjustment position, that is, the screen is adjusted in the brightness.
- the input gray scale value of the pixel located in the mura area can be changed or replaced by the Mura compensation data, so that the pixel points in the mura area can be The pixels of other areas output the same display brightness value.
- the Mura phenomenon of the screen can be compensated, so that the pixels of the screen have uniform brightness.
- the first brightness value corresponding to the display of each pixel point for normal display in the current gear position of the brightness adjustment can be determined according to the current gear position adjusted by the brightness.
- S304 Determine a first input grayscale value corresponding to the first brightness value based on the preset gamma gamma correction lookup table.
- the gamma correction lookup table is a brightness value of the screen and an initial input of the screen under the specified gear position of the brightness adjustment. Gamma correction relationship for grayscale values.
- the brightness control of the screen when the brightness adjustment of the screen is adjusted from the specified position of the original brightness adjustment to the current position of the brightness adjustment, the brightness of each pixel on the screen also needs to change accordingly. Ensure the correct display of the image. In order to determine the display output of the screen for the screen at this time, it is necessary to re-determine the first brightness value under the current gear position of each pixel point display brightness adjustment according to the gamma curve characteristic between the screen input and output, each pixel point The first input grayscale value that should have.
- the preset gamma correction can also be used when the screen is in the current gear position of the brightness adjustment.
- the lookup table obtains a first input grayscale value that is actually input by each pixel on the screen to maintain a corresponding first brightness value under the current gear position of the brightness adjustment.
- the actual input grayscale value of each pixel of the screen is obtained by using the preset gamma correction lookup table, it can be obtained by formula calculation.
- the first input grayscale value can be used as the pixel point.
- the actual input and use the preset Gamma correction lookup table to achieve the correct display brightness output, so that the screen is adjusted to the current gear position of the brightness adjustment, to achieve the correct display of the picture.
- each initial pixel point on the screen needs to output the same second grayscale value, and then the mura compensation is used to make the brightness of each pixel on the screen be consistent. Finally, when the screen brightness is adjusted, the screen brightness is changed. The correct correspondence between the input grayscale value of the pixel and the output luminance value, so that the brightness of the image displayed on the screen is consistent with the brightness of the image to be displayed.
- the brightness of the screen is corrected based on the same preset gamma correction look-up table before and after the step of mura compensation, so that the screen brightness can be controlled while maintaining the uniformity of the screen display by using the mura compensation step, while the screen is
- the input grayscale value has a correct correspondence with the output luminance value, so that the screen image shows normal brightness and brightness changes. This is done separately from the existing mura compensation step and the gamma correction step, and the mura compensation step is performed by the optical manufacturer, and the gamma correction step is mainly performed by the driver chip manufacturer to control the screen brightness compared to the same preset.
- the Gamma correction lookup table operates so that it can be integrated into the same hardware architecture for better integration.
- the gamma correction is performed on the screen including the Mura area before the Demura is performed on the screen, and the gamma correction is performed on the screen subjected to the Demura operation during the brightness adjustment, thereby ensuring the uniformity of the screen and the screen.
- the correct brightness display is always achieved during the brightness adjustment process.
- Demura's previous gamma correction is based on the same gamma correction look-up table during the brightness adjustment process, which can achieve better hardware integration and save storage space. Reduced hardware costs and better hardware integration.
- the embodiment of the present application further provides a screen brightness control device to perform the screen brightness control method in the foregoing embodiment.
- the screen brightness control apparatus 100 provided in this embodiment may include:
- the brightness determining module 61 is configured to determine a first brightness value corresponding to the screen under the current gear position of the brightness adjustment.
- the first gamma correction module 62 is configured to determine a first input grayscale value corresponding to the first brightness value based on the preset gamma correction lookup table, where the gamma correction lookup table is the brightness value of the screen under the specified gear position of the brightness adjustment Gamma correction relationship with the initial input grayscale value of the screen.
- the brightness adjustment module 63 is configured to control a display brightness value of the screen according to the first input grayscale value.
- the brightness determining module 61 the first gamma correction module 62, and the brightness adjusting module 63, please refer to the description of the method side steps S101 to S103.
- the gamma correction lookup table may include a plurality of discrete grayscale values and a plurality of display luminance values, the number of grayscale values is equal to the number of display luminance values, and the grayscale values are in one-to-one correspondence with the display luminance values, and the discrete grays The number of order values is equal to the total order of the grayscale values of the screen.
- the gamma correction lookup table may also include a plurality of discrete grayscale values and a plurality of display luminance values, the number of grayscale values being equal to the number of display luminance values, and the grayscale values corresponding to the display luminance values in one-to-one correspondence, discrete grayscales The number of values is less than the total order of the grayscale values of the screen.
- the two-dimensional coordinate points formed by the display brightness values corresponding to any of the gray scale values and the discrete gray scale values are located on a Gamma curve, wherein the abscissa of the Gamma curve represents the gray scale value, The ordinate of the Gamma curve represents the display brightness value.
- the preset condition is met between the current brightness value of the screen under the current gear position and the previous brightness value of the previous gear position of the brightness adjustment, wherein the current brightness value corresponds to the same input gray level value as the previous brightness value,
- the condition be that the ratio of the difference between the brightness value of the adjacent gear position and the previous brightness value satisfies Weber's law.
- the luminance value difference is a difference between the current luminance value and the previous luminance value.
- the maximum brightness value supported by the screen in the specified gear position is greater than the maximum brightness value supported by the screen in the current gear position of the brightness adjustment.
- the specified gear position is the maximum gear position supported when the screen brightness is adjusted.
- the first gamma module 62 is specifically configured to first determine that the brightness value of the screen display is an initial input grayscale value corresponding to the screen when the first brightness value corresponding to the current gear position of the brightness adjustment is adjusted; and then use the Gamma-based correction lookup table.
- the determined input grayscale value replaces the initial input grayscale value as the first input grayscale value corresponding to the first luminance value.
- the correspondence between the plurality of grayscale values and the plurality of display luminance values in the gamma correction lookup table conforms to a Gamma correction formula, wherein the display luminance value is an input of a Gamma correction formula, and the grayscale value is an output of a Gamma correction formula.
- the control device may further include: a gamma correction lookup table acquisition module 66, configured to calculate a plurality of grayscale values corresponding to the plurality of display luminance values in one-to-one based on the plurality of display luminance values and the correction formula.
- the first gamma correction module 62 is further configured to obtain the current gear position closest to the brightness adjustment in the gamma correction lookup table. a display brightness value of the first first brightness value; and a gray level value corresponding to the display brightness value of the first brightness value in the current gear position closest to the brightness adjustment as the first input gray level value corresponding to the first brightness value .
- the first gamma correction module 62 is specifically configured to determine the current gear position and the brightness adjustment based on the gamma correction lookup table.
- the first first brightness value is directly adjacent to the two display brightness values; and then the linear interpolation equation is established based on the directly adjacent two display brightness values and their corresponding gray level values; finally, the current file is adjusted according to the linear interpolation equation and the brightness
- the first luminance value under the bit acquires a first input grayscale value corresponding to the first luminance value.
- the uniformity of the screen display is ensured.
- the initial preset brightness values of the respective pixels on the screen are the second brightness values.
- the obtaining module 62 is further configured to determine, according to the preset gamma correction lookup table, a corresponding second input grayscale value when the corresponding luminance value is the second luminance value in the initial luminance adjusted gear position; and then the second Enter the grayscale value as the grayscale value for each pixel input of the screen.
- FIG. 7 another screen brightness control device 200 is provided in FIG. 7, similar to the screen brightness control device 100 in FIG. 7, and the screen brightness control device 200 also includes the above respective modules.
- the screen brightness control device 200 may further include:
- the second gamma correction module 64 is configured to determine a second input grayscale value corresponding to the second brightness value based on the preset gamma correction lookup table before the Demura is performed on the screen.
- the second gamma correction module 64 is further configured to use the second input grayscale value as an input grayscale value of each pixel of the screen.
- the apparatus further includes a Mura correction module 65 for performing Demura on the screen.
- a Mura correction module 65 for performing Demura on the screen.
- the specific functions of the second gamma correction module 64 and the Mura correction module 65 can be seen in the description of the method side steps S301 to S302 and the like.
- each module of the apparatus shown in FIG. 6 to FIG. 7 is only a division of a logical function, and may be integrated into one physical entity or physically separated in whole or part.
- these modules can all be implemented by software in the form of processing component calls; or all of them can be realized in the form of hardware; some modules can be realized by software in the form of processing component calls, and some modules are realized by hardware.
- the first gamma correction module 62 may be a separately set processing element, or may be integrated in one of the chips of the device, or may be stored in the memory of the device in the form of a program, by some A processing component invokes and performs the functions of the first gamma correction module 62.
- the implementation of other modules is similar.
- each step of the above method or each of the above units may be completed by an integrated logic circuit of hardware in the processor element or an instruction in a form of software.
- the above modules may be one or more integrated circuits configured to implement the above methods, such as one or more application-specific integrated circuits (ASICs), or one or more digital signal processors (digital) Signal processor, DSP), or one or more field-programmable gate arrays (FPGAs).
- ASICs application-specific integrated circuits
- DSP digital signal processors
- FPGAs field-programmable gate arrays
- the processing component can be a general purpose processor, such as a central processing unit (CPU) or other processor that can invoke the program.
- these modules can be integrated and implemented in the form of a system-on-a-chip (SOC).
- SOC system-on-a-chip
- FIG. 8 is a schematic structural diagram of hardware of a terminal device according to an embodiment of the present application.
- the terminal device 300 includes a processor 71, a first gamma selector 72, a first gamma correction controller 73, and a screen 74.
- the processor 71 is configured to determine a corresponding first brightness value of the screen 74 under the current gear position of the brightness adjustment.
- the first gamma selector 72 is configured to determine a first input grayscale value corresponding to the first brightness value based on the preset gamma correction lookup table, where the gamma correction lookup table is the brightness value of the screen under the specified gear position of the brightness adjustment The gamma correction relationship of the initial input grayscale value of the screen.
- the first gamma correction controller 73 is configured to control the display brightness value of the screen according to the first input grayscale value.
- the terminal device in this embodiment can perform the method for controlling the brightness of the screen in the foregoing embodiment.
- the specific processes and steps of the method for controlling the brightness of the screen have been described in detail in the foregoing embodiments, and details are not described herein again.
- the first gamma selector 72 can be used to determine the first input grayscale value corresponding to the first brightness value according to the preset gamma correction lookup table, and then The first gamma correction controller 73 controls the display luminance value of the screen 74 based on the first input grayscale value.
- the specific functions and functions performed by the first gamma selector 72 are similar to those of the first gamma correction module 62 in the foregoing embodiment, and the specific functions and functions performed by the first gamma correction controller 73 are similar to the foregoing embodiments.
- the function of the medium brightness adjustment module 63 will not be described here.
- the first gamma selector 72 may be integrated on the processor 71 or may be hardware logic or hardware circuits independent of the processor 71.
- the first gamma correction controller 73 can generally be hardware independent of the processor 71, such as a driver circuit or the like.
- the terminal device 300 may further include a memory 75 for storing a preset gamma correction lookup table.
- the screen 74 is usually composed of an organic light emitting display (OLED) or an active-matrix organic light emitting diode (AMOLED). Exemplarily, the screen 74 is used for the OLED screen.
- the first gamma correction controller in the terminal device can be obtained according to the first gamma selector.
- the gray scale value is input to generate a corresponding voltage for driving. When the screen is connected to different voltages, different brightnesses can be displayed, thereby displaying the display brightness value corresponding to the input gray scale value.
- the first gamma correction controller 73 may include a voltage generator and a brightness controller.
- the voltage generator can be used to generate a corresponding reference voltage according to the input grayscale value; and the brightness controller can be used to display the display brightness value corresponding to the input grayscale value based on the reference voltage control screen.
- the voltage generator 731 may be a digital to analog converter (DAC).
- the digital-to-analog converter is configured to convert the input grayscale value into an analog reference voltage value, so that the brightness controller 732 can control the display brightness value of the screen according to the reference voltage, so that the screen displays the corresponding display brightness value when the power is on.
- the digital-to-analog converter can change the input grayscale value to an actual reference voltage value after receiving the input grayscale value of the digital signal.
- the corresponding reference voltage value will also change, so that the screen can emit different brightness lights under different reference voltage values and current values to display the actual image.
- the communication between the data and the signal can be realized between the processor 71, the first gamma selector 72, the first gamma correction controller 73 and the memory 75 by means of a communication bus or other data path. Since the memory 75 and the processor 71, the first gamma selector 72, and the first gamma correction controller 73 are electrically connected, the preset gamma correction lookup table stored in the memory 75 can be transmitted to the first gamma selector.
- the input gray scale value that the pixel should have, and let the first gamma correction controller 73 The display luminance value or the like of each pixel of the screen 74 is controlled in accordance with the input grayscale value.
- the processor 71 is usually a control center of the terminal device, and can be directly connected to different hardware parts such as the memory 75 by using a communication bus, and executed by running or executing software programs and/or modules, and calling data stored in the memory.
- the processor 71 may be a Micro Control Unit (MCU), or a central processing unit (CPU), or a separate system-on-a-chip (SOC), or may be One or more integrated circuits configured to implement the above methods, such as: one or more application specific integrated circuits (ASICs), or one or more microprocessors (digital singnal processors, DSPs), or One or more field programmable gate arrays (FPGAs) and the like.
- MCU Micro Control Unit
- CPU central processing unit
- SOC separate system-on-a-chip
- ASICs application specific integrated circuits
- DSPs digital singnal processors
- FPGAs field programmable gate arrays
- the processor 71 may include one or more processing units; and different instructions and programs are separately executed by different processing units to perform different functions, respectively.
- the memory 75 can be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM), or other information that can store information and instructions.
- Type of dynamic storage device also can be electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc Storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or can be used to carry or store desired program code in the form of instructions or data structures and can be Any other medium accessed by the computer, but is not limited to this.
- Memory 74 may be present independently and coupled to processor 71 and first gamma selector 72 via a bus. The memory 75 can also be integrated with the processor 71.
- the memory 75 can also be used to store application code that executes the solution of the present application, and is controlled by the processor 71 for execution.
- the processor 71 is configured to execute the application code stored in the memory 75, thereby implementing the method for controlling the brightness of the screen provided by the above embodiment of the present application.
- the terminal device may also be used to perform a Demura step to compensate for pixel points whose luminance values are not uniform.
- FIG. 9 Another terminal device is provided in FIG. 9, similar to the terminal device in FIG. 8, and the terminal device 400 also includes the above-described processor 71, first gamma selector 72, first gamma correction controller 73, and screen 74.
- the terminal device 400 may further include: a second gamma selector 76 and a second gamma correction controller 77.
- the second gamma selector 76 is configured to determine a second input grayscale value corresponding to the second brightness value based on the preset gamma correction lookup table before the Demura is performed on the screen 74.
- the second gamma correction controller 77 is configured to control the display brightness value of each pixel of the screen according to the second input grayscale value.
- the functions and functions of the second gamma selector 76 and the second gamma correction controller 77 are the functions of the second gamma correction module in the foregoing embodiment, and details are not described herein again.
- the second gamma selector 76 may be integrated on the processor 71 or may be hardware independent of the processor 71.
- the second gamma correction controller 77 is typically hardware independent of the processor 71, such as a driver circuit or the like.
- the terminal device 400 needs to work in conjunction with other external devices to obtain mura compensation data.
- the external device typically includes sensing elements for sensing the actual brightness of the screen 75, and exemplary, may be a high magnification camera or the like.
- the corresponding brightness values of the pixels of the screen 75 under the initial gear position of the brightness adjustment are all the second brightness values.
- the second gamma selector 76 is preset according to the preset.
- the gamma correction lookup table determines a second grayscale value corresponding to the second luminance value, and the second gamma correction controller 77 controls the display luminance value of each pixel point using the second input grayscale value.
- the sensing element measures the actual brightness displayed by the screen 75
- the terminal device 400 can obtain the Mura compensation data according to the relationship between the actual brightness of the screen 75 and the input grayscale value, for example, a Mura compensation table, and according to The mura compensation table compensates for the brightness of each pixel in the screen 75, so that the brightness of the entire screen 75 can be kept uniform.
- the luminance value of each pixel in the screen 75 can be maintained as the second luminance value.
- the terminal device 400 may include a Mura correction controller 78 dedicated to obtaining the Mura compensation data and performing Mura compensation.
- the Mura correction controller 78 can be integrated with the processor 71, or it can be a separate hardware or circuit or the like.
- the second gamma correction controller 76 can also include a voltage generator and a brightness controller.
- the voltage generator can be used to generate a corresponding reference voltage according to the input grayscale value; and the brightness controller can be used to display the display brightness value corresponding to the input grayscale value based on the reference voltage control screen.
- the specific structure and function of the voltage generator and the brightness controller can be seen in the description in the foregoing embodiments, and details are not described herein again.
- the terminal device may further include an I/O subsystem for connecting the external device and the terminal device itself.
- the I/O subsystem can be used to implement data interaction with an external device, thereby implementing input and output of data collected by an external device, and controlling the working state of the external device.
- the terminal device further includes a Pulse Width Modulation (PWM) dimmer 79, and the PWM dimmer 79 can modulate the on/off of the internal transistor gate or the switching device such as the MOS transistor base.
- PWM Pulse Width Modulation
- a series of pulses of equal pulse width are generated and different equivalent analog outputs are achieved by varying the width or duty cycle of the pulses to adjust the output brightness of screen 75.
- the PWM dimmer 79 and the screen 75 are electrically connected, and the PWM dimmer 79 can receive the digital signal from the control chip and convert the digital signal into pulses with different pulse widths or duty cycles. The voltage signals with different output amplitudes are different.
- each pixel on the screen 75 also displays different brightness, thereby realizing normal image display and brightness adjustment.
- the PWM dimmer 79 can be electrically coupled to the processor 71 or as part of a Gamma correction controller to adjust the display brightness of the screen 75 based on data such as input grayscale values.
- the above embodiments it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof.
- a software program it may be implemented in whole or in part in the form of a computer program product.
- the computer program product includes one or more computer instructions.
- the computer program instructions When the computer program instructions are loaded and executed on a computer, the processes or functions described in accordance with embodiments of the present application are generated in whole or in part.
- the computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device.
- the computer instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be from a website site, computer, server or data center Transmission to another website site, computer, server or data center via wired (eg coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (eg infrared, wireless, microwave, etc.).
- the computer readable storage medium can be any available media that can be accessed by a computer or a data storage device that includes one or more servers, data centers, etc. that can be integrated with the media.
- the usable medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (such as a solid state disk (SSD)) or the like.
- a magnetic medium eg, a floppy disk, a hard disk, a magnetic tape
- an optical medium eg, a DVD
- a semiconductor medium such as a solid state disk (SSD)
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Abstract
本申请提供一种屏幕亮度的控制方法、装置及终端设备。本申请的屏幕亮度的控制方法包括以下步骤:先确定屏幕在亮度调整的当前档位下对应的第一亮度值;然后基于预设的Gamma校正查找表确定与第一亮度值对应的第一输入灰阶值,其中,Gamma校正查找表为在亮度调整的指定档位下屏幕的亮度值与屏幕的初始输入灰阶值的Gamma校正关系;最后根据第一输入灰阶值控制屏幕的显示亮度值。本申请能够在亮度调整时进行正确的亮度显示,且硬件资源占用较少。
Description
本申请要求于2018年5月9日提交中国国家知识产权局、申请号为201810438207.5、申请名称为“屏幕亮度的控制方法、装置及终端设备”的中国专利申请的优先权,其全部内容通过引用结合在本申请中。
本申请涉及显示器显示领域,尤其涉及一种屏幕亮度的控制方法、装置及终端设备。
有机发光二极管显示器件由于具备自发光、厚度薄、对比度高、可视角度大等优点,是下一代手机面板的主要发展方向。其中,主动矩阵有机发光二级体(Active-matrix organic light emitting diode,AMOLED)因其具有较好的可挠性而成为了发展重点。
目前,当屏幕的显示亮度发生改变时,为了在屏幕的当前亮度下对图像画面进行正常显示,需要调整显示输入数据,以使显示输入数据适应屏幕的当前亮度。在现有的一种亮度控制方式中,会将屏幕的亮度调整范围划分为多个不同亮度调节点,每个亮度调节点均配置有独立的对应关系,该对应关系可以表示屏幕的原始显示输入数据和对应于该区段的亮度的显示输入数据之间的映射关系,并通常查找表的形式进行存储。每个亮度调节点的查找表可看作独立的存储器或者寄存器。当屏幕的亮度调整至某一亮度调节点时,即可通过对应于该亮度调节点的查找表获取相应的显示输入数据,最后通过伽马(Gamma)校正获取线束输出数据,以进行屏幕的输出显示。
然而,现有技术中,每个已有的对应关系都需要经过独立的测量工序才能获得,且多个对应关系需要多个存储器进行存储,成本较高;且若屏幕的当前亮度没有位于现有的亮度调节点上时,还需要通过线性内插等手段才能获取相应的显示输入数据,造成面板的亮度显示不准确。
发明内容
本申请提供一种屏幕亮度的控制方法、装置及终端设备,能够在亮度调整时进行正确的亮度显示,且硬件资源占用较少。
第一方面,本申请提供一种屏幕亮度的控制方法,包括先确定屏幕在亮度调整的当前档位下对应的第一亮度值;然后基于预设的Gamma校正查找表确定与第一亮度值对应的第一输入灰阶值,Gamma校正查找表为在亮度调整的指定档位下,屏幕的亮度值与屏幕的初始输入灰阶值的Gamma校正关系;最后根据第一输入灰阶值控制屏幕的显示亮度值。
这样能够在对屏幕的亮度进行调整时,依靠在亮度调整的指定档位下亮度值与输入灰阶值之间的Gamma校正关系获得亮度调整的其它档位下亮度值和输入灰阶值的 对应关系,从而可以基于指定档位下的Gamma校正关系对亮度调整的其它档位下屏幕显示的亮度实现Gamma校正,不需要存储其他档位下的Gamma校正关系,有效的节省了硬件资源。
可选的,屏幕包含不均匀Mura区域,若屏幕的各像素点在初始亮度调整的档位下对应的亮度值均为第二亮度值,确定屏幕在亮度调整的当前档位下对应的第一亮度值之前,该方法还包括:先在对屏幕进行Demura之前,基于预设的Gamma校正查找表确定与第二亮度值时对应的第二输入灰阶值;然后根据第二输入灰阶值控制屏幕的各像素点的显示亮度值。
这样在对屏幕进行Demura之前对包含Mura区域的屏幕进行Gamma校正,并在亮度调整的过程中对经过Demura操作的屏幕进行Gamma校正,既可以确保屏幕的均匀性,又可以使屏幕在亮度调整的过程中始终实现正确的亮度显示,此外Demura之前进行的Gamma校正是基于亮度调整过程中同一个Gamma校正查找表进行的,可以实现较好的硬件整合性,且节省了存储空间,降低了硬件成本。
可选的,Gamma校正查找表包括以下任意一种:多个离散的灰阶值以及多个显示亮度值,灰阶值的数量等于显示亮度值的数量,灰阶值与显示亮度值一一对应,离散的灰阶值的数量等于屏幕的灰阶值的总阶数;或者,多个离散的灰阶值以及多个显示亮度值,灰阶值的数量等于显示亮度值的数量,灰阶值与显示亮度值一一对应,离散的灰阶值的数量小于屏幕的灰阶值的总阶数。
这样可以利用目前的硬件对有限个整数灰阶值以及相对应的显示亮度值之间的对应关系进行存储和表达,既能够较为准确的表示输入灰阶值和显示亮度值之间的对应关系,也能够节约存储器空间或者处理能力等硬件资源。
可选的,离散的灰阶值和离散的灰阶值中任一个灰阶值对应的显示亮度值构成的二维坐标点均位于一条Gamma曲线上,其中,Gamma曲线的横坐标表示灰阶值,Gamma曲线的纵坐标表示显示的亮度值。这样每个离散的灰阶值以及对应的显示亮度值均能够满足Gamma曲线,使亮度得到正确显示。
可选的,屏幕在当前档位下的当前亮度值与亮度调整的前一档位的先前亮度值之间满足预设条件,其中该当前亮度值与该先前亮度值对应相同的输入灰阶值,预设条件为:相邻档位的亮度值差值与先前亮度值的比例满足韦伯定律。其中,亮度值差值为当前亮度值与先前亮度值之间的差值。这样屏幕在实现亮度调节时,屏幕的明暗变化可以均匀过渡,使人眼较为适应。
可选的,屏幕在指定档位下所支持的最大亮度值大于屏幕在亮度调整的当前档位下所支持的最大亮度值。这样无论屏幕的亮度调整的档位调整至哪个档位,像素点在该档位下对应的亮度值均会被包括在屏幕在指定档位下像素点显示亮度值与输入灰阶值的Gamma校正关系之中。
可选的,指定档位为屏幕亮度调整时所支持的最大档位。
可选的,基于预设的Gamma校正查找表确定与亮度值对应的输入灰阶值具体包括:先确定屏幕显示的亮度值为亮度调整的当前档位下对应的亮度值时屏幕对应的初始输入灰阶值;然后用基于Gamma校正查找表确定的输入灰阶值替换初始输入灰阶值,以作为与亮度值对应的输入灰阶值。
可选的,Gamma校正查找表中的多个灰阶值和多个显示亮度值的对应关系符合Gamma校正公式,其中,显示亮度值为Gamma校正公式的输入,灰阶值为Gamma校正公式的输出。而基于预设的Gamma校正查找表确定与亮度值对应的输入灰阶值,具体包括:基于多个显示亮度值和Gamma校正公式计算得到与多个显示亮度值一一对应的多个灰阶值。这样只需要一组预设的Gamma校正查找表,即可确定屏幕在不同基准亮度值下对应的Gamma校正查找表,节省了存储空间,降低了硬件成本;且由于该组离散的数值包括了所有整数灰阶值以及对应显示亮度值之间的对应关系,因而确定的输入灰阶值精度更高,屏幕亮度调整的精度也更高。
可选的,Gamma校正公式为:f=B
1/γ*(N-1)。
其中,f为归一化处理后的亮度调整的当前档位下第一亮度值对应的灰阶值,而γ为预设的Gamma校正查找表中的Gamma值,N为灰阶的总个数。
可选的,当亮度调整的当前档位下的第一亮度值没有包含在Gamma校正查找表中时,基于预设的Gamma校正查找表确定与第一亮度值对应的第一输入灰阶值包括:先获得Gamma校正查找表中最接近亮度调整的当前档位下的第一亮度值的显示亮度值;再将最接近亮度调整的当前档位下的第一亮度值的显示亮度值对应的灰阶值作为与第一亮度值对应的第一输入灰阶值。
可选的,当计算得到的灰阶值不是小数时,该方法还包括对计算得到的灰阶值取整,将取整之后的结果作为与显示的第一亮度值对应的第一输入灰阶值。
可选的,当亮度调整的当前档位下的第一亮度值没有包含在Gamma校正查找表中时,基于预设的Gamma校正查找表确定与屏幕亮度值对应的输入灰阶值具体包括:先基于Gamma校正查找表确定与亮度调整的当前档位下的第一亮度值直接相邻的两个显示亮度值;再基于直接相邻的两个显示亮度值及其对应的灰阶值建立线性插值方程;最后根据线性插值方程和亮度调整的当前档位下的第一亮度值获取与第一亮度值对应的第一输入灰阶值。
这样只需要一组预设的Gamma校正查找表,即可确定屏幕在不同亮度调整的档位下对应的Gamma校正查找表,节省了存储空间,降低了硬件成本;且所采用的预设Gamma校正查找表中仅包括有限个输入灰阶值与显示亮度值之间的对应关系,而其它为被包含在预设Gamma校正查找表中的对应关系是通过简单的线性插值运算方式得到的,在实现较高的灰阶值输入精度的同时,运算速度较快,处理器开销较小。
可选的,确定屏幕在亮度调整的当前档位下显示的第一亮度值之前,该方法还包括接收亮度调整信号,亮度调整信号用于指示将屏幕的显示亮度调整至亮度调整的当前档位。
第二方面,本申请还提供一种屏幕亮度的控制装置,包括:亮度确定模块,用于确定屏幕在亮度调整的当前档位下对应的第一亮度值;第一伽马Gamma校正模块,用于基于预设的Gamma校正查找表确定与第一亮度值对应的第一输入灰阶值,Gamma校正查找表为在亮度调整的指定档位下,屏幕的亮度值与屏幕的初始输入灰阶值的Gamma校正关系;以及亮度调整模块,用于根据第一输入灰阶值控制屏幕的显示亮度值。
这样能够在对屏幕的亮度进行调整时,依靠在亮度调整的指定档位下亮度值与输 入灰阶值之间的Gamma校正关系获得亮度调整的其它档位下亮度值和输入灰阶值的对应关系,从而可以基于指定档位下的Gamma校正关系对亮度调整的其它档位下屏幕显示的亮度的实现Gamma校正,不需要存储其他档位下的Gamma校正关系,从而有效的节省了硬件资源。
可选的,屏幕包含不均匀Mura区域,若屏幕的各像素点在初始亮度调整的档位下对应的亮度值均为第二亮度值,装置还包括:第二Gamma校正模块,用于在对屏幕进行Demura之前,基于预设的Gamma校正查找表确定当屏幕在初始档位下显示的亮度值为第二亮度值时对应的第二输入灰阶值;第二Gamma校正模块还用于根据第二输入灰阶值控制屏幕的各像素点的显示亮度;此外,装置还包括Mura校正模块,用于对屏幕进行Demura。
这样在对屏幕进行Demura之前对包含Mura区域的屏幕进行Gamma校正,并在亮度调整的过程中对经过Demura操作的屏幕进行Gamma校正,既可以确保屏幕的均匀性,又可以使屏幕在亮度调整的过程中始终实现正确的亮度显示,此外Demura之前进行的Gamma校正是基于亮度调整过程中同一个Gamma校正查找表进行的,可以实现较好的硬件整合性,且节省了存储空间,降低了硬件成本,且硬件整合性较好。
可选的,Gamma校正查找表包括以下任意一种:多个离散的灰阶值以及多个显示亮度值,灰阶值的数量等于显示亮度值的数量,灰阶值与显示亮度值一一对应,离散的灰阶值的数量等于屏幕的灰阶值的总阶数;或者,多个离散的灰阶值以及多个显示亮度值,灰阶值的数量等于显示亮度值的数量,灰阶值与显示亮度值一一对应,离散的灰阶值的数量小于屏幕的灰阶值的总阶数。
这样可以利用目前的硬件对有限个整数灰阶值以及相对应的显示亮度值之间的对应关系进行存储和表达,既能够较为准确的表示输入灰阶值和显示亮度值之间的对应关系,也能够节约存储器空间或者处理能力等硬件资源。
可选的,离散的灰阶值和离散的灰阶值中任一灰阶值对应的显示亮度值构成的二维坐标点均位于一条Gamma曲线上,其中,Gamma曲线的横坐标表示灰阶值,Gamma曲线的纵坐标表示显示的亮度值。
可选的,屏幕在当前档位下的当前亮度值与在亮度调整的前一档位下的先前亮度值之间满足预设条件,其中,当前亮度值与先前亮度值对应相同的输入灰阶值,预设条件为:相邻档位的亮度值差值与先前亮度值的比例满足韦伯定律,其中,亮度值差值为当前亮度值与先前亮度值之间的差值。这样屏幕在实现亮度调节时,屏幕的明暗变化可以均匀过渡,使人眼较为适应。
可选的,屏幕在指定档位下所支持的最大亮度值大于屏幕在亮度调整的当前档位下所支持的最大亮度值。这样无论屏幕的亮度调整的档位调整至哪个档位,像素点在该档位下对应的亮度值均会被包括在屏幕在指定档位下像素点显示亮度值与输入灰阶值的Gamma校正关系之中。
可选的,指定档位为亮度调整时所支持的最大档位。
可选的,第一Gamma模块具体用于:先确定屏幕显示的亮度值为亮度调整的当前档位下对应的第一亮度值时屏幕对应的初始输入灰阶值;再用基于Gamma校正查找表确定的输入灰阶值替换初始输入灰阶值,以作为与第一亮度值对应的第一输入灰 阶值。
可选的,Gamma校正查找表中的多个灰阶值和多个显示亮度值的对应关系符合Gamma校正公式,其中,显示亮度值为Gamma校正公式的输入,灰阶值为Gamma校正公式的输出;而控制装置还包括:Gamma校正查找表获取模块,具体用于基于多个显示亮度值和校正公式计算得到与多个显示亮度值一一对应的多个灰阶值。
这样只需要一组预设的Gamma校正查找表,即可确定屏幕在亮度调整的不同档位下对应的Gamma校正查找表,节省了存储空间,降低了硬件成本;且由于该组离散的数值包括了所有整数灰阶值以及对应显示亮度值之间的对应关系,因而确定的输入灰阶值精度更高,屏幕亮度调整的精度也更高。
可选的,Gamma校正公式为:f=B
1/γ*(N-1);其中,f为归一化处理后的亮度调整的当前档位下第一亮度值对应的第一输入灰阶值,而γ为预设的Gamma校正查找表中的Gamma值,N为灰阶的总个数。
可选的,当亮度调整的当前档位下的第一亮度值没有包含在Gamma校正查找表中时,第一Gamma校正模块还用于:先获得Gamma校正查找表中最接近亮度调整的当前档位下的第一亮度值的显示亮度值;然后将最接近亮度调整的当前档位下的第一亮度值的显示亮度值对应的灰阶值作为与第一亮度值对应的第一输入灰阶值。
可选的,当亮度调整的当前档位下的第一亮度值没有包含在Gamma校正查找表中时,第一Gamma校正模块具体用于:先基于Gamma校正查找表确定与亮度调整的当前档位下的第一亮度值直接相邻的两个显示亮度值;然后基于直接相邻的两个显示亮度值及其对应的灰阶值建立线性插值方程;最后根据线性插值方程和亮度调整的当前档位下的第一亮度值获取与第一亮度值对应的第一输入灰阶值。
这样可以利用目前的硬件对有限个整数灰阶值以及相对应的显示亮度值之间的对应关系进行存储和表达,既能够较为准确的表示输入灰阶值和显示亮度值之间的对应关系,也能够节约存储器空间或者处理能力等硬件资源。
第三方面,本申请提供一种终端设备,终端设备包括:处理器、第一Gamma选择器,第一Gamma校正控制器和屏幕。其中,处理器用于确定屏幕在当前亮度调整的档位下对应的第一亮度值。第一Gamma选择器用于基于预设的Gamma校正查找表确定与第一亮度值对应的第一输入灰阶值,Gamma校正查找表为在亮度调整的指定档位下,屏幕的亮度值与屏幕的初始输入灰阶值的Gamma校正关系。第一Gamma校正控制器用于根据第一输入灰阶值控制屏幕的显示亮度值。
这样能够在对屏幕的亮度进行调整时,在依靠亮度调整的指定档位下亮度值与输入灰阶值之间的Gamma校正关系获得亮度调整的其它档位下亮度值和输入灰阶值的对应关系,从而可以基于指定档位下的Gamma校正关系对亮度调整的其它档位下屏幕显示的亮度的实现Gamma校正,不需要存储其他档位下的Gamma校正关系,从而有效的节省了硬件资源。
可选的,屏幕包含不均匀Mura区域,若屏幕的各像素点在亮度调整的初始档位下对应的亮度值均为第二亮度值,终端设备还包括第二Gamma选择器和第二Gamma校正控制器;第二Gamma选择器,用于在对屏幕进行Demura之前,基于预设的Gamma校正查找表确定与第二亮度值对应的第二输入灰阶值;第二Gamma校正控制器还用 于根据第二输入灰阶值控制屏幕的所各像素点的显示亮度值。
这样在对屏幕进行Demura之前对包含Mura区域的屏幕进行Gamma校正,并在亮度调整的过程中对经过Demura操作的屏幕进行Gamma校正,既可以确保屏幕的均匀性,又可以使屏幕在亮度调整的过程中始终实现正确的亮度显示,此外Demura之前进行的Gamma校正是基于亮度调整过程中同一个Gamma校正查找表进行的,可以实现较好的硬件整合性,且节省了存储空间,降低了硬件成本,且硬件整合性较好。
可选的,终端设备还包括存储器,用于存储预设的Gamma校正查找表。
可选的,Gamma校正控制器包括:电压生成器和亮度控制器,电压生成器,用于根据输入灰阶值生成参考电压;亮度控制器,用于基于参考电压控制屏幕显示与所述输入灰阶值对应的显示亮度值。
图1是本申请实施例提供的一种屏幕亮度的控制方法的流程示意图;
图2是亮度调整的不同档位下Gamma曲线的示意图;
图3是本申请实施例提供的一种确定与亮度调整的当前档位下第一亮度值对应的第一输入灰阶值的流程示意图;
图4是本申请实施例提供的屏幕亮度的控制方法中Gamma校正查找表对应的Gamma曲线示意图;
图5是本申请实施例提供的另一种屏幕亮度的控制方法的流程示意图;
图6是本申请实施例提供的一种屏幕亮度的控制装置的结构示意图;
图7是本申请实施例提供的另一种屏幕亮度的控制装置的结构示意图;
图8是本申请实施例提供的一种终端设备的硬件结构示意图;
图9是本申请实施例提供的另一种终端设备的硬件结构示意图。
屏幕在进行显示时,由于人眼对不同亮度的敏感度不一致,或者屏幕自身具有光电特性,所以屏幕所显示出的图像的亮度与原始输入图像的原始亮度之间通常并不一致,而是存在着一定偏差。此时,屏幕输出的图像和输入图像相比就会存在失真现象,造成屏幕显示颜色与输入的图像的颜色差异较大,或者是屏幕对图像的显示过亮或过暗等。示例性的,当屏幕显示的颜色从黑到白变化时,屏幕的输入的灰阶值也要变化,但这个变化不是线性的,屏幕显示器的物理特性决定了如果输入的灰阶值是线性变化的,输出的亮度值就不是线性的,为了保证显示出来的亮度值与希望屏幕呈现的亮度值不存在偏差,就需要对屏幕输入的灰阶值进行校正,即对屏幕进行Gamma校正过程,使其显示出期望的亮度。其中,对屏幕进行Gamma校正,可以使屏幕输入的灰阶值与输出的亮度之间的变化关系满足一条对应关系曲线,该曲线即为Gamma曲线。当屏幕输入灰阶值与输出亮度值之间满足该Gamma曲线时,即可让屏幕显示预设的亮度和色彩。
利用Gamma曲线进行屏幕的亮度校正时,当屏幕整体亮度发生改变,或者屏幕上个别像素点的输入输出特性发生变化,均会影响到屏幕亮度的整体显示,因而需要 对屏幕进行亮度校正,使其显示正常的亮度。
图1是本申请实施例一提供的一种屏幕亮度的控制方法的流程示意图。如图1所示,本实施例提供的屏幕亮度的控制方法,具体可以包括如下步骤:
S101、确定屏幕在亮度调整的当前档位下对应的第一亮度值。
具体的,为了适应不同的应用场合,可选的,屏幕可以具有多个用于调整亮度的不同档位,在不同的亮度调整的档位下屏幕可显示的亮度值的范围不同,下面对屏幕的亮度调整的档位进行举例说明,屏幕本身能够显示的最大亮度值为500尼特(nit),假如该屏幕具有5个不同亮度调整的档位,第一个亮度调整的档位,下屏幕可显示的亮度值的范围为0-100nit,第二个亮度调整的档位下,屏幕可显示的亮度值的范围为0-200nit,…,第五个亮度调整的档位下屏幕可显示的亮度值的范围为0-500nit,对应的,该屏幕具有的5个亮度调整的档位可以对应屏幕的亮度条上的5个刻度,例如屏幕亮度条上最右侧的刻度对应第五个亮度调整的档位,向左移一个刻度对应第四个亮度调整的档位,以此类推,屏幕亮度条上最左侧的刻度对应第一个亮度调整的档位(即可显示的亮度范围最小,屏幕的亮度也最暗)。对应于不同的用于调整亮度的档位,屏幕的原始图像在显示固定的明暗关系时,相同明亮程度的区域所对应的亮度值也会随之产生改变。应当理解,上述所列举的数据只是对屏幕的亮度调整的档位进行举例说明,并不对屏幕的亮度调整的档位和对应的可显示的亮度值的范围造成限制。
由于图像是依靠屏幕中各像素点之间所形成的相对明暗关系而显示出来,当屏幕的亮度调整的档位不同时,基于同一幅显示图像,屏幕上各像素点之间仍旧会保持相同的明暗比例,以使整个显示图像在基准亮度值改变时能够保持原有的纹理和图案等画面特征。具体的,当屏幕的亮度调整的档位改变时,各个像素点在该档位下显示的亮度值也会跟随着档位的改变而随之一同变化,在一种可选的情况中,屏幕的亮度调整的档位与各像素点所显示的亮度值之间存在正相关性,这样即可让图像完成整体的明暗调整,而不损坏图像自身的图案和纹理等细节。所以,可以在亮度调整至当前档位时,确定出屏幕各像素点在当前档位下对应的第一亮度值。
由于屏幕上各个像素点相互独立,因而每个像素点所具有的亮度值也是相互独立的,并只会随着屏幕的亮度调整的档位的变化而改变。因而屏幕在某个亮度调整的档位,例如是亮度调整的当前档位时,屏幕上各个像素点各自均会具有一个独立的第一亮度值,且屏幕显示不同图像时,各个像素点所显示出的亮度值可以相同或不同。具体的,在显示同一图像时,如果屏幕的亮度调整的档位发生调整,则可以先确定屏幕输入的灰阶值最大时所显示的亮度值,并根据具体的比例或者其它正相关关系而确定各像素点为显示其它灰阶值而随之调整到的显示亮度值。容易理解的是,各像素点所显示出的第一亮度值与屏幕的亮度调整的档位可以呈正相关的关系,即第一亮度值会随着屏幕的显示亮度调整的档位的改变方向而同向变化,当屏幕的档位由表示较暗画面的档位变为表示较亮画面的基准时,各像素点的第一亮度值相应变大;而当屏幕的亮度调整的档位由较亮画面的档位变为较暗画面的档位时,各像素点的第一亮度值会相应变小。
S102、基于预设的Gamma校正查找表确定与第一亮度值对应的第一输入灰阶值,Gamma校正查找表为在亮度调整的指定档位下,屏幕的亮度值与屏幕的初始输入灰阶 值的Gamma校正关系。
具体的,当屏幕在进行显示时,当像素点输入一定的灰阶值时,会相应的通过施加不同的驱动电压等手段而显示一定的亮度值,从而在屏幕上正常显示图像。而屏幕在进行显示时,因为人眼的敏感度或者是屏幕自身光电特性,会导致屏幕输出的图像和输入图像之间会存在失真现象,例如是屏幕显示颜色与输入的图像的颜色差异较大或者是屏幕显示的亮度与输入图像的原始亮度存在差异等。为了避免屏幕显示的亮度值与原始图像的亮度值出现偏差,就需要对屏幕输入的灰阶值进行校正;可选的,可以通过改变屏幕输入的电压改变屏幕的灰阶值输入,可选的,可以通过校正屏幕输入的电压使得屏幕显示出的图像的亮度值与实际输入的图像的亮度值相等或呈线性关系。
在一种可选的情况中,为了避免该失真现象,可以对屏幕显示的输出亮度值以及屏幕的输入灰阶值之间的关系进行Gamma校正,从而调整屏幕输入和输出之间的响应曲线,以矫正屏幕实际显示的图像在亮度上的偏差。
其中,屏幕在某一亮度调整的档位下,屏幕任一像素点显示的亮度值与输入的灰阶值的Gamma校正关系既可以是连续的,也可以是离散的。例如,屏幕在某一亮度调整的档位下,任一像素点显示的亮度值与输入的灰阶值之间的对应关系会遵循同一条响应曲线,也就是Gamma曲线,此时,即可利用该Gamma曲线对该档位下,像素点显示的亮度值与输入的灰阶值之间的对应关系进行表示,从而形成亮度值和输入灰阶值之间的Gamma校正关系。示例性的,Gamma曲线的横坐标可以表示输入的灰阶值,而Gamma曲线的纵坐标可以表示显示的亮度值。此时无论像素点显示哪一个亮度,均能够在Gamma曲线上找到其对应的输入灰阶值。这样像素点所显示的亮度值和对应的输入灰阶值均为连续不间断的,当需要根据像素点显示的亮度值获取对应输入灰阶值时,能够找到相应的准确输入灰阶值。
而一般受限于存储空间以及面板精度等硬件制约因素,屏幕面板上输入的灰阶值通常为离散的正整数,因此屏幕像素点显示的亮度值与输入的灰阶值的对应关系往往并不是一条连续的曲线,而是位于Gamma曲线上的一些离散的点。因而可以将某一亮度调整的档位下,像素点显示的亮度值和输入的灰阶值之间对应关系采用一组离散的数据进行表示。其中,每一亮度值以及其对应的输入的灰阶值均可表征为上述Gamma曲线上的一个离散的点,也就是说,离散的灰阶值以及灰阶值所对应的显示亮度值所构成的二维坐标点均位于Gamma曲线之上。此处,示例性的,仍可以将灰阶值作为Gamma曲线的横坐标,而显示的亮度值作为Gamma曲线的纵坐标。其中,该组数据中离散的点的数量可以是屏幕所能显示的灰阶值的总数量,例如当屏幕为8位(8bit)灰阶输入时,屏幕能显示的灰阶值为0-255区间内的任一个整数共256个,此时预设的对应关系中可以存储256组离散的数据,对应Gamma曲线上256个离散的点,而屏幕为10位(10bit)灰阶输入时,屏幕能显示的灰阶值为0-1023内的任一个整数共1204种,此时预设的Gamma校正关系中可以存储1024组离散的数据,对应Gamma曲线上1024个离散的点。示例性的,预设的Gamma校正关系中的数据格式可以为(Code0,Lum),其中Code0为像素点输入的灰阶值,对应Gamma曲线的横坐标,Lum为像素点输入的灰阶值为Code0时显示的亮度值,对应Gamma曲线的纵坐标。这样即可根据该Gamma校正关系获得已知亮度值所对应的输入的灰阶值,或者 根据已知的灰阶值获得对应的显示亮度值等。此外,当屏幕像素点的输入灰阶值为离散的整数值时,灰阶值的数量变为了有限的数值,因而在某一亮度调整的档位下显示的亮度值与输入的灰阶值之间的对应关系的数量也会为有限个,例如是256个(对应8bit)或者1024个(对应10bit)等;这样可以利用目前的硬件对有限个整数灰阶值以及相对应的显示亮度值之间的对应关系进行存储和表达,既能够较为准确的表示输入灰阶值和显示亮度值之间的对应关系,也能够节约存储器空间或者处理能力等硬件资源。
在一种可选的情况中,预设的Gamma校正关系只包括屏幕能够显示的所有灰阶值中的部分灰阶值及其对应的亮度值,例如对于8bit屏幕,预设的Gamma校正关系中可以只包括30组输入灰阶值与显示亮度值的Gamma校正关系,该30组之外的其他灰阶值和对应的亮度值可以利用该组数据中已有的亮度值和灰阶值之间的Gamma校正关系求取获得,具体的,可以采用插值计算等手段获得Gamma校正关系中剩余的部分。这样和离散数据中包括所有Gamma校正关系的方式相比,由于Gamma校正关系的数量较少,所以所需要的硬件资源进一步减少,并能够利用差值计算等手段获取与实际对应关系相近的结果,实现较为准确的校正效果。
进行Gamma校正时,通常可以采用多种方式获取屏幕为某一个亮度调整的档位时,其像素点的输入灰阶值和输出亮度值之间的正确Gamma校正关系。在一种可选的情况中,为了对屏幕进行伽马校正,可以利用Gamma校正查找表来确定屏幕输出亮度和输入灰阶值之间的Gamma校正关系。Gamma校正查找表中通常存储有屏幕的初始输入灰阶值以及对应的屏幕亮度值,实际为屏幕初始输入灰阶值以及对应的屏幕亮度值之间的映射表,当需要获取特定的屏幕亮度值所对应的输入灰阶值,或者获取特定的灰阶值所能够输出的亮度值时,都可以通过Gamma校正查找表进行查找获取。其中,Gamma校正查找表通常可以采取在生产线上现场测量的形式而得到。具体可以在生产线的测量工位上,利用图像产生器等外部设备使屏幕输入一定的预设输入灰阶值,同时利用采样设备对屏幕对应显示的亮度值进行采样测量,这样以此类推,测量出不同输入灰阶值以及相应的显示亮度值,从而逐个建立输入灰阶值与显示亮度值之间的一一对应关系,并将所获取到的对应关系写入寄存器或者是存储器之中,并按照一定顺序排列成列表的形式,也就是Gamma校正查找表。在进行Gamma校正时,即可在该Gamma校正查找表中获取想要的输入灰阶值或显示亮度值。
具体的,屏幕输入的灰阶值具有不同的灰阶等级,示例性的,输入的灰阶值可以为0-255中的任意值,示例性的,每个不同的灰阶输入均对应一个亮度输出值。此时,Gamma校正查找表中可存放屏幕所有的输入灰阶值与对应的输出亮度值之间的关系。在一种可选的情况中,根据屏幕显示特性的不同,屏幕的灰阶值可以为不同的位数,例如8位(8bit)或者10位(10bit)等,当屏幕输入的灰阶值为8bit时,该屏幕上的像素点可以具有2
8=256个不同的灰阶数,即像素点输入的灰阶值可以为0-255内的任一个整数;可选的,当屏幕输入的灰阶值为10bit时,该屏幕的像素点可以具有2
10=1024个灰阶数,对应的,像素点输入的灰阶值可以为0-1023内的任一个整数。相应的,Gamma校正查找表中可以存放有不同的输入灰阶值和输出亮度值之间的Gamma校正关系,从而根据不同的亮度输出值查找像素点所应有的灰阶输入,并进而进行该像素 点的电压等参数的调整。
可选的,受限于硬件存储空间等参数,Gamma校正查找表中一般仅包括有屏幕在一个亮度调整的档位下,屏幕的初始输入灰阶值与屏幕显示的亮度值之间的Gamma校正关系。示例性的,Gamma校正查找表可以为在亮度调整的指定档位下,屏幕的亮度值与屏幕的初始输入灰阶值的Gamma校正关系。
其中,亮度调整的档位主要指当屏幕在该档位下,屏幕的初始输入灰阶值会和预先指定的亮度值具有一定对应关系,从而让屏幕整体维持在某一个亮度水平范围内。而亮度调整的档位发生改变时,对应于像素点的同一个初始输入灰阶值,会在新的亮度调整的档位下下相应的显示不同亮度值。这样可以使屏幕显示出不同亮度状态下的同一幅画面。在一种可选的情况中,Gamma校正查找表中可以包括两组数据,且第一组数据中每个数据均在第二组数据中存在一个对应的数据,这样令第一组数据为屏幕输入的灰阶值,而第二组数据为相应的显示亮度值,即可通过Gamma校正查找表根据输入的灰阶值查找到相应的显示亮度值,或者是根据显示亮度值查找到相应的输入灰阶值。
在一种可选的情况中,屏幕在显示一幅均匀的纯色图像时,应当理解,均匀的纯色图像为所有像素点具有相同像素值的图像,屏幕中的每个像素点显示相同的亮度值,也就是每个像素点所显示的亮度均一样;相应的,每个像素点的初始输入灰阶值均相同。而在一种可选的情况中,屏幕显示一幅非均匀图像时,屏幕中的不同像素点通常会具有不同的灰阶值输入,从而呈现出图像的明暗纹理,此时,不同的灰阶值也会相应的显示出不同的亮度值,因而让屏幕上各个不同像素点具有不同的亮度,应当理解,非均匀图像为具有一种以上颜色的图像,可选的,非均匀图像可以具有较为丰富的纹理特征。
下面以屏幕显示均匀的纯色图像,例如是均匀的纯白图像时,对基于预设的伽马Gamma校正查找表确定与屏幕在亮度调整的指定档位下亮度值所对应的输入灰阶值的大致过程进行说明。示例性的,假设屏幕当前显示的亮度值为屏幕可以显示的最大灰阶值所对应亮度值,此时,由于屏幕显示均匀,因而屏幕上所有像素点均会对应输入相同的灰阶值,而屏幕上各像素点所显示的亮度值也均等于该最大灰阶值对应的亮度值,且屏幕上用于调整屏幕亮度的亮度条位于最大刻度处(例如可以位于亮度条的最右侧)。因而在Gamma校正查找表中确定像素点显示该亮度值时对应的灰阶值输入,将查到的该灰阶值作为屏幕各像素点实际输入的灰阶值,也就是屏幕上各个像素在显示对应该亮度调整的指定档位的亮度值时,所应具有的灰阶值,从而使得屏幕实际显示出的亮度与所希望显示的亮度没有偏差。示例性的,在本申请实施例中,由于屏幕显示的是均匀的纯色图像,因而理想情况下屏幕的每个像素点显示的亮度值相等;在Gamma校正查找表中确定该理想情况下输出的亮度值对应的初始输入灰阶值,并将该灰阶值作为每个像素点的输入,以使得屏幕显示出的实际亮度值等于该理想情况下的亮度值。在一种可选的情况中,可以通过改变用于驱动屏幕各像素点发光的电压值来调整各像素点的灰阶值输入,例如可以调高或降低屏幕的输入电压来增大或减小像素点输入的灰阶值。
这样经过Gamma校正后,可以避免屏幕显示出的画面出现过暗、过亮或者亮度 不均匀等现象。
在一种可选的情况中,当屏幕显示一幅非均匀的图像时,当屏幕的像素点显示的亮度不同时,对应的灰阶值输入也不同。在这种情况下,确定屏幕中每个像素点所希望显示出的亮度,并在Gamma校正查找表中对应查找每个像素点的所希望显示的亮度值对应的灰阶值输入,将该查找到的灰阶值输入作为屏幕实际输入的灰阶值,可选的,通过控制屏幕的像素点的驱动电压使得屏幕输入的灰阶值为从Gamma校正查找表中查到的灰阶值,在对屏幕进行Gamma校正之后,使得屏幕的每个像素点显示出的亮度值均与输入的图像的亮度值相同,而不会出现亮度值偏差,例如显示出的画面出现过暗、过亮或者亮度不均匀等现象。
而当屏幕的亮度调整的档位发生变化时,屏幕在亮度调整的当前档位下的当前亮度值,与亮度调整的前一档位的先前亮度值之间通常需要满足一定的预设条件,其中,当前亮度值与先前亮度值对应相同的输入灰阶值。这样能够避免屏幕从之前指定档位对应的亮度值调整到亮度调整的当前档位对应的亮度值时,由于屏幕的明暗变化过于明显而造成人眼视觉不适。
具体的,为了在屏幕亮度调整时,使屏幕的明暗变化达到均匀过渡的效果。作为一种可选的方式,相邻档位的亮度值差值与先前亮度值的比例满足韦伯定律(Web-Fechner Law)。其中,亮度值差值为当前亮度值与先前亮度值之间的差值。
具体的,进行亮度调节时,屏幕的亮度可以在一定的亮度调节范围内变化。其中,由于硬件等限制,屏幕的亮度并不是平滑调节的,而是将亮度调节范围等间隔划分为若干个亮度调节点,每个亮度调节点均对应一个独立的亮度值,且屏幕调节时会依次经过不同的亮度调节点,因而屏幕的亮度也会相应的依次显示为不同亮度调节点所对应的亮度值。可以理解的是,当屏幕的亮度调整的档位由原先的亮度调整的档位,也就是亮度调整前的档位调整至亮度调整的当前档位时,屏幕在两个不同档位下的对应于相同输入灰阶值的亮度值,也就是当前档位下的当前亮度值与前一档位的先前亮度值可以为相邻的两个亮度调节点所具有的亮度值,这样如果屏幕在两个不同亮度调整的档位下亮度值的差值过大,则屏幕在这两个相邻亮度调节点之间调节时,亮度值的差距就会过大,使得屏幕的亮度呈现跳变的效果,严重影响用户的视觉体验。而根据韦伯定律,人眼感觉的差别阈限会随着原来刺激量的变化而变化。因而为了避免屏幕在亮度调节时出现闪烁等现象,相邻两个亮度调节点之间的亮度变化量需要减少至人肉眼不会感觉剧烈变化的程度,也就是需要让亮度值差值,也就是当前亮度值和先前亮度值之间的差值,与屏幕在亮度调整的前一档位的先前亮度值之间的比例关系小于一定阈值。此时,屏幕的两个不同亮度调整档位下的亮度值之间的亮度值差值的大小随着作为调整前档位所对应同一灰阶值的亮度值的大小而改变。当屏幕的亮度值较大时,屏幕的亮度较亮,此时即使亮度的改变较大,也不易让肉眼感受到;而当屏幕亮度值较小时,屏幕处于较暗的亮度,此时,肉眼对于亮度的变化较为敏感,因而需要保持较小的亮度值差值。一般的,当前亮度值和先前亮度值通常为屏幕在亮度调整的该档位下对应的最大亮度。
具体的,根据经验数据,可得到该阈值可以为0.017,也就是说当屏幕实现亮度调节时,相邻两个亮度调节点之间的亮度值差值和屏幕在亮度调整的前一档位下先前亮 度值之间比率小于或等于0.017,即可让屏幕在进行亮度调整时实现较为平滑的亮度改变过程,使肉眼难以察觉单位亮度变化量的跳变。例如亮度调整前的档位所对应的最大亮度值为L时,则亮度值差值△L与L之间的比值△L/L≤0.017,改变后的亮度值L’=L-△L≥0.983。
可以理解的是,由于屏幕在进行亮度调节时,可能需要经过若干个亮度调节点才能调整至所期望的亮度值,而此时每相邻两个亮度调节点之间的亮度值差值均应小于或等于亮度调整前的档位对应同一预设灰阶值的亮度值的0.017倍,即L
N-L
N-1≤0.017*L
N,从而让每两个亮度调节点之间的亮度改变均为人肉眼不易感觉到剧烈变化的程度,这样屏幕由初始亮度调整至期望亮度的全过程中,人肉眼均不易感到屏幕亮度剧烈变化,从而保证了用户的视觉体验。
而当屏幕的亮度调整的档位发生改变,屏幕上各像素点显示的亮度均相应变动,在一种可选的情况中,屏幕在亮度调整的当前档位下屏幕可显示的最大亮度值为亮度调整前的档位的最大亮度值的0.983倍,相应的,屏幕可显示的其他亮度值也为亮度调整前的档位所对应亮度值的0.983倍。
为了在屏幕的亮度调整的档位变动至任何一个亮度调整的档位时,均可以利用某一个亮度调整的指定档位下的Gamma校正关系或者是Gamma校正查找表来确定像素点显示的亮度为亮度调整的当前档位时,屏幕任一个像素点的灰阶值。具体的,可以让屏幕在指定档位下所支持的最大亮度值大于屏幕在亮度调整的当前档位下能够显示的最大亮度值。且可选的,指定档位可以为亮度调整时所支持的最大档位,这样由于该指定档位下屏幕所支持的最大亮度值反映了屏幕所能达到的最大亮度值,因而无论屏幕的亮度调整的档位调整至哪个档位,像素点在该档位下对应的亮度值均会被包括在屏幕在指定档位下像素点显示亮度值与输入灰阶值的Gamma校正关系之中。
然而,屏幕的亮度调整至当前的档位时,由于亮度调整前后,始终采用同一块屏幕硬件进行显示,因而屏幕基于人眼对不同亮度的敏感度不一致或者屏幕自身光电特性的原因,显示的图像亮度与原始图像的输入亮度(即像素点的灰阶值)之间所呈现出的非线性变化仍应当符合Gamma曲线,才能保证画面具有正常的亮度和色彩。应当理解,亮度调整的档位变化之后的Gamma曲线与亮度调整之前的Gamma曲线并非为同一条曲线,示例性的,如图2所示,实线为亮度调整的档位改变前的Gamma曲线,虚线为亮度调整的档位改变后的Gamma曲线。从图2中可以得出,像素点输入同一个灰阶值(即x坐标相同)在不同的Gamma曲线上会对应不同的亮度值(对应不同的y坐标)。但是,理论上输入同一个灰阶值时,在同一块屏幕硬件上只能显示同一个亮度值,因此需要对屏幕上各像素点输入的灰阶值和显示的亮度值的Gamma校正关系进行校正,使得在不同亮度调整的档位下输入的灰阶值与显示的亮度值的Gamma校正关系始终符合gamma曲线,即当屏幕上的像素点输入同一个初始的灰阶值时在不同的亮度调整档位下会显示出不同的亮度值。示例性的,假如像素点输入的灰阶值为1023,在原先的亮度调整档位下该像素点显示的亮度值为500nit(在实线中对应的y坐标为500),改变屏幕的亮度调整档位之后,在亮度调整的调整后的档位下同样输入的灰阶值为1023显示的亮度值需要进行相应调整,才可以使得输入灰阶值与显示亮度值在调整后的基准下也符合伽马曲线(对应图2中的虚线),在一种可选 的情况中,调整后的亮度值为原先亮度值的0.983倍,此时输入灰阶值为1023时显示的亮度值为491.5nit(在虚线中对应的y坐标为491.5)。
应当理解,上述只列举了两个不同亮度调整的档位下的Gamma曲线,相应的,图2中也只画出了两个不同亮度调整的档位下的Gamma曲线,在实际情况中,屏幕的每一个亮度调整的档位都会对应一条不同的Gamma曲线,为了使得屏幕像素点输入的灰阶值与显示的亮度值的Gamma校正关系在亮度调整的不同的档位下均符合Gamma曲线,理论上需要在每个亮度调整的档位下对屏幕均进行量测,以得到不同档位对应的Gamma曲线并分别存储在寄存器或存储器中,但是这种做法会占用多条生产线进行量测,占用量测资源,同时会占用大量的存储空间,提高硬件成本。在本申请实施例中,可以只量测某一个亮度调整的指定档位下屏幕像素点输入的灰阶值与显示的亮度值对应的Gamma曲线,并基于该曲线计算出亮度调整的其他档位下输入灰阶值和显示亮度值对应的Gamma曲线,节省了生产线量测资源和硬件存储资源。在一种可选的情况中,可以选取屏幕能够显示的最大亮度值对应的档位作为亮度调整的指定档位,并在该亮度调整的档位下对屏幕输入的灰阶值和显示的亮度值的Gamma校正关系进行量测得到一组Gamma曲线,该Gamma曲线包含了屏幕从最小亮度值一直到最大亮度值时的所有亮度值,在调整档位之后,屏幕显示的亮度值会小于亮度调整的指定档位下的亮度值,因而屏幕显示的亮度值和对应的输入灰阶值依然可以在该Gamma曲线中找到,因此可以将最大亮度值对应的亮度调整的档位下的Gamma曲线预先存储在存储器或寄存器中,在亮度调整的档位发生改变之后,基于该预先存储的Gamma曲线计算得到其他亮度调整的档位下输入灰阶值和显示的亮度值的Gamma曲线,以实现对其他档位下的输入灰阶值和显示的亮度值的对应关系进行校正。
由于屏幕在某一亮度调整的档位下,屏幕任一像素点显示的亮度值与输入的灰阶值的对应关系既可以是连续的,也可以是离散的。因而屏幕在某一亮度调整的档位下,任一像素点显示的亮度值与输入的灰阶值之间的对应关系可以遵循同一条曲线,也就是上述的Gamma曲线,此时,即可利用该Gamma曲线对该亮度调整的档位下,像素点显示的亮度值与输出的灰阶值之间的Gamma校正关系进行表示。此时无论像素点显示哪一个亮度,均能够在Gamma曲线上找到其对应的输入灰阶值。
此外,当屏幕像素点显示的亮度值与输入的灰阶值的Gamma校正关系受限于硬件等制约因素而无法用连续的曲线进行表达时,也可以将某一亮度调整的档位下,像素点显示的亮度值和输入的灰阶值之间的Gamma校正查找表采用离散的数据进行表示。其中,每一亮度值以及其对应的输入的灰阶值均可表征在上述Gamma曲线上的一个离散的点。具体的,Gamma校正查找表可以包括多个离散的灰阶值以及多个显示亮度值,其中,灰阶值的数量等于显示亮度值的数量,且灰阶值与显示亮度值一一对应,离散的灰阶值的数量等于屏幕的灰阶值的总阶数。这样即可根据该Gamma校正查找表获得已知亮度值所对应的输入的灰阶值,或者根据已知的灰阶值获得对应的显示亮度值等。其中,当某个亮度值不包含在该组离散数据所表示的对应关系中时,可以利用已有的亮度值和灰阶值,并通过插值计算等手段获得该亮度值对应的输入灰阶值。
此外,在利用离散数据表达Gamma校正查找表中屏幕像素点显示的亮度值与输 入的灰阶值之间的Gamma校正关系时,同样采用一组离散的数据进行表示,但该组离散的数据中,只包括所有对应关系中的部分对应关系,而所有对应关系中剩余的未知对应关系则可以利用该组数据中已有的亮度值和灰阶值之间的对应关系求取获得,具体的,Gamma校正查找表中同样包括多个离散的灰阶值以及多个显示亮度值,灰阶值和显示亮度值数量相等且一一对应,但离散的灰阶值的数量小于屏幕的灰阶值的总阶数。此时,可以采用插值计算等手段获得剩余的对应关系。一般的,此时该组离散的数据中所包含的部分Gamma校正关系通常在Gamma曲线上呈等间隔设置的离散的点。
为了便于解释,依然以图2为例进行说明。实线为在生产线上量测得到的亮度调整的指定档位下输入灰阶值与显示亮度值对应的Gamma曲线,在一种可选的情况中,屏幕能够显示的最大亮度值为500nit,那么则选取500nit对应的亮度调整的档位作为亮度调整的指定档位,而由于此时屏幕的最大亮度值对应于输入的最大灰阶值,例如是灰阶值1023,则此时亮度调整的指定档位下的Gamma曲线会满足上述灰阶值1023与亮度值500nit之间的Gamma校正关系。在调整亮度调整的档位之后,屏幕能够显示的最大亮度值变为491.5nit,此时初始的输入灰阶值与显示亮度值的Gamma校正关系应该符合如图2虚线所示的Gamma曲线,然而这条虚线所示的Gamma曲线实际并不存在(即没有实际量测也并未存储在存储器或寄存器中),此时观察可得,亮度调整的档位调整之后的亮度值491.5nit在实线代表的Gamma曲线中可以找到对应的输入灰阶值,因此可以在实线中找到显示亮度值491.5nit需要输入的灰阶值为多少。在图2的实线中,显示亮度值为491.5nit对应的输入灰阶值应该为1015,将查到的1015作为初始输入灰阶值为1023的像素点的真实输入的灰阶值,即将1023替换为1015,即可使调整后的档位下显示的亮度值为491.5nit。
可以理解的是,亮度调整的档位变化之后的Gamma曲线并没有进行实际测量,也并未存储在存储器之中,而只是通过一系列运算求取得到。且可选的,在实际使用时,只需要求取有限个输入灰阶值和显示亮度值之间的Gamma校正关系即可,在这种情况下输入灰阶值和显示亮度值之间的对应关系为Gamma曲线上一些离散的点。
应当理解,在亮度调整的档位变化之后,初始输入灰阶值为1023时并不能使显示的亮度值为491.5nit,例如原始输入的图像源为一张大熊猫的照片,大熊猫白色毛毛区域的输入灰阶值为1023,在亮度调整的档位改变之前初始输入灰阶值为1023的白色区域显示的亮度值为500nit,在亮度调整的档位发生变化之后,初始输入灰阶值为1023的白色区域显示的亮度值应该变为491.5nit。如果不进行校正,所以初始输入灰阶值为1023的白色区域实际上是不能显示出491.5nit的亮度的,而基于实线对应的Gamma曲线可以得到输出491.5nit需要输入的灰阶值为1015,此时,将1015作为图像源中白色区域的实际灰阶值输入给屏幕的像素点,这样就可以使得图像源中灰阶值为1023的区域显示的亮度值为491.5nit。1023是图像源中的白色区域的初始输入灰阶值,1015为白色区域实际输入的灰阶值,在一种可选的情况中,假设,初始的输入灰阶值为Code0,实际输入的灰阶值为Code1,则可以利用函数f(.)来表征图像源中原始的灰阶值与实际输入的灰阶值的对应关系,即Code1=f(Code0)。进一步的,实际输入的灰阶值Code1与显示的亮度值之间的对应关系可以用函数G(.)来表征,假设显示的亮度值 为Lum,则Lum=G(Code1)。应当理解,图2中示出的Gamma曲线的横坐标为图像源原始输入的灰阶值Code0,纵坐标为显示的亮度值Lum,初始输入灰阶值和显示的亮度值的对应关系可以用一个复合函数来表征,即Lum=G(Code1)=G(f(Code0))。因此,在亮度调整的档位改变之后,先确定原始输入的灰阶值Code0对应需要显示的亮度值Lum,然后可以基于预先存储的Gamma曲线得到档位改变之前(为了便于理解,将量测Gamma曲线的亮度调整的档位作为亮度调整的档位改变之前的档位)显示亮度值为Lum时应当输入的灰阶值Code1,将Code1作为Code0对应的像素点的实际输入的灰阶值,也就是第一输入灰阶值,就可以使得该像素点显示的亮度值为Lum,即第一输入灰阶值对应的第一亮度值。
这样,可以确定在屏幕在亮度调整的档位改变后,像素点显示对应于亮度调整的当前档位的第一亮度值时,其对应的输入的第一灰阶值应为实际上像素点所应该输入的灰阶值,也就是Code1。由于不同的输入灰阶值会对应不同的驱动电压,因而也会在屏幕上显示出不同的亮度,因而相应的,用于驱动该像素点的电压并不是Code0所对应的电压值,而是Code1所对应的电压值。
示例性的,假设屏幕为10bit,且始终以白色均匀画面进行显示,则屏幕各像素点所显示的亮度值均相同且都等于屏幕在亮度调整的指定档位下的最大亮度值,即像素点显示亮度为500nit,而对应输入的灰阶值为最大灰阶值1023。当屏幕进行亮度调整时,可以让屏幕从亮度调整的指定档位变化到当前档位时屏幕的亮度值差值为一个固定值,例如该固定值可以取亮度调整的档位变化前的最大亮度值的0.017倍,即△L=L*0.017的阈值,对应的,屏幕上亮度条上的亮度调节点也会相应的移动一格位置刻度。
当屏幕的亮度调整的档位改变至亮度调整的当前档位时,屏幕的最大亮度可以调整到500*(1-0.017)=491.5nit,即亮度调节点在亮度条上移动一格刻度时,屏幕的最大亮度值会由500nit变化至491.5nit,此时,屏幕的初始输入灰阶值Code0不变,而实际对应的输入灰阶值Code1需要改变为其它灰阶值,以显示对应的亮度值。
具体的,由于屏幕在亮度调整的指定档位下的初始输入灰阶值和显示亮度值之间的Gamma校正关系已经预先存储在存储器或寄存器中,该Gamma校正关系可以为一个Gamma校正查找表,可选的,该Gamma校正查找表中可以是一条连续的Gamma曲线,也可以是位于该Gamma曲线上的部分离散的点,因而当屏幕为亮度调整的当前档位时,为了找出各像素点为显示亮度调整的当前档位对应的亮度值而应具有的实际输入灰阶值,也可利用该预设的Gamma校正查找表,获取屏幕上各像素点为了显示亮度调整的当前档位下对应的第一亮度值而所需要的第一输入灰阶值。
S103、根据第一输入灰阶值控制屏幕的显示亮度值。
当重新确定了为了进行正确的图像画面显示,屏幕各个像素点实际应该输入的灰阶值后,即可将该灰阶值作为屏幕上各像素点为了显示在亮度调整的当前档位下对应的第一亮度值,而所应具有的实际输入灰阶值,也就是第一输入灰阶值,并在显示时,将源图像中各像素点的原始灰阶值替换为该实际灰阶值,这样在经过预设Gamma校正查找表处理后,即可得到屏幕在亮度调整的当前档位下的屏幕显示输出。
这样经过上述步骤后,在屏幕的亮度调整的档位发生变化,例如从亮度调整的指定档位调整至亮度调整的当前档位时,随着屏幕整体亮度的改变,屏幕上各个像素点 即可以显示新的亮度值,使屏幕在新的整体亮度下进行图像画面的正常显示。为了使像素点显示新的亮度值,可以基于原先预设的Gamma校正查找表查找到为显示该新的亮度值时,像素点所对应的输入灰阶值,并用该输入灰阶值替换屏幕上源图像的初始灰阶值,以在保持源图像的纹理和图案等特征时,实现图像整体亮度的改变,该过程中,进行Gamma校正过程所用到的始终为同一个Gamma校正查找表。和现有技术中,通过在硬件中预存多个对应不同屏幕亮度预设点的Gamma校正查找表,且并在屏幕调节至不同亮度时,调取对应的Gamma校正查找表进行Gamma校正过程相比,本实施例中的屏幕亮度的控制方法能够显著减少硬件存储空间,从而降低制造成本。此外和基于已知的几个预设亮度值下的Gamma校正查找表插值获得其他亮度值对应的Gamma校正查找表的方法相比,本实施例中的屏幕亮度的方法无论屏幕调节至哪一个亮度调整的档位,均可以通过预设的Gamma校正查找表经过运算而得到对应的输入,因而具有较高的校正精度。
本实施例中,屏幕亮度的控制方法包括先确定屏幕在亮度调整的当前档位下对应的亮度值;再基于预设的伽马Gamma校正查找表确定与亮度值对应的输入灰阶值,Gamma校正查找表为在亮度调整的指定档位下,屏幕的亮度值与屏幕的初始输入灰阶值的Gamma校正关系;最后根据输入灰阶值控制屏幕的亮度。这样可以依靠亮度调整的指定档位下亮度值与输入灰阶值之间的Gamma校正关系获得亮度调整的其它档位下亮度值和输入灰阶值的对应关系,可以基于指定档位下的Gamma校正关系对亮度调整的其它档位下屏幕显示的亮度的实现Gamma校正,不需要存储其他档位下的Gamma校正关系,有效的节省了硬件资源。
进行屏幕的亮度校正过程中,由于一般受限于硬件,屏幕像素点的每一显示亮度值与输入灰阶值之间的对应关系通常会采用一系列离散的点进行表示。以屏幕为10位(10bit)为例,其用于表示显示亮度值与输入灰阶值之间的对应关系的离散的点一共可以有1024个,且每个离散的点均对应灰阶值0-1023中的一个灰阶值以及相应的显示亮度值。这样可以用Gamma校正查找表表示显示亮度值与输入灰阶值之间的对应关系,即Gamma校正查找表可以包括多个离散的灰阶值以及多个显示亮度值,其中,灰阶值的数量等于显示亮度值的数量,且灰阶值与显示亮度值一一对应,离散的灰阶值的数量等于屏幕的灰阶值的总阶数。这样在执行前述实施例中的S102步骤时,即可在基于预设的伽马Gamma校正查找表确定与亮度调整的当前档位下对应的第一亮度值所对应的第一输入灰阶值时,利用这些离散的点所表示的Gamma校正关系获得为亮度调整的当前档位下的第一亮度值而相对应的第一输入灰阶值。
本实施例中,Gamma校正查找表中的多个灰阶值和多个显示亮度值的对应关系可以符合Gamma校正公式,其中,显示亮度值为Gamma校正公式的输入,灰阶值为Gamma校正公式的输出。因而作为一种可选的实施方式,基于预设的Gamma校正查找表确定与亮度调整的当前档位下对应的第一亮度值所对应的第一输入灰阶值的步骤,具体可以包括以下步骤:
基于多个显示亮度值和Gamma校正公式计算得到与多个显示亮度值一一对应的多个灰阶值。
具体的,由于Gamma校正查找表中的灰阶值和显示亮度值均位于Gamma曲线上, 因而可以通过Gamma曲线所对应的Gamma校正公式进行计算,以获取显示亮度值所对应的灰阶值。其中,Gamma曲线所对应的Gamma校正公式通常为幂函数。在根据Gamma校正公式进行求取时,可以先获取屏幕的多个显示亮度值,并根据这些显示亮度值以及Gamma校正公式获取为显示各个显示亮度值而应具有的多个灰阶值。
在上述步骤中,对于不同的屏幕,屏幕会具有不同的亮度调节范围;例如是屏幕的亮度值最高可以为500nit或者800nit不等,因而在使用像素点显示的亮度值获取对应的实际输入灰阶值之前,一般可以设法消除各个亮度值的量纲,例如可以使屏幕在亮度调整的指定档位下的最大亮度值和屏幕在亮度调整的当前档位下的最大亮度值,以及像素点对应亮度调整的当前档位下的第一亮度值和像素点的在亮度调整的指定档位下所显示的亮度值之间的绝对值关系转变为相对值关系,从而消除不同量纲的影响,简化计算过程并提高结果的准确性。
具体的,为了消除亮度值的量纲影响,屏幕的亮度调整的档位在从亮度调整的指定档位调整到亮度调整的当前档位后,可以对各像素中任一像素点在亮度调整的当前档位下对应的第一亮度值进行归一化处理。而经过归一化处理后的亮度值为无量纲值,因而可以直接将其代入,从而得到该像素点在亮度调整的当前档位下的第一亮度值与指定档位下的亮度值之间的相对比例关系。
可选的,对亮度调整的当前档位下对应的第一亮度值进行归一化处理时,具体可以根据公式(1)获得归一化处理后的亮度值。
F
2=F
1*B
2/B
1 (1)
其中,F
2为经过归一化处理后的亮度调整的当前档位下对应的第一亮度值,而F
1为归一化处理后的亮度调整的指定档位下对应的亮度值,B
2为屏幕在亮度调整的当前档位下对应的最大亮度值,B
1为屏幕在亮度调整的指定档位下对应的最大亮度值。
示例性的,亮度调整的指定档位下对应的亮度值经过归一化处理后,通常可以简化为无量纲的纯数字,以便于后续计算。
示例性的,屏幕可以显示纯色图像,此时,屏幕处于亮度调整的指定档位时,且可以让屏幕上各像素点显示的亮度值均为屏幕在亮度调整的指定档位下的最大亮度值。具体的,屏幕在亮度调整的指定档位下的最大亮度值和每个像素点的亮度值均为500nit时,对该亮度值进行归一化处理,则归一化后的亮度调整的指定档位下对应的亮度值可以为:500/500=1。
这样,当屏幕的亮度调整的档位需要调整至亮度调整的当前档位时,例如是此时屏幕在亮度调整的当前档位下的最大亮度值可以为491.5nit时,根据上述公式(1)即可计算得出归一化处理后的亮度调整的当前档位下对应的第一亮度值F
2=1*491.5/500=0.983。
之后,即可基于预设的Gamma校正查找表将归一化处理后的亮度调整的当前档位下对应的第一亮度值对应的灰阶值确定为任一个像素点对应的第一输入灰阶值。
具体的,获得了各像素点中任一个像素点在亮度调整的当前档位下的第一亮度值,并进行归一化处理,从而得到了经过归一化处理后的亮度调整的当前档位下第一亮度值,即0.983后,即可根据预设的Gamma校正查找表,计算得到与该无量纲值所对应的灰阶值,也就是在屏幕在亮度调整的当前档位时,该像素点为显示对应的第一亮度 值而应具有的对应的实际输入灰阶值,即第一输入灰阶值。
具体的,将Gamma校正查找表中输入灰阶值作为横坐标,而对应的输出亮度值作为纵坐标,可得到一条输入灰阶值以及输出亮度值之间的响应曲线Y=(X+e)
γ,其中,Y为输出亮度值,X为输入灰阶值,e为补偿系数,而γ即为曲线的乘幂值,也称伽马值。该曲线即为该Gamma校正查找表所对应的Gamma曲线。且在预设的Gamma校正查找表中的所有灰阶值和亮度值之间的关系均满足幂函数关系。因而可以通过Gamma校正查找表中的幂函数关系得到第二预设亮度值对应的灰阶值。例如,Gamma校正查找表所对应的曲线如图2所示。其中,图2中的横轴为输入灰阶值,而纵轴为输出亮度值,而Gamma校正曲线如图2中实线所示。
作为一种可选的方式,基于预设的Gamma校正查找表确定与归一化处理后的亮度调整的当前档位下的第一亮度值对应的第一输入灰阶值的步骤,具体可以先根据公式(2)获得与归一化处理后的亮度调整的当前档位下的第一亮度值对应的第一输入灰阶值。
f=F
2
1/γ*(N-1) (2)
其中,f为归一化处理后的亮度调整的当前档位下第一亮度值对应的第一输入灰阶值,而γ为预设的Gamma校正查找表中的Gamma值,N为灰阶的总个数。
获得f之后,即可将f确定为任一个像素点对应的输入灰阶值。
具体的,预设的Gamma校正查找表中的Gamma值即为响应曲线的Gamma值,在一种可选的情况中,可以取γ=2.2等。应当理解,灰阶的总个数表示灰度从黑到白(对应二进制数从0到1)一共存在多少个灰阶值,例如,当输入的灰阶值为8bit时,有256个灰阶值即0-255,其中灰阶值取0时对应黑色,灰阶值取255时对应白色;当输入的灰阶值为10bit时,有1024个灰阶值,其中灰阶值取0时对应黑色,灰阶值取1023时对应白色。由于不同屏幕通常具有不同的灰阶个数,例如当输入的灰阶值为8比特时可以具有2
8=256个灰阶,而10位屏幕可以具有2
10=1024个灰阶,因而N的值也会随屏幕的不同而产生变化。本实施例中,可以取N=1024,即屏幕总共具有1024个灰阶。
此外,作为一种可选的方式,由于通过Gamma校正公式所计算获得的结果可能是小数,而Gamma校正查找表中所存储的灰阶值均为整数。这样亮度调整的当前档位下的第一亮度值没有包含在Gamma校正查找表中时,基于预设的Gamma校正查找表确定与第一亮度值对应的第一输入灰阶值的步骤具体还可以包括:先获得Gamma校正查找表中最接近亮度调整的当前档位下的第一亮度值的显示亮度值;然后将最接近预设亮度值的显示亮度值对应的灰阶值作为与第一亮度值对应的第一输入灰阶值。
依然举例进行说明,在利用公式(1)得到了归一化处理后的第一亮度值为0.983后,即可将该值代入公式(2)中进行计算,可得f=0.983
1/2.2*(1024-1)=1015.06,该数值包含小数,而在已有的用于表示显示亮度值与输入灰阶值之间的对应关系的离散的点中,每个离散点的灰阶值均为整数,所以该结果并不包含在预设的Gamma校正查找表中。此时,可以取与该计算结果最近似的整数作为其对应的灰阶值,则具有该灰阶值的点对应的显示亮度可以近似为亮度调整的当前档位下对应的亮度值。此处由于f=1015.06,因而可以取与该f值最接近的整数1015,该1015即为经过归一化处理 后的亮度调整的当前档位下的第一亮度值所对应的第一输入灰阶值,而所有离散的点中表示灰阶值1015的点即可近似显示该亮度调整的当前档位下的第一亮度值。
当通过一系列离散的点表示显示亮度值和输入灰阶值之间的对应关系时,由于每个离散的点均表示一个整数灰阶值,因而通过这些离散的点所得到的灰阶值结果和实际显示亮度调整的当前档位下的亮度值所需要的输入灰阶值较为接近。例如在上述计算过程中,计算得到的灰阶值1015和实际显示亮度调整的当前档位下的第一亮度值所具有的第一输入灰阶值1015.06之间只有很小的误差(0.06),即小于一个整数灰阶值,而当预设的Gamma校正查找表内灰阶值的数量较多(例如10bit的屏幕具有1024个不同灰阶值)时,相邻两个灰阶值所对应显示的亮度值之间仅存在较小的差异,因而能够在节约存储器空间或者处理能力等硬件资源的同时,较为准确的表示输入灰阶值和显示亮度值之间的对应关系。
例如,在图2中,假设亮度未改变前,屏幕在亮度调整的指定档位下进行显示,此时,屏幕的最大亮度值为500nit。此时,亮度值为500nit的像素点对应的输入灰阶值为1023,且该档位下像素点为其它亮度值对应的输入灰阶值可以根据该档位下的Gamma曲线获得,示例性的,当屏幕的亮度调整的指定档位为最大亮度值对应500nit的档位时,其对应的Gamma曲线可以是如图2中的实线所示的Gamma曲线。此时,Gamma曲线上的点b的纵坐标为某一个像素点的在亮度调整的指定档位下的亮度值F1,假设和屏幕在该亮度调整的指定档位下的最大亮度值相同,均为500nit,而a点横坐标为该像素点的在亮度调整的指定档位下的亮度值F1对应的灰阶值,容易理解其为1023,如箭头1所示。
当将屏幕的亮度调整的档位由指定档位调整至亮度调整的当前档位时,此时,最大亮度值由亮度调整的指定档位下的500nit调整为亮度调整的当前档位下的491.5nit。示例性的,此时屏幕对应的Gamma曲线可以是虚线所示的Gamma曲线;应当理解,当屏幕的亮度调整的档位改变时,像素点输入灰阶值与显示的亮度值对应的Gamma曲线也会改变,即不同基准对应不同Gamma曲线。在本申请实施例中,只有一组Gamma曲线,当屏幕的亮度调整的档位变化之后,要基于该唯一的一组Gamma曲线获取其他基准亮度下的Gamma曲线,并获取相应档位情况下每个亮度值对应的输入灰阶值。此时,该像素点的亮度值也会随之变化,并变为亮度调整的当前档位下的亮度值F2,如图2中箭头2所示。示例性的,亮度调整的当前档位下的亮度值F2和屏幕在亮度调整的当前档位下的最大亮度值相同,均为491.5nit。
当屏幕调整亮度调整的当前档位时,其最大亮度值相应的变为491.5nit,此时输入灰阶值为1023时对应的亮度值为491.5nit,然而,最大亮度值为491.5nit时的档位所对应的Gamma曲线实际上并不存在,因此要基于亮度调整的指定档位,也就是最大亮度值为500nit所对应的Gamma曲线,即图2中的实线获取亮度值显示为491.5nit时,其对应的输入灰阶值实际上应该是多少,并将屏幕上源图像的初始输入灰阶值替换为该实际输入灰阶值,以进行屏幕在亮度调整的当前档位下像素点的正常亮度显示。具体的,在获取像素点显示亮度调整的当前档位下的亮度值F2时所对应的输入灰阶值,需要利用新的亮度调整的当前档位下亮度值F2在原先屏幕亮度调整的指定档位下的Gamma校正曲线上的对应点,也就是图中的点a,具体如箭头3所示。
此时点a的纵坐标为亮度调整的当前档位下的亮度值F2,示例性的,和屏幕在亮度调整的当前档位下的最大亮度值均为491.5nit,而点a的横坐标即为屏幕基准亮度调整后,像素点在显示亮度调整的当前档位下的亮度值时对应的灰阶值f,因而可以通过Gamma校正曲线上点a的位置获取点a的横坐标,例如是1015,即像素点显示亮度调整的当前档位下的亮度值时对应的灰阶值f,如箭头4所示。这样,即可将1015作为某像素点在显示491.5nit时的实际输入灰阶值。对应的,屏幕的最大亮度值为491.5的亮度调整的档位下,屏幕上其他像素点的为显示各自在亮度调整的当前档位下的第一亮度值而对应的实际的第一输入灰阶值也可以通过相同的方法确定。
其中,需要说明的是,屏幕各像素点的灰阶值通常具有一个范围,即均会小于或等于一个最大灰阶值,这样曲线上的点均会位于横坐标为最大灰阶值max的竖直线的左方。通常的,最大灰阶值通常为屏幕显示全白画面时所输入的灰阶值。
本实施例中,在对屏幕的亮度进行调整时,让屏幕的输入灰阶值和显示的亮度值之间的对应关系始终符合伽马曲线,在调整的过程中避免屏幕显示的亮度出现灰阶色偏。同时该方法只需要一组离散的数值来表示输入灰阶值与显示亮度值之间的对应关系,并基于这组离散的数值确定屏幕在亮度调整的档位改变后,为了显示应有的亮度而应该具有的实际输入灰阶值,节省了存储空间,降低了硬件成本;且由于该组离散的数值包括了所有整数灰阶值以及对应显示亮度值之间的对应关系,因而确定的输入灰阶值精度更高,屏幕亮度调整的精度也更高。
为了进一步减少占用的存储空间、降低硬件成本,预设Gamma校正查找表中通常存储个数有限的离散的数值,例如可以只测量30种典型输入灰阶值与显示的亮度值的对应关系,此时预设的对应关系为30组离散的点,该30组离散的点均位于同一条Gamma曲线上,可选的,该预设的对应关系可以称为Gamma校正查找表,可选的,该30组离散的点可以在Gamma曲线上等间隔分布。这样虽然Gamma校正查找表中存储了多个灰阶值以及对应的显示亮度值,但灰阶值的数量小于屏幕所能显示灰阶值的总数量。这样屏幕的亮度调整的档位由亮度调整的指定档位调整为亮度调整的当前档位时,屏幕上各像素点在亮度调整的当前档位下所显示的亮度值可能并未被储存在该预设Gamma校正表之中。因而,在执行实施例一的屏幕亮度的控制方法中的S102步骤,也就是基于预设的Gamma校正查找表确定与亮度调整的当前档位下亮度值对应的输入灰阶值时,也可以采用线性插值的方法进行灰阶值的获取计算。图3是本申请实施例提供的一种确定与亮度调整的当前档位下第一亮度值对应的第一输入灰阶值的流程示意图。如图3所示,本实施例中,作为另一种可选的实施方式,基于预设的Gamma校正查找表确定与亮度调整的当前档位下亮度值对应的输入灰阶值的步骤,具体可以包括以下步骤:
S201、基于Gamma校正查找表确定与亮度调整的当前档位下的第一亮度值直接相邻的两个显示亮度值。
其中,为了节省硬件资源,在预设的Gamma校正查找表中仅包含有输出亮度值与输入灰阶值的所有Gamma校正关系中的一部分。因而如果屏幕由亮度调整的指定档位调整至亮度调整的当前档位,而像素点对应亮度调整的当前档位下的第一亮度值未包含在该部分Gamma校正关系中时,则可以通过线性插值方法获得与亮度调整的 当前档位下的第一亮度值所对应第一输入灰阶值近似的灰阶值,并将该近似的灰阶值作为屏幕的实际输入灰阶值,这样屏幕即可实现在亮度调整的当前档位下的正常亮度显示。
由于Gamma校正查找表中各个亮度值与灰阶值的对应关系均位于一条Gamma曲线上,因而当Gamma曲线中的弧段长度较小时,可以用直线进行近似替换,而满足该直线方程的亮度值与灰阶值,也可近似相当于位于Gamma曲线上。
示例性的,可以选择在Gamma校正查找表中选择几组合适的亮度值与灰阶值之间的已知的对应关系,例如,可以选两组输出亮度值与输入灰阶值的对应关系,并根据这些对应关系进行线性插值计算。具体的,可以选择与亮度调整的当前档位下的第一亮度值直接相邻的两个显示亮度值。由于这两个显示亮度值和亮度调整的当前档位下的第一亮度值直接相邻,因而亮度调整的当前档位下的第一亮度值位于这两个显示亮度值之间,且这两个显示亮度值为Gamma校正查找表中与亮度调整的当前档位下第一亮度值相邻的亮度值。
S202、基于直接相邻的两个显示亮度值及其对应的灰阶值建立线性插值方程。
获得了与亮度调整的当前档位下的第一亮度值直接相邻的两个显示亮度值之后,即可根据这两个显示亮度值以及相应的灰阶值建立一个近似满足Gamma曲线中对应弧段的线性插值方程,例如是直线方程等。在一种可选的情况中,直线方程为一元方程,变量和因变量的个数均只有一个。通过合适的亮度值与灰阶值取值,该直线方程也能够近似满足亮度调整的当前档位下的第一亮度值以及对应的第一输入灰阶值之间的关系,即可作为线性插值方程使用,例如当屏幕由指定档位调整到亮度调整的当前档位时,即可以根据直接相邻的两个显示亮度值以及对应灰阶值建立线性插值方程。
具体的,可以将亮度值和灰阶值中的一个作为方程的变量,而另一个作为方程的因变量,从而将包括屏幕在亮度调整的指定档位下的最大亮度值以及对应灰阶值在内的多个对应关系代入该线性插值方程中,从而反推出该线性插值方程的具体表达式。示例性的,假设屏幕在指定档位下的最大亮度值为两个直接相邻的显示亮度值中的一个,则屏幕在指定档位下的最大亮度值以及对应灰阶值可以作为第一组变量和因变量,并在预设的Gamma校正查找表中选择与亮度调整的当前档位下的第一亮度值相邻,且小于第一亮度值的亮度值以及对应的灰阶值作为第二组变量与因变量;将其作为方程的已知参数,而将方程中原先的参数作为待求取量进行求取。通过多组变量和因变量即可反求出方程原先已知参数的具体数值;将参数的具体数值代入方程后,即可求得线性插值方程,下面对求取线性插值方程的过程进行举例说明。
作为其中一种可选的实施方式,在基于直接相邻的两个显示亮度值及其对应的灰阶值建立线性插值方程时,与亮度调整的当前档位下的第一亮度值直接相邻的两个显示亮度值分别为指定档位下的最大亮度值以及另一相邻亮度值。图4是本申请实施例提供的屏幕亮度的控制方法中Gamma校正查找表对应的Gamma曲线示意图。如图4所示,由于预设的Gamma校正查找表中的亮度值和灰阶值均位于以输入灰阶值为横轴坐标,显示的亮度值为纵轴坐标的同一条Gamma曲线上,因而屏幕在亮度调整的指定档位下的最大亮度值以及对应的灰阶值分别为该Gamma曲线上点A的纵坐标以及横坐标,而屏幕各像素点在指定档位下的亮度值以及与该亮度值所对应的灰阶值即 分别为Gamma曲线上点B的纵坐标以及横坐标。此时,即可以在Gamma曲线上选择一个C点,C点的纵坐标为两个直接相邻的显示亮度值中的另一相邻亮度值,而横坐标为该另一相邻亮度值所对应的灰阶值。
由于屏幕像素点在亮度调整的当前档位下的第一亮度值位于两个直接相邻的显示亮度值之间,因而B点也会位于A点和C点之间。这样如果通过A点和C点作一直线,则B点也会近似处于该直线上,从而可以根据A点和C点坐标求取该直线的方程表达式,并将其作为线性插值方程进行B点坐标的求取。
具体的,可以根据公式Y
1=a*X
1+b以及Y
2=a*x
2+b确定a和b。
其中,Y
1为屏幕在亮度调整的指定档位下的最大亮度值,X
1为屏幕在亮度调整的指定档位下的最大亮度值对应的灰阶值,Y
2为C点的亮度值,X
2为C点对应的灰阶值。
由于线性插值方程为一条直线的方程表达式,所以可以令该线性插值方程为y=a*x+b;其中,x为横坐标,也就是灰阶值;y为纵坐标,也就是灰阶值对应的亮度值,而a为线性插值方程所表示的直线的斜率,b为线性插值方程所表示的直线在y轴上的截距。由于线性插值方程所表示的直线经过A点和C点,因而可以将A点与C点的横纵坐标代入该线性插值方程,即可求出a和b的值。
在上一步骤中得到了a和b的具体数值之后,即可令a表示线性插值方程所表示的直线的斜率,而b为线性插值方程所表示的直线在纵轴上的截距,从而根据a和b的实际数值建立线性插值方程。该线性插值方程所代表的直线即可近似模拟Gamma曲线在A点与C点之间的弧段。
S203、根据线性插值方程和亮度调整的当前档位下的第一亮度值获取与第一亮度值对应的第一输入灰阶值。
而当根据直接相邻的两个亮度值和灰阶值对应关系获得线性插值方程后,即可将各像素点中任一个像素点的在亮度调整的当前档位下的第一亮度值作为变量代入该线性插值方程中,而所求取的方程因变量即可近似等于该像素点在显示亮度调整的当前档位下的第一亮度值所对应的第一输入灰阶值,如步骤S303所示。
具体的,该步骤中,可以根据公式y=a*x+b
获取任一个像素点对应的输入灰阶值,其中,y为亮度调整的当前档位下的第一亮度值,x为亮度调整的当前档位下的第一亮度值对应的第一输入灰阶值。这样以亮度调整的当前档位下的第一亮度值为纵坐标,和亮度调整的当前档位下的第一亮度值对应的第一输入灰阶值为横坐标的点均位于一条以a为斜率,以b为在y轴上的截距的直线之上。其中,a和b的具体数值均已求出,因而可以直接根据公式求取得到各像素点中任一个像素点所对应的灰阶值。对屏幕上各个像素点均进行如上处理,即可得到屏幕的档位为亮度调整的当前档位时,各像素点所应输入的第一输入灰阶值。此外,也可以根据其它线性插值算法建立线性插值公式,并以预设Gamma校正查找表中的输入灰阶值和显示的亮度值之间的关系确定线性插值公式的具体表达式,并用该线性插值公式求取和亮度调整的当前档位下第一亮度值对应的第一输入灰阶值,作为各像素点中任一像素点在显示亮度调整的当前档位下的第一亮度值时对应的第一输入灰阶值。
本实施例中,在对屏幕的亮度进行调整时,使屏幕的输入灰阶值和显示的亮度值之间始终符合伽马曲线,在调整的过程中避免屏幕显示的亮度出现灰阶色偏与亮度闪烁;同时该方法只需要指定档位下的Gamma校正关系,即可确定屏幕在亮度调整的其它档位对屏幕显示的亮度进行Gamma校正,不需要存储其他档位下的Gamma校正关系,节省了存储空间,降低了硬件成本;且所采用的预设Gamma校正查找表中仅包括有限个输入灰阶值与显示亮度值之间的对应关系,而其它为被包含在预设Gamma校正查找表中的对应关系是通过简单的线性插值运算方式得到的,在实现较高的灰阶值输入精度的同时,运算速度较快,处理器开销较小。
当屏幕为AMOLED等屏幕时,由于AMOLED显示面板在生产过程中,会由于工艺原因(例如整面的蒸镀均匀性以及膜厚控制等)而导致个别像素点的发光特性发生变化,此时,个别像素点在驱动电压相同时,流经的电流大小会出现大小不一的现象,这样就会造成屏幕上个别像素点在显示时出现亮度不均(Mura)。而为了对屏幕的Mura现象进行校正,屏幕还需要进行对Mura现象进行补偿消除,即Demura步骤。因而在前述实施例的基础上,屏幕亮度的控制方法中还可以加入用于消除Mura现象的步骤。图5是本申请实施例提供的另一种屏幕亮度的控制方法的流程示意图。如图5所示,当屏幕包含不均匀Mura区域,且屏幕的各像素点在初始亮度调整的档位下对应的亮度值均为第二亮度值时,本实施例提供的屏幕亮度的控制方法中,为了在对屏幕进行亮度控制的同时进行屏幕Mura现象的校正和补偿,确定屏幕在亮度调整的当前档位下对应的亮度值之前,还可以包括如下步骤:
S301、在对屏幕进行Demura之前,基于预设的Gamma校正查找表确定与第二亮度值对应的第二输入灰阶值。
具体的,由于屏幕在进行显示时,因为人眼的敏感度或者是屏幕自身光电特性,会导致屏幕输出的图像和输入图像之间会存在失真现象,因而为了避免屏幕显示的亮度值与原始图像的亮度值出现偏差,就需要对屏幕输入的灰阶值进行校正。具体的,在进行伽马校正时,可以利用预设的Gamma校正查找表对屏幕的像素点进行伽马补偿,以获取屏幕在指定档位下,各像素点显示的亮度值为第二亮度值时各像素点对应的输入灰阶值,从而即可校正屏幕实际显示的图像在亮度上的偏差。其中获取输入灰阶值的具体方式和步骤可见前述实施例中步骤S102的具体说明,此处不再赘述。
当屏幕的各个像素点在初始亮度调整的档位下显示的第二亮度值均为相同值,例如是屏幕在初始亮度调整的档位下的最大亮度值时,则屏幕为均色画面显示。这样就可以基于预设的Gamma校正查找表确定当屏幕在初始亮度调整的档位下,像素点显示最大亮度值所对应的第二输入灰阶值。
S302、根据第二输入灰阶值控制屏幕的各像素点的显示亮度值。
获得了第二输入灰阶值后,即可将各个像素点的输入灰阶值均确定为该第二输入灰阶值,这样屏幕的像素点应显示与第二输入灰阶值对应的第二亮度值,因而可以根据该第二输入灰阶值控制各像素点的显示亮度,使屏幕进行显示。
此时,屏幕中包括有Mura区域,即各像素点中包含有亮度值不均匀的像素点,因而需要进行Demura调整,使所有像素点在显示画面时保持均匀的亮度。
具体的,由于屏幕中可能存在有Mura现象,因而当屏幕上各像素点均输入相同 的灰阶值时,可能会在某些区域或者某些像素点呈现出与其它像素点不同的亮度输出。因而,需要进行Demura步骤,让屏幕上各像素点的相同灰阶值的输入均能够对应输出相同亮度值。由于mura补偿是以伽马校正后的亮度数据为基础,因而补偿步骤需要根据预设的Gamma校正查找表对屏幕的初始像素点进行伽马校正,以使屏幕输出亮度值与输入灰阶值之间遵循伽马曲线的步骤之后。
其中,进行补偿的方法具有较多的种类,例如实现内部补偿或者外部补偿等。进行补偿时,通常会获取像素点在输入指定灰阶值时,示例性的,为第二输入灰阶值时对应呈现的实际亮度值,或者是像素点在输出一定亮度值时,示例性的,为屏幕在初始亮度调整的档位下的最大亮度值时像素点对应输入的灰阶值,并根据像素点的灰阶值与亮度值之间的关系进行补偿,使屏幕上各个像素点的输入输出特性保持一致。
具体的,进行补偿时,通常可以利用让屏幕上各像素点均输入相同的第二输入灰阶值,此时若屏幕上不存在mura区域,则屏幕所输出的亮度应该处处相等,且均为第二亮度值。因而可以利用高倍照相机等设备对屏幕进行拍摄,获取屏幕上每一像素点的实际显示亮度。如果屏幕存在Mura现象,则出现Mura现象的区域中像素点的亮度会异于区域外像素点的亮度。这样即可对照相机所拍摄的数据进行分析后,利用补偿数据,例如是Mura补偿表,来对每个像素点的亮度进行补偿,使整个屏幕能够进行亮度的均匀显示。具体的,补偿数据中可以包括有待补偿的像素点在屏幕中的坐标以及像素点显示统一亮度时,在进行补偿前后的灰阶值的对应关系。
其中,为了方便后续进行亮度控制,在步骤S301中,可以让屏幕中每个像素点的亮度值均为屏幕在初始亮度调整的档位下对应的最大亮度值,也就是屏幕在该亮度调整的档位下显示全白颜色时的亮度。示例性的,当屏幕的整体均输出该最大亮度值时,可以利用Mura补偿数据对位于mura区域内的像素点的输入灰阶值进行更改或者是替换,从而让mura区域内的像素点能够和其它区域的像素点输出同样的显示亮度值。
这样通过Demura步骤之后,即可对屏幕的Mura现象进行补偿,从而使屏幕各像素点具有均匀的亮度。
S303、确定屏幕在亮度调整的当前档位下对应的第一亮度值。
由于经过Demura步骤之后,屏幕能够进行均匀显示,因而之后即可根据亮度调整的当前档位,确定各像素点为了在亮度调整的当前档位下正常显示而对应显示的第一亮度值。
S304、基于预设的伽马Gamma校正查找表确定与第一亮度值对应的第一输入灰阶值,Gamma校正查找表为在亮度调整的指定档位下,屏幕的亮度值与屏幕的初始输入灰阶值的Gamma校正关系。
当屏幕进行亮度控制,例如是将屏幕的亮度调整的档位从原先的亮度调整的指定档位调整至亮度调整的当前档位时,屏幕上各个像素点的亮度也需要随之发生变化,以保证图像画面的正确显示。为了确定此时屏幕对于画面的显示输出,需要根据屏幕输入和输出之间的伽马曲线特性,重新确定屏幕各个像素点显示亮度调整的当前档位下的第一亮度值时,各个像素点所应具有的第一输入灰阶值。
具体的,由于屏幕的输入灰阶值和输出亮度值之间的关系可以通过预设的Gamma校正查找表而获得,因而当屏幕在亮度调整的当前档位时,也可利用预设的Gamma 校正查找表,获取屏幕上各像素点为了在亮度调整的当前档位下保持对应的第一亮度值而所需要实际输入的第一输入灰阶值。在利用预设的Gamma校正查找表获取屏幕各像素点的实际输入灰阶值时,可以通过公式计算的方式进行求取。其中得具体步骤可以参见前述实施例中各步骤相关说明,此处不再赘述。
S305、根据第一输入灰阶值控制屏幕的显示亮度值。
在获得了为了让屏幕在亮度变化后进行画面正常显示,各个像素点为了显示对应的亮度所应具有的实际的第一输入灰阶值后,即可将该第一输入灰阶值作为像素点的实际输入,并利用预设的Gamma校正查找表实现正确的显示亮度输出,从而让屏幕调整为亮度调整的当前档位时,实现画面的正确显示。
本实施例中,首先需要使屏幕上各初始像素点输出相同的第二灰阶值,然后利用mura补偿使屏幕上各个像素点的亮度表现一致,最后在屏幕亮度调节时,获取屏幕亮度改变后,像素点的输入灰阶值和输出亮度值之间的正确对应关系,从而使屏幕显示出的图像的亮度与想要显示的图像的亮度一致。这样在mura补偿的步骤的前后都基于同一个预设Gamma校正查找表对屏幕的亮度进行校正,因而能够在利用mura补偿步骤保持屏幕显示均匀性的同时,实现对屏幕亮度的控制,同时屏幕的输入灰阶值与输出亮度值之间具有正确的对应关系,使屏幕图像显示正常的亮度和明暗变化。这样和现有的mura补偿步骤与Gamma校正步骤分开进行,且mura补偿步骤由光学厂家进行,而Gamma校正步骤主要由驱动芯片厂家完成的屏幕亮度的控制方法相比,只需要利用同一个预设Gamma校正查找表进行操作,因而可以将其整合成利用同一个硬件架构实现,整合性较好。
本实施例中,在对屏幕进行Demura之前对包含Mura区域的屏幕进行Gamma校正,并在亮度调整的过程中对经过Demura操作的屏幕进行Gamma校正,既可以确保屏幕的均匀性,又可以使屏幕在亮度调整的过程中始终实现正确的亮度显示,此外Demura之前进行的Gamma校正是基于亮度调整过程中同一个Gamma校正查找表进行的,可以实现较好的硬件整合性,且节省了存储空间,降低了硬件成本,且硬件整合性较好。
本申请实施例还提供一种屏幕亮度的控制装置,以执行前述实施例中的屏幕亮度的控制方法。如图6所示,本实施例提供的屏幕亮度的控制装置100可以包括:
亮度确定模块61,用于确定屏幕在亮度调整的当前档位下对应的第一亮度值。
第一Gamma校正模块62,用于基于预设的Gamma校正查找表确定与第一亮度值对应的第一输入灰阶值,Gamma校正查找表为在亮度调整的指定档位下,屏幕的亮度值与屏幕的初始输入灰阶值的Gamma校正关系。
亮度调整模块63,用于根据第一输入灰阶值控制屏幕的显示亮度值。上述亮度确定模块61、第一Gamma校正模块62以及亮度调整模块63的具体功能具体请参照方法侧步骤S101至S103部分的描述。
可选的,Gamma校正查找表可以包括多个离散的灰阶值以及多个显示亮度值,灰阶值的数量等于显示亮度值的数量,灰阶值与显示亮度值一一对应,离散的灰阶值的数量等于屏幕的灰阶值的总阶数。
或者,Gamma校正查找表也可以包括多个离散的灰阶值以及多个显示亮度值,灰 阶值的数量等于显示亮度值的数量,灰阶值与显示亮度值一一对应,离散的灰阶值的数量小于屏幕的灰阶值的总阶数。
可选的,离散的灰阶值和离散灰阶值中任一灰阶值对应的显示亮度值构成的二维坐标点均位于一条Gamma曲线上,其中,Gamma曲线的横坐标表示灰阶值,Gamma曲线的纵坐标表示显示亮度值。
可选的,屏幕在当前档位下的当前亮度值与亮度调整的前一档位的先前亮度值之间满足预设条件,其中当前亮度值与先前亮度值对应相同的输入灰阶值,预设条件为:相邻档位的亮度值差值与先前亮度值的比例满足韦伯定律。其中,亮度值差值为当前亮度值与先前亮度值之间的差值。
可选的,屏幕在指定档位下所支持的最大亮度值大于屏幕在亮度调整的当前档位下所支持的最大亮度值。
可选的,指定档位为屏幕亮度调整时所支持的最大档位。
可选的,第一Gamma模块62具体用于先确定屏幕显示的亮度值为亮度调整的当前档位下对应的第一亮度值时屏幕对应的初始输入灰阶值;再用基于Gamma校正查找表确定的输入灰阶值替换初始输入灰阶值,以作为与第一亮度值对应的第一输入灰阶值。
可选的,Gamma校正查找表中的多个灰阶值和多个显示亮度值的对应关系符合Gamma校正公式,其中,显示亮度值为Gamma校正公式的输入,灰阶值为Gamma校正公式的输出;此时,控制装置还可以包括:Gamma校正查找表获取模块66,用于基于多个显示亮度值和校正公式计算得到与多个显示亮度值一一对应的多个灰阶值。
可选的,亮度调整的当前档位下的第一亮度值没有包含在Gamma校正查找表中时,第一Gamma校正模块62还用于先获得Gamma校正查找表中最接近亮度调整的当前档位下的第一亮度值的显示亮度值;再将最接近亮度调整的当前档位下的第一亮度值的显示亮度值对应的灰阶值作为与第一亮度值对应的第一输入灰阶值。
可选的,当亮度调整的当前档位下的第一亮度值没有包含在Gamma校正查找表中时,第一Gamma校正模块62具体用于先基于Gamma校正查找表确定与亮度调整的当前档位下的第一亮度值直接相邻的两个显示亮度值;再基于直接相邻的两个显示亮度值及其对应的灰阶值建立线性插值方程;最后根据线性插值方程和亮度调整的当前档位下的第一亮度值获取与第一亮度值对应的第一输入灰阶值。
可选的,为了消除屏幕上个别像素点在显示时的亮度不均(Mura)现象,保证屏幕显示的均匀性,此时,屏幕上各个像素点的初始预设亮度值均为第二亮度值,且获取模块62还用于基于预设的gamma校正查找表确定当在初始亮度调整的档位下对应亮度值为第二亮度值时,所对应的第二输入灰阶值;然后将第二输入灰阶值作为屏幕的各个像素点输入的灰阶值。
此时,为了保证屏幕显示的均匀性,图7中提供另一种屏幕亮度的控制装置200,和图7中的屏幕亮度的控制装置100类似,屏幕亮度的控制装置200同样包括上述各个模块,且屏幕亮度的控制装置200还可以包括:
第二Gamma校正模块64,用于在对屏幕进行Demura之前,基于预设的Gamma校正查找表确定与第二亮度值对应的第二输入灰阶值。
第二Gamma校正模块64还用于将第二输入灰阶值作为屏幕的各像素点的输入灰阶值。
此外,装置还包括Mura校正模块65,用于对屏幕进行Demura。其中,第二Gamma校正模块64以及Mura校正模块65的具体功能可见前述方法侧步骤S301至S302等部分的描述。
需要说明的是,应理解图6至图7所示装置的各个模块的划分仅仅是一种逻辑功能的划分,实际实现时可以全部或部分集成到一个物理实体上,也可以物理上分开。且这些模块可以全部以软件通过处理元件调用的形式实现;也可以全部以硬件的形式实现;还可以部分模块通过软件通过处理元件调用的形式实现,部分模块通过硬件的形式实现。例如,第一Gamma校正模块62可以为单独设立的处理元件,也可以集成在该装置的某一个芯片中实现,此外,也可以以程序的形式存储于该装置的存储器中,由该装置的某一个处理元件调用并执行该第一Gamma校正模块62的功能。其它模块的实现与之类似。此外这些模块全部或部分可以集成在一起,也可以独立实现。这里所述的处理元件可以是一种集成电路,具有信号的处理能力。在实现过程中,上述方法的各步骤或以上各个单元可以通过处理器元件中的硬件的集成逻辑电路或者软件形式的指令完成。
以上这些模块可以是被配置成实施以上方法的一个或多个集成电路,例如:一个或多个特定集成电路(application-specific integrated circuit,ASIC),或,一个或多个数字信号处理器(digital signal processor,DSP),或,一个或者多个现场可编程门阵列(field-programmable gate array,FPGA)等。再如,当以上某个模块通过处理元件调度程序的形式实现时,该处理元件可以是通用处理器,例如中央处理单元(central processing unit,CPU)或其它可以调用程序的处理器。再如,这些模块可以集成在一起,以片上系统(system-on-a-chip,SOC)的形式实现。
图8是本申请实施例提供的一种终端设备的硬件结构示意图。如图8所示,该终端设备300包括:处理器71、第一Gamma选择器72、第一Gamma校正控制器73和屏幕74。
其中,处理器71用于确定屏幕74在亮度调整的当前档位下对应的第一亮度值。
第一Gamma选择器72用于基于预设的Gamma校正查找表确定与第一亮度值对应的第一输入灰阶值,Gamma校正查找表为在亮度调整的指定档位下,屏幕的亮度值与屏幕的初始输入灰阶值的Gamma校正关系。
第一Gamma校正控制器73用于根据第一输入灰阶值控制屏幕的显示亮度值。
这样,本实施例中的终端设备,可以执行前述实施例中的屏幕亮度的控制方法,屏幕亮度的控制方法的具体过程和步骤已在前述实施例中进行了详细说明,此处不再赘述。
这样,当处理器71确定了第一亮度值后,即可利用第一Gamma选择器72根据预设的Gamma校正查找表确定与该第一亮度值对应的第一输入灰阶值,然后再让第一Gamma校正控制器73根据该第一输入灰阶值控制屏幕74的显示亮度值。其中,第一Gamma选择器72所执行的具体功能和作用类似于前述实施例中第一Gamma校正模块62的功能,而第一Gamma校正控制器73所执行的具体功能和作用类似于前 述实施例中亮度调整模块63的功能,此处不再赘述。
其中,第一Gamma选择器72可以集成于处理器71上,也可以为独立于处理器71的硬件逻辑或硬件电路。而第一Gamma校正控制器73通常可以为独立于处理器71的硬件,例如是驱动电路等。
此外,可选的,终端设备300中还可以包括存储器75,存储器75用于存储预设的gamma校正查找表。
其中,屏幕74通常为由有机发光显示器(Organic Light Emitting Display,简称OLED)或者主动矩阵有机发光二级体(Active-matrix organic light emitting diode,AMOLED)构成。示例性的,以屏幕74为OLED屏幕进行说明,为了让OLED屏幕的各个像素点进行期望的亮度和颜色显示输出,终端设备中的第一Gamma校正控制器可以根据第一Gamma选择器所获取的输入灰阶值而产生相应的电压进行驱动,屏幕通入不同的电压时,即可显示不同的亮度,从而显示与输入灰阶值对应的显示亮度值。
具体的,第一Gamma校正控制器73可以包括有电压生成器以及亮度控制器。其中,电压生成器能够用于根据输入灰阶值而生成相应的参考电压;而亮度控制器可以用于基于参考电压控制屏幕显示与输入灰阶值对应的显示亮度值。
其中,由于输入灰阶值通常为数字信号,为了将输入灰阶值转换成为模拟的电压值,可选的,电压生成器731可以为数模转换器(Digital to analog converter,DAC)。数模转换器用于将输入的灰阶值转换为模拟的参考电压值,这样亮度控制器732即可根据该参考电压控制屏幕的显示亮度值,以使屏幕在通电时显示对应的显示亮度值。具体的,数模转换器能够在接收到呈数字信号的输入灰阶值后,将该输入灰阶值变为实际的参考电压值。当输入的灰阶值不同时,对应的参考电压值也会随之改变,这样屏幕就可以在不同的参考电压值以及电流值激发下发出不同亮度的光线,显示实际图像。
其中,处理器71、第一Gamma选择器72、第一Gamma校正控制器73和存储器75之间可以利用通信总线或者其它数据通路实现数据和信号之间的传输。由于存储器75和处理器71、第一Gamma选择器72以及第一Gamma校正控制器73之间具有电性连接,因而存储器75中所存储的预设gamma校正查找表可以传输给第一Gamma选择器72,以让第一Gamma选择器72根据该预设gamma校正查找表查找屏幕74的亮度调整的档位变化后,像素点所应具有的输入灰阶值,并让第一Gamma校正控制器73根据输入灰阶值控制屏幕74各像素点的显示亮度值等。
其中,处理器71通常为终端设备的控制中心,并可以利用通信总线与存储器75等不同硬件部分直线连接,并通过运行或执行软件程序和/或模块,以及调用存储在存储器内的数据,执行终端设备的各种功能和处理数据,从而完成屏幕的亮度控制操作。处理器71可以是微控制单元(Microcontroller Unit,MCU),或者是中央处理器(central processing unit,CPU),或者是独立的片上系统(system-on-a-chip,SOC),还可以是被配置成实施以上方法的一个或多个集成电路,例如:一个或多个特定集成电路(application specific integrated circuit,ASIC),或,一个或多个微处理器(digital singnal processor,DSP),或,一个或者多个现场可编程门阵列(field programmable gate array, FPGA)等。
可选的,处理器71可包括一个或多个处理单元;并利用不同的处理单元分别执行上述不同指令和程序,以分别执行不同功能。
而存储器75可以是只读存储器(read-only memory,ROM)或可存储静态信息和指令的其他类型的静态存储设备,随机存取存储器(random access memory,RAM)或者可存储信息和指令的其他类型的动态存储设备,也可以是电可擦可编程只读存储器(electrically erasable programmable read-only memory,EEPROM)、只读光盘(compact disc read-only memory,CD-ROM)或其他光盘存储、光碟存储(包括压缩光碟、激光碟、光碟、数字通用光碟、蓝光光碟等)、磁盘存储介质或者其他磁存储设备、或者能够用于携带或存储具有指令或数据结构形式的期望的程序代码并能够由计算机存取的任何其他介质,但不限于此。存储器74可以是独立存在,通过总线与处理器71以及第一Gamma选择器72相连接。存储器75也可以和处理器71集成在一起。
除了存储预设的gamma校正查找表之外,可选的,存储器75还可以用于存储执行本申请方案的应用程序代码,并由处理器71来控制执行。处理器71用于执行存储器75中存储的应用程序代码,从而实现本申请上述实施例提供的屏幕亮度的控制方法。
此外,由于OLED屏幕或者是AMOLED屏幕自身工艺的原因,经常会出现个别像素点的发光特性发生变化,从而造成屏幕上个别像素点在显示时出现亮度不均(Mura)现象。为了消除OLED屏幕的亮度不均(Mura)现象,可选的,终端设备还可以用于进行Demura步骤,从而对亮度值不均匀的像素点进行补偿。图9中提供另一种终端设备,和图8中的终端设备类似,终端设备400同样包括上述处理器71、第一Gamma选择器72、第一Gamma校正控制器73和屏幕74。此外,若屏幕74的各像素点在亮度调整的初始档位下对应的亮度值均为第二亮度值,则终端设备400还可以包括:第二Gamma选择器76和第二Gamma校正控制器77。其中,第二Gamma选择器76用于在对屏幕74进行Demura之前,基于预设的Gamma校正查找表确定与第二亮度值对应的第二输入灰阶值。而第二Gamma校正控制器77,用于根据第二输入灰阶值控制屏幕的各像素点的显示亮度值。具体的,第二Gamma选择器76以及第二Gamma校正控制器77的功能和作用如前述实施例中第二Gamma校正模块的功能,此处不再赘述。
其中,第二Gamma选择器76可以集成于处理器71上,也可以为独立于处理器71的硬件。而第二Gamma校正控制器77通常为独立于处理器71的硬件,例如是驱动电路等。
具体的,终端设备400需要和其它外部设备配合工作,以获取mura补偿数据,外部设备通常包括有用于感测屏幕75实际亮度的感测元件,示例性的,可以是高倍的照相机等。当屏幕75在测试信号的驱动下进行显示时,屏幕75的各像素点在亮度调整的初始档位下对应的亮度值均为第二亮度值,此时,第二Gamma选择器76根据预设的Gamma校正查找表确定与第二亮度值对应的第二灰阶值,第二Gamma校正控制器77会利用第二输入灰阶值控制各像素点的显示亮度值。此时,感测元件就会测量屏幕75显示的实际亮度,然后终端设备400即可根据屏幕75的实际亮度和输入灰阶值之间的关系获得Mura补偿数据,例如是Mura补偿表,并根据mura补偿表对屏幕75中 各像素点的亮度进行补偿,让整块屏幕75的亮度均能够保持均匀一致。在本实施例中,示例性的,可以让屏幕75中每个像素点的亮度值均保持为第二亮度值。
其中,示例性的,终端设备400中可以包括有专门用于获得Mura补偿数据,并进行Mura补偿的Mura校正控制器78。Mura校正控制器78可以和处理器71集成设置,也可以为单独的硬件或电路等。
此外,第二Gamma校正控制器76同样可以包括有电压生成器以及亮度控制器。其中,电压生成器能够用于根据输入灰阶值而生成相应的参考电压;而亮度控制器可以用于基于参考电压控制屏幕显示与输入灰阶值对应的显示亮度值。电压生成器以及亮度控制器的具体结构和功能可见前述实施例中的说明,此处不再赘述。
为了和高倍照相机等外部设备协同工作,终端装置中还可以包括用于连接外部设备以及终端装置本身的I/O子系统。I/O子系统可以用来实现和外部设备之间的数据交互,从而实现外部设备所采集的数据的输入输出,以及对外部设备的工作状态控制等。
此外,终端设备中还包括有脉冲宽度调制(Pulse Width Modulation,PWM)调光器79,PWM调光器79能够对内部的晶体管栅极或者MOS管基极等开关器件的通断进行调制,从而产生一系列脉冲宽度相等的脉冲,并通过改变脉冲的宽度或者占空比来实现不同的等效模拟输出,从而调节屏幕75的输出亮度。示例性的,PWM调光器79和屏幕75电性连接,PWM调光器79可以接收来自控制芯片的数字信号,并将数字信号转化为脉冲宽度或者占空比不同的脉冲,此时即可等效输出幅值大小不同的电压信号,随着电压信号的大小不同,屏幕75上每个像素点也会显示出不同的亮度,由此实现了图像的正常显示以及亮度调整。示例性的,PWM调光器79可以和处理器71之间电性连接或者是作为Gamma校正控制器中的一部分,以根据输入灰阶值等数据调整屏幕75的显示亮度。
在上述实施例中,可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件程序实现时,可以全部或部分地以计算机程序产品的形式来实现。该计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行计算机程序指令时,全部或部分地产生按照本申请实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中,或者从一个计算机可读存储介质向另一个计算机可读存储介质传输,例如,所述计算机指令可以从一个网站站点、计算机、服务器或者数据中心通过有线(例如同轴电缆、光纤、数字用户线(digital subscriber line,DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可以用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质(例如,软盘、硬盘、磁带),光介质(例如,DVD)、或者半导体介质(例如固态硬盘(solid state disk,SSD))等。
Claims (24)
- 一种屏幕亮度的控制方法,其特征在于,包括:确定所述屏幕在亮度调整的当前档位下对应的第一亮度值;基于预设的伽马Gamma校正查找表确定与所述第一亮度值对应的第一输入灰阶值,所述Gamma校正查找表为在亮度调整的指定档位下,所述屏幕的亮度值与所述屏幕的初始输入灰阶值的Gamma校正关系;根据所述第一输入灰阶值控制所述屏幕的显示亮度值。
- 根据权利要求1所述的控制方法,其特征在于,所述屏幕包含不均匀Mura区域,若所述屏幕的各像素点在亮度调整的初始档位下对应的亮度值均为第二亮度值,所述确定所述屏幕在亮度调整的当前档位下对应的第一亮度值之前,所述方法还包括:在对所述屏幕进行Demura之前,基于所述预设的Gamma校正查找表确定与所述第二亮度值对应的第二输入灰阶值;根据所述第二输入灰阶值控制所述屏幕的所述各像素点的显示亮度值。
- 根据权利要求1所述的控制方法,其特征在于,所述Gamma校正查找表包括以下任意一种:多个离散的灰阶值以及多个显示亮度值,所述灰阶值的数量等于所述显示亮度值的数量,所述灰阶值与所述显示亮度值一一对应,所述离散的灰阶值的数量等于所述屏幕的灰阶值的总阶数;或者,多个离散的灰阶值以及多个显示亮度值,所述灰阶值的数量等于所述显示亮度值的数量,所述灰阶值与所述显示亮度值一一对应,所述离散的灰阶值的数量小于所述屏幕的灰阶值的总阶数。
- 根据权利要求3所述的控制方法,其特征在于,所述离散的灰阶值和所述离散的灰阶值中任一灰阶值对应的显示亮度值构成的二维坐标点均位于一条Gamma曲线上,其中,所述Gamma曲线的横坐标表示灰阶值,所述Gamma曲线的纵坐标表示显示亮度值。
- 根据权利要求1-4任一项所述的控制方法,其特征在于,所述屏幕在所述当前档位下的当前亮度值与亮度调整的前一档位的先前亮度值之间满足预设条件,其中所述当前亮度值与所述先前亮度值对应相同的输入灰阶值,所述预设条件为:相邻档位的亮度值差值与所述先前亮度值的比例满足韦伯定律Webber Law,其中,所述亮度值差值为所述当前亮度值与所述先前亮度值之间的差值。
- 根据权利要求1-5任一项所述的控制方法,其特征在于,所述屏幕在所述指定档位下所支持的最大亮度值大于所述屏幕在所述当前档位下所支持的最大亮度值。
- 根据权利要求1-6任一项所述的控制方法,其特征在于,所述指定档位为亮度调整时所支持的最大档位。
- 根据权利要求3-7任一项所述的控制方法,其特征在于,所述Gamma校正查找表中的所述多个灰阶值和所述多个显示亮度值的对应关系符合Gamma校正公式,其中,所述显示亮度值为所述Gamma校正公式的输入,所述灰阶值为所述Gamma校正公式的输出;所述基于预设的Gamma校正查找表确定与所述第一亮度值对应的第一输入灰阶 值,具体包括:基于所述多个显示亮度值和所述校正公式计算得到与所述多个显示亮度值一一对应的多个第一灰阶值。
- 根据权利要求1-8任一项所述的控制方法,其特征在于,当所述亮度调整的当前档位下的所述第一亮度值没有包含在所述Gamma校正查找表中时,所述基于预设的Gamma校正查找表确定与所述第一亮度值对应的第一输入灰阶值包括:获得所述Gamma校正查找表中最接近所述亮度调整的当前档位下的第一亮度值的显示亮度值;将所获得的显示亮度值对应的灰阶值作为与所述第一亮度值对应的第一输入灰阶值。
- 根据权利要求1-9任一项所述的控制方法,其特征在于,当所述亮度调整的当前档位下的所述第一亮度值没有包含在所述Gamma校正查找表中时,所述基于预设的Gamma校正查找表确定与所述第一亮度值对应的第一输入灰阶值具体包括:基于所述Gamma校正查找表确定与所述亮度调整的当前档位下的第一亮度值直接相邻的两个显示亮度值;基于所述直接相邻的两个显示亮度值及其对应的灰阶值建立线性插值方程;根据所述线性插值方程和所述亮度调整的当前档位下的第一亮度值获取与所述第一亮度值对应的第一输入灰阶值。
- 一种屏幕亮度的控制装置,其特征在于,包括:亮度确定模块,用于确定所述屏幕在亮度调整的当前档位下对应的第一亮度值;第一伽马Gamma校正模块,用于基于预设的Gamma校正查找表确定与所述第一亮度值对应的第一输入灰阶值,所述Gamma校正查找表为在亮度调整的指定档位下,所述屏幕的亮度值与所述屏幕的初始输入灰阶值的Gamma校正关系;亮度调整模块,用于根据所述第一输入灰阶值控制所述屏幕的显示亮度值。
- 根据权利要求11所述的控制装置,其特征在于,所述屏幕包含不均匀Mura区域,若所述屏幕的各像素点在初始亮度调整的档位下对应的亮度值均为第二亮度值,所述装置还包括:第二Gamma校正模块,用于在对所述屏幕进行Demura之前,基于所述预设的Gamma校正查找表确定与所述第二亮度值对应的第二输入灰阶值;所述第二Gamma校正模块还用于根据所述第二输入灰阶值控制所述屏幕的所述各像素点的显示亮度;所述装置还包括:Mura校正模块,用于对所述屏幕进行所述Demura。
- 根据权利要求11或12所述的控制装置,其特征在于,所述Gamma校正查找表包括以下任意一种:多个离散的灰阶值以及多个显示亮度值,所述灰阶值的数量等于所述显示亮度值的数量,所述灰阶值与所述显示亮度值一一对应,所述离散的灰阶值的数量等于所述屏幕的灰阶值的总阶数;或者,多个离散的灰阶值以及多个显示亮度值,所述灰阶值的数量等于所述显示亮度值的数量,所述灰阶值与所述显示亮度值一一对应,所述离散的灰阶值的数量小于所述 屏幕的灰阶值的总阶数。
- 根据权利要求13所述的控制装置,其特征在于,所述离散的灰阶值和所述离散的灰阶值中任一灰阶值对应的显示亮度值构成的二维坐标点均位于一条Gamma曲线上,其中,所述Gamma曲线的横坐标表示灰阶值,所述Gamma曲线的纵坐标表示显示亮度值。
- 根据权利要求11-14任一项所述的控制装置,其特征在于,所述屏幕在所述当前档位下的当前亮度值与亮度调整的前一档位下的先前亮度值满足预设条件,其中,所述当前亮度值与所述先前亮度值对应相同的输入灰阶值,所述预设条件为:相邻档位的亮度值差值与所述先前亮度值的比例满足韦伯定律Webber Law,其中,所述亮度值差值为所述当前亮度值与所述先前亮度值之间的差值。
- 根据权利要求12-15任一项所述的控制装置,其特征在于,所述屏幕在所述指定档位下所支持的最大亮度值大于所述屏幕在所述当前档位下所支持的最大亮度值。
- 根据权利要求12-16任一项所述的控制装置,其特征在于,所述指定档位为所述屏幕能够显示最大亮度值时对应的档位。
- 根据权利要求14-17任一项所述的控制装置,其特征在于,所述Gamma校正查找表中的所述多个灰阶值和所述多个显示亮度值的对应关系符合Gamma校正公式,其中,所述显示亮度值为所述Gamma校正公式的输入,所述灰阶值为所述Gamma校正公式的输出;所述控制装置还包括:Gamma校正查找表获取模块,具体用于:基于所述多个显示亮度值和所述校正公式计算得到与所述多个显示亮度值一一对应的多个灰阶值。
- 根据权利要求12-18任一项所述的控制装置,其特征在于,当所述亮度调整的当前档位下的所述第一亮度值没有包含在所述Gamma校正查找表中时,所述第一Gamma校正模块还用于:获得所述Gamma校正查找表中最接近所述亮度调整的当前档位下的第一亮度值的显示亮度值;将所获得的显示亮度值对应的灰阶值作为与所述第一亮度值对应的第一输入灰阶值。
- 根据权利要求12-19任一项所述的控制装置,其特征在于,当所述亮度调整的当前档位下的所述第一亮度值没有包含在所述Gamma校正查找表中时,所述第一Gamma校正模块具体用于:基于所述Gamma校正查找表确定与所述亮度调整的当前档位下的第一亮度值直接相邻的两个显示亮度值;基于所述直接相邻的两个显示亮度值及其对应的灰阶值建立线性插值方程;根据所述线性插值方程和所述亮度调整的当前档位下的第一亮度值获取与所述第一亮度值对应的第一输入灰阶值。
- 一种终端设备,其特征在于,所述终端设备包括:处理器、第一Gamma选择器,第一Gamma校正控制器和屏幕;所述处理器,用于确定所述屏幕在当前亮度调整的档位下对应的第一亮度值;所述第一Gamma选择器,用于基于预设的Gamma校正查找表确定与所述第一亮度值对应的第一输入灰阶值,所述Gamma校正查找表为在亮度调整的指定档位下, 所述屏幕的亮度值与所述屏幕的初始输入灰阶值的Gamma校正关系;所述第一Gamma校正控制器,用于根据所述第一输入灰阶值控制所述屏幕的显示亮度值。
- 根据权利要求21所述的终端设备,其特征在于,所述屏幕包含不均匀Mura区域,若所述屏幕的各像素点在亮度调整的初始档位下对应的亮度值均为第二亮度值,所述终端设备还包括:第二Gamma选择器和第二Gamma校正控制器;所述第二Gamma选择器,用于在对所述屏幕进行Demura之前,基于所述预设的Gamma校正查找表确定与所述第二亮度值对应的第二输入灰阶值;所述第二Gamma校正控制器,还用于根据所述第二输入灰阶值控制所述屏幕的所述各像素点的显示亮度值。
- 根据权利要求21或22所述的终端设备,其特征在于,还包括:存储器,所述存储器,用于存储所述预设的Gamma校正查找表。
- 根据权利要求21-23任一项所述的终端设备,其特征在于,所述Gamma校正控制器包括:电压生成器和亮度控制器,所述电压生成器,用于根据输入灰阶值生成参考电压;所述亮度控制器,用于基于所述参考电压控制所述屏幕显示与所述输入灰阶值对应的显示亮度值。
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CN110473502A (zh) | 2019-11-19 |
US20210049966A1 (en) | 2021-02-18 |
EP3770899A1 (en) | 2021-01-27 |
EP3770899A4 (en) | 2021-08-11 |
US11200844B2 (en) | 2021-12-14 |
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