CN1971696A - Method for controlling brightness of image subarea - Google Patents

Abstract

The invention discloses a method for controlling the brightness of image partitions. It firstly inputs a display image, then divides the display image into multiple blocks, calculates the average brightness of each block, and then calculates the average brightness of each block according to the average brightness of each block. Control the brightness of the corresponding block, and further establish a look-up table for storing multiple color values and corresponding multiple weighted color values. Brightness control is performed for each block; the method of the present invention can also be used to control the brightness of LEDs of a backlight module.

Description

Image partition brightness control method

technical field

The invention relates to a brightness control method, in particular to an image partition brightness control method for controlling the brightness of an image displayed on a liquid crystal display.

Background technique

Currently, the contrast ratio of a liquid crystal display is an important factor for display image quality. However, a black background image is input to the liquid crystal display, and the liquid crystal display is not dark enough to display the black background image due to light leakage. Generally speaking, the contrast ratio of this LCD TV is about 10 ³ , but it is still insufficient compared with the contrast ratio of traditional CRT or PDP TVs.

In order to improve the problem of insufficient contrast, a high dynamic contrast LCD system (High Dynamic Contrast LCD System) is proposed. The system uses a backlight module with light-emitting diodes to improve the contrast, so that the contrast of the LCD exceeds 10 ⁴ . Based on cost and mass production considerations, the image displayed by the liquid crystal display is divided into n x m blocks, the brightness of each block can be independently controlled, a simple way can determine the brightness of each block, through each The average brightness of the block, the calculation method of the average brightness of each block first takes the maximum color value of multiple pixels in each block, accumulates the multiple maximum color values of each block and divides it by the value of each block The number of pixels contained, that is, the average brightness of each block is obtained. The equation of the average brightness is as follows:

${\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; block</span>}}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Wherein, the max(R, G, B) is the maximum color value of each pixel, and the n is the number of pixels contained in each block.

Although the above-mentioned method can make the backlight module stable and free from other noise interference, the backlight module cannot display details of darker patterns, resulting in lowered display quality of the liquid crystal display. Therefore, those skilled in the art cannot meet the needs of users in actual use.

Therefore, in view of the above problems, a novel image partition brightness control method is proposed, which can not only improve the defect that the liquid crystal cannot display darker patterns, but also improve the contrast of the image displayed by the liquid crystal display, and is used to control the backlight module. The brightness of the light-emitting diodes can make the backlight module stable and free from interference from other noises.

Contents of the invention

The main purpose of the present invention is to provide a brightness control method for image partitions, which improves the image contrast displayed by a liquid crystal display.

Another object of the present invention is to provide a brightness control method for image partitions, which improves the quality of darker images displayed by the liquid crystal display.

Another object of the present invention is to provide a brightness control method for image partitions, which can be used to control the brightness of LEDs in a backlight module, so that the backlight module is stable and less susceptible to other noise interference.

Another object of the present invention is to provide a method for controlling the brightness of image partitions, and further establish a lookup table (Lookup table, LUT), according to which the average brightness of each block can be quickly calculated, which has simplified and complicated operations process, reducing computing time and speeding up the processing speed of partition brightness control.

In order to achieve the above object, the present invention provides a method for controlling the brightness of image partitions. The method first inputs a display image, and then divides the display image into a plurality of blocks. Each block of the plurality of blocks has a plurality of pixels. Perform a weighted operation on the maximum color value of each pixel to obtain a weighted color value of each pixel, and then accumulate multiple weighted color values of each block and divide by the number of pixels to obtain a brightness of each block average value, and then the brightness of the corresponding block is controlled by the average brightness value.

Establish a lookup table based on the multiple maximum color values and the corresponding multiple weighted color values, the lookup table stores multiple color values and the corresponding multiple weighted color values, the lookup table is established in the liquid crystal display, the liquid crystal The display controls the brightness of each block of the displayed image according to the look-up table.

Adopting the brightness control method of image divisions of the present invention can improve the contrast of the images displayed by the liquid crystal display, improve the quality of darker images displayed by the liquid crystal display, and can be used to control the brightness of the light-emitting diodes of the backlight module to improve the stability of the backlight module. Interferenced by other noises, and the present invention further establishes the look-up table, the average brightness of each block can be quickly calculated according to the look-up table, which has the advantages of simplifying the complex calculation process, reducing calculation time and speeding up the brightness control process of the partition The effect of speed.

Description of drawings

Fig. 1 is the basic flow schematic diagram of the present invention;

Fig. 2 is the look-up table schematic diagram of a preferred embodiment of the present invention:

FIG. 3 is a relationship diagram between color values and weighted color values in another preferred embodiment of the present invention; and

Fig. 4 is a schematic flow chart of another preferred embodiment of the present invention.

Among them, reference signs:

color value 1

Color value 1a

color value 1b

color value 1c

Weighted Color Value 2

Weighted Color Value 2a

Weighted Color Value 2b

Weighted Color Value 2c

Relationship curve 3

Detailed ways

In order to enable your review committee members to have a further understanding and understanding of the structural features and the achieved effects of the present invention, I would like to use a preferred embodiment and a detailed description, as follows:

Referring to Fig. 1, it is a schematic flow chart of the present invention. As shown in the figure: the present invention is a method for controlling the brightness of image partitions. First, step S10 is executed to input a display image to a liquid crystal display, and then step S11 is executed to divide the display image into multiple blocks, and then step S12 is executed. Each block of the plurality of blocks has a plurality of pixels, each pixel of the plurality of pixels has a maximum color value, and a weighted operation is performed on the maximum color value of each pixel, which means that the maximum color value of each pixel The color value is multiplied by a weighting coefficient, and the weighting coefficient can be a multiple, a power, or calculated based on the backlight brightness and liquid crystal transmittance of the liquid crystal display. After the above weighting operation, a value of each pixel can be obtained. weighted color value, and then execute step S13, accumulate multiple weighted color values of each block and divide by the number of pixels contained in each block to obtain an average brightness of each block, and finally according to the brightness of each block The average value controls the brightness of the corresponding block, and the equation for calculating the average brightness value of each block is as follows:

${\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; block</span>}}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Wherein, the max(R, G, B) is the maximum color value of each pixel, the f is a weighting coefficient, and the f[max(R, G, B)] is obtained by weighting the maximum color value of each pixel The weighted color values of , and the n is the number of pixels contained in each block.

According to step S12, the display image is divided into a plurality of blocks, each block of the plurality of blocks includes a plurality of pixels, and the color value of each pixel ranges from 0 to 255, and includes a red color value (R), a green value (G) and a blue value (B), according to the red value, green value and blue value contained in the color value of the pixel, take a maximum value, which is the maximum color of the pixel Values, such as: the color value of this pixel includes red value, green value and blue value, the red value is 216, the green value is 134, and the blue value is 18, so the maximum color value of this pixel is 216, The maximum color value of each pixel can be obtained by the above method, and then steps S12 and S13 are executed to obtain the average brightness value of each block.

Referring to FIG. 2, after performing the above steps S11 to S13, a lookup table is established based on the multiple maximum color values and corresponding multiple weighted color values, the lookup table includes multiple color values 1 and corresponding multiple weighted color values 2. As shown in FIG. 2, it is a schematic diagram of a look-up table in a preferred embodiment of the present invention. The look-up table includes multiple color values 1 and corresponding multiple weighted color values 2, such as: when the color value 1a is 1 , the weighted color value 2a is 2; when the color value 1b is 2, the weighted color value 2b is 4; and when the color value 1c is 255, the weighted color value 2c is 510, the color value 1 The range is between 0 and 255. In addition, according to the weighted color value 2, it is the product of the color value 1 and the weighted coefficient, so it is calculated that the weighted coefficient of this embodiment uses a multiple, the multiple is 2, and the weighted coefficient It can also be a power or calculated based on the backlight brightness and liquid crystal transmittance of the liquid crystal display.

After the look-up table is established, the look-up table is established in the liquid crystal display, and when an image is input, the average brightness of each block of the image divided into multiple blocks can be calculated according to the look-up table, and The brightness of the corresponding block is controlled according to the average brightness of each block.

Referring to FIG. 3 , it is a relationship diagram of color values and weighted color values in another preferred embodiment of the present invention. As shown in the figure: the relationship between the color value and the weighted color value contains a relationship curve 3, from the relationship curve 3, it can be seen that the range of the color value is between 0 and 255, and the weighted color value is the maximum color Value multiplied by a weighting coefficient, so the weighting coefficient can be calculated from the relationship curve 3, but the weighting coefficient is not a multiple, that is, it may be a power or calculated based on the backlight brightness and liquid crystal transmittance of the liquid crystal display out. The look-up table is established according to the relationship curve 3, and when the brightness control of the image displayed on the liquid crystal display is performed in the future, the average brightness of each block of the image can be calculated according to the look-up table, and then the brightness control of the partitions can be achieved. Purpose.

Fig. 4 is a schematic flow chart of another preferred embodiment of the present invention. As shown in the figure: the image partition brightness control method of this embodiment first executes step S20, input a display image to a liquid crystal display, and then executes step S21, divides the display image into multiple blocks, and each block has multiple pixels, then execute step S22 to obtain the maximum color value of each pixel, input it to a look-up table that stores multiple color values and corresponding multiple weighted color values, find out the corresponding weighted color value, and find out each area After a plurality of weighted color values of the block, step S23 is performed to accumulate the plurality of weighted color values of each block and divide by the number of pixels contained in each block to obtain an average brightness value of each block, and then use The brightness average controls the brightness of the corresponding block. In this embodiment, the average brightness of each block is calculated according to the look-up table, which can simplify the complicated calculation process, reduce the calculation time and speed up the processing speed of the brightness control of each area.

From the above, it can be seen that the brightness control method for image partitions of the present invention can enhance the contrast of the image displayed by the liquid crystal display, improve the quality of the darker image displayed by the liquid crystal display, and can be used to control the brightness of the light-emitting diodes of the backlight module to improve the brightness of the backlight module. The stability is not disturbed by other noises, and the present invention further establishes the look-up table, and the average brightness of each block can be quickly calculated according to the look-up table, which has the advantages of simplifying the complex calculation process, reducing calculation time and speeding up partitioning Brightness controls the efficacy of processing speed.

Certainly, the present invention also can have other various embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these Corresponding changes and deformations should belong to the scope of protection of the appended claims of the present invention.

Claims (23)

1. An image partition brightness control method, characterized in that, comprising: input an image; dividing the image into a plurality of blocks; Each block of the plurality of blocks has a plurality of pixels, and a weighted operation is performed on the maximum color value of each pixel to obtain a weighted color value of each pixel; and A plurality of weighted color values of each block are accumulated and divided by the number of pixels contained in each block to obtain an average brightness value of each block. 2 . The method for controlling brightness of image partitions according to claim 1 , wherein the color value of the pixel includes a red value, a green value and a blue value. 3 . 3. The image partition brightness control method according to claim 1, wherein the maximum color value is the maximum value among the color values of the pixel. 4 . The image partition brightness control method according to claim 3 , wherein the maximum color value ranges from 0 to 255. 5. The image partition brightness control method according to claim 1, wherein the weighting operation is performed on the maximum color value of each pixel, and the maximum color value of each pixel is multiplied by a weighting coefficient. 6. The method for controlling brightness of image partitions according to claim 5, wherein the weighting coefficient is a multiple. 7. The image partition brightness control method according to claim 5, wherein the weighting coefficient is a power of one. 8 . The method for controlling brightness of image partitions according to claim 5 , wherein the weighting coefficient is calculated according to the backlight brightness of the liquid crystal display and the liquid crystal transmittance. 9. The image partition brightness control method according to claim 1, wherein a look-up table is further established according to the plurality of maximum color values and the corresponding weighted color values of multiple colors, and the look-up table stores a plurality of color values and Corresponding multiple weighted color values. 10 . The image partition brightness control method according to claim 9 , wherein the range of the color value is between 0 and 255. 11 . 11. The method for controlling the brightness of image partitions according to claim 9, wherein the color value corresponding to the weighted color value is multiplied by the weighting coefficient. 12 . The method for controlling brightness of image partitions according to claim 9 , wherein the look-up table is established in a liquid crystal display, and the liquid crystal display controls the brightness of each block of the image according to the look-up table. 13 . The method for controlling brightness of image partitions according to claim 1 , further being used for controlling the brightness of a light emitting diode of a backlight module. 14 . 14. An image partition brightness control method, characterized in that it comprises: input an image; dividing the image into a plurality of blocks; each of the plurality of blocks has a plurality of pixels, and inputting the maximum color value of each pixel into a look-up table to find the corresponding weighted color value; and A plurality of weighted color values of each block are accumulated and divided by the number of pixels contained in each block to obtain an average brightness value of each block. 15. The method for controlling brightness of image partitions according to claim 14, wherein the color value of the pixel comprises a red value, a green value and a blue value. 16. The image partition brightness control method according to claim 14, wherein the maximum color value is the maximum value among the color values of the pixel. 17 . The method for controlling brightness of image partitions according to claim 16 , wherein the maximum color value ranges from 0 to 255. 18 . 18. The method for controlling the brightness of image partitions according to claim 14, wherein the look-up table stores a plurality of color values and corresponding weighted color values. 19. The method for controlling brightness of image partitions according to claim 14, wherein the range of the color value is between 0 and 255. 20 . The method for controlling brightness of image partitions according to claim 14 , wherein the color value corresponding to the weighted color value is multiplied by a weighting coefficient. 21 . 21. The method for controlling brightness of image partitions according to claim 20, wherein the weighting coefficient is a multiple. 22. The image partition brightness control method according to claim 20, wherein the weighting coefficient is a power of one. 23. The brightness control method for image partitions according to claim 20, wherein the weighting coefficient is calculated according to the backlight brightness of the liquid crystal display and the liquid crystal transmittance.

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