TWI779794B - Current limiting method, driving circuit and display based on picture brightness distribution - Google Patents

Abstract

A current limiting method based on picture brightness distribution, which includes: performing a color gamut conversion on the previous frame of RGB data to obtain a pixel brightness distribution in a color space; counting the pixel brightness distribution to obtain a high-brightness pixel group and a low-brightness pixel group, and perform a weighted average calculation on the high-brightness pixel group and the low-brightness pixel group to obtain a first average value and a second average value, and the first average value and the second average value value to obtain a difference; determine an R value lookup table, a G value lookup table and a B value lookup table according to the difference; and according to the R value lookup table, the G value lookup table and the B value lookup table The value lookup table maps a set of (R, G, B) input data to generate a set of (R, G, B) output data.

Description

Current limiting method, driving circuit and display based on screen brightness distribution

The present invention relates to a current limiting method of a self-luminous display, in particular to a current limiting method based on screen brightness distribution.

In general self-luminous displays, such as OLED or LED displays, in order to reduce power consumption and prolong the life of its light-emitting elements, the driving current is reduced when the displayed image meets certain conditions (eg, the displayed image is a high-brightness static image).

A possible way to reduce the overall operating current is ACL (automatic current limiter; automatic current limiter), which determines the brightness reduction degree of the current frame according to the average pixel brightness of a previous frame.

However, when the monitor displays a static picture, if the pixel data of half of the static picture belongs to high brightness (for example, the brightness value is 255), and the pixel data of the other half of the screen belongs to low brightness (for example, the brightness value is 0) At this time, the average pixel brightness is about 127. At this time, the general ACL will think that the brightness of this screen is medium brightness and will hardly lower the brightness. The visual content of the static picture will basically remain unchanged, while the power consumption of the display can be further reduced, and the life of the light-emitting elements of the display can be further extended.

In order to solve the above problems, there is an urgent need in the art for a novel current limiting method for self-luminous displays.

One purpose of the present invention is to disclose a current limiting method based on screen brightness distribution, which can determine the brightness of R, G, and B sub-pixels in a high-gray The distribution of individual reduction amounts in the step range, thereby further reducing the power consumption of a self-luminous display without affecting the chroma content of the picture, and thereby prolonging its service life.

Another object of the present invention is to disclose a current limiting method based on the brightness distribution of the screen, which can dynamically update the distribution of the reduction amount to provide corresponding high-brightness pixel down-pressure for different screen data with different brightness average differences in real time processing, thereby adaptively reducing the power consumption and prolonging the lifetime of self-emissive displays.

In order to achieve the aforementioned purpose, a current limiting method based on picture brightness distribution is proposed, which includes: performing a color gamut conversion to the previous frame of RGB data to obtain a pixel brightness distribution in a color space; counting the pixel brightness distribution to obtaining a high-brightness pixel group and a low-brightness pixel group, and performing a weighted average calculation on the high-brightness pixel group and the low-brightness pixel group respectively to obtain a first average value and a second average value; Carrying out a subtraction operation between an average value and the second average value to obtain a difference; determining an R value lookup table, a G value lookup table, and a B value lookup table according to the difference; and according to the R value lookup table, The G value lookup table and the B value lookup table map a piece of (R, G, B) input data to generate a piece of (R, G, B) output data.

In one embodiment, the color space represents each pixel with a luminance data and a chroma data.

In one embodiment, the color space may be a YUV space or a YCbCr space.

In one embodiment, the high-brightness pixel group and the low-brightness pixel group use a mid-brightness value as a cut-off point, that is, pixels greater than or equal to the mid-brightness value are classified into the high-brightness pixel group, and pixels smaller than The pixels with medium luminance values are classified into the low luminance pixel group.

In one embodiment, the R value lookup table, the G value lookup table and the B value lookup table are all used to map an input grayscale value to an output grayscale value, wherein, when the input grayscale value is not high At a threshold, the output grayscale value is equal to the input grayscale value; and when the input grayscale value is higher than the threshold, the output grayscale value is equal to the input grayscale value minus a tone The amount of reduction is proportional to the input gray scale value and the difference.

In one embodiment, each of the (R, G, B) output data is used to generate a corresponding current to drive a self-luminous display panel, and the self-luminous display panel can be a micro light-emitting diode display noodle panel, mini light emitting diode display panel, quantum dot light emitting diode display panel or organic light emitting diode display panel.

To achieve the aforementioned purpose, the present invention further proposes a driving circuit, which includes a brightness calculation unit, a brightness distribution analysis unit, a lookup table generation unit and a gray scale adjustment unit to perform a current limiting program on a self-luminous display panel, The current limiting program includes: the brightness calculation unit receives a frame of RGB data from an RGB input stream, and performs a color gamut conversion on the frame of RGB data to obtain a pixel brightness distribution N(Y) in a color space, wherein , Y represents pixel brightness, and N represents the number of pixels; the brightness distribution analysis unit counts the pixel brightness distribution N(Y) to obtain a high-brightness pixel group and a low-brightness pixel group, and the high-brightness pixel group and the low-brightness pixel group Performing a weighted average calculation on the pixel group to obtain a first average value and a second average value, and performing a subtraction operation on the first average value and the second average value to obtain a difference; the look-up table generating unit Determine an R value lookup table, a G value lookup table, and a B value lookup table according to the difference, wherein the R value lookup table, G value lookup table, and B value lookup table are all used to convert an input gray scale value is mapped to an output grayscale value, wherein, when the input grayscale value is not higher than a threshold value, the output grayscale value is equal to the input grayscale value; and when the input grayscale value is higher than the When the threshold value is reached, the output grayscale value is equal to the input grayscale value minus a reduction amount, and the reduction amount is proportional to the input grayscale value and proportional to the difference; and the grayscale The adjustment unit maps a piece of (R, G, B) input data in the RGB input stream according to the R value lookup table, the G value lookup table and the B value lookup table to generate a piece of (R, G, B) output data, thereby generating an RGB output stream.

In one embodiment, the color space represents each pixel with a luminance data and a chroma data.

In one embodiment, the color space may be a YUV space or a YCbCr space.

In one embodiment, the high-brightness pixel group and the low-brightness pixel group use a mid-brightness value as a cut-off point, that is, pixels greater than or equal to the mid-brightness value are classified into the high-brightness pixel group, and pixels smaller than The pixels with medium luminance values are classified into the low luminance pixel group.

In one embodiment, each of the (R, G, B) output data is used to generate a corresponding current to drive the self-luminous display panel, and the self-luminous display panel can be a micro-light-emitting diode display panel, mini light emitting diode display panel, quantum dot light emitting diode display panel or organic light emitting diode display panel.

To achieve the aforementioned purpose, the present invention further provides a display, which has the aforementioned driving circuit and a self-luminous display panel.

In order to enable your review committee members to further understand the structure, features and purpose of the present invention, drawings and detailed descriptions of preferred specific embodiments are hereby attached.

Principle of the present invention is:

(1) Statistically calculate the pixel brightness distribution of the previous frame of RGB data in a color space to obtain a high-brightness pixel group and a low-brightness pixel group;

(2) Determining the distribution of individual reduction amounts of R, G, and B sub-pixels in a high gray scale range according to the difference between the average values of the high-brightness pixel group and the low-brightness pixel group; and

(3) Correspondingly downgrade the grayscale values of the R subpixel, G subpixel and B subpixel in the high grayscale range of a current frame of RGB data according to the three individual downscale distributions to generate a frame of RGB Output data so that a self-luminous display can further reduce power consumption when displaying one of two areas of high brightness difference, and thus extend its service life.

Please refer to FIG. 1 , which shows a flow chart of an embodiment of the current limiting method based on the brightness distribution of the screen of the present invention. As shown in Figure 1, the current limiting method based on the brightness distribution of the picture includes: performing a color gamut conversion to the RGB data of the previous frame to obtain a pixel brightness distribution in a color space (step a); counting the pixel brightness distribution to obtain obtaining a high-brightness pixel group and a low-brightness pixel group, and performing a weighted average calculation on the high-brightness pixel group and the low-brightness pixel group respectively to obtain a first average value and a second average value; Carrying out a subtraction operation between an average value and the second average value to obtain a difference (step b); determining an R value lookup table, a G value lookup table and a B value lookup table according to the difference (step c); And mapping a piece of (R, G, B) input data according to the R value lookup table, the G value lookup table and the B value lookup table to generate a piece of (R, G, B) output data (step d).

In step a, the color space may be a color space in which each pixel is represented by a luminance data and a chroma data, for example, the color space may be a YUV space or a YCbCr space, wherein Y represents brightness, (U, V) and (Cb, Cr) are combined to represent chroma.

In step b, the high-brightness pixel group and the low-brightness pixel group use a mid-brightness value (for example, 128) as the dividing point, that is, pixels greater than or equal to the mid-brightness value are classified as the high-brightness pixels group, and the pixels with less than the middle brightness value are classified into the low brightness pixel group. For example, if the brightness distribution of the pixel has N brightness values between 0 and 127, M brightness values between 128 and 255, and N and M are both non-negative integers, then the low brightness pixel group has N brightness values value, and the high brightness pixel group has M brightness values.

In step c, the R value lookup table, G value lookup table and B value lookup table are all used to map an input grayscale value to an output grayscale value, wherein the input grayscale value is not higher than When a threshold value (for example, 127), the output grayscale value is equal to the input grayscale value; and when the input grayscale value is higher than the threshold value, the output grayscale value is equal to the input grayscale value minus A downscaling amount is removed, and the downscaling amount is proportional to the input gray scale value and proportional to the difference. Please refer to Fig. 2, which depicts a grayscale conversion curve corresponding to the R value lookup table, G value lookup table and B value lookup table, wherein the degree of depression of the grayscale conversion curve is proportional to the difference Proportional.

In step d, each (R, G, B) output data is used to generate a corresponding current to drive a self-luminous display panel, and the self-luminous display panel can be a micro light-emitting diode display panel, a mini A light emitting diode display panel, a quantum dot light emitting diode display panel or an organic light emitting diode display panel.

According to the above description, the present invention provides a driving circuit. Please refer to FIG. 3 , which shows a block diagram of an embodiment of the driving circuit of the present invention. As shown in FIG. 3 , a drive circuit 100 includes a brightness calculation unit 110, a brightness distribution analysis unit 120, a lookup table generation unit 130, a gray scale adjustment unit 140 and a drive unit 150 to control a self-luminous display panel 200 Execute a current limiting program, the current limiting program includes:

(1) The brightness calculation unit 110 receives a frame of RGB data from an RGB input stream RGBIN, and performs a color gamut conversion on the frame of RGB data to obtain a pixel brightness distribution N(Y) in a color space, wherein, Y Represents pixel brightness, N represents the number of pixels. That is, relative to the current RGB input stream RGB _IN , the pixel brightness distribution N(Y) output by the brightness calculation unit 110 represents the pixel brightness distribution of the previous frame of RGB data. In addition, the color space may be a color space in which each pixel is represented by a luminance data and a chroma data, for example, the color space may be a YUV space or a YCbCr space, where Y represents brightness, (U, V) and (Cb, Cr) are combined to represent chroma.

(2) The brightness distribution analysis unit 120 counts the pixel brightness distribution N(Y) to obtain a high-brightness pixel group and a low-brightness pixel group, and performs a weighted average calculation on the high-brightness pixel group and the low-brightness pixel group respectively Obtain a first average value and a second average value, and perform a subtraction operation on the first average value and the second average value to obtain a difference Y _D . In addition, the high-brightness pixel group and the low-brightness pixel group use a mid-brightness value (for example, 128) as the dividing point, that is, pixels greater than or equal to the mid-brightness value are classified into the high-brightness pixel group, and pixels smaller than The pixels with medium brightness values are classified into the low brightness pixel group. For example, if the brightness distribution of the pixel has N brightness values between 0 and 127, M brightness values between 128 and 255, and N and M are both non-negative integers, then the low brightness pixel group has N brightness values value, and the high brightness pixel group has M brightness values.

(3) The lookup table generating unit 130 determines an R value lookup table LUT _R , a G value lookup table LUT _G and a B value lookup table LUT _B according to the difference Y _D , wherein the R value lookup tables LUT _R , G Both the value lookup table LUT _G and the B value lookup table LUT _B are used to map an input grayscale value to an output grayscale value, wherein, when the input grayscale value is not higher than a threshold (for example, 127), The output grayscale value is equal to the input grayscale value; and when the input grayscale value is higher than the threshold, the output grayscale value is equal to the input grayscale value minus a reduction amount, and the The amount of reduction is proportional to the input gray scale value and the difference Y _D .

(4) The grayscale adjustment unit 140 maps one of the current RGB input stream RGB _IN according to the R value lookup table LUT _R , the G value lookup table LUT _G and the B value lookup table LUT _B (R, G, B ) input data to generate a piece of (R, G, B) output data, thereby generating an RGB output stream RGB _OUT , wherein each piece of (R, G, B) output data is used to make the drive unit 150 generate a corresponding analog The voltage V _A is used to drive the self-luminous display panel 200 to generate a corresponding pixel current. In addition, the self-luminous display panel 200 can be a micro light emitting diode display panel, a mini light emitting diode display panel, a quantum dot light emitting diode display panel or an organic light emitting diode display panel.

According to the above description, the present invention further provides a display. Please refer to FIG. 4 , which shows a block diagram of an embodiment of the display of the present invention. As shown in FIG. 4 , a display 300 has a driving circuit 310 and a self-luminous display panel 320 , wherein the driving circuit 310 is realized by the driving circuit 100 , and the self-luminous display panel 320 is realized by the self-luminous display panel 200 .

With the design disclosed above, the present invention has the following advantages:

1. The current limiting method based on the screen brightness distribution of the present invention can determine the individual adjustment of the R, G, and B sub-pixels in a high gray scale range according to the brightness average difference between the high brightness group and the low brightness group of a frame of display data. Drop-down distribution, thereby further reducing the power consumption of a self-luminous display without affecting the chroma content of the picture, and thereby prolonging its service life.

2. The current limiting method based on the picture brightness distribution of the present invention can dynamically update the distribution of the reduction amount to instantly provide corresponding high-brightness pixel down-press processing for different picture data with different brightness average differences, thereby adaptively Reduce power consumption and extend lifespan of self-illuminating displays.

What is disclosed in this case is a preferred embodiment. For example, any partial changes or modifications derived from the technical ideas of this case and easily deduced by those who are familiar with the technology are within the scope of the patent right of this case.

To sum up, regardless of the purpose, means and efficacy of this case, it shows that it is very different from the conventional technology, and its first invention is practical, and it does meet the patent requirements of the invention. I implore your review committee to understand it clearly and grant a patent as soon as possible. Society is for the Most Prayer.

100: drive circuit 110: Brightness calculation unit 120: Luminance distribution analysis unit 130: lookup table generation unit 140: grayscale adjustment unit 150: drive unit 200: self-luminous display panel 300: display 310: drive circuit 320: self-luminous display panel Step a: Perform a color gamut conversion on the previous frame of RGB data to obtain a pixel brightness distribution in a color space Step b: count the pixel brightness distribution to obtain a high-brightness pixel group and a low-brightness pixel group, and perform a weighted average calculation on the high-brightness pixel group and the low-brightness pixel group respectively to obtain a first average value and a second average value, and performing a subtraction operation on the first average value and the second average value to obtain a difference Step c: Determine an R value lookup table, a G value lookup table and a B value lookup table according to the difference Step d: Map a piece of (R, G, B) input data according to the R value lookup table, the G value lookup table and the B value lookup table to generate a piece of (R, G, B) output data

FIG. 1 shows a flow chart of an embodiment of the current limiting method based on the brightness distribution of the screen of the present invention. FIG. 2 shows a grayscale conversion curve corresponding to the R value look-up table, the G value look-up table and the B value look-up table described in the process shown in FIG. 1 . FIG. 3 shows a block diagram of an embodiment of the driving circuit of the present invention. FIG. 4 shows a block diagram of an embodiment of the display of the present invention.

Step a: Perform a color gamut conversion on the previous frame of RGB data to obtain a pixel brightness distribution in a color space

Step b: count the pixel brightness distribution to obtain a high-brightness pixel group and a low-brightness pixel group, and perform a weighted average calculation on the high-brightness pixel group and the low-brightness pixel group respectively to obtain a first average value and a second average value, and performing a subtraction operation on the first average value and the second average value to obtain a difference

Step c: Determine an R value lookup table, a G value lookup table and a B value lookup table according to the difference

Step d: Map a piece of (R, G, B) input data according to the R value lookup table, the G value lookup table and the B value lookup table to generate a piece of (R, G, B) output data

Claims (12)

A current limiting method based on picture brightness distribution, which includes: performing a color gamut conversion on the previous frame of RGB data to obtain a pixel brightness distribution in a color space; counting the pixel brightness distribution to obtain a high-brightness pixel group and a low-brightness pixel group, and perform a weighted average calculation on the high-brightness pixel group and the low-brightness pixel group to obtain a first average value and a second average value, and the first average value and the second average value value to obtain a difference; determine an R value lookup table, a G value lookup table and a B value lookup table according to the difference; and according to the R value lookup table, the G value lookup table and the B value lookup table The value lookup table maps a set of (R, G, B) input data to generate a set of (R, G, B) output data. The current limiting method based on the brightness distribution of the screen as described in item 1 of the scope of the patent application, wherein the color space represents each pixel with a brightness data and a saturation data. The current limiting method based on the brightness distribution of the screen as described in item 2 of the scope of the patent application, wherein the color space is a YUV space or a YCbCr space. The current limiting method based on the brightness distribution of the screen as described in item 1 of the scope of the patent application, wherein the high-brightness pixel group and the low-brightness pixel group use a middle brightness value as a cut-off point, that is, greater than or equal to the middle brightness value Pixels with luminance values are classified into the high luminance pixel group, and pixels with a luminance value smaller than the middle luminance value are classified into the low luminance pixel group. The current limiting method based on the brightness distribution of the screen as described in item 1 of the scope of the patent application, wherein the R value lookup table, the G value lookup table and the B value lookup table are all used to map an input grayscale value to an output grayscale value, wherein, when the input grayscale value is not higher than a threshold value, the output grayscale value is equal to the input grayscale value; and when the input grayscale value is higher than the threshold value, the The output grayscale value is equal to the input grayscale value minus a downscaling amount, and the downscaling amount is proportional to the input grayscale value and the difference. The current limiting method based on the brightness distribution of the screen as described in item 1 of the scope of the patent application, wherein each of the (R, G, B) output data is used to generate a corresponding current to drive a self-luminous display display panel, and the self-luminous display panel is composed of micro light emitting diode display panel, mini light emitting diode display panel, quantum dot light emitting diode display panel and organic light emitting diode display panel A display panel of choice. A driving circuit, comprising a luminance calculation unit, a luminance distribution analysis unit, a lookup table generation unit and a gray scale adjustment unit to execute a current limiting program for a self-luminous display panel, the current limiting program includes: the luminance calculation unit Receive a frame of RGB data from an RGB input stream, and perform a color gamut conversion on the frame of RGB data to obtain a pixel brightness distribution N(Y) in a color space, where Y represents pixel brightness, and N represents the number of pixels The brightness distribution analysis unit counts the pixel brightness distribution N(Y) to obtain a high-brightness pixel group and a low-brightness pixel group, and performs a weighted average calculation on the high-brightness pixel group and the low-brightness pixel group respectively to obtain A first average value and a second average value, and performing a subtraction operation on the first average value and the second average value to obtain a difference; the lookup table generation unit determines an R value lookup table according to the difference . A G value lookup table and a B value lookup table, wherein the R value lookup table, G value lookup table and B value lookup table are all used to map an input grayscale value to an output grayscale value, wherein , when the input grayscale value is not higher than a threshold, the output grayscale value is equal to the input grayscale value; and when the input grayscale value is higher than the threshold value, the output grayscale value is equal to The input gray scale value minus a drop amount, and the drop amount is proportional to the input gray scale value and the difference; and the gray scale adjustment unit looks up the table according to the R value, the The G value lookup table and the B value lookup table map a piece of (R, G, B) input data in the RGB input stream to generate a piece of (R, G, B) output data, thereby generating an RGB output stream. The driving circuit described in claim 7 of the patent application, wherein the color space represents each pixel with a brightness data and a saturation data. The driving circuit as described in item 8 of the scope of the patent application, wherein the color space is a YUV space or a YCbCr space. The drive circuit described in item 7 of the scope of the patent application, wherein, the high-brightness pixel group and the low-brightness pixel group use a mid-brightness value as a boundary point, that is, pixels greater than or equal to the mid-brightness value are classified as Similar to the high-brightness pixel group, pixels smaller than the middle-brightness value are classified into the low-brightness pixel group. The drive circuit described in item 7 of the scope of the patent application, wherein each of the (R, G, B) output data is used to generate a corresponding current to drive the self-luminous display panel, and the self-luminous display The panel is a display panel selected from the group consisting of micro light emitting diode display panel, mini light emitting diode display panel, quantum dot light emitting diode display panel and organic light emitting diode display panel. A display, which has a driving circuit and a self-luminous display panel as described in any one of items 7 to 11 of the patent application scope.

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