Display driving chip, image display method and display device

Abstract

The invention discloses a display driving chip, an image display method and a display device, and relates to the technical field of display, and the display driving chip comprises an obtaining module which is used for obtaining a plurality of input pixel values in one-to-one correspondence with a plurality of pixels of an image; the duty ratio determining module is used for determining a target duty ratio for controlling backlight brightness when the image is displayed based on the plurality of input pixel values; and the pixel value determination module is used for determining a plurality of adjusted pixel values corresponding to the plurality of input pixel values based on the pixel value mapping information corresponding to the duty ratio, the pixel value mapping information indicates that the adjusted pixel values corresponding to different input pixel values are different, and the adjusted pixel values and the target duty ratio are used for displaying the image. The plurality of adjusted pixel values determined in the application are different, so that the pixels with different input pixel values are displayed according to different adjusted pixel values, and the contrast among different pixels is ensured.

Description

Technical Field

[0001] This application relates to the field of display technologies, and in particular, to a display driving chip, an image display method, and a display device. Background Art

[0002] In the field of display technologies, the brightness of each pixel displayed by a display device is jointly affected by the brightness value of the backlight and the pixel value of the pixel. The brightness value of the backlight and the pixel value during display are both adjusted by a display driving chip in the display device. To reduce the power consumption when displaying an image, the display driving chip adaptively reduces the brightness value of the backlight to adjust the power consumption required to output the backlight. When the brightness of the backlight decreases, the display driving chip also correspondingly adjusts the pixel value of the pixel to keep the displayed brightness meet the display requirements. Summary of the Invention

[0003] This application provides a display driving chip, an image display method, and a display device, which can be used to improve the display quality of an image. The technical solutions are as follows:

[0004] On the one hand, this application provides a display driving chip, which includes: an acquisition module, configured to acquire a plurality of input pixel values of an image, and the plurality of input pixel values correspond to the plurality of pixels of the image one by one; a duty ratio determination module, configured to determine a target duty ratio of a backlight control signal based on the plurality of input pixel values, and the target duty ratio is used to control the backlight brightness when displaying an image; a pixel value determination module, configured to determine a plurality of adjusted pixel values corresponding to the plurality of input pixel values based on pixel value mapping information corresponding to the target duty ratio, the pixel value mapping information indicates the correspondence between the plurality of input pixel values and the plurality of adjusted pixel values, the pixel value mapping information indicates that the adjusted pixel values corresponding to different input pixel values are different, and the plurality of adjusted pixel values and the target duty ratio are used to display an image.

[0005] In a possible implementation manner, the pixel value determination module is configured to: when at least two intermediate pixel values corresponding to two different input pixel values are the same, determine a plurality of adjusted pixel values corresponding to the plurality of input pixel values based on pixel value mapping information corresponding to the target duty ratio, and the intermediate pixel value corresponding to any input pixel value is determined based on a reference product and the brightness value corresponding to the target duty ratio.

[0006] In a possible implementation, the pixel value determination module is further configured to: obtain first mapping information corresponding to a target duty cycle, where the first mapping information indicates the correspondence between multiple input pixel values and multiple first display brightness values, and the first display brightness value corresponding to any input pixel value refers to the brightness value of the pixel displayed based on any input pixel value when the display duty cycle is the target duty cycle, and the contrast between any two first display brightness values meets the contrast requirement, and the first display brightness values corresponding to different input pixel values are different; perform gamma inverse transformation on the multiple first display brightness values in the first mapping information based on the gamma correction parameter to obtain pixel value mapping information, and the first display brightness value corresponding to any input pixel value is gamma-inverted to the adjusted pixel value corresponding to any input pixel value.

[0007] In a possible implementation, the pixel value determination module is configured to: obtain second mapping information corresponding to a target duty cycle, where the second mapping information indicates the correspondence between multiple input pixel values and multiple second display brightness values, and the second display brightness value corresponding to any input pixel value refers to the brightness value of the pixel displayed based on any input pixel value when the display duty cycle is the target duty cycle, and the second display brightness values corresponding to different input pixel values are different; adjust one or more second display brightness values in the second mapping information based on the contrast requirement to obtain the first mapping information.

[0008] In a possible implementation, the pixel value determination module is configured to: obtain third mapping information corresponding to a target duty cycle, where the third mapping information indicates the correspondence between multiple input pixel values and multiple first brightness values, and the ratio between the first brightness value corresponding to any input pixel value greater than or equal to the specified pixel value and the third display brightness value corresponding to any input pixel value is the target duty cycle, and the third display brightness value corresponding to any input pixel value refers to the brightness value of the pixel displayed based on the maximum pixel value when the display duty cycle is the reference duty cycle; perform a tone mapping on the third mapping information to obtain the second mapping information, and the tone mapping is used to convert the first brightness values corresponding to multiple input pixel values into second display brightness values, and the second display brightness values corresponding to different input pixel values are different.

[0009] In a possible implementation, the multiple input pixel values include a first pixel value and a second pixel value, and the pixel value mapping information includes the first pixel value and the adjusted pixel value corresponding to the first pixel value; the pixel value determination module is configured to: determine the adjusted pixel value corresponding to the first pixel value in the pixel value mapping information; for any second pixel value, determine the adjusted pixel value corresponding to any second pixel value based on one or more first pixel values in the multiple first pixel values that are closest in size to any second pixel value and the adjusted pixel values corresponding to the one or more first pixel values.

[0010] In a possible implementation, a duty cycle determination module is configured to: determine a target duty cycle corresponding to a reference pixel value in the mapping information between pixel values and duty cycles, where the reference pixel value is calculated based on a plurality of input pixel values and indicates the overall display requirement of the image.

[0011] In a possible implementation, the target duty cycle is greater than a duty cycle threshold.

[0012] On the other hand, an image display method is provided, which includes: obtaining a plurality of input pixel values of an image, where the plurality of input pixel values correspond one-to-one to a plurality of pixels of the image; determining a target duty cycle of a backlight control signal based on the plurality of input pixel values, where the target duty cycle is used to control the backlight brightness when displaying the image; determining a plurality of adjusted pixel values corresponding to the plurality of input pixel values based on the pixel value mapping information corresponding to the target duty cycle, where the pixel value mapping information indicates the correspondence between the plurality of input pixel values and the plurality of adjusted pixel values, and the adjusted pixel values corresponding to different input pixel values indicated by the pixel value mapping information are different, and the plurality of adjusted pixel values and the target duty cycle are used to display the image.

[0013] In a possible implementation, determining a plurality of adjusted pixel values corresponding to a plurality of input pixel values based on the pixel value mapping information corresponding to the target duty cycle includes: when there are at least two intermediate pixel values corresponding to two different input pixel values that are the same, determining a plurality of adjusted pixel values corresponding to the plurality of input pixel values based on the pixel value mapping information corresponding to the target duty cycle, where the intermediate pixel value corresponding to any input pixel value is determined based on a reference product and the brightness value corresponding to the target duty cycle.

[0014] In a possible implementation, before determining a plurality of adjusted pixel values corresponding to a plurality of input pixel values based on the pixel value mapping information corresponding to the target duty cycle, it further includes: obtaining first mapping information corresponding to the target duty cycle, where the first mapping information indicates the correspondence between the plurality of input pixel values and a plurality of first display brightness values, and the first display brightness value corresponding to any input pixel value refers to the brightness value of the pixel displayed based on any input pixel value when the display duty cycle is the target duty cycle, and the contrast between any two first display brightness values meets the contrast requirement, and the first display brightness values corresponding to different input pixel values are different; performing gamma inverse transformation on the plurality of first display brightness values in the first mapping information based on gamma correction parameters to obtain the pixel value mapping information, and the first display brightness value corresponding to any input pixel value is gamma-inverted to the adjusted pixel value corresponding to any input pixel value.

[0015] In a possible implementation, obtaining the first mapping information corresponding to the target duty cycle includes: obtaining the second mapping information corresponding to the target duty cycle, where the second mapping information indicates the correspondence between multiple input pixel values and multiple second display brightness values. The second display brightness value corresponding to any input pixel value refers to the brightness value of the pixel displayed based on any input pixel value when the display duty cycle is the target duty cycle, and the second display brightness values corresponding to different input pixel values are different; based on the contrast requirement, adjusting one or more of the second display brightness values in the second mapping information to obtain the first mapping information.

[0016] In a possible implementation, obtaining the second mapping information corresponding to the target duty cycle includes: obtaining the third mapping information corresponding to the target duty cycle, where the third mapping information indicates the correspondence between multiple input pixel values and multiple first brightness values. The ratio between the first brightness value corresponding to any input pixel value greater than or equal to the specified pixel value and the third display brightness value corresponding to any input pixel value is the target duty cycle. The third display brightness value corresponding to any input pixel value refers to the brightness value of the pixel displayed based on the maximum pixel value when the display duty cycle is the reference duty cycle; performing a tone mapping on the third mapping information to obtain the second mapping information, where the tone mapping is used to convert the first brightness values corresponding to multiple input pixel values into second display brightness values, and the second display brightness values corresponding to different input pixel values are different.

[0017] In a possible implementation, the multiple input pixel values include a first pixel value and a second pixel value, and the pixel value mapping information includes the first pixel value and the adjusted pixel value corresponding to the first pixel value; based on the pixel value mapping information corresponding to the target duty cycle, determining the adjusted pixel values corresponding to the multiple input pixel values includes: determining the adjusted pixel value corresponding to the first pixel value in the pixel value mapping information; for any second pixel value, based on one or more first pixel values in the multiple first pixel values that are closest in size to the any second pixel value and the adjusted pixel values corresponding to the one or more first pixel values, determining the adjusted pixel value corresponding to the any second pixel value.

[0018] In a possible implementation, based on the multiple input pixel values, determining the target duty cycle of the backlight control signal includes: in the mapping information between the pixel value and the duty cycle, determining the target duty cycle corresponding to the reference pixel value, where the reference pixel value is calculated based on the multiple input pixel values and the reference pixel value indicates the overall display requirement of the image.

[0019] In a possible implementation, the target duty cycle is greater than the duty cycle threshold.

[0020] On the other hand, a display device is provided, and the display device includes any one of the possible display driver chips described above.

[0021] The technical solution provided by this application at least brings the following beneficial effects:

[0022] The adjusted pixel values corresponding to different input pixel values indicated by the pixel value mapping information in this application are different. Therefore, the multiple determined adjusted pixel values are different, ensuring that pixels with different input pixel values can still be displayed according to different adjusted pixel values, ensuring that pixels with different input pixel values have contrast during display, and improving the overall display quality of the image. Description of the Drawings

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 is a schematic structural diagram of a display driving chip provided by an embodiment of this application;

[0025] Figure 2 is a schematic diagram of the mapping information between pixel values and duty ratios in the form of a line graph provided by an embodiment of this application;

[0026] Figure 3 is a schematic diagram of the pixel value mapping information in the form of a table provided by an embodiment of this application;

[0027] Figure 4 is a schematic diagram of a deformed third mapping information provided by an embodiment of this application;

[0028] Figure 5 is a schematic diagram of the third mapping information after tune mapping provided by an embodiment of this application;

[0029] Figure 6 is a schematic diagram of a deformed second mapping information provided by an embodiment of this application;

[0030] Figure 7 is a schematic diagram of another deformed second mapping information provided by an embodiment of this application;

[0031] Figure 8 is a schematic diagram of a deformed first mapping information provided by an embodiment of this application;

[0032] Figure 9 is a schematic diagram of the pixel value mapping information in the form of a line provided by an embodiment of this application;

[0033] Figure 10It is a schematic diagram of a display effect provided by an embodiment of the present application;

[0034] Figure 11 It is a schematic diagram of measurement data provided by an embodiment of the present application;

[0035] Figure 12 It is a schematic diagram of another display effect provided by an embodiment of the present application;

[0036] Figure 13 It is a schematic diagram of another display effect provided by an embodiment of the present application;

[0037] Figure 14 It is a schematic diagram of another display effect provided by an embodiment of the present application;

[0038] Figure 15 It is a schematic flowchart of an image display method provided by an embodiment of the present application. Detailed implementation manners

[0039] To make the objectives, technical solutions and advantages of the present application clearer, the following will further describe the embodiments of the present application in detail with reference to the accompanying drawings.

[0040] Content Adaptive Backlight Control (CABC) is a technology for controlling the brightness of the backlight output by the backlight source of a display device. Through CABC, the brightness of the backlight can be dynamically controlled according to the characteristics of the display content to optimize the display effect and save energy.

[0041] The backlight source is usually located on the back or side of the display panel in the display device. If the backlight source is located on the side of the display panel, the backlight output by the backlight source is side-injected backlight. Optical elements such as a light guide plate in the display panel evenly distribute the light on the side to the entire back of the display panel, so that the liquid crystal molecules can modulate the light and present an image. If the backlight source is located on the back of the display panel, the backlight output by the backlight source is direct-lit backlight, and a diffuser plate in the display device evenly projects the light onto the display panel.

[0042] A Liquid Crystal Display (LCD) is a display device based on liquid crystal molecules. In a liquid crystal display, the backlight output by the backlight source passes through the liquid crystal layer in the liquid crystal panel (Open Cell, OC). The liquid crystal molecules in the liquid crystal layer change their alignment directions based on the pixel values, control the polarization and transmittance of the backlight, and accurately control the display brightness of the pixels to achieve image display. It can be seen that the display brightness of each pixel displayed by the liquid crystal display is jointly affected by the brightness value of the backlight and the pixel value of the pixel.

[0043] When a traditional LCD displays an image, the brightness of the backlight is usually 100%. Since the brightness of the backlight is proportional to the power consumption when the LCD displays an image, the power consumption is relatively high when the brightness of the backlight is 100%. To reduce the power consumption, the LCD usually adaptively reduces the brightness of the backlight through the CABC technology to adjust the power consumption required for the output backlight. When the brightness of the backlight decreases, to keep the display brightness value of the pixel stable, it is necessary to correspondingly adjust the pixel value of the pixel to maintain the display brightness of the pixel and ensure the display quality of the image.

[0044] The related technology adjusts the brightness of the backlight according to the input pixel values of multiple pixels of the image, and then, based on the brightness of the backlight, takes the input pixel value as the target display brightness value of the pixel, inversely calculates the pixel values of each pixel required under the adjusted backlight, and displays the image according to the determined pixel values, so that under the combined action of the adjusted pixel value and the brightness value of the backlight, the display brightness value of the pixel reaches the target display brightness value. For example, the relationship between the pixel value of the pixel, the brightness value of the backlight, and the display brightness value can be shown as the following formula (1).

[0045] BL*OC=1 (1)

[0046] Where BL represents the brightness value of the backlight, OC represents the pixel value when the LCD displays an image, and 1 is the result of normalizing the display brightness value. Formula (1) means that the product of the brightness value of the backlight corresponding to any pixel and the pixel value when displaying the pixel is equal to the display brightness value of the pixel. If BL is reduced from 100% to 83.1%, the value of OC needs to be increased by about 1.2 times to keep the product as 1, so that the display brightness value of the pixel is the target display brightness value, thereby stabilizing the display quality of the image.

[0047] However, the pixel values required for display determined in the related technology may exceed the pixel value range that the display panel can display. For example, if the brightness value of the adjusted backlight is 50%, the adjusted pixel value needs to be twice the pixel value before adjustment. If the pixel value before adjustment is greater than 128, the adjusted pixel value is greater than 255, exceeding the maximum pixel value (255) that the display panel can display. The related technology will adjust all pixel values greater than 255 to 255. For example, if the input pixel value is 200, it is adjusted to 400, and then 400 is adjusted to 255, resulting in pixels corresponding to different input pixel values before adjustment being displayed according to the same pixel value, making the display brightness of pixels corresponding to different input pixel values the same, reducing the contrast between different pixels in the image and the overall display quality of the image.

[0048] An embodiment of the present application provides a display driver integrated circuit (DDIC). This display driver integrated circuit can be used to accurately display images. During the CABC process, it can not only reduce power consumption but also improve contrast, thereby improving the display quality of images.

[0049] Refer to Figure 1 , which shows a schematic structural diagram of a display driver integrated circuit 10 provided by an embodiment of the present application. The display driver integrated circuit 10 includes a timing controller (TCON). Optionally, the display driver integrated circuit 10 further includes at least one of a source driver or a gate driver.

[0050] As Figure 1 shown, the display driver integrated circuit 10 includes an acquisition module 11, a duty ratio determination module 12, and a pixel value determination module 13. Each module is a circuit module within the TCON of the display driver integrated circuit 10. Different modules can be implemented by different hardware circuits within the TCON or by the same hardware circuit within the TCON.

[0051] The acquisition module 11 is configured to acquire a plurality of input pixel values of an image, and the plurality of input pixel values correspond one-to-one to a plurality of pixels of the image; the duty ratio determination module 12 is configured to determine a target duty ratio of a backlight control signal based on the plurality of input pixel values, and the target duty ratio is used to control the backlight brightness when displaying an image; the pixel value determination module 13 is configured to determine a plurality of adjusted pixel values corresponding to the plurality of input pixel values based on pixel value mapping information corresponding to the target duty ratio. The pixel value mapping information indicates the correspondence between the plurality of input pixel values and the plurality of adjusted pixel values. The adjusted pixel values corresponding to different input pixel values indicated by the pixel value mapping information are different. The plurality of adjusted pixel values and the target duty ratio are used to display an image.

[0052] Among them, obtaining multiple input pixel values of the image acquired by the acquisition module 11 refers to the original pixel values of multiple pixels in the image. The multiple input pixel values can be sent by the main control chip at the front end of the display driver chip 10 to the display driver chip 10. For example, a main control chip such as a System on a Chip (SOC) decodes, scales, or performs color processing operations on the signal of the image to be displayed, obtains the input pixel values of the image for realizing image display, that is, the original pixel values of multiple pixels in the image, and transmits them to the display driver chip 10. The acquisition module 11 in the display driver chip 10 can directly receive the multiple input pixel values sent by the main control chip, or after other circuits for receiving data in the display driver chip 10 receive the multiple input pixel values, transmit them to the acquisition module 11. After the acquisition module 11 obtains the multiple input pixel values of the image, the duty cycle determination module 12 and the pixel value determination module 13 adjust the backlight brightness of the display panel and the pixel values required for each pixel during display based on the multiple input pixel values, so that the display effect conforms to the input pixel values.

[0053] The way for the duty cycle determination module 12 to adjust the backlight brightness of the display panel can be: by adjusting the target duty cycle of the backlight control signal for controlling the backlight brightness when displaying an image, the adjustment of the backlight brightness is realized. The backlight is the light output by the backlight source in the display device, and the backlight source is usually a Light Emitting Diode (LED). The backlight control signal is a Pulse Width Modulation (PWM) signal, and the backlight control signal can control whether the LED is turned on. In one cycle, the longer the time the LED is turned on, the longer the time the LED emits light, and the higher the backlight brightness in this cycle; conversely, the lower the backlight brightness in this cycle. Therefore, the duty cycle determination module 12 can control the ratio of the light-emitting time to the non-light-emitting time of the LED in one cycle by controlling the target duty cycle of the backlight control signal, thereby realizing the adjustment of the backlight brightness. Before adjusting the backlight brightness, the duty cycle determination module 12 can determine the target duty cycle of the backlight control signal based on the multiple input pixel values.

[0054] Exemplarily, the duty cycle determination module 12 may determine the target duty cycle of the backlight control signal corresponding to the reference pixel value in the mapping information between the pixel value and the duty cycle. The reference pixel value is calculated based on multiple input pixel values and indicates the overall display requirement of the image. The mapping information between the pixel value and the duty cycle indicates different duty cycles corresponding to different pixel values. The mapping information between the pixel value and the duty cycle may be set based on experience or user requirements, and the mapping information between the pixel value and the duty cycle may be configured in the memory corresponding to the duty cycle determination module 12. The memory corresponding to the duty cycle determination module 12 is, for example, the memory within the duty cycle determination module 12 or the memory connected to the duty cycle determination module 12. During the process of the duty cycle determination module 12 determining the target duty cycle, the duty cycle determination module 12 reads the mapping information between the pixel value and the duty cycle in the corresponding memory and determines the target duty cycle corresponding to the reference pixel value based on the mapping information.

[0055] Exemplarily, the reference pixel value may be the average value of multiple input pixel values, or other values that can indicate the overall display requirement of the image. For example, the reference pixel value may be determined based on the average value of multiple input pixel values and the maximum values of the three channels of the image in red, green, and blue (RGB). The average value of multiple input pixel values may be the RGB average value or the YUV (a color encoding method) average value. In YUV, Y represents luminance, and U and V represent chrominance.

[0056] Taking the average value of multiple input pixel values as the RGB average value as an example, the average value of multiple input pixels can be calculated by the following formula (2).

[0057] APL avg = R avg × Coe R + G avg × Coe G + R avg × Coe B (2)

[0058] APL in formula (2) avg is the average value of multiple input pixel values, representing the average pixel level (APL) of multiple input pixel values, and may also represent the average gray level of multiple input pixel values. R avg is the average value of the red components of multiple input pixel values, Coe R is the weight of the red component of the input pixel value, G avg is the average value of the green components of multiple input pixel values, Coe G is the weight of the green component of the input pixel value, B avgis the average value of the blue components of multiple input pixel values, Coe B is the weight of the blue component of the input pixel value. Among them, Coe R , Coe G and Coe B sum to 1, and the values of Coe R , Coe G and Coe B can be set based on experience or user requirements.

[0059] In addition, the maximum values of the RGB three channels of multiple input pixel values can be calculated based on the following formula (3).

[0060] APL max = Max(R × Coe R + G × Coe G + B × Coe B ) (3)

[0061] APL max in formula (3) is the maximum pixel value calculated based on the components of the RGB three channels. MAX (maximum value) is the maximum value function. R is the pixel value of the red component of any one of the multiple input pixel values. Coe R is the weight of the red component of the input pixel value. G is the pixel value of the green component of any one of the input pixel values. Coe G is the weight of the green component of the input pixel value. B is the pixel value of the blue component of any one of the input pixel values. Coe B is the weight of the blue component of the input pixel value. By calculating R × Coe R + G × Coe G + B × Coe B , the calculated pixel value corresponding to any one of the input pixel values is obtained. The calculated pixel values corresponding to each of the multiple input pixel values are calculated in the same way, and the maximum calculated pixel value among the calculated pixel values corresponding to the multiple input pixel values is determined through the MAX function. The maximum calculated pixel value can also represent the maximum gray level corresponding to the multiple input pixel values.

[0062] The average value of multiple input pixels reflects the average display requirement of the image, and the maximum calculated pixel value reflects the highest brightness display requirement of the image. Therefore, based on the average value of multiple input pixel values and the maximum calculated pixel value, a reference pixel value that can indicate the overall display requirement of the image can be determined.

[0063] Optionally, the reference pixel value can be determined based on the following formula (4).

[0064] APL = round(apl rate×APL avg +(1 - apl rate )×APL max ) (4)

[0065] In formula (4), APL is the reference pixel value, round (rounding) is the rounding function, and apl rate is the weight corresponding to the average value of multiple input pixel values, and APL avg is the average value of multiple input pixel values, and 1 - apl rate is the weight corresponding to the maximum pixel value, and APL max is the maximum calculated pixel value corresponding to multiple input pixels. The value of apl rate can be set based on experience or user requirements. If the uniformity during image display is more important, then the value of apl rate is larger, and if the highest display brightness during image display is more important, then the value of apl rate is smaller, so that the value of 1 - apl rate is larger.

[0066] After determining the reference pixel value, the target duty ratio of the backlight control signal required for the displayed image can be determined based on the mapping information between the pixel value and the duty ratio. Regarding the form of the mapping information between the pixel value and the duty ratio, the embodiments of the present application do not make any limitations. Exemplarily, the mapping information between the pixel value and the duty ratio can be in the form of a line graph, a table, etc. Refer to Figure 2 , which shows a schematic diagram of the mapping information between the pixel value and the duty ratio in the form of a line graph provided by the embodiments of the present application. Figure 2 In [reference], the horizontal axis represents different pixel values. The number of bits of the pixel value is 8 bits (bit), that is, the pixel value is represented by an 8 - bit binary number. The pixel value can be any value from 0 to 255. In this case, the reference pixel value determined by the duty ratio determination module 12 is also a pixel value represented by an 8 - bit binary number and belongs to the range between 0 and 255. Figure 2 In [reference], the vertical axis represents the backlight output percentage, that is, the duty ratio corresponding to different pixel values. The duty ratio can be any value from 0% to 100%. The pixel value and the duty ratio are in one - to - one correspondence. For example, when the reference pixel value is 0, the backlight output percentage is 40%, that is, the corresponding target duty ratio is 40%. When the reference pixel value is 160, the backlight output percentage is 55%, that is, the corresponding target duty ratio is 55%.

[0067] In addition, the mapping information between the pixel value and the duty ratio can also be in the form of a table. Refer to Table 1, which shows a schematic illustration of the mapping information between the pixel value and the duty ratio in the form of a table provided by the embodiments of the present application.

[0068] Table 1

[0069] Pixel value Duty cycle Contrast requirement 0 40％ None 128 40％ Contrast > 4.5; reference value 7.2 256 40％ Contrast > 2.5; reference value 7.3 384 45％ Contrast > 2.0; reference value 7.4 512 50％ None 640 55％ None 768 60％ None 896 70％ None 1023 90％ None

[0070] The first column in Table 1 shows some possible values of the pixel value. Taking the number of bits of the pixel value being 10 bits as an example, that is, the pixel value can be represented by a 10-bit binary number, and the pixel value can be any value from 0 to 1023. The second column shows the values of the duty cycle corresponding to the pixel value, and the third column also shows the contrast ratio (CR) requirements corresponding to the pixel value. For example, when the reference pixel value is 0, the corresponding target duty cycle is 40%, and the corresponding contrast requirement is Not Available (NA), that is, when the reference pixel value is 0, no requirement is made for the contrast of the image display. When the reference pixel value is 384, the corresponding target duty cycle is 45%, and the corresponding contrast requirement is that the contrast is greater than 2.0, and the reference value (ref) is 7.4, that is, when the reference pixel value is 384, the optimal contrast is 7.4, but as long as the contrast of the displayed image is greater than 2.0, the displayed image meets the contrast requirement.

[0071] Regardless of the form of the mapping information between the pixel value and the duty cycle, the duty cycle determination module 12 can determine the target duty cycle of the backlight control signal corresponding to the reference pixel value through the mapping information between the pixel value and the duty cycle.

[0072] In a possible implementation manner, the target duty cycle of the backlight control signal determined in the embodiments of the present application is greater than the duty cycle threshold. The duty cycle threshold can be based on experience or set by the user. For example, the duty cycle threshold can be 10% or 20%, etc. Controlling the target duty cycle of the backlight control signal to be greater than the duty cycle threshold ensures that the brightness of the backlight is not too low and guarantees the realization of the basic display function. For example, when the user adjusts the display brightness based on the On Screen Display (OSD) function, the target duty cycle of the backlight control signal is controlled above the duty cycle threshold, so that the user can see the menu bar for adjusting the display brightness and realize the basic display function.

[0073] After determining the target duty cycle of the backlight control signal, the pixel value determination module 13 can determine the adjusted pixel values of multiple input pixel values corresponding to the target duty cycle of the backlight control signal, so as to realize high-quality display of the image based on the multiple adjusted pixel values. Exemplarily, the pixel value determination module 13 can determine the multiple adjusted pixel values corresponding to the multiple input pixel values based on the pixel value mapping information corresponding to the target duty cycle of the backlight control signal. The pixel value mapping information indicates the corresponding relationship between the multiple input pixel values and the multiple adjusted pixel values, and the adjusted pixel values corresponding to different input pixel values indicated by the pixel value mapping information are different.

[0074] Among them, the form of the pixel value mapping information can be a line chart, a table, text, etc. The pixel value mapping information may include one or more input pixel values and the adjusted pixel values corresponding to the one or more input pixel values.

[0075] For example, Figure 3 FIG. shows a schematic diagram of pixel value mapping information in a table form provided by an embodiment of the present application. Figure 3 The shown pixel value mapping information includes pixel value mapping information corresponding to multiple duty cycles. Figure 3 One row in is the pixel value mapping information corresponding to a certain duty cycle. For example, the row of 3 / 16 is the pixel value mapping information corresponding to a duty cycle of 3 / 16. When the input pixel value of any pixel is 128 in the case of a duty cycle of 3 / 16, the adjusted pixel value corresponding to the input pixel value is 207.4132.

[0076] Before determining the multiple adjusted pixel values corresponding to the multiple input pixel values based on the pixel value mapping information corresponding to the target duty cycle of the backlight control signal, the pixel value determination module 13 will obtain the pixel value mapping information corresponding to the target duty cycle of the backlight control signal. Exemplarily, the pixel value determination module 13 may read the pixel value mapping information corresponding to the target duty cycle of the backlight control signal from the connected memory, or calculate the pixel value mapping information corresponding to the target duty cycle of the backlight control signal. The pixel value mapping information corresponding to the target duty cycle of the backlight control signal stored in the memory may be calculated and stored in the memory by the pixel value determination module 13 previously, or transmitted to the memory by the main control chip in front of the display driving chip 10.

[0077] Next, taking the example where the pixel value mapping information corresponding to the target duty ratio is calculated by the pixel value determination module 13, the process of calculating the pixel value mapping information corresponding to the target duty ratio will be described. The pixel value determination module 13 can obtain the first mapping information corresponding to the target duty ratio of the backlight control signal. Among them, the first mapping information indicates the correspondence between multiple input pixel values and multiple first display brightness values. The first display brightness value corresponding to any input pixel value means: when the display duty ratio is the target duty ratio, the brightness value of the pixel displayed based on any input pixel value. The first mapping information indicates that the first display brightness values corresponding to different input pixel values are different, and the contrast between any two first display brightness values meets the contrast requirement. For example, the first mapping information corresponding to the target duty ratio of the backlight control signal includes: when the display duty ratio is the target duty ratio, the first display brightness value b1 corresponding to the input pixel value a1; the first display brightness value b2 corresponding to the input pixel value a2. The first display brightness value b1 is the display brightness value of the pixel corresponding to the input pixel value a1 when the display panel corresponding to the display driver chip 10 performs image display according to the backlight corresponding to the target duty ratio and the adjusted pixel value corresponding to the input pixel value a1. The first display brightness value b2 is the display brightness value of the pixel corresponding to the input pixel value a2 when the display panel performs image display according to the backlight corresponding to the target duty ratio and the adjusted pixel value corresponding to the input pixel value a2. The contrast between the first display brightness value b1 and the first display brightness value b2 (for example, the ratio of the first display brightness value b1 to the first display brightness value b2, or the ratio of the first display brightness value b2 to the first display brightness value b1) meets the contrast requirement corresponding to the input pixel value a1 and the input pixel value a2. For example, if the contrast requirement corresponding to the input pixel value a1 and the input pixel value a2 is greater than x, then the contrast between the first display brightness value b1 and the first display brightness value b2 is greater than x.

[0078] After the pixel value determination module 13 obtains the first mapping information corresponding to the target duty ratio, it will perform a gamma inverse transformation on the multiple first display brightness values in the first mapping information based on the gamma correction parameter, so as to obtain the pixel value mapping information corresponding to the target duty ratio. The first display brightness value corresponding to any input pixel value is gamma-inverted to the adjusted pixel value corresponding to any input pixel value.

[0079] The first display brightness value and the adjusted pixel value corresponding to the input pixel value satisfy the gamma transformation function. The gamma inverse transformation function is shown in the following formula (5).

[0080] y = x γ (5)

[0081] In formula (5), γ is the gamma value, that is, the gamma correction parameter. The gamma correction parameter is set based on experience or user requirements, for example, it is 2.2. y is the first display brightness value, and x is the adjusted pixel value, that is, the pixel value finally used to implement image display. Since in the embodiment of the present application, the pixel value determination module 13 needs to determine the corresponding adjusted pixel value based on the input pixel value, the pixel value determination module 13 can perform gamma inverse transformation on the first mapping information to gamma inverse transform the first display brightness value into the adjusted pixel value, so as to obtain the relationship between the input pixel value and the adjusted pixel value, that is, obtain the pixel value mapping information corresponding to the target duty cycle.

[0082] The gamma inverse transformation function is shown in the following formula (6).

[0083]

[0084] In formula (6), γ is the gamma correction parameter, and the gamma correction parameter is the same as the gamma correction parameter in formula (5). y is the first display brightness value, and x is the adjusted pixel value. After performing gamma inverse transformation on the first display brightness value corresponding to each input pixel value in the first mapping information according to the above formula (6), the adjusted pixel value corresponding to each input pixel value can be obtained, and the acquisition of the pixel value mapping information corresponding to the target duty cycle is realized.

[0085] The embodiment of the present application does not limit the manner in which the pixel value determination module 13 obtains the first mapping information. For example, the pixel value determination module 13 can obtain the second mapping information corresponding to the target duty cycle; then, based on the contrast requirement, adjust one or more second display brightness values in the second mapping information to obtain the first mapping information. Among them, the second mapping information indicates the corresponding relationship between multiple input pixel values and multiple second display brightness values. The second display brightness value corresponding to any input pixel value refers to the brightness value of the pixel displayed based on any input pixel value when the display duty cycle is the target duty cycle, and the second display brightness values corresponding to different input pixel values are different.

[0086] The difference between the second display brightness value included in the second mapping information and the first display brightness value included in the first mapping information is that: although the second display brightness values corresponding to different input pixel values indicated by the second mapping information are different, they may not meet the contrast requirement; after adjusting one or more second display brightness values in the second mapping information based on the contrast requirement, the first display brightness values corresponding to different input pixel values indicated by the obtained first mapping information are different and meet the contrast requirement.

[0087] For example, the second display brightness value corresponding to the input pixel value a2 indicated by the second mapping information is b2, and the second display brightness value corresponding to the input pixel value a3 is b3. The values of the input pixel value a2 and the input pixel value a3 are different, and the values of the second display brightness value b2 and the second display brightness value b3 are different. The ratio between the second display brightness value b3 and the second display brightness value b2 is d1, and d1 is the contrast ratio corresponding to the input pixel value a2 and the input pixel value a3. The contrast ratio d1 may be less than the contrast requirement corresponding to the input pixel value a2 and the input pixel value a3.

[0088] The contrast requirement includes the minimum ratio of the display brightness values corresponding to any two input pixel values. For example, the minimum ratio G64_32_lim of the display brightness values corresponding to the input pixel value 64 and the input pixel value 32 is 4.53; the minimum ratio G96_64_lim of the display brightness values corresponding to the input pixel value 96 and the input pixel value 64 is 2.53; the minimum ratio G128_96_lim of the display brightness values corresponding to the input pixel value 128 and the input pixel value 96 is 2.1.

[0089] The first display brightness value corresponding to the input pixel value a2 indicated by the first mapping information is b4, and the first display brightness value corresponding to the input pixel value a3 is b5. The values of the first display brightness value b4 and the first display brightness value b5 are different, and the ratio between the first display brightness value b4 and the first display brightness value b5 is d2, and d2 is greater than or equal to the contrast requirement corresponding to the input pixel value a2 and the input pixel value a3.

[0090] Exemplarily, before processing the second mapping information corresponding to the target duty ratio to obtain the first mapping information corresponding to the target duty ratio, the pixel value determination module 13 also needs to obtain the second mapping information. The process for the pixel value determination module 13 to obtain the second mapping information may include: obtaining the third mapping information corresponding to the target duty ratio; performing a tone mapping on the third mapping information to obtain the second mapping information. The third mapping information therein indicates the correspondence between a plurality of input pixel values and a plurality of first brightness values. The ratio between the first brightness value corresponding to any input pixel value greater than or equal to the specified pixel value and the third display brightness value corresponding to any input pixel value is the target duty ratio, and the third display brightness value corresponding to any input pixel value refers to the brightness value of the pixel displayed based on any input pixel value when the display duty ratio is the reference duty ratio. The reference duty ratio refers to 100%. The specified pixel value refers to the pixel value obtained by rounding up the product of the maximum input pixel value and the target duty ratio.

[0091] For example, if the target duty cycle is 50% and the maximum input pixel value is 1023, the specified pixel value is 512. When the input pixel value a1 is greater than 512, the third mapping information corresponding to the target duty cycle indicates that the first luminance value corresponding to the input pixel value a1 is c1. Wherein, the ratio between the first luminance value c1 and the third display luminance value e1 corresponding to the input pixel value a1 is the target duty cycle f. The third display luminance value e1 refers to the display luminance value of the pixel corresponding to the maximum pixel value when the display panel performs image display according to the backlight corresponding to a duty cycle of 100%.

[0092] Correspondingly, when the input pixel value is less than the specified pixel value, the first luminance value corresponding to the pixel value is the luminance value obtained by performing gamma transformation on the pixel value.

[0093] Performing tone mapping on the third mapping information is used to convert the first luminance values corresponding to multiple input pixel values into second display luminance values, so that the second display luminance values corresponding to different input pixel values are different, thereby obtaining the second mapping information.

[0094] Next, according to the generation order of each mapping information, the process of generating each mapping information will be described.

[0095] Exemplarily, first is the process of obtaining the third mapping information. Sampling the possible duty cycles (from 0 to 1) to obtain multiple alternative duty cycles. The multiple alternative duty cycles can be obtained by uniform sampling or non-uniform sampling. The hardware realizability of obtaining multiple alternative duty cycles by uniform sampling is stronger and the flexibility is also stronger. The sampling interval can be flexibly set based on experience or user requirements. Taking the case where multiple alternative duty cycles are obtained by uniform sampling as an example, the multiple alternative duty cycles are 0, 1 / 16, 2 / 16, 3 / 16, …, 15 / 16, 1, a total of 17 alternative duty cycles.

[0096] Based on the gamma correction parameter, calculate the first luminance values corresponding to various input pixel values under different alternative duty cycles respectively. For example, through the above formula (5), the input pixel value can be converted into the corresponding first luminance value. In this case, x in formula (5) is the input pixel value, γ is the gamma correction parameter, and y is the first luminance value.

[0097] See Figure 4 , which shows a deformed third mapping information provided by an embodiment of the present application. Figure 4 Shows multiple Gamma-2.2-Level (G2L) clip curves with a gamma correction parameter of 2.2. One of the curves corresponds to one alternative duty cycle, and a total of 17 curves correspond to the above 17 alternative duty cycles. Figure 4The horizontal axis represents the input pixel values in gray level, ranging from 0 to 1023 respectively. The vertical axis represents the ratio of the first luminance value to the luminance value corresponding to the maximum pixel value of 1023 with a duty cycle of 1, that is, the ratio of the first luminance value to the third display luminance value.

[0098] Taking the fourth curve from bottom to top in Figure 4 as an example, the specified input pixel value corresponding to the target duty cycle of 3 / 16 is 192. When the maximum pixel value is 1023 and the duty cycle is 1, the corresponding luminance value is 6839010. If any input pixel value is greater than 192, after calculation according to formula (1), the adjusted pixel value is greater than 1023, and the display panel can only display according to 1023. Therefore, when the target duty cycle is 3 / 16 and the input pixel value is greater than 192, the first luminance value corresponding to this input pixel value is 1282314, which is the maximum display luminance value corresponding to the target duty cycle of 3 / 16, and the ratio to the luminance value corresponding to the maximum pixel value is 3 / 16. When the input pixel value is less than 192, after the input pixel value is adjusted by formula (1) to obtain the adjusted pixel value, the product of the adjusted pixel value and the target duty cycle of 3 / 16 is the same as the product of this input pixel value and the maximum duty cycle of 1. Therefore, when the input pixel value is less than 192, the luminance value corresponding to the adjusted pixel value at a duty cycle of 3 / 16 is still the luminance value corresponding to this input pixel value at a duty cycle of 1. For example, when the input pixel value is 100, the corresponding first luminance value is approximately 25118.9, and the ratio to the maximum luminance value (i.e., the third display luminance value) is approximately 0.0036.

[0099] It can be seen from Figure 4 that due to the constraint of the alternative duty cycle, when any input pixel value is greater than the specified pixel value corresponding to the alternative duty cycle, the curve is truncated. That is, only the maximum luminance that can be displayed corresponding to this alternative duty cycle can be displayed. For example, when the alternative duty cycle is 3 / 16 and the gray value corresponding to the input pixel value is 600 and the corresponding first luminance value is greater than 3 / 16, the first luminance value corresponding to the input pixel value of 600 is changed to 3 / 16 to avoid luminance overflow. After the curve is truncated, in a curve corresponding to the same alternative duty cycle, the first luminance values corresponding to multiple input pixel values are the same. That is, if the image is displayed according to the first luminance values corresponding to multiple input pixel values, the display luminance of the pixels corresponding to multiple input pixel values is the same, and the contrast of the image display is insufficient, resulting in the loss of details in the image.

[0100] To avoid the phenomenon of insufficient contrast and detail loss in image display caused by curve truncation, it is necessary to adjust the third mapping information so that at the same alternative duty ratio, the brightness values corresponding to different input pixel values are different, ensuring that the display brightness of pixels corresponding to different input pixel values is different, improving the contrast of image display, and retaining the details in the image.

[0101] Therefore, tone mapping can be performed on the third mapping information to adjust the truncated curve into a smooth curve without horizontal lines. For example, the truncated curve can be adjusted into an S-shaped curve through formulas such as Bezier Curve formula, Spline Curve formula, or Polynomial Fitting formula.

[0102] See Figure 5 , which shows a schematic diagram of the third mapping information after tone mapping provided by an embodiment of the present application. Figure 5 In it, different curves represent the relationship between the second display brightness value and the third display brightness value corresponding to the input pixel value under different backlight duty ratios (i.e., alternative duty ratios). From Figure 5 it can be seen that after tone mapping, the truncated curve is adjusted into an S-shaped curve, and there are no two points with the same value on one curve. The first brightness value corresponding to the input pixel value is converted into the second display brightness value. The first brightness value and the second display brightness value corresponding to any input pixel value may be the same or different at the same alternative duty ratio, and the second display brightness values corresponding to any two different input pixel values are different at the same alternative duty ratio, retaining as much detail in the image as possible.

[0103] In addition, since the OSD needs to ensure that the user can see the menu bar when adjusting the display parameters of the display device, the backlight cannot be too low. Therefore, the second brightness values corresponding to each input pixel value at duty ratios of 0 and 1 / 16 are set to 0, that is, the duty ratio of the backlight control signal cannot be lower than 1 / 16.

[0104] Optionally, normalization processing can be performed on the third mapping information after tone mapping to facilitate subsequent processing. See Figure 6 , which shows a schematic diagram of a deformed second mapping information provided by an embodiment of the present application. Figure 6Shows multiple normalized standard (norm) curves, with one alternative duty cycle corresponding to one curve, and the maximum value on one curve being 1. For any curve, the value on the horizontal axis is the input pixel value, and the value on the vertical axis is the ratio of the second display brightness value corresponding to the input pixel value to the second display brightness value corresponding to the maximum input pixel value at this duty cycle. For example, when the alternative duty cycle is 3 / 16, the input pixel value is 100, the second brightness value of the corresponding pixel is 25118.9, and the second display brightness corresponding to the highest pixel value 1023 is 7535670, then the ratio corresponding to the vertical axis is 0.03.

[0105] Optionally, the normalized mapping information can also be sampled, that is, the second mapping information can be obtained by sampling the normalized third mapping information, or can be directly sampled from the third mapping information. Saving the second mapping information obtained after sampling can save the resources for storing the second mapping information. Exemplarily, referring to Figure 7 , shows a schematic diagram of a deformed second mapping information provided by an embodiment of the present application. Figure 7 Each curve in is a standard sampling curve, and only the values of 9 binding points are stored for each curve, which are the ratios between the second display brightness values corresponding to the input pixel values of 0, 128, 256, 384, 512, 640, 768, 896, 1023 and the second display brightness value corresponding to the maximum pixel value 1023. Connecting the adjacent two binding points corresponding to the same alternative duty cycle, the broken lines corresponding to each alternative duty cycle are obtained, that is, the deformed second mapping information, and the deformed second mapping information can be used to calculate the second mapping information.

[0106] As shown in Table 1, users have certain requirements for the contrast of image display under different duty cycles. Therefore, the second mapping information can be adjusted according to the contrast requirement, so that the adjusted mapping information meets the contrast requirement.

[0107] Exemplarily, for the second mapping information corresponding to any alternative duty cycle, the adjustment can be made from the higher input pixel value to the lower input pixel value. Fix the second display brightness value corresponding to the input pixel value 512, adjust the second display brightness value corresponding to the input pixel value 384, and obtain the first display brightness value corresponding to the input pixel value 384 to meet the contrast requirement that G512 / G384 (i.e., the contrast between the input pixel value 512 and the input pixel value 384) > 2.0. Then, based on the adjusted second display brightness value corresponding to the input pixel value 384, adjust the second display brightness value corresponding to the input pixel value 256 to obtain the first display brightness value corresponding to the input pixel value 256 to meet the contrast requirement that G384 / G256 > 2.5. Based on the adjusted second display brightness value corresponding to the input pixel value 256, adjust the second display brightness value corresponding to the input pixel value 128 to obtain the first display brightness value corresponding to the input pixel value 128 to meet the contrast requirement that G256 / 1286 > 4.5. By adjusting the values of the binding points on the broken lines corresponding to each alternative duty cycle, the first mapping information corresponding to each alternative duty cycle is obtained. Exemplarily, see Figure 8 , which shows a schematic diagram of a deformed first mapping information provided by an embodiment of the present application. Figure 8 Compared with Figure 7 , the values of one or more binding points on each broken line are adjusted so that the ratio between two adjacent binding points (first display brightness values) on the same broken line is the modified contrast, meeting the contrast requirement.

[0108] After obtaining the first mapping information, perform a gamma inverse transformation on the first mapping information to inverse-transform the first display brightness value corresponding to the input pixel value into the adjusted pixel value, obtaining the pixel value mapping information, so that the pixel value determination module 13 can quickly determine the adjusted pixel value according to the pixel value mapping information and the input pixel value, realizing efficient and high-quality display of the image. Exemplarily, see Figure 9 , which shows a schematic diagram of a broken-line form of pixel value mapping information provided by an embodiment of the present application. Figure 9 The vertical axis in Figure 9 becomes the adjusted pixel value, and the horizontal axis remains the input pixel value. Figure 3 The pixel value mapping information shown in

[0109] Regardless of the form of the pixel value mapping information, the pixel value determination module 13 can determine multiple adjusted pixel values corresponding to multiple input pixel values based on the pixel value mapping information corresponding to the determined target duty cycle. Taking the target duty cycle as 3 / 16, the pixel value mapping information is as Figure 3Taking the example shown, if the input pixel value of any pixel is 384, then under the condition that the target duty cycle is 3 / 16, the adjusted pixel value corresponding to this input pixel value is 628.4914.

[0110] Since the pixel value mapping information may be determined based on the sampled second mapping information, the pixel value mapping information may not include the adjusted pixel values corresponding to each of the input pixel values among the multiple input pixel values, but only includes the adjusted pixel values corresponding to some of the input pixel values. Therefore, for different input pixel values, the method for determining the adjusted input pixel value is different.

[0111] Exemplarily, the multiple input pixel values include a first pixel value and a second pixel value. The pixel value mapping information includes the first pixel value and the adjusted pixel value corresponding to the first pixel value, but does not include the second pixel value and the adjusted pixel value corresponding to the second pixel value. In this case, the pixel value determination module 13 can determine the adjusted pixel value corresponding to the first pixel value in the pixel value mapping information. By the method of searching for the adjusted pixel value corresponding to the first pixel value in the pixel value mapping information, the adjusted pixel value corresponding to the first pixel value can be quickly determined.

[0112] For any second pixel value, based on one or more first pixel values among the multiple first pixel values that are closest in size to any second pixel value and the adjusted pixel values corresponding to the one or more first pixel values, determine the adjusted pixel value corresponding to any second pixel value. Taking the determination of the adjusted pixel value corresponding to the second pixel value based on two first pixel values among the multiple first pixel values that are closest in size to any second pixel value and the adjusted pixel values corresponding to these two first pixel values as an example, the pixel value determination module 13 can determine the linear function satisfied by the two first pixel values that are closest in size to the second pixel value and the adjusted pixel values corresponding to these two first pixel values, and determine the adjusted pixel value corresponding to the second pixel value based on this linear function.

[0113] See Figure 3, taking the determined target duty cycle as 5 / 16 and the second pixel value as 300 as an example, the two first pixel values closest to the second pixel value 300 in the pixel value mapping information corresponding to the target duty cycle 5 / 16 are the first pixel value 256 and the first pixel value 384. The adjusted pixel value corresponding to the first pixel value 256 is 389.8596, and the adjusted pixel value corresponding to the first pixel value 384 is 594.4904. The linear function determined based on the first pixel value 384 and the corresponding adjusted pixel value 594.4904, the first pixel value 256 and the corresponding adjusted pixel value 389.8596 is y = 1.598678x - 20.401968, where x is the input pixel value, such as the first pixel value or the second pixel value, and y is the adjusted pixel value corresponding to the input pixel value. Substituting the second pixel value 300 into the determined linear function, the adjusted pixel value corresponding to the second pixel value 300 is determined to be 459.201432.

[0114] In a possible implementation manner, the target duty cycle determined based on the reference pixel value does not belong to the alternative duty cycles. Taking the pixel value mapping information stored in the pixel value determination module 13 as Figure 3 shown as an example, if the target duty cycle determined based on the reference pixel value is 7 / 32, the pixel value mapping information stored in the pixel value determination module 13 does not include the pixel value mapping information corresponding to the target duty cycle 7 / 32. Therefore, before the pixel value determination module 13 determines the adjusted pixel values corresponding to multiple input pixel values, it will also calculate the pixel value mapping information corresponding to the target duty cycle 7 / 32.

[0115] The method for calculating the pixel value mapping information corresponding to any non-alternative duty cycle is: determining the two alternative duty cycles closest to the non-alternative duty cycle among multiple alternative duty cycles, and determining the pixel value mapping information corresponding to the non-alternative duty cycle based on each input pixel value and the corresponding adjusted pixel value included in the pixel value mapping information corresponding to the two alternative duty cycles.

[0116] Still taking the pixel value mapping information stored in the memory corresponding to the pixel value determination module 13 as Figure 3Taking the following as an example, if the non - alternative duty cycle is 7 / 32, the two alternative duty cycles closest to the non - alternative duty cycle 7 / 32 are 3 / 16 and 4 / 16 respectively. Then, based on the adjusted pixel values corresponding to any input pixel value at a duty cycle of 3 / 16 and the adjusted pixel values corresponding to the duty cycle of 4 / 16, the adjusted pixel value corresponding to the input pixel value at a duty cycle of 7 / 32 is determined. For example, a linear function can be determined based on the adjusted pixel values corresponding to any input pixel value at a duty cycle of 3 / 16 and the adjusted pixel values corresponding to the duty cycle of 4 / 16, and based on the linear function, the adjusted pixel value corresponding to the input pixel value at the non - alternative duty cycle of 7 / 32 is determined.

[0117] Taking the input pixel value of 512 as an example, the adjusted pixel value corresponding to the input pixel value 512 at the alternative duty cycle of 3 / 16 is 880.5675, and the adjusted pixel value corresponding to the input pixel value 512 at the alternative duty cycle of 4 / 16 is 860.6886. Then the determined linear function is b = - 318.0624a + 940.2042, where b is the adjusted pixel value corresponding to the input pixel value 512, and a is the duty cycle, which can be an alternative duty cycle or a non - alternative duty cycle. Then, based on the linear function, the adjusted pixel value corresponding to the input pixel value 512 at the non - alternative duty cycle of 7 / 32 is 870.62805. Based on a similar process, the adjusted pixel values corresponding to various input pixel values at a duty cycle of 7 / 32 can be determined.

[0118] In a possible implementation manner, after obtaining multiple input pixel values, the pixel value determination module 13 may not directly determine multiple adjusted pixel values according to the target duty cycles corresponding to the multiple input pixel values. Instead, it can first determine the intermediate pixel values corresponding to the multiple input pixel values when the backlight brightness value is the backlight brightness value corresponding to the target duty cycle according to the above formula (1) and the reference product. The intermediate pixel value corresponding to any input pixel value is determined based on the reference product and the brightness value corresponding to the target duty cycle. That is, by changing BL in formula (1) from the maximum duty cycle 1 to the backlight brightness value corresponding to the target duty cycle, the value of OC is determined under the condition that the product remains unchanged, and the determined value of OC is the intermediate pixel value. And according to the situation of the multiple intermediate pixel values, it is determined whether it is necessary to determine the adjusted pixel values corresponding to the multiple input pixel values according to the pixel value mapping information provided in the embodiments of the present application. The reference product corresponding to any input pixel value is the product of the input pixel value and the backlight brightness value when the duty cycle of the backlight control signal is 100%, or 1 after normalization.

[0119] Optionally, when there are at least two intermediate pixel values corresponding to two different input pixel values that are the same, the pixel value determination module 13 may determine multiple adjusted pixel values corresponding to multiple input pixel values based on the pixel value mapping information corresponding to the target duty ratio.

[0120] For example, the value of the input pixel value a6 is different from the value of the input pixel value a7. However, if the intermediate pixel value e6 corresponding to the input pixel value a6 determined based on formula (1) and the intermediate pixel value e7 corresponding to the input pixel value a7 are the same, it means that if the image is displayed according to the intermediate pixel values e6 and e7, there will be a loss of contrast, resulting in the loss of image details. In this case, the pixel value determination module 13 may re-determine the adjusted pixel values corresponding to multiple input pixel values according to the pixel value mapping information provided in the embodiments of the present application, so that the adjusted pixel values corresponding to different input pixel values are different, reducing the loss of contrast. The method of determining the adjusted pixel values corresponding to multiple input pixel values according to the pixel value mapping information may refer to the previous description and will not be elaborated here.

[0121] Regardless of the method used to determine the adjusted pixel values corresponding to multiple input pixel values, after the pixel value determination module 13 determines the adjusted pixel values corresponding to multiple input pixel values, it may transmit the determined adjusted pixel values to the driver, and the driver applies pressure to the liquid crystal molecules in the display panel according to the adjusted pixel values, changing the arrangement of the liquid crystal molecules on the display panel. In addition, the duty ratio determination module 12 will also generate a backlight control signal according to the determined target duty ratio, thereby controlling the backlight brightness of the display panel. The liquid crystal molecules in the display panel then adjust the backlight based on the arrangement, thereby realizing the display of each pixel, that is, realizing the display of the image.

[0122] See Figure 10 , which shows a schematic diagram of a display effect provided by the embodiments of the present application. Figure 10 It includes the display effects corresponding to different input pixel values, and the input pixel values are represented by gray values. For example, when the gray value corresponding to the input pixel value is 0, the displayed pixel is black. As the gray value corresponding to the input pixel value increases, the brightness of the pixel is higher and the color is closer to white. The colors of the pixels displayed based on different input pixel values are different.

[0123] See Figure 11 , which shows a schematic diagram of a measurement data provided by the embodiments of the present application. Figure 11 The first column in represents the reference pixel values in the form of gray values, the second column represents the user-requested duty ratio corresponding to the reference pixel values, and the third column represents the duty ratio calculated based on the embodiments of the present application corresponding to the reference pixel values.Figure 11 It can be seen that the duty cycle corresponding to the reference pixel value calculated based on the embodiments of the present application is close to the duty cycle required by the user. Therefore, it can be considered that the duty cycle corresponding to the reference pixel value calculated based on the embodiments of the present application meets the user requirements, and the test results are all passed.

[0124] See Figures 12 to 14 , which shows a schematic diagram of the display effect provided by the embodiments of the present application. Figure 12 It shows the display effects corresponding to the gray values of 32 and 64 corresponding to the pixel values. Based on the brightness measured by the colorimeter at the position of the circle, the brightness value when the gray value corresponding to the input pixel value is 32 is 3.299 nits (nit, the unit of brightness), and the brightness value when the gray value corresponding to the input pixel value is 64 is 15.810 nits. Then the contrast ratio G64 / G32 between the gray value 64 and the gray value 32 = 15.810 nits / 3.299 nits = 4.79 (> 4.5), that is, the contrast ratio meets the contrast ratio requirement.

[0125] Figure 13 It shows the display effects corresponding to the gray values of 64 and 96 corresponding to the pixel values. Based on the brightness measured by the colorimeter at the position of the circle, the brightness value when the gray value corresponding to the input pixel value is 64 is 15.959 nits, and the brightness value when the gray value corresponding to the input pixel value is 96 is 41.504 nits. Then the contrast ratio G96 / G64 between the gray value 96 and the gray value 64 = 41.504 nits / 15.959 nits = 2.6 (requirement > 2.5), that is, the contrast ratio meets the contrast ratio requirement.

[0126] Figure 14 It shows the display effects corresponding to the gray values of 96 and 128 corresponding to the pixel values. Based on the brightness measured by the colorimeter at the position of the circle, the brightness value when the gray value corresponding to the input pixel value is 96 is 41.870 nits, and the brightness value when the gray value corresponding to the input pixel value is 128 is 89.856 nits. Then the contrast ratio G128 / G96 between the gray value 128 and the gray value 96 = 89.856 nits / 41.870 nits = 2.15 (requirement > 2), that is, the contrast ratio meets the contrast ratio requirement.

[0127] In summary, the adjusted pixel values corresponding to different input pixel values indicated by the pixel value mapping information in the present application are different, so the determined multiple adjusted pixel values are different, ensuring that pixels with different input pixel values can still be displayed according to different adjusted pixel values, ensuring the contrast between different pixels, and improving the overall display quality of the image.

[0128] In an exemplary embodiment, an image display method is provided, which can improve the display contrast and display quality.

[0129] Referring to Figure 15 , a schematic flowchart of an image display method provided by an embodiment of the present application is shown. The method includes but is not limited to S1501 to S1503 as follows.

[0130] S1501, obtaining a plurality of input pixel values of an image, where the plurality of input pixel values correspond one-to-one to the plurality of pixels of the image.

[0131] S1502, based on the plurality of input pixel values, determining a target duty ratio of a backlight control signal, where the target duty ratio is used to control the backlight brightness when displaying an image.

[0132] Determining the target duty ratio of the backlight control signal based on the plurality of input pixel values includes: in the mapping information between the pixel value and the duty ratio, determining the target duty ratio corresponding to a reference pixel value, where the reference pixel value is calculated based on the plurality of input pixel values, and the reference pixel value indicates the overall display requirement of the image.

[0133] In a possible implementation, the target duty ratio is greater than a duty ratio threshold.

[0134] S1503, based on the pixel value mapping information corresponding to the target duty ratio, determining a plurality of adjusted pixel values corresponding to the plurality of input pixel values, where the pixel value mapping information indicates the correspondence between the plurality of input pixel values and the plurality of adjusted pixel values, the pixel value mapping information indicates that the adjusted pixel values corresponding to different input pixel values are different, and the plurality of adjusted pixel values and the target duty ratio are used to display an image.

[0135] In a possible implementation, before determining the plurality of adjusted pixel values corresponding to the plurality of input pixel values based on the pixel value mapping information corresponding to the target duty ratio, it further includes: obtaining first mapping information corresponding to the target duty ratio, where the first mapping information indicates the correspondence between the plurality of input pixel values and the plurality of first display brightness values, and the first display brightness value corresponding to any input pixel value refers to the brightness value of the pixel displayed based on any input pixel value when the display duty ratio is the target duty ratio, the contrast between any two first display brightness values meets the contrast requirement, and the first display brightness values corresponding to different input pixel values are different; based on the gamma correction parameter, performing gamma inverse transformation on the plurality of first display brightness values in the first mapping information to obtain the pixel value mapping information, and the first display brightness value corresponding to any input pixel value is gamma-inverted to the adjusted pixel value corresponding to any input pixel value.

[0136] Exemplarily, obtaining the first mapping information corresponding to the target duty cycle includes: obtaining the second mapping information corresponding to the target duty cycle, where the second mapping information indicates the correspondence between a plurality of input pixel values and a plurality of second display brightness values, and the second display brightness value corresponding to any input pixel value refers to the brightness value of the pixel displayed based on any input pixel value when the display duty cycle is the target duty cycle, and the second display brightness values corresponding to different input pixel values are different; adjusting one or more second display brightness values in the second mapping information based on the contrast requirement to obtain the first mapping information.

[0137] Among them, obtaining the second mapping information corresponding to the target duty cycle includes: obtaining the third mapping information corresponding to the target duty cycle, where the third mapping information indicates the correspondence between a plurality of input pixel values and a plurality of first brightness values, and the ratio between the first brightness value corresponding to any input pixel value greater than or equal to the specified pixel value and the third display brightness value corresponding to any input pixel value is the target duty cycle, and the third display brightness value corresponding to any input pixel value refers to the brightness value of the pixel displayed based on the maximum pixel value when the display duty cycle is the reference duty cycle; performing a tone mapping on the third mapping information to obtain the second mapping information, and the tone mapping is used to convert the first brightness values corresponding to a plurality of input pixel values into second display brightness values, and the second display brightness values corresponding to different input pixel values are different.

[0138] The plurality of input pixel values include a first pixel value and a second pixel value, and the pixel value mapping information includes the first pixel value and the adjusted pixel value corresponding to the first pixel value; determining the adjusted pixel values corresponding to the plurality of input pixel values based on the pixel value mapping information corresponding to the target duty cycle includes: determining the adjusted pixel value corresponding to the first pixel value in the pixel value mapping information; for any second pixel value, determining the adjusted pixel value corresponding to any second pixel value based on one or more first pixel values in the plurality of first pixel values that are closest in size to any second pixel value and the adjusted pixel values corresponding to the one or more first pixel values.

[0139] In a possible implementation manner, determining the adjusted pixel values corresponding to the plurality of input pixel values based on the pixel value mapping information corresponding to the target duty cycle includes: when there are at least two different input pixel values whose corresponding intermediate pixel values are the same, determining the adjusted pixel values corresponding to the plurality of input pixel values based on the pixel value mapping information corresponding to the target duty cycle, and the intermediate pixel value corresponding to any input pixel value is determined based on the reference product and the brightness value corresponding to the target duty cycle.

[0140] In an exemplary embodiment, a display device is provided, and the display device includes any one of the possible display driving chips described above.

[0141] It should be noted that the information involved in this application (including but not limited to user device information, user personal information, etc.), data (including but not limited to data for analysis, stored data, displayed data, etc.) and signals are all authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data need to comply with the relevant laws, regulations and standards of relevant countries and regions. For example, the pixel values involved in this application are obtained under full authorization.

[0142] It should be understood that the term "a plurality of" mentioned herein refers to two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0143] It should be noted that the terms "first", "second", etc. (if any) in the description and claims of this application are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of this application described here can be implemented in an order other than those illustrated or described here. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. On the contrary, they are only examples of devices and methods consistent with some aspects of this application as detailed in the appended claims.

[0144] The above are only exemplary embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the principles of this application shall be included in the protection scope of this application.

Claims

1. A display driver chip, characterized in that: The display driver chip comprises: An acquisition module, used for acquiring a plurality of input pixel values ​​of an image, wherein the plurality of input pixel values ​​correspond one-to-one to a plurality of pixels of the image; a duty cycle determination module, configured to determine a target duty cycle of a backlight control signal based on the plurality of input pixel values, wherein the target duty cycle is used to control the backlight brightness when displaying the image; A pixel value determination module is used to determine a plurality of adjusted pixel values ​​corresponding to the plurality of input pixel values ​​based on pixel value mapping information corresponding to the target duty cycle, the pixel value mapping information indicating a correspondence between the plurality of input pixel values ​​and the plurality of adjusted pixel values, the pixel value mapping information indicating that different input pixel values ​​correspond to different adjusted pixel values, the plurality of adjusted pixel values ​​and the target duty cycle are used to display the image.

2. The display driver chip according to claim 1, characterized in that: The pixel value determination module is used to: In the case where there are at least two identical intermediate pixel values ​​corresponding to two different input pixel values, multiple adjusted pixel values ​​corresponding to the multiple input pixel values ​​are determined based on the pixel value mapping information corresponding to the target duty cycle, and the intermediate pixel value corresponding to any input pixel value is determined based on the reference product and the brightness value corresponding to the target duty cycle.

3. The display driver chip according to claim 1 or 2, characterized in that: The pixel value determination module is further used for: Acquire first mapping information corresponding to the target duty cycle, the first mapping information indicating a correspondence between the plurality of input pixel values ​​and a plurality of first display brightness values, the first display brightness value corresponding to any input pixel value refers to a brightness value of a pixel displayed based on the any input pixel value when the display duty cycle is the target duty cycle, the contrast between any two first display brightness values ​​meets the contrast requirement, and different input pixel values ​​correspond to different first display brightness values; Based on the gamma correction parameters, gamma inverse transformation is performed on multiple first display brightness values ​​in the first mapping information to obtain the pixel value mapping information, and the first display brightness value corresponding to any input pixel value is gamma inverse transformed into an adjusted pixel value corresponding to the any input pixel value.

4. The display driver chip according to claim 3, characterized in that: The pixel value determination module is used to: acquiring second mapping information corresponding to the target duty cycle, the second mapping information indicating a correspondence between the plurality of input pixel values ​​and a plurality of second display brightness values, the second display brightness value corresponding to any input pixel value being a brightness value of a pixel displayed based on the any input pixel value when the display duty cycle is the target duty cycle, and different input pixel values ​​corresponding to different second display brightness values; Based on the contrast requirement, one or more second display brightness values ​​in the second mapping information are adjusted to obtain the first mapping information.

5. The display driver chip according to claim 4, characterized in that: The pixel value determination module is used to: Acquire third mapping information corresponding to the target duty cycle, the third mapping information indicating a correspondence between the plurality of input pixel values ​​and the plurality of first brightness values, a ratio between a first brightness value corresponding to any input pixel value greater than or equal to a specified pixel value and a third display brightness value corresponding to the any input pixel value being the target duty cycle, and the third display brightness value corresponding to the any input pixel value being a brightness value of a pixel displayed based on a maximum pixel value when the display duty cycle is a reference duty cycle; The third mapping information is subjected to tune mapping to obtain the second mapping information, wherein the tune mapping is used to convert the first brightness values ​​corresponding to the multiple input pixel values ​​into second display brightness values, and different input pixel values ​​correspond to different second display brightness values.

6. The display driver chip according to any one of claims 1 to 5, characterized in that: The multiple input pixel values ​​include a first pixel value and a second pixel value, the pixel value mapping information includes the first pixel value and an adjusted pixel value corresponding to the first pixel value; the pixel value determination module is used to: Determining an adjusted pixel value corresponding to the first pixel value in the pixel value mapping information; For any second pixel value, the adjusted pixel value corresponding to any second pixel value is determined based on one or more first pixel values ​​among the multiple first pixel values ​​that are closest in size to the any second pixel value and the adjusted pixel values ​​corresponding to the one or more first pixel values.

7. An image display method, characterized in that: The method comprises: Acquire a plurality of input pixel values ​​of an image, wherein the plurality of input pixel values ​​correspond one-to-one to a plurality of pixels of the image; Determining a target duty cycle of a backlight control signal based on the plurality of input pixel values, wherein the target duty cycle is used to control backlight brightness when displaying the image; Based on the pixel value mapping information corresponding to the target duty cycle, multiple adjusted pixel values ​​corresponding to the multiple input pixel values ​​are determined, the pixel value mapping information indicates the corresponding relationship between the multiple input pixel values ​​and the multiple adjusted pixel values, the pixel value mapping information indicates that different input pixel values ​​correspond to different adjusted pixel values, and the multiple adjusted pixel values ​​and the target duty cycle are used to display the image.

8. The method according to claim 7, characterized in that The determining, based on the pixel value mapping information corresponding to the target duty cycle, a plurality of adjusted pixel values ​​corresponding to the plurality of input pixel values ​​comprises: In the case where there are at least two identical intermediate pixel values ​​corresponding to two different input pixel values, multiple adjusted pixel values ​​corresponding to the multiple input pixel values ​​are determined based on the pixel value mapping information corresponding to the target duty cycle, and the intermediate pixel value corresponding to any input pixel value is determined based on the reference product and the brightness value corresponding to the target duty cycle.

9. The method according to claim 7 or 8, characterized in that: Before determining the plurality of adjusted pixel values ​​corresponding to the plurality of input pixel values ​​based on the pixel value mapping information corresponding to the target duty cycle, the method further includes: Acquire first mapping information corresponding to the target duty cycle, the first mapping information indicating a correspondence between the plurality of input pixel values ​​and a plurality of first display brightness values, the first display brightness value corresponding to any input pixel value refers to a brightness value of a pixel displayed based on the any input pixel value when the display duty cycle is the target duty cycle, the contrast between any two first display brightness values ​​meets the contrast requirement, and different input pixel values ​​correspond to different first display brightness values; Based on the gamma correction parameters, gamma inverse transformation is performed on multiple first display brightness values ​​in the first mapping information to obtain the pixel value mapping information, and the first display brightness value corresponding to any input pixel value is gamma inverse transformed into an adjusted pixel value corresponding to the any input pixel value.

10. The method according to claim 9, characterized in that The acquiring first mapping information corresponding to the target duty cycle includes: acquiring second mapping information corresponding to the target duty cycle, the second mapping information indicating a correspondence between the plurality of input pixel values ​​and a plurality of second display brightness values, the second display brightness value corresponding to any input pixel value being a brightness value of a pixel displayed based on the any input pixel value when the display duty cycle is the target duty cycle, and different input pixel values ​​corresponding to different second display brightness values; Based on the contrast requirement, one or more second display brightness values ​​in the second mapping information are adjusted to obtain the first mapping information.

11. The method according to claim 10, characterized in that The acquiring second mapping information corresponding to the target duty cycle includes: Acquire third mapping information corresponding to the target duty cycle, the third mapping information indicating a correspondence between the plurality of input pixel values ​​and the plurality of first brightness values, a ratio between a first brightness value corresponding to any input pixel value greater than or equal to a specified pixel value and a third display brightness value corresponding to the any input pixel value being the target duty cycle, and the third display brightness value corresponding to the any input pixel value being a brightness value of a pixel displayed based on a maximum pixel value when the display duty cycle is a reference duty cycle; The third mapping information is subjected to tune mapping to obtain the second mapping information, wherein the tune mapping is used to convert the first brightness values ​​corresponding to the multiple input pixel values ​​into second display brightness values, and different input pixel values ​​correspond to different second display brightness values.

12. A display device, characterized in that: The display device comprises the display driver chip as described in any one of claims 1-6.

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