TWI774476B - Control method applied to a display - Google Patents

Abstract

A control method applied to a display includes: determining a first backlight information according to an image, wherein the first backlight information includes a plurality of first brightness values; transforming the first backlight information into a second backlight information when the image is a first pattern image, wherein the second backlight information includes a plurality of second brightness values; and controlling brightness of light-emitting areas of backlight plate of the display based on the plurality of second brightness value.

Description

Control method applied to display

The present invention relates to a control method applied to a display, in particular to a control method of a backlight panel of a display.

A liquid crystal display with a local dimming system controls the brightness of each zone of the backlight panel according to the image, so each pixel of the image needs to be compensated to meet the brightness requirements of the image. Taking the example of displaying an image with a large gray area and a small white area, the backlight brightness distribution will change from the gray area to the white area, which means that the pixels of the image need to be compensated to obtain the desired The brightness and color the image should have. However, the luminance actually output by the compensated pixel may be different from the desired luminance, resulting in a compensation error. If the brightness of the backlight from the gray area to the white area is very different, more compensation for the pixels is required, and the resulting compensation error may be so obvious that the human eye can easily perceive it.

The purpose of the present invention is to provide a control method applied to a display.

According to the present invention, a control method applied to a display, the display includes a backlight plate, the backlight plate includes a plurality of light-emitting regions, the control method includes the following steps: determining a first backlight information according to an image, the first backlight information including a plurality of first luminance values, the plurality of first luminance values include a first maximum luminance value and a first minimum luminance value, and the first maximum luminance value and the first minimum luminance value have a first difference; When the image is an image of a first type, the first backlight information is converted into a second backlight information, the second backlight information includes a plurality of second brightness values, wherein the second brightness values include a first two maximum brightness values and a second minimum brightness value, the second maximum brightness value and the second minimum brightness value have a second difference value, the second difference value is smaller than the first difference value; and according to the plurality of first The two brightness values respectively control the brightness of the plurality of light-emitting regions.

In the control method of the present invention, when the image is an image of the first type, the dynamic range of luminance of the backlight panel is reduced to avoid unexpected deviation of the image displayed by the display.

FIG. 1 shows a flow chart of the control method of the present invention. The control method of the present invention is applied to a display. As shown in FIG. 2 , the display 10 includes a display panel 12 and a backlight panel 14 . The display panel 12 is used to display images. The backlight panel 14 is located below the display panel 12 and has a plurality of light-emitting regions 142, each of which includes a plurality of light-emitting elements (not shown in the figure), such as light-emitting diodes. FIG. 3 shows an image 20 for display on the display 10 . The image 20 can be divided into a plurality of sub-areas 22 corresponding to a plurality of light-emitting areas 142 respectively, and each sub-area 22 includes a plurality of pixels. The control method shown in FIG. 1 is executed by a processing unit (not shown in the figure) in the display 10 , and the processing unit may be integrated into a timing controller (not shown in the figure) of the display 10 .

The image 20 is transmitted to the display 10 in the form of a set of image signals. The content of the set of image signals includes brightness information, which determines the brightness of all the pixels of the image 20 . The display 10 displays the image 20 according to the set of image signals. In order to make the present invention easier to understand, this specification uses the image 20 to describe various embodiments, but those skilled in the field of display technology should understand that the following embodiments are actually still using the image signal corresponding to the image 20 to perform various operation, processing and judgment.

Referring to FIG. 1 , FIG. 2 and FIG. 3 , step S10 includes determining a first backlight information according to the image 20 . The first backlight information includes a plurality of first brightness values BK_original, wherein the plurality of first brightness values BK_original includes a first maximum brightness value Max1 and a first minimum brightness value Min1, as shown in FIG. 4 , the first maximum brightness value Max1 There is a first difference value Dif1 with the first minimum luminance value Min1. The plurality of first brightness values BK_original in the first backlight information respectively correspond to the plurality of light-emitting regions 142 of the backlight panel, and are originally intended to be used to control the brightness of the plurality of light-emitting regions 142 . It is well known to those skilled in the art of local dimming to calculate the luminance values of a plurality of light-emitting regions of the backlight panel according to an image, and details are not repeated here.

After determining the first backlight information, step S12 is performed. Step S12 includes determining whether an image 20 is an image of a first type. The image 20 is one of a plurality of consecutive images transmitted to the display 10 for display on the display 10 . In one embodiment, the brightness distribution of most of the images of the first type does not change drastically, and only a small part of the brightness is significantly different from other parts. The images of the first type include, but are not limited to, mostly monochrome images, or mostly gradient images. When it is determined in step S12 that the image 20 is an image of the first type, step S14 is performed. Step S12 can also be understood as judging whether the image 20 needs to be processed, and if necessary, proceed to the subsequent steps S14 to S16. When it is determined in step S12 that the image 20 is not an image of the first type, no processing is required, and thus the operation ends. In the embodiment of FIG. 1 , step S12 is continued after step S10 , but the present invention is not limited to this. For example, step S10 and step S12 may be performed simultaneously.

When it is determined that the image 20 is an image of the first type, step S14 is performed. Step S14 includes converting the first backlight information into a second backlight information, the second backlight information includes a plurality of second brightness values BK_remaped, wherein the plurality of second brightness values BK_remaped includes a second maximum brightness value Max2 and a first brightness value Max2. Two minimum luminance values Min2, as shown in FIG. 4 , the second maximum luminance value Max2 and the second minimum luminance value Min2 have a second difference Dif2, and the second difference Dif2 is smaller than the first difference Dif1. The oblique line 32 in FIG. 4 can be understood as the relationship between the first brightness value BK_original and the second brightness value BK_remaped. Finally, step S16 is performed to control the brightness of the plurality of light-emitting regions 142 according to the plurality of second brightness values BK_remapped. In one embodiment, step S16 further includes updating the display panel 12 according to an image A (not shown in the figure) generated by compensating an image B (not shown in the figure) according to the second backlight information image. The image B may be the image 20, the previous image of the image 20, or the first two images of the image 20,

。將第一背光資訊的多個第一亮度值BK_original代入該公式可得到第二背光資訊的多個第二亮度值BK_remapped。 In one embodiment, the method for converting the first backlight information into the second backlight information in step S14 includes: according to the first maximum brightness value Max1, the first minimum brightness value Min1, the second maximum brightness value Max2 and the second minimum brightness value The relationship between Min2 determines a formula, such as

. Substituting a plurality of first brightness values BK_original of the first backlight information into the formula can obtain a plurality of second brightness values BK_remapped of the second backlight information.

In another embodiment, the method for converting the first backlight information into the second backlight information includes according to the first maximum brightness value Max1, the first minimum brightness value Min1, the second maximum brightness value Max2 and the second minimum brightness value Min2 The relationship between the two determines a look up table, and the look up table is used to convert a plurality of first luminance values BK_original of the first backlight information into a plurality of second luminance values BK_remapped of the second backlight information.

In one embodiment, the second maximum brightness value Max2 and the second minimum brightness value Min2 may be preset values. In one embodiment, the second difference Dif2 may be a preset value, the second maximum brightness value Max2 may be determined according to the first maximum brightness value Max1, and the second minimum brightness value Min2 may be subtracted from the second maximum brightness value Max2. The second difference is obtained by Dif2. The manner of determining the second maximum brightness value Max2 according to the first maximum brightness value Max1 includes taking the first maximum brightness value Max1 as the second maximum brightness value Max2.

In one embodiment, step S12 includes two stages. The first stage is to execute the process shown in FIG. 5 for each sub-region 22, and the second stage is to determine whether the image 20 conforms to the result obtained in the first stage. Image of the first type. In FIG. 5 , step S1211 includes counting the number of pixels corresponding to different luminance values in a sub-region 22 . According to the statistical result of step S1211, step S1212 determines a maximum pixel number Z and its corresponding third luminance value K. For example, according to the luminance value of each pixel in a sub-area 22, the number of pixels of each luminance value in the sub-area 22 can be counted, and the result shown in FIG. 6 or FIG. 7 can be obtained. According to the results of the aforementioned statistics, the maximum number of pixels Z and the third luminance value K they have can be found. Taking FIG. 6 as an example, the number of pixels with the third luminance value K is the largest, and there are Z1 pixels with the third luminance value K. Taking FIG. 7 as an example, the number of pixels with the third luminance value K is the largest, and there are Z2 pixels with the third luminance value K. Next, step S1213 is performed to determine whether the maximum number of pixels Z is greater than the first threshold VT1. When the maximum number of pixels Z is greater than the first threshold value VT1 (eg, as shown in FIG. 7 ), step S1214 is performed to set the main luminance value of the sub-region 22 as the third luminance value K of the Z pixels. When the maximum number of pixels Z is smaller than the first threshold value VT1 (for example, as shown in FIG. 6 ), step S1215 is performed to mark the sub-region 22 . The way of marking the sub-region 22 is, for example, marking the sub-region 22 as "0" or "NaN". After all the sub-regions 22 have completed the setting or marking of the main luminance values, the second stage of step S12 can be performed.

The first threshold VT1 may be set to be half or more of the number of pixels in a sub-region 22 . For example, the sub-region 22 includes 100 pixels, and the first threshold value can be set to 50. When the maximum number of pixels Z is greater than 50, it means that more than half of the pixels in the sub-area 22 have the third luminance value K. Therefore, the third luminance value K can be used to represent the main luminance of the sub-area 22 . When the maximum number of pixels Z is less than 50, it means that the luminance distribution in the sub-area 22 is not obviously concentrated at a certain luminance value, so the sub-area 22 is marked to indicate that no luminance can be used to represent this sub-area 22 . Via the first stage of step S12, each sub-region 22 is determined with its main luminance value or marked. The second stage of step S12 is to determine whether the image 20 is an image of the first type according to the result of the first stage. In one embodiment, the second stage of step S12 includes the flow shown in FIG. 8 . Step S12201 includes selecting a target area from the image 20 . Each target area includes a plurality of adjacent sub-areas 22 . One embodiment of selecting a target area is shown in FIG. 9 . In FIG. 9 , the target areas 24 , 26 and 28 are sequentially selected in a sliding manner, and each selected target area includes 3×3 sub-areas 22 . The display 10 can first select the target area 24 , and then move to the right to select the target area 26 , or move downward to select the target area 28 . In step S12201, the target regions can be selected in sequence in this way. After all sub-regions 22 have been selected, step S12206 determines that all target regions have been subjected to the judgment process. The sliding method in FIG. 9 is one of the methods for selecting the target area, and the present invention is not limited thereto.

After selecting a target area, step S12202 is performed. Step S12202 is to determine whether the selected target area includes the marked sub-area 22 . If the target area includes the marked sub-area 22 , step S12203 is performed to ignore the target area, and step S12206 is performed to determine whether all target areas have been selected. If the determination in step S12206 is no, then go back to step S12201 to select the next target area. If the determination in step S12206 is yes, it is determined that the image 20 is not an image of the first type, as shown in step S12210.

If it is determined in step S12202 that the target area does not contain the marked sub-areas 22, then proceed to step S12204 to obtain the maximum and minimum values of the main luminance values of multiple adjacent sub-areas 22 in the target area, and calculate the maximum and minimum values The third difference between the values. The next step S12205 determines whether the third difference is smaller than the second threshold VT2. If it is determined in step S12205 that the third difference is not less than the second threshold VT2, then step S12206 is performed to determine whether all target regions have been selected. If it is determined in step S12205 that the third difference value is smaller than the second threshold value VT2, then step S12207 is performed to accumulate the number of target areas whose third difference value is smaller than the second threshold value VT2. In one embodiment, the display 10 includes a counter (not shown), and whenever there is a target area whose third difference is smaller than the second threshold VT2, the count value of the counter is incremented by 1 to accumulate the number of areas. Step S12208 is to determine whether the number of regions accumulated in step S12207 is greater than a third preset value VT3. When it is determined in step S12208 that the number of regions is greater than a third threshold value VT3, step S12209 is performed to determine that the image 20 is an image of the first type. If it is determined in step S12208 that the number of regions is less than the third threshold VT3, step S12206 is performed to check whether all target regions have been selected.

10A to 10C illustrate the effects of the present invention. Suppose Figure 10A is the desired image, most of which is gray, and only a small triangle is white. If the first backlight information determined according to FIG. 10A is directly used to control the backlight panel and compensate the image, the image displayed on the display will be as shown in FIG. 10B , with unevenness in the gray area around the white triangle. This is because the dynamic range (Min1~Max1) of the first backlight information is large, and the image after compensation using the first backlight information will also have a large dynamic range of brightness, which makes the compensation error of the image more obvious, resulting in The uneven phenomenon shown in Fig. 10B. With the control method proposed by the present invention, the image displayed on the display will be as shown in FIG. 10C , and no unevenness occurs in the gray area around the white triangle. This is because the present invention converts the first backlight information into the second backlight information has a smaller dynamic range ((Min2~Max2), therefore, the image compensated by using the second backlight information will also have a smaller dynamic range of brightness, The compensation error of the image becomes less obvious.

According to the above description, the control method of the present invention can be understood as comprising the following steps: A. Determine a first backlight information according to an image, the first backlight information includes a plurality of first brightness values, the plurality of first brightness values include a first maximum brightness value and a first minimum brightness value, the first brightness value the maximum luminance value and the first minimum luminance value have a first difference; B. When the image is an image of a first type, convert the first backlight information into a second backlight information, the second backlight information includes a plurality of second brightness values, wherein the plurality of second brightness values include a second maximum brightness value and a second minimum brightness value, the second maximum brightness value and the second minimum brightness value have a second difference value, the second difference value is smaller than the first difference value; and C. Control the brightness of the plurality of light-emitting regions of the backlight panel respectively according to the plurality of second brightness values.

The above description is only an embodiment of the present invention, and is not intended to limit the present invention in any form. Although the present invention has been disclosed as above by embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field, Within the scope of not departing from the technical solution of the present invention, when the technical content disclosed above can be used to make some changes or modifications to equivalent embodiments with equivalent changes, but any content that does not depart from the technical solution of the present invention, according to the technical essence of the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

10: Display 12: Display panel 14: Backlight panel 142: Glowing area 20: Video 22: Sub-areas 24: Target area 26: Target area 28: Target area 32: Slash

FIG. 1 shows a flow chart of the control method of the present invention. Figure 2 shows an embodiment of the display of the present invention. FIG. 3 shows an image for display on the display of FIG. 2 . FIG. 4 shows the relationship between the first luminance value and the second luminance value. FIG. 5 shows an embodiment of the first stage of step S10 in FIG. 1 . FIG. 6 shows an embodiment in which the number of pixels is less than the first threshold VT1. FIG. 7 shows an embodiment in which the number of pixels is greater than the first threshold VT1. FIG. 8 shows an embodiment of the second stage of step S10 in FIG. 1 . FIG. 9 shows an embodiment of selecting a target area. 10A to 10C illustrate the effects of the control method of the present invention.

Claims (11)

A control method applied to a display, the display includes a backlight plate, the backlight plate includes a plurality of light-emitting regions, the control method includes the following steps: A. Determine a first backlight information according to a first image, the first backlight information including a plurality of first luminance values, the plurality of first luminance values include a first maximum luminance value and a first minimum luminance value, and the first maximum luminance value and the first minimum luminance value have a first difference; B. When the first image is an image of a first type, convert the first backlight information into a second backlight information, the second backlight information includes a plurality of second brightness values, wherein the plurality of second brightness values The value includes a second maximum brightness value and a second minimum brightness value, the second maximum brightness value and the second minimum brightness value have a second difference value, and the second difference value is smaller than the first difference value; and C . Control the brightness of the plurality of light-emitting regions respectively according to the plurality of second brightness values. The control method of claim 1, wherein the second maximum brightness value and the second minimum brightness value are preset values. The control method of claim 1, wherein the second difference is a predetermined value, and the step B further comprises: determining the second maximum brightness value according to the first maximum brightness value; and the second maximum brightness value The second minimum luminance value is obtained by subtracting the second difference value. The control method of claim 3, wherein the step of determining the second maximum brightness value comprises using the first maximum brightness value as the second maximum brightness value. The control method of claim 1, wherein the first image includes a plurality of sub-regions corresponding to the plurality of light-emitting regions, the method further comprises determining whether the first image is an image of the first type, and determining the first image The method of whether it is the image of the first type includes: D1. Perform the following steps for each of the sub-regions; D11. Count the number of pixels corresponding to different brightness values D12. According to the statistical result of step D11, determine a maximum number of pixels and its corresponding third brightness value; and D13. When When the maximum number of pixels is greater than a first threshold, the third brightness value is used as the main brightness value of the sub-region, and when the maximum number of pixels is less than the first threshold, the sub-region is marked; and D2. According to As a result of step D1, it is determined whether the first image is an image of the first type. The control method of claim 5, wherein the step D2 comprises: D21. Selecting a plurality of target areas from the first image, wherein each target area includes a plurality of adjacent sub-areas; D22. For each of the target areas The target area performs the following steps: judging whether the target area includes a marked sub-area; when the target area does not include the marked sub-area, calculating the main A third difference between the maximum value and the minimum value of the luminance value; and determining whether the third difference is less than a second threshold; D23. Calculate the target area where the third difference is less than the second threshold and D24. When the number of regions is greater than a third threshold value, determine that the first image is an image of the first type. The control method of claim 1, wherein the step B comprises: determining a formula according to the relationship between the first maximum brightness value, the first minimum brightness value, the second maximum brightness value and the second minimum brightness value

; and substitute a plurality of first brightness values of the first backlight information into the formula

to obtain a plurality of second brightness values of the second backlight information; wherein, Dif2 is the second difference value, Max1 is the first maximum brightness value, Min1 is the first minimum brightness value, and Max2 is the second maximum brightness value value, BK_original is the first luminance value, and BK_remapped is the second luminance value. The control method of claim 1, wherein the step B comprises: determining a look-up table according to the first maximum brightness value, the relationship between the first minimum brightness value, the second maximum brightness value and the second minimum brightness value; and The lookup table is used to convert a plurality of first luminance values of the first backlight information into a plurality of second luminance values of the second backlight information. The control method of claim 1, wherein the display further comprises a display panel, and the control method further comprises: updating the display panel according to a second image, wherein the second image compensates a third image according to the second backlight information generated image. The control method of claim 9, wherein the third image is the first image, an image preceding the first image, or two preceding images of the first image. The control method of claim 1, further comprising determining whether the first image is an image of the first type, wherein the image of the first type includes mostly monochrome images or mostly gradient images layer image.

Images