Method and device for realizing local highlight display according to average picture brightness

Abstract

The invention discloses a method and a device for realizing local highlight display according to average picture brightness. The specific calculation process comprises the steps that for input picture data (in an RGB format), RGB color space data are firstly converted to an XYZ color space, a Y value representing brightness is mainly calculated, then average picture brightness (APL) is calculated, a parameter gain value used for adjusting the brightness is calculated according to an APL value look-up table, the gain value serves as a coefficient to adjust the size of output data, and the larger the data is, the higher the brightness is.

Description

Technical Field

[0001] The invention relates to an image brightness method, belongs to the field of image processing, and particularly to a method and device for realizing local highlight display according to average picture brightness. Background Art

[0002] Average Pixel Luminance (APL for short, average pixel brightness, i.e. the average brightness of each pixel). On X / XS phones, the color of the UI displayed on the OLED screen directly affects energy consumption. Brighter colors = higher energy consumption (high APL), conversely, darker colors = lower energy consumption (low APL). The relationship between APL and brightness is as follows: Figure 4 shown.

[0003] In some scenarios of mobile phones, it is necessary to improve the contrast of the screen display, such as starry sky pictures, fireworks, etc., to achieve better visual effects. At the same time, it is also necessary to balance the power consumption of the application scenario when the brightness is increased, so it is necessary to configure different peak brightness according to the different average screen brightness of the screen. The lower the average screen brightness, the higher the peak brightness. In view of the above problems, the present invention proposes a method and device for realizing local highlight display according to the average screen brightness. Summary of the invention

[0004] The present invention provides a method for realizing local highlight display according to average picture brightness, comprising:

[0005] Step 1: Input screen data;

[0006] Step 2: Convert RGB color space to XYZ color space

[0007] Step 3, calculating the average screen brightness;

[0008] Step 4: Look up the table to calculate the brightness adjustment parameter gain;

[0009] Step 5: Adjust the brightness using the gain value.

[0010] In step 2, the Y value of each pixel in the input image is calculated according to the following transformation matrix:

[0011]

[0012] If the resolution of the input image is h*v, v is the number of rows, h is the number of horizontal pixels, i and j represent the vertical and horizontal coordinates of the pixel, the Y value of each pixel is calculated as follows:

[0013] Y[i,j]=0.299*R[i,j]+0.578*G[i,j]+0.114*B[i,j],i∈[0,v),j∈[0,h).

[0014] Step three includes: calculating the average screen brightness based on the brightness value of each pixel:

[0015]

[0016] Step 4 includes:

[0017] First, a one-dimensional lookup table LUT of the relationship between brightness and gain value is established, as shown in the following formula.

[0018]

[0019] in represents n+1 binding point values, Y=[gain0, gain1, ..., gain n ] represents the gain values ​​corresponding to n+1 binding points, which can be obtained by arbitrary calculation The value can be calculated by looking up the table to get a gain value. First, determine The value falls between the two binding points. Assuming it falls at the binding point and If the value is between , the corresponding gain value is calculated by the following formula.

[0020]

[0021] Step 5 includes that there is a γ curve relationship between the general brightness and the input data. If the input data bit depth is m, the maximum brightness is Lv max , then the brightness corresponding to different input data is:

[0022]

[0023] The adjusted brightness is:

[0024]

[0025] The changing relationship between Lv and λ is configured by adjusting the one-dimensional lookup table LUT so that the brightness presents a linear or nonlinear changing trend.

[0026] The present invention also provides a device for realizing local highlight display according to average picture brightness, comprising: an APL statistical unit: performing data conversion according to input data to obtain the brightness value of each pixel, and then calculating the average picture brightness value according to the brightness value of each pixel;

[0027] LUT: The lookup table stores the relationship between the average picture brightness value and the brightness adjustment parameters;

[0028] Brightness control unit: calculates the brightness adjustment parameter based on the average screen brightness value, and then adjusts the corresponding brightness of the screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Shown is a flow chart of the present invention;

[0030] Figure 2 The present invention is shown Schematic diagram of the relationship between the change of and Lv;

[0031] Figure 3 Shown is a schematic structural diagram of the present invention;

[0032] Figure 4 The figure shows the relationship between APL and brightness.

[0033] Figure 5 The figure shows the contrast of the screen display in different application scenarios. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In such Figure 5 In the application scenario shown, it is necessary to increase the contrast of the screen display to achieve a better visual effect.

[0036] See also Figure 1 , which is shown as a method for realizing local highlight display according to average screen brightness, including:

[0037] Step 1: Input screen data;

[0038] Step 2: Convert RGB color space to XYZ color space

[0039] Step 3, calculating the average screen brightness;

[0040] Step 4: Look up the table to calculate the brightness adjustment parameter gain;

[0041] Step 5: Adjust the brightness using the gain value.

[0042] In step 2, the Y value of each pixel in the input image is calculated according to the following transformation matrix:

[0043]

[0044] If the resolution of the input image is h*v, v is the number of rows, h is the number of horizontal pixels, i and j represent the vertical and horizontal coordinates of the pixel, the Y value of each pixel is calculated as follows:

[0045] Y[i,j]=0.299*R[i,j]+0.578*G[i,j]+0.114*B[i,j],i∈[0,v),j∈[0,h).

[0046] Step three includes: calculating the average screen brightness based on the brightness value of each pixel:

[0047]

[0048] Step 4 includes:

[0049] First, a one-dimensional lookup table LUT of the relationship between brightness and gain value is established, as shown in the following formula.

[0050]

[0051] in represents n+1 binding point values, Y=[gain0, gain1, ..., gain n ] represents the gain values ​​corresponding to n+1 binding points, which can be obtained by arbitrary calculation The value can be calculated by looking up the table to get a gain value. First, determine The value falls between the two binding points. Assuming it falls at the binding point and If the value is between , the corresponding gain value is calculated by the following formula.

[0052]

[0053] Step 5 includes that there is a γ curve relationship between the general brightness and the input data. If the input data bit depth is m, the maximum brightness is Lv max , then the brightness corresponding to different input data is:

[0054]

[0055] The adjusted brightness is:

[0056]

[0057] like Figure 2 As shown, The changing relationship between Lv and λ is configured by adjusting the one-dimensional lookup table LUT so that the brightness presents a linear or nonlinear changing trend.

[0058] See also Figure 3 , which is a device for realizing local highlight display according to average screen brightness, including: APL statistical unit: performing data conversion according to input data to obtain the brightness value of each pixel, and then calculating the average screen brightness value according to the brightness value of each pixel;

[0059] LUT: The lookup table stores the relationship between the average picture brightness value and the brightness adjustment parameters;

[0060] Brightness control unit: calculates the brightness adjustment parameter based on the average screen brightness value, and then adjusts the corresponding brightness of the screen.

[0061] The present invention proposes a method and device for realizing local highlight display according to average picture brightness, which can not only improve the contrast of picture display, but also take into account the problem of balancing power consumption when the brightness is increased in application scenarios.

[0062] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the appended claims and their equivalents.

Claims

1. A method for realizing local highlight display according to average picture brightness, characterized in that: include: Step 1: Input screen data; Step 2: Convert RGB color space to XYZ color space Step 3, calculating the average screen brightness; Step 4: Look up the table to calculate the brightness adjustment parameter gain; Step 5: Adjust the brightness using the gain value.

2. The method for realizing local highlight display according to average picture brightness according to claim 1, characterized in that: In step 2, the Y value of each pixel in the input image is calculated according to the following conversion matrix: If the resolution of the input image is h*v, v is the number of rows, h is the number of horizontal pixels, i and j represent the vertical and horizontal coordinates of the pixel, the Y value of each pixel is calculated as follows: Y[i,j]=0.299*R[i,j]+0.578*G[i,j]+0.114*B[i,j],i∈[0,v),j∈[0,h).

3. The method for realizing local highlight display according to average picture brightness according to claim 2, characterized in that: The step three includes: calculating the average picture brightness according to the brightness value of each pixel: 。 4. The method for realizing local highlight display according to average picture brightness according to claim 3, characterized in that: The fourth step comprises: First, a one-dimensional lookup table LUT of the relationship between brightness and gain value is established, as shown in the following formula. in represents n+1 binding point values, Y=[gain0, gain1, ..., gain n ] represents the gain values ​​corresponding to n+1 binding points, which can be obtained by arbitrary calculation The value can be calculated by looking up the table to get a gain value. First, determine The value falls between the two binding points. Assuming it falls at the binding point and If the value is between , the corresponding gain value is calculated by the following formula. 。 5. The method for realizing local highlight display according to average picture brightness according to claim 4, characterized in that: The step 5 includes: generally, there is a γ curve relationship between brightness and input data. If the input data bit depth is m, the maximum brightness is Lv max , then the brightness corresponding to different input data is: The adjusted brightness is: The changing relationship between Lv and λ is configured by adjusting the one-dimensional lookup table LUT so that the brightness presents a linear or nonlinear changing trend.

6. A device for realizing local highlight display according to average picture brightness, using a method for realizing local highlight display according to average picture brightness according to any one of claims 1 to 5, characterized in that: include: APL statistical unit: converts the input data to obtain the brightness value of each pixel, and then calculates the average brightness value of the picture based on the brightness value of each pixel; LUT: The lookup table stores the relationship between the average picture brightness value and the brightness adjustment parameters; Brightness control unit: calculates the brightness adjustment parameter based on the average screen brightness value, and then adjusts the corresponding brightness of the screen.

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