Dimming value filter device and image data processing device

Abstract

This invention provides a dimming value filtering device and an image data processing device. According to an embodiment, contrast and deep blacks can be enhanced by differentially performing spatial filtering based on the location of blocks in a video image.

Description

Technical Field

[0001] This embodiment relates to a display technology for improving contrast and deep blacks by efficiently controlling local dimming. Background Technology

[0002] Of all the components that make up an electronic device, the display device consumes the most power. Display devices are continuously switched on while providing information to the user, and require a continuous output of light during this time. Therefore, display devices consume more power than any other component.

[0003] To this end, electronics manufacturers have continued to research and develop technologies to reduce the power consumption of display devices. Typical examples include technologies for switching display devices to standby mode or turning on only a portion of the display panel.

[0004] However, this technology limits the amount of power consumed by the display device by suppressing the user environment to some extent, and will inevitably cause some inconvenience to the user.

[0005] On the other hand, the following technologies are being developed to reduce the power consumption of display devices without changing the user environment or by changing the environment to a degree that is barely perceptible to the user, and a representative of such technologies is local dimming technology.

[0006] Local dimming refers to a technique used to drive a backlight source locally at different brightness levels. According to local dimming, multiple backlight units (BLUs) can divide the display panel into multiple areas, and can emit light with different brightness levels to each divided area. The brightness of each backlight source can be determined by relating it to a representative brightness value for the area to which the light is emitted. According to existing technology, the representative brightness value is obtained by deriving the maximum grayscale of the pixels in the area to which the light is emitted, and then averaging the maximum grayscale.

[0007] However, this traditional method may be insufficient for handling deep or pure blacks, thus reducing contrast. Due to the low contrast and difficulty in achieving deep blacks, it may be difficult to apply this traditional method to places requiring high contrast and complete blacks, such as the corners or edges of a vehicle's dashboard.

[0008] In addition, areas illuminated by backlights need to be able to enhance luminance or blackness in a given environment, but conventional methods do not provide the flexibility related to whether the area needs enhanced luminance or blackness.

[0009] Furthermore, the area illuminated by the backlight is non-constant and irregular, meaning each area can have different brightness. Only by reflecting this area non-uniformity in the representative brightness values ​​can appropriate dimming values ​​be calculated, and efficient dimming be achieved.

[0010] Additionally, spatial filtering can be performed on the dimming value of a region of a video image, and after this processing, the brightness of that region can become equal to the brightness of adjacent regions. Achieving equal brightness in a region may be difficult to achieve deep blacks or high contrast. Therefore, spatial filtering needs to be avoided in regions, corners, or edges of the video image where deep blacks or high contrast are desired. Thus, spatial filtering needs to be applied differentially to each region of the video image.

[0011] In this regard, this embodiment attempts to provide a local dimming technique, which includes spatial filtering techniques for achieving deep blacks or high contrast. Summary of the Invention

[0012] In view of the above background, one aspect of this disclosure is to provide a local dimming technique for calculating a value representing brightness by means of black image data analysis that takes into account the relative importance of black levels in a block.

[0013] Another aspect of this disclosure is to provide a local dimming technique that can enhance luminance or black features via a gamma variable during processing that takes into account the relative importance of black levels.

[0014] Another aspect of this disclosure is to provide a local dimming technique for calculating a value representing brightness by reflecting the area non-uniformity between blocks of a video image.

[0015] Another aspect of this disclosure is to provide a local dimming technique for differentially performing spatial filtering based on the location of blocks in a video image.

[0016] In one aspect, this disclosure provides a dimming value filtering device for spatially filtering a dimming value used to adjust the brightness of each block of a backlight. The dimming value filtering device includes: a mask generation circuit configured to generate a plurality of masks that are different from each other; a mask application circuit configured to select one of the plurality of masks based on the location of the block and apply the selected mask to the block; a filtering result calculation circuit configured to calculate a filtered dimming value for the block based on the selected mask; and a transmission / reception circuit configured to transmit the filtered dimming value.

[0017] Regarding the dimming value filtering device, each mask includes multiple coefficients, and the filtering result calculation circuit uses the coefficients to calculate the filtered dimming value for the block.

[0018] Regarding the dimming filter, the location of the block can be one of the center, edge, and corner of the video image.

[0019] Regarding the dimming value filtering device, the plurality of masks may include a central mask applied to a block located in the center of the video image, an edge mask applied to a block located at the edge of the video image, and a corner mask applied to a block located at the corner of the video image.

[0020] Regarding the dimming value filtering device, the mask may include multiple coefficients corresponding to the block and its neighboring blocks, and the filtering result calculation circuit can calculate the filtered dimming value by performing arithmetic operations on the dimming value of the block and its neighboring blocks and the multiple coefficients.

[0021] Regarding the dimming value filtering device, the filtering result calculation circuit can compare the result of the arithmetic operation with the dimming value of the block before the arithmetic operation, and if the result of the arithmetic operation is greater than the dimming value of the block before the arithmetic operation, it outputs the result of the arithmetic operation as the dimming value after filtering.

[0022] Regarding the dimming value filtering device, the filtering result calculation circuit can compare the result of the arithmetic operation with the dimming value of the block before the arithmetic operation, and if the result of the arithmetic operation is less than the dimming value of the block before the arithmetic operation, output the dimming value of the block before the arithmetic operation as the dimming value after filtering.

[0023] Regarding the dimming value filtering device, the neighboring blocks may include horizontal blocks adjacent to the block in the horizontal direction, vertical blocks adjacent to the block in the vertical direction, and corner blocks adjacent to the block in the diagonal direction.

[0024] Regarding the dimming value filtering device, the plurality of coefficients may include a central coefficient corresponding to the block, a horizontal coefficient corresponding to the horizontal block, a vertical coefficient corresponding to the vertical block, and a corner coefficient corresponding to the corner block.

[0025] Regarding the dimming value filtering device, the central coefficient may have a value greater than the horizontal coefficient, the vertical coefficient, and the corner coefficient.

[0026] Regarding the dimming value filtering device, the filtering result calculation circuit can calculate the filtered dimming value by multiplying the dimming value of the block by the central coefficient, multiplying the dimming value of the horizontal block by the horizontal coefficient, multiplying the dimming value of the vertical block by the vertical coefficient, multiplying the dimming value of the corner block by the corner coefficient, and then adding all the multiplication results together.

[0027] Regarding the dimming value filtering device, the plurality of masks may include a central mask applied to a block located in the center of the video image, an edge mask applied to a block located at the edge of the video image, and a corner mask applied to a block located at the corner of the video image, and the central coefficient of the corner mask may have a value greater than the central coefficient of the central mask and the edge mask.

[0028] Regarding the dimming value filtering device, the plurality of masks may include a central mask applied to a block located in the center of the video image, an edge mask applied to a block located at the edge of the video image, and a corner mask applied to a block located at the corner of the video image, and the central coefficient of the central mask may have a value smaller than the central coefficients of the corner mask and the edge mask.

[0029] Regarding the dimming value filtering device, the mask application circuit can specify the region in the video image to be filtered, and apply one of the plurality of masks to the blocks included in the region. Regarding the dimming value filtering device, the mask application circuit can apply different masks to the respective blocks included in the region based on their positions.

[0030] Regarding the dimming filter, the area can be predetermined and stored.

[0031] Another embodiment provides an image data processing apparatus, comprising: a block acquisition circuit configured to divide a video image into multiple regions and designate each region as a block; a dimming value calculation circuit configured to calculate a brightness value for each block and calculate a dimming value corresponding to the block for adjusting the brightness of a backlight based on the brightness value; a dimming value filtering device configured to receive the dimming value, generate multiple masks, select one of the multiple masks based on the position of the block in the video image, and apply the selected mask to the block to calculate a filtered dimming value; and a dimming output circuit configured to output a dimming control signal for driving the backlight based on the dimming value to a backlight driving device.

[0032] Regarding the image data processing apparatus, the dimming value filtering device can specify a region of interest and filter the dimming value of blocks located outside the region of interest, thereby reducing the difference between the dimming value of blocks located outside the region of interest and the dimming value of adjacent neighboring blocks.

[0033] Regarding the image data processing apparatus, the dimming value filtering device can specify a region of interest and filter the dimming values ​​of blocks included in the region of interest, thereby increasing the difference between the dimming values ​​of blocks located within the region of interest and the dimming values ​​of adjacent neighboring blocks.

[0034] Regarding the image data processing apparatus, the mask may include multiple coefficients in matrix form, which are used to perform arithmetic operations on the dimming values ​​of the block and its neighboring blocks.

[0035] As described above, according to this disclosure, high contrast and deep blacks can be achieved.

[0036] Furthermore, according to this disclosure, black and lightness features can be selectively enhanced, thereby flexibly adjusting black and lightness.

[0037] Furthermore, according to this disclosure, efficient local dimming can be provided by taking into account various optical characteristics such as block area non-uniformity. Attached Figure Description

[0038] Figure 1 This is a configuration diagram of a display device according to an exemplary embodiment;

[0039] Figure 2 This is a configuration diagram of an image data processing apparatus according to an exemplary embodiment;

[0040] Figure 3 This is a configuration diagram of the data analysis circuit and the filtering circuit according to an embodiment;

[0041] Figure 4 This is a schematic diagram of a gamma curve representing brightness values, used to interpret the relative importance of black image data according to an exemplary embodiment.

[0042] Figure 5 This is a schematic diagram of screen segmentation for a backlight unit, according to an exemplary embodiment, in which features for explaining the area non-uniformity of blocks are reflected in the brightness values.

[0043] Figure 6 This is a flowchart illustrating local dimming of an image data processing apparatus according to an exemplary embodiment;

[0044] Figure 7This is a configuration diagram of a dimming value filtering device and an image data processing device including the dimming value filtering device according to another embodiment;

[0045] Figure 8 This is a configuration diagram of the spatial filtering circuit of a dimming value filtering device according to another embodiment;

[0046] Figure 9 This is a schematic diagram illustrating a video image and blocks included therein according to another exemplary embodiment;

[0047] Figure 10 This is a schematic diagram illustrating a mask for spatial filtering according to another embodiment;

[0048] Figure 11 This is a first schematic diagram illustrating a spatial filtering region according to another exemplary embodiment;

[0049] Figure 12 This is a second schematic diagram illustrating a spatial filtering region according to another exemplary embodiment;

[0050] Figure 13 This is a diagram according to another embodiment for explaining the application of a mask to blocks for spatial filtering;

[0051] Figure 14 It is a diagram according to another exemplary embodiment for interpreting a moving mask to apply the mask to a block; and

[0052] Figure 15 This is a flowchart illustrating spatial filtering of an image data processing apparatus according to another embodiment. Detailed Implementation

[0053] Figure 1 This is a configuration diagram of a display device according to an exemplary embodiment.

[0054] Reference Figure 1 The display device 100 may include a host 140, an image data processing device 110, a data driving device 150, a gate driving device 160, a display panel 130, a backlight driving device 120, etc.

[0055] The host 140 can recognize user operations and generate image data or dimming control signals based on user operations.

[0056] Image data in the display device 100 can be converted into various formats. To distinguish between the original image data and the converted image data, the image data generated and transmitted by the host 140 will be referred to as the original image data RGB, and the image data generated and transmitted by the image data processing device 110 will be referred to as the converted image data RGB'. Additionally, the dimming value included in the dimming control signal in the display device 100 can be adjusted. To distinguish between the pre-adjustment dimming control signal and the post-adjustment dimming control signal, the dimming control signal generated and transmitted by the host 140 will be referred to as the pre-adjustment dimming control signal DMS, and the dimming control signal generated and transmitted by the image data processing device 110 will be referred to as the post-adjustment dimming control signal DMS'.

[0057] When viewing the signal stream, the image data generated by the host 140 is converted by the image data processing unit 110 and then sent to the data driving unit 150. Furthermore, the dimming control signal generated by the host 140 is adjusted by the image data processing unit 110 and then sent to the backlight driving unit 120.

[0058] Image data processing apparatus 110 is configured to convert image data and adjust dimming control signals. Image data processing apparatus 110 can analyze raw image data RGB for a plurality of pixels P disposed on display panel 130, and can calculate representative luminance values ​​for the plurality of pixels P. Since the plurality of pixels P have different luminance values, image data processing apparatus 110 calculates representative luminance values ​​that can represent the plurality of pixels P. The representative luminance value can be, for example, the average luminance value of the plurality of pixels P. Optionally, the representative luminance value can be, for example, the mode luminance value or the maximum luminance value of the plurality of pixels P. Image data processing apparatus 110 can calculate the representative luminance values ​​for the plurality of pixels P using methods known as cumulative density function (CDF) or average pixel level (APL). The representative luminance value can include values ​​related to CDF or APL.

[0059] The image data processing apparatus 110 can calculate an adjusted dimming value for driving the backlight 132 based on a representative brightness value or a corrected representative brightness value. Here, the dimming value can be understood as a dimming brightness value. The larger the dimming value, the larger the brightness value of the backlight 132. For example, if the dimming value is 100%, the backlight 132 can be driven at maximum brightness, while if the dimming value is 0%, the backlight 132 can be driven at minimum brightness, or the backlight 132 can be turned off.

[0060] As the representative brightness value decreases, the image data processing device 110 can reduce the adjusted dimming value of the backlight 132. In other words, as the representative brightness value decreases, the image data processing device 110 can reduce the brightness of the backlight 132.

[0061] Image data processing apparatus 110 can convert the original image data RGB according to the adjusted dimming value to compensate for the grayscale of each pixel. Image data processing apparatus 110 can calculate a factor called gain, use this gain to convert the original image data RGB, and compensate for the grayscale. As the dimming value is adjusted, the brightness (or luminance) of the pixel may differ. However, if the grayscale displayed by the pixel is adjusted using gain according to the adjusted dimming value, the pixel may maintain its original brightness. For example, image data processing apparatus 110 can convert the original image data RGB such that the grayscale of each pixel increases as the adjusted dimming value decreases. Then, the brightness of each pixel can be maintained as is. Here, the gain may have the characteristic of increasing grayscale. The rate of decrease of the pixel's dimming value and the rate of increase of grayscale may be different from each other and may vary depending on the pixel level.

[0062] The image data processing device 110 can generate an adjusted dimming control signal DMS' based on the adjusted dimming value, and can output the adjusted dimming control signal DMS' to the backlight driving device 120. On the other hand, the display panel 130 can be configured with a plurality of pixels P, and can be configured with data lines and gate lines connected to the plurality of pixels P. The gate driving device 160 can send a scan signal SS to the gate line to connect each pixel P to the data line, and the data driving device 150 can supply a data voltage Vdata corresponding to the image data to the data line to drive each pixel P.

[0063] The image data processing apparatus 110 can send a gate control signal GCS to the gate driver 160 and a data control signal DCS to the data driver 150, thereby controlling the driving timing associated with each pixel P. In this regard, the gate driver 160 is referred to as the gate driver GDIC, the data driver 150 as the source driver SDIC, and the image data processing apparatus 110 as the timing controller TCON.

[0064] The backlight 132 can be arranged in the background of the display panel 130, and the backlight 132 can be driven by the backlight driving device 120.

[0065] The backlight driver 120 can control the brightness of the light source constituting the backlight 132. The light source can be, for example, a fluorescent lamp (FL) series or a light-emitting diode (LED) series.

[0066] The backlight driver 120 can control the dimming of the backlight 132. For example, the backlight driver 120 can control the dimming of the backlight 132 using an analog dimming technique that reduces the amount of power PBL supplied to the backlight 132 while continuously driving the backlight 132. As another example, the backlight driver 120 can control the dimming of the backlight 132 using a pulse width modulation (PWM) technique that adjusts the ratio between the on-time and off-time while discontinuously driving the backlight 132. According to an embodiment, the PWM technique can be a scheme that uses the amount of voltage charged at a capacitor or the like to control the brightness of the backlight based on a PWM signal.

[0067] In analog dimming technology, the dimming control signals DMS and DMS' can be in the form of analog voltage or analog current, while in PWM technology, the dimming control signals DMS and DMS' can be in the form of PWM signals.

[0068] Figure 2 This is a configuration diagram of an image data processing apparatus according to an embodiment.

[0069] Reference Figure 2 The image data processing device 110 may include a block acquisition circuit 210, a data analysis circuit 220, a dimming value calculation circuit 230, a filtering circuit 240, a light quantity calculation circuit 250, a dimming control circuit 260, a dimming output circuit 270, a gain calculation circuit 280, and a data conversion circuit 290.

[0070] The block acquisition circuit 210 can receive a video image and acquire multiple blocks associated with that video image. A block is a portion of the video image displayed on the display panel 130 and can represent a region or segment. A block is a unit of backlight illumination, and the backlight can illuminate each block using a different amount of light. The backlight can control dimming by using different dimming values ​​for each block of the video image.

[0071] The data analysis circuit 220 can calculate a representative luminance value for a single block by analyzing the raw image data (RGB) of a video image comprising multiple blocks. The data analysis circuit 220 can calculate representative luminance values ​​for the R, G, and B raw image data to generate appropriate dimming values ​​for local dimming. The representative luminance value may include the average pixel level (APL). The representative luminance value may include the average value, median value, or a value obtained by applying a histogram or pooling process.

[0072] For example, the data analysis circuit 220 can use the maximum value among the R, G, and B raw image data as a representative brightness value. Alternatively, the data analysis circuit 220 can use a value obtained by applying appropriate weights to the R, G, and B raw image data and summing all the applied results as a representative brightness value. Alternatively, the data analysis circuit 220 can use the value of the RGB mapping of the raw image data to a specific curve as a representative brightness value.

[0073] The data analysis circuit 220 can reflect the relative importance of the black image data included in a block in the representative brightness value to correct the representative brightness value. The data analysis circuit 220 can correct the representative brightness value by using a gamma variable to adjust the relative importance of the black image data.

[0074] The data analysis circuit 220 can reflect the area non-uniformity between blocks in the corrected representative brightness value, so as to re-correct the corrected representative brightness value. The area of ​​each block of the video image displayed on the display panel 130 can be different. For example, in a video image displayed on a vehicle dashboard, the area of ​​the central block can be larger than the area of ​​the corner or edge blocks. In addition, the area of ​​the edge blocks can be larger than the area of ​​the corner blocks.

[0075] The dimming value calculation circuit 230 can calculate the dimming value. The dimming value calculation circuit 230 can calculate the initial dimming value DMV for each region based on the representative brightness value. The dimming value calculation circuit 230 can calculate the initial dimming value DMV for the representative brightness value using a logarithmic function, an exponential function, or a user-defined function. Here, the dimming value calculation circuit 230 can calculate the initial dimming value DMV based on the recorrected representative brightness value that reflects the relative importance of the black image data and the area non-uniformity between blocks.

[0076] The filter circuit 240 can filter the dimming value. The filter circuit 240 can use filtering to adjust the initial dimming value DMV to generate a filtered dimming value DMV'. The filter circuit 240 can perform spatial filtering. Since the initial dimming values ​​DMV associated with multiple regions of the video image are different from each other, there is a deviation, and the filter circuit 240 can adjust this deviation. Primarily, when the initial dimming value DMV of a block is less than the initial dimming value DMV of neighboring blocks, the filter circuit 240 can reduce the deviation by increasing the initial dimming value DMV of that block. Alternatively, when the initial dimming value DMV of a block is greater than the initial dimming value DMV of neighboring blocks, the filter circuit 240 can decrease the initial dimming value DMV of that block to reduce the deviation. Therefore, the filter circuit 240 can prevent artifacts caused by deviation.

[0077] The filter circuit 240 can use a weighted sum to adjust the dimming value. The filter circuit 240 can receive the weighted sum back and generate a new weighted sum to perform stable filtering.

[0078] Additionally, the filter circuit 240 can perform temporal filtering. The filter circuit 240 can use temporal filtering to adjust for inter-frame deviations in the dimming value. The dimming value can change between the current frame and the next frame, and the filter circuit 240 can reduce the deviation between the dimming value of the current frame and the dimming value of the next frame. The filter circuit 240 can prevent flickering that occurs as the deviation in the dimming value between frames increases.

[0079] The light quantity calculation circuit 250 can calculate the light quantity of the backlight and send the calculated light quantity to the gain calculation circuit 280 to reflect the light quantity in the gain calculation. The light quantity calculation circuit 250 can calculate the light quantity using the light spread function (LSF) and the filtered dimming value DMV'.

[0080] The dimming control circuit 260 can ultimately determine the dimming value. The dimming control circuit 260 can determine the filtered dimming value DMV' as the final dimming value. The dimming control circuit 260 can send the filtered dimming value DMV' to the dimming output circuit 270. When there are conditions to be reflected in order to determine the dimming value, the dimming control circuit 260 can adjust the filtered dimming value DMV' by reflecting these conditions, and can determine the adjusted filtered dimming value DMV' as the final dimming value.

[0081] The dimming output circuit 270 can convert a dimming value into a dimming control signal and output the dimming control signal to the backlight driver. The dimming output circuit 270 can also convert the filtered dimming value DMV' into an adjusted dimming control signal DMS'. The input dimming control signal and the adjusted dimming control signal DMS' preferably have the same type. For this purpose, the dimming output circuit 270 can control the period or frequency of the adjusted dimming control signal DMS' to match the period or frequency of the input dimming control signal. The gain calculation circuit 280 can calculate the gain Q for compensating the original image data RGB based on the dimming value. The gain calculation circuit 280 can receive the filtered dimming value DMV' from the light quantity calculation circuit 250 and calculate the gain Q for compensating the original image data RGB based on the filtered dimming value DMV'. Specifically, although the grayscale of the original image data RGB and the filtered dimming value DMV' are changed, the gain Q can be a necessary factor for making the pixels produce the same brightness.

[0082] The data conversion circuit 290 can generate converted image data RGB' from the original image data RGB by using a gain Q. The data conversion circuit 290 can apply the finally determined gain Q to the R image data, G image data, and B image data to generate the converted image data RGB'.

[0083] Figure 3 This is a configuration diagram of an image data processing apparatus according to an embodiment.

[0084] Reference Figure 3 The data analysis circuit 220 may include a brightness value calculation circuit 310, a black image data analysis circuit 320, and a non-uniformity correction circuit 330.

[0085] The representative brightness value calculation circuit 310 can calculate the representative brightness value for a block of a video image displayed on the display panel 130. The representative brightness value calculation circuit 310 can use APL as the representative brightness value. The representative brightness value calculation circuit 310 can calculate APL by averaging the maximum gray levels of the pixels in a block.

[0086] The representative luminance value calculation circuit 310 can generate histogram data by creating a histogram of the original image data RGB, or it can generate cumulative density function (CDF) data by accumulating histogram data. The representative luminance value calculation circuit 310 can calculate APL based on the histogram data or the cumulative density function (CDF) data.

[0087] The black image data analysis circuit 320 can reflect the relative importance of black image data in a representative brightness value to generate a corrected representative brightness value. For example, the black image data analysis circuit 320 can reflect the relative importance of black image data in the APL to generate a corrected APL (APL_C1). The black image data analysis circuit 320 can generate the corrected representative brightness value by adjusting a gamma variable used to control the relative importance of the black image data. Here, the relative importance of the black image data can include the ratio of the number of pixels displaying black to the total number of pixels included in a block. The black image data analysis circuit 320 can increase or decrease the corrected representative brightness value based on whether the value of the gamma variable is greater than or less than a specific value.

[0088] The black image data analysis circuit 320 can use a gamma curve to obtain a corrected representative brightness value. The gamma curve can have different shapes depending on the gamma variable. Alternatively, a gamma curve can be formed using values ​​stored in a lookup table (LUT).

[0089] The non-uniformity correction circuit 330 can reflect the area non-uniformity between one block and another in the corrected representative luminance value to generate a recorrected representative luminance value. For example, the non-uniformity correction circuit 330 can reflect the ratio of the area of ​​one block to the area of ​​another block in the corrected APL (APL_C1) to generate a recorrected APL (APL_C2). The non-uniformity correction circuit 330 can use illuminance data ALS that includes illuminance information to generate the recorrected APL (APL_C2).

[0090] When the variance of the levels of all pixels within a block meets a certain condition, the non-uniformity correction circuit 330 can determine the corrected representative brightness value as is, without affecting the recorrected representative brightness value. That is, the non-uniformity correction circuit 330 may not reflect the factor in the corrected representative brightness value. Here, the pixel level may include the grayscale indicated by the pixel.

[0091] The non-uniformity correction circuit 330 can reflect the area non-uniformity between one block and another in the corrected representative luminance value to generate a recorrected representative luminance value. When the variance of the levels of all pixels included in the block meets a condition, the non-uniformity correction circuit 330 can reflect a factor in the corrected representative luminance value and determine the result as the recorrected representative luminance value. This factor will be described later.

[0092] When the non-uniformity compensation circuit 330 transmits the recalibrated APL (APL_C2) to the dimming value calculation circuit 230, the dimming value calculation circuit 230 can generate the initial dimming value DMV and transmit it to the filter circuit 240.

[0093] The filter circuit 240 may include a spatial filter circuit 340 and a temporal filter circuit 350. The filter circuit 240 can generate and output a filtered dimming value DMV' by filtering the initial dimming value DMV.

[0094] The spatial filter circuit 340 can make the brightness of the blocks uniform by adjusting the deviation of the dimming value related to multiple blocks of the video image.

[0095] The time filter circuit 350 can filter the dimming value, so that the dimming value changes smoothly to the target dimming value. The time filter circuit 350 can smoothly change the dimming value to prevent flickering when the dimming value of a frame deviates greatly from the dimming value of the previous frame.

[0096] Figure 4 This is a schematic diagram, according to an exemplary embodiment, of how the relative importance of black image data is reflected in gamma curves representing brightness values.

[0097] Reference Figure 4The black image data analysis circuit can use gamma variables and gamma curves based on the gamma variables to generate corrected representative brightness values ​​that reflect the relative importance of the black image data.

[0098] The black image data analysis circuit can correct the representative luminance value by reflecting the relative importance of the black image data in the representative luminance value via Equation 1, which includes a gamma variable. APL is used as the representative luminance value, and this processing can be performed independently for each block.

[0099] [Formula 1]

[0100]

[0101] Here, APL can represent the luminance value, and APL_C1 can represent the corrected luminance value. The ratio of the number of black pixels (#black pixels) to the total number of pixels in a block (#pixels) represents the relative importance of the black image data. The gamma variable (γ) controls this ratio.

[0102] If the gamma variable is less than 1, the corrected representative brightness value can be reduced; if the gamma variable is greater than 1, the corrected representative brightness value can be increased. The value of the gamma variable can be determined by the user configuration. When the user configures the gamma variable to be less than 1 to enhance the black features of a block, the black image data analysis circuit can emphasize the black features by reducing the corrected representative brightness value. Optionally, if the user configures the gamma variable to be greater than 1 to enhance the lightness features of a block, the black image data analysis circuit can emphasize the lightness features by increasing the corrected representative brightness value.

[0103] The black image data analysis circuit can use a gamma curve based on the gamma variable to generate a corrected representative brightness value. The gamma curve can be formed using values ​​stored in a lookup table.

[0104] For example, if the gamma variable is less than 1 and thus emphasizes black features, the black image data analysis circuit can use the black gamma curve CV_BL. The black image data analysis circuit can generate a corrected APL (APL_C1) by matching the APL with the black gamma curve CV_BL. Alternatively, when the gamma variable is greater than 1 and thus emphasizes lightness features, the black image data analysis circuit can use the lightness gamma curve CV_LU. The black image data analysis circuit can generate a corrected APL (APL_C1) by matching the APL with the lightness gamma curve CV_LU.

[0105] Depending on whether the user emphasizes black or lightness characteristics, the gamma variable and corresponding gamma curve can be adjusted, and the corrected representative brightness value can be adjusted differently. Therefore, it can improve the flexibility and freedom of control over black and lightness characteristics.

[0106] Figure 5 This is a schematic diagram of screen segmentation for backlight units, according to an exemplary embodiment, in which features for explaining the area non-uniformity of blocks are reflected in the brightness values.

[0107] The non-uniformity correction circuit of the data analysis circuit can use a factor to reflect the brightness characteristics caused by the area non-uniformity between blocks in the representative brightness value. Here, the area non-uniformity between blocks can be additionally reflected in the corrected representative brightness value, which already reflects the relative importance of the black image data.

[0108] Reference Figure 5 This shows a block of video image 1 with non-uniform area.

[0109] Video image 1 can be composed of multiple blocks with different areas. For example, video image 1 displayed on a vehicle dashboard can be composed of blocks of different areas. Video image 1 can be composed of four types of blocks based on area. Here, the values ​​can be in "mm" or can be omitted. The size of the area can be calculated in terms of width and length. The first block BLK1 can have a first size of 4048 (=92×44), the second block BLK2 can have a second size of 5456 (=124×44), the third block BLK3 can have a third size of 7268 (=92×79), and the fourth block BLK4 can have a fourth size of 9796 (=124×79).

[0110] Multiple blocks can have different areas depending on their location (e.g., near the center, in a corner, and at the edge). For example, the first block BLK1 can be located in a corner and can have the smallest size. The fourth block BLK4 can be located near the center and can have the largest size. The second block BLK2 and the third block BLK3 can be located at the edge and can have a central area larger than the first block BLK1 but smaller than the fourth block BLK4. The second block BLK2 and the third block BLK3 are located at the edge, but the area of ​​the second block BLK2 can be smaller than the area of ​​the third block BLK3 depending on its location.

[0111] Typically, the brightness can be brighter in the fourth block (BLK4) located near the center, and darker in the second and third blocks (BLK2 and BLK3) located at the corners and edges. To compensate for this brightness non-uniformity, a physical method is used to increase the brightness in the second and third blocks (BLK2 and BLK3) located at the corners and edges. However, due to this method, the contrast between the second and third blocks (BLK2 and BLK3) located at the corners and edges may be reduced. Therefore, the brightness difference may vary within each block from the first block (BLK1) to the fourth block (BLK4). Due to this brightness difference, the blacks in the second and third blocks (BLK2 and BLK3) located at the corners and edges may be brighter than those in other blocks.

[0112] To correct the brightness difference caused by the non-uniformity of the area of ​​the blocks, as described above, the non-uniformity correction circuit of the data analysis circuit can modify the representative brightness value. The non-uniformity correction circuit can reflect the non-uniformity of the area of ​​the blocks in the corrected representative brightness value, which reflects the relative importance of the black image data.

[0113] For example, a non-uniformity correction circuit can use variance to generate a recorrected representative luminance value from a corrected representative luminance value. The non-uniformity correction circuit can obtain the variance and calculate the recorrected representative luminance value using Equation 2 below. APL can then be used as the representative luminance value.

[0114] [Equation 2]

[0115]

[0116] If VAR BLK =0:APL_C2=APL_C1

[0117] If VAR BLK ≠0: APL_C2=APL_C1·G

[0118]

[0119] Here, VAR BLK It is the variance, where n is the total number of pixels in a block, and x is the variance. i is the luminance data (e.g., brightness or grayscale) of each pixel, and avg is the average of the luminance data of all pixels in a block. Therefore, if the variance is 0, the non-uniformity correction circuit can treat the corrected representative luminance value as is as the recorrected representative luminance value. If the variance is not 0, the non-uniformity correction circuit can incorporate a factor G into the corrected representative luminance value to calculate the recorrected representative luminance value.

[0120] G can be a factor used to correct for area non-uniformity of the blocks. G can vary depending on the area of ​​each block. Additionally, illuminance data (ALS) can be added to obtain G. G_BLK1, G_BLK2, G_BLK3, and G_BLK4 can be factors used when correcting representative luminance values ​​for each of the first blocks (BLK1) to the fourth blocks (BLK4). Each factor can be the ratio of the area of ​​the corresponding block to the area of ​​the largest block. For example, the first factor G_BLK1 can be the ratio of the number of pixels in the first block (#pixels of BLK1) to the number of pixels in the fourth block (#pixels of BLK4). The fourth factor G_BLK4 can be the ratio of the number of pixels in the fourth block (#pixels of BLK4). Factors can have values ​​that increase in the direction from the first factor G_BLK1 to the fourth factor G_BLK4.

[0121] The non-uniformity correction circuit reflects a factor corresponding to the corrected representative luminance value (corrected APL(APL_C1)) of the corresponding block, which is used to obtain the recorrected representative luminance value (recorrected APL(APL_C2)). Therefore, the first block BLK1, located at the corner, has the smallest recorrected representative luminance value, the fourth block BLK4, located near the center, has the largest recorrected representative luminance value, and the second and third blocks BLK2 and BLK3, located at the edges, can have intermediate values.

[0122] Figure 6 This is a flowchart illustrating local dimming of an image data processing apparatus according to an exemplary embodiment. (Refer to...) Figure 6 In operation S602, the image data processing device can receive a video image including multiple regions, analyze the raw image data for the video image, and calculate a representative brightness value for a block.

[0123] The image data processing apparatus can create a histogram of the raw image data to calculate representative brightness values. Alternatively, the image data processing apparatus can use CDF (Concentration-Based Function) data. For example, if the raw image data is 8-bit, the image data processing apparatus can calculate histogram data by identifying the frequencies for values ​​from 0 to 255. Furthermore, the image data processing apparatus can calculate CDF data by accumulating the frequencies for CDF data. The image data processing apparatus can then calculate APL (Average Probability of Light) based on the CDF data.

[0124] In operation S604, the image data processing device can generate a first corrected representative brightness value by reflecting the relative importance of the black image data included in a block in the representative brightness value.

[0125] The image data processing device can receive the value of a gamma variable from an external source and adjust the relative importance of black image data based on the value of the gamma variable. If the value of the gamma variable is less than 1, the image data processing device can enhance black features by decreasing the corrected representative brightness value. When the value of the gamma variable is greater than 1, the image data processing device can enhance brightness features by increasing the corrected representative brightness value. In operation S606, the image data processing device can reflect the area non-uniformity between one block and another in the first corrected representative brightness value to generate a second corrected representative brightness value.

[0126] In operation S608, the image data processing device can calculate a dimming value for adjusting the brightness of the backlight based on the second corrected representative brightness value.

[0127] In operation S610, the image data processing device can generate a dimming control signal based on the dimming value and output the dimming control signal to the backlight driving device.

[0128] Figure 7 This is a configuration diagram of a dimming value filtering device and an image data processing device including the dimming value filtering device according to another embodiment.

[0129] Reference Figure 7 According to another embodiment, the image data processing apparatus 710 may include a block acquisition circuit 210, a data analysis circuit 220, a dimming value calculation circuit 230, a dimming control circuit 260, a dimming output circuit 270, a gain calculation circuit 280, a data conversion circuit 290, and a dimming value filtering device 711. Here, the block acquisition circuit 210, data analysis circuit 220, dimming value calculation circuit 230, dimming control circuit 260, dimming output circuit 270, gain calculation circuit 280, and data conversion circuit 290 can perform the functions described above. Figure 2 It performs the same function as described in the text. Additionally, the dimming value filter 711 can perform the same function as... Figure 2 It has the same function as the filter circuit 240 in the video image, and performs a unique function for differential spatial filtering based on the region of the video image. This unique function will be described below.

[0130] The dimming value filtering device 711 may include a time filtering circuit 711-A and a spatial filtering circuit 711-B. The time filtering circuit 711-A filters the dimming value to smoothly change it to the target dimming value. The time filtering circuit 711-A smoothly changes the dimming value to prevent flickering when the dimming value of one frame deviates significantly from the dimming value of the previous frame. The spatial filtering circuit 711-B can make the brightness uniform between adjacent areas of the video image by adjusting the dimming value deviation between multiple blocks of the video image. The time filtering circuit 711-A and the spatial filtering circuit 711-B each include their own components, but may share some components. For example, the time filtering circuit 711-A and the spatial filtering circuit 711-B may be controlled by a single control circuit.

[0131] The dimming value filtering device 711 can receive dimming values ​​(e.g., initial dimming value (DMV)) related to multiple blocks of a video image from the dimming value calculation circuit 230. The dimming value filtering device 711 can perform different filtering on the dimming value of each of the multiple blocks based on the position of each block in the video image. Here, the filtering can be understood as spatial filtering. The dimming value filtering device 711 can output the filtered dimming value DMV' as the filtering result of the dimming value. The filtered dimming value DMV' can be sent to the dimming control circuit 260 or the gain calculation circuit 280.

[0132] Figure 8 This is a configuration diagram of a dimming value filtering device and an image data processing device including the dimming value filtering device according to another embodiment.

[0133] Reference Figure 8 The spatial filtering circuit 711-B of the dimming value filtering device 711 may include a transmitting and receiving circuit 810, a mask generation circuit 820, a mask application circuit 830, and a filtering result calculation circuit 840. The spatial filtering circuit 711-B of the dimming value filtering device 711 can perform spatial filtering on the dimming value used to adjust the brightness of the backlight, and thus can output the filtered dimming value.

[0134] Mask generation circuit 820 can generate a mask including coefficients. Coefficients can be understood as factors to be used in calculations related to a dimming value associated with a block of a video image. For example, when the dimming value indicates the duty cycle of a PWM, the coefficients can be constants that define the duty cycle equally as the dimming value. The mask can change the dimming value of each block while moving blocks of the video image. In this disclosure, spatial filtering can be understood as a process in which mask application circuit 830 performs calculations on the coefficients of the mask and the dimming values ​​of the blocks to generate new dimming values. The mask can include at least one coefficient, where each coefficient corresponds to a block. For example, the mask can be in matrix form. The coefficients are arranged in the space of each matrix, and each coefficient can be calculated corresponding to the dimming value of each block.

[0135] Furthermore, the mask generation circuit 820 can generate multiple masks. That is, the mask generation circuit 820 can generate multiple masks of the same type or different types. Here, masks of different types can include different coefficients, or they can include the same coefficients arranged in different positions. On the other hand, masks of the same type can represent masks with all coefficients being the same and arranged in the same position.

[0136] The mask application circuit 830 can apply a mask to blocks of a video image. Therefore, if the mask application circuit 830 applies a mask to correspond to a block, the filtering result calculation circuit 840 can perform calculations of the mask coefficients and the dimming value for a block. Here, the mask application circuit 830 can apply a mask to correspond to each block while moving the mask along multiple blocks of the video image.

[0137] Furthermore, the mask application circuit 830 can select one of the multiple masks generated by the mask generation circuit 820 based on the position of multiple blocks in the video image, and can apply the selected mask to each block. Here, the mask application circuit 830 can select and apply the same mask or different masks based on the position of the blocks. For example, the mask application circuit 830 can apply a first mask to the block located in the center of the video image, and can apply a second mask, different from the first mask, to the block located in the corner. Optionally, the mask application circuit 830 can apply the same first mask to blocks located at the edge of the video image and blocks located in the corner.

[0138] The filtering result calculation circuit 840 calculates the filtered dimming value by performing calculations on dimming values ​​and mask coefficients related to multiple blocks of the video image. When the mask application circuit 830 applies the mask along multiple blocks to correspond to each block, the filtering result calculation circuit 840 can perform calculations on the mask coefficients and the dimming values ​​of the blocks. Thus, the dimming value can be converted into a filtered dimming value.

[0139] The transmitting and receiving circuit 810 can be from Figure 7 The dimming value calculation circuit 230 receives the dimming value related to the block. The transmitting / receiving circuit 810 can send the filtered dimming value generated in the spatial filtering circuit 711-B to... Figure 7 dimming control circuit 260 or Figure 7 Gain calculation circuit 280.

[0140] Figure 9 This is a schematic diagram illustrating a video image and the blocks included therein, according to another embodiment.

[0141] Reference Figure 9 An example of video image 1 can be shown here. Video image 1 shown here may be related to a vehicle dashboard.

[0142] The image data processing device can divide the video image 1 into multiple regions, and can designate each region as a block. The designated block can be located in the center, edge, or corner of the video image 1.

[0143] A corner block (BLK_corner) can represent a block located at the farthest endpoints of video image 1 along its diagonal direction. An edge block (BLK_edge) can represent a block located at the point closest to the boundary of video image 1, and can include blocks located between corner blocks (BLK_corner). A center block (BLK_center) can represent a block located near the center of video image 1, and can include all remaining blocks except for corner blocks (BLK_corner) and edge blocks (BLK_edge).

[0144] The areas of each block can differ from one another or can be partially different. However, this is not a limitation, and the area of ​​each block can be equal. The area of ​​each block can vary depending on the configuration of the block acquisition circuitry of the image data processing device. For example, in Figure 9 In this context, the areas of the corner block (BLK_corner), the edge block (BLK_edge), and the center block (BLK_center) can be different. The center block (BLK_center) can have the largest area, while the corner block (BLK_corner) can have the smallest area. The edge block (BLK_edge) can have an area that is somewhere between the areas of BLK_center and BLK_corner.

[0145] Figure 10 This is a schematic diagram illustrating a mask for spatial filtering according to another embodiment.

[0146] Reference Figure 10 An example of a mask can be shown. The mask generation circuit of the dimming filter can generate multiple masks. The mask application circuit can select multiple different masks for each block and apply the selected masks to the corresponding blocks.

[0147] For example, multiple masks can include those applied to corners. Figure 9 The corner mask M_corner of the block BLK_corner is applied to the area located at the edge. Figure 9 The edge mask M_edge of the block BLK_edge and applied to the center Figure 9 The central mask M_center of the block BLK_center. Therefore, when the block to be filtered is located in one of the corners, edges, or the center, the mask application circuit can select the mask corresponding to the corresponding position and apply the selected mask to the block to be filtered.

[0148] A mask may include coefficients to be used in calculations related to the dimming value of a block. A mask may include multiple coefficients. The mask is in matrix form, and the coefficients may be included in each space of the matrix. When spatial filtering is performed on a block, neighboring blocks adjacent to that block may also be involved in the computation. Therefore, one coefficient corresponds to the target block, and the others correspond to neighboring blocks, and thus can be involved in the computation. The computation using multiple coefficients will be described later.

[0149] These coefficients are pre-configured by the user, and data about the configured coefficients can be stored in memory such as registers.

[0150] Therefore, the coefficients of the mask can be named differently based on their position in the matrix. The coefficients located in the middle of the matrix can be named central coefficients, the coefficients located horizontally to the central coefficient can be named horizontal coefficients, the coefficients located vertically to the central coefficient can be named vertical coefficients, and the coefficients located diagonally to the central coefficient can be named corner coefficients.

[0151] For example, in Figure 10 In the corner mask M_corner, the center coefficient can be 1, and the horizontal, vertical, and corner coefficients can be 0. Optionally, in the edge mask M_edge, the center coefficient can be 0.40, and the horizontal and vertical coefficients can be 0.15. Optionally, in the center mask M_center, the center coefficient can be 0.36, the horizontal coefficient can be 0.12, the vertical coefficient can be 0.12, and the corner coefficient can be 0.04.

[0152] Furthermore, the center coefficient, horizontal coefficient, vertical coefficient, and corner coefficient can have the same or different values. For example, in the corner mask M_corner, the center coefficient can be different from the horizontal coefficient, vertical coefficient, and corner coefficient, while the horizontal coefficient, vertical coefficient, and corner coefficient can be the same. In the edge mask M_edge and the center mask M_center, the center coefficient can be different from the horizontal coefficient and vertical coefficient, while the horizontal coefficient and vertical coefficient can be the same.

[0153] Additionally, the center coefficient of a mask can have a larger value than the perimeter coefficients (i.e., the horizontal, vertical, and corner coefficients). A mask can make the brightness or luminance of a block distinct or obscure relative to adjacent blocks. Here, the center coefficient can have a larger value than the perimeter coefficient. The center coefficient can have a larger value when making the brightness or luminance of a block distinct, compared to when it makes the brightness or luminance of a block obscure.

[0154] For example, in the corner mask M_corner, the center coefficient is 1 and the perimeter coefficient is 0, so the center coefficient can be greater than the perimeter coefficient. In the edge mask M_edge, the center coefficient is 0.40, and the horizontal and vertical coefficients are 0.15, so the center coefficient can be greater than the horizontal and vertical coefficients. In the center mask M_center, the center coefficient is 0.36, the horizontal and vertical coefficients are 0.12, and the corner coefficient is 0.04, so the center coefficient can be greater than the perimeter coefficient.

[0155] Furthermore, the center coefficient can be different for each mask. The center coefficient applied to the corners and edges of the video image can be greater than the center coefficient applied to the center of the video image. Additionally, the center coefficient applied to the corners of the video image can be greater than the center coefficient applied to the edges of the video image.

[0156] For example, since contrast should be high at the corners and edges of a video image, and the brightness of a block needs to be different, the center coefficients of the corner mask M_corner and the edge mask M_edge can be greater than the center coefficient of the center mask M_center. Furthermore, the contrast at the corners of a video image should be higher than the contrast at its edges, and the brightness of a block should be sharp; therefore, the center coefficient of the corner mask M_corner can be greater than the center coefficient of the edge mask M_edge. Thus, as... Figure 10 As shown, the center coefficient of the corner mask M_corner can be 1, the center coefficient of the edge mask M_edge can be 0.40, and the center coefficient of the center mask M_center can be 0.36.

[0157] Furthermore, to make the brightness or luminance of a block clearer than its neighboring blocks, the coefficients can be concentrated in the center of the mask. Therefore, as with mask M_corner, the central coefficients are high, and the peripheral coefficients become 0, thus eliminating the possibility of peripheral coefficients. On the other hand, to make the brightness or luminance of a block blurry compared to its neighboring blocks, the coefficients can be evenly distributed across the mask. Therefore, as with the central mask M_center, the central coefficients are low, and peripheral coefficients with non-zero values ​​can exist uniformly.

[0158] Figure 11 This is a first schematic diagram showing a spatial filtering region according to another embodiment.

[0159] Reference Figure 11 This shows the region in video image 1 where spatial filtering will be performed. In the following text, this region will be referred to as the region of interest (ROI) (see [link to video image 1]). Figure 11 (The pattern area). The region of interest (ROI) is pre-configured by the user, and data about the configured ROI can be stored in memory such as registers.

[0160] The dimming filter of the image data processing apparatus can perform spatial filtering on the video image 1 using a first mask, and can also perform spatial filtering on blocks in a Region of Interest (ROI) using a second mask different from the first mask. Here, an ROI can be understood as a region with high contrast where the brightness of one block needs to be sharper than that of adjacent blocks. For example, a region of interest (ROI) may include a corner or edge of the video image 1. Additionally, the second mask may include coefficients configured to increase the contrast of the blocks. For example, the second mask may be a corner mask or an edge mask.

[0161] For example, the dimming value filtering device can perform spatial filtering on all blocks of video image 1. However, the dimming value filtering device can apply a center mask to the block BLK_center located in the center, and apply masks different from the center mask to the blocks BLK_corner located in the corners and BLK_edge located at the edges. The dimming value filtering device can apply corner masks to the blocks BLK_corner located in the corners, and can apply edge masks to the blocks BLK_edge located at the edges.

[0162] Figure 12 This is a second schematic diagram showing the spatial filtering region according to another embodiment.

[0163] Reference Figure 12The Region of Interest (ROI) can be changed. The mask application circuitry of the dimming filter can change the ROI based on the configuration stored in the registers. The ROI can include a block BLK_corner located at the corner and a block BLK_edge located at the edge. Optionally, the ROI can also include a portion of a block BLK_center located in the center.

[0164] Therefore, the mask application circuit of the dimming filter can treat the block BLK_center located in the center of the ROI as the block BLK_edge located at the edge, and apply the edge mask to the block BLK_center instead of the central mask. If it is necessary to improve the contrast of the block BLK_center located in the center of the ROI, a corner mask can be applied to the block BLK_center.

[0165] Figure 13 This is a diagram illustrating the application of a mask to blocks for spatial filtering, according to another embodiment. (See also...) Figure 13 The mask application circuit of the dimming filter can select one of multiple masks based on the location of a block in the video image and apply the selected mask to that block. In the following, as an example, a mask with multiple coefficients comprising a 3×3 matrix can be described.

[0166] The mask application circuitry can select and apply different masks based on the location or brightness of blocks within the moving video image 1. Here, the brightness of the block can include representative brightness values ​​such as APL. If a block is located in the center, or if a block has a high APL, the mask application circuitry can apply a central mask M_center to that block. The central mask M_center is essentially used by the mask application circuitry for spatial filtering and can help blur the brightness of the block. When a block is located in a corner or at an edge, or if a block has a low APL, the mask application circuitry can apply a corner mask M_corner or an edge mask M_edge. The corner mask M_corner or edge mask M_edge are masks specifically used by the mask application circuitry to emphasize deep blacks and improve contrast, and can help sharpen the brightness of the block.

[0167] Additionally, the block to which the mask is applied can be called the central block, and the blocks adjacent to the central block can be called neighboring blocks. Among the neighboring blocks, blocks horizontally adjacent to the central block are called horizontal blocks, blocks vertically adjacent to the central block are called vertical blocks, and blocks diagonally adjacent to the central block are called corner blocks. Furthermore, the mask can include multiple coefficients in matrix form corresponding to the central block, horizontal blocks, vertical blocks, and corner blocks.

[0168] For example, a mask application circuit can apply a central mask M_center to a block BLK_center located in the center. The central mask M_center has a 3×3 matrix form with a center coefficient of 0.36, a horizontal coefficient of 0.12, a vertical coefficient of 0.12, and a corner coefficient of 0.04. Therefore, a block with a center coefficient of 0.36 can be a central block, a block with a horizontal coefficient of 0.12 can be a horizontal block, a block with a vertical coefficient of 0.12 can be a vertical block, and a block with a corner coefficient of 0.04 can be a corner block (see [link to relevant documentation]). Figure 13 (The pattern area in the middle).

[0169] Additionally, the mask application circuitry can apply an edge mask M_edge to a block BLK_edge located at the edge. The center mask M_center can have a 3×3 matrix with a center coefficient of 0.40, a horizontal coefficient of 0.15, a vertical coefficient of 0.15, and a corner coefficient of 0. Therefore, a block with a center coefficient of 0.40 can be a center block, a block with a horizontal coefficient of 0.15 can be a horizontal block, a block with a vertical coefficient of 0.15 can be a vertical block, and a block with a corner coefficient of 0 can be a corner block (see [link to documentation]). Figure 13 (The pattern area in the middle).

[0170] Additionally, the mask application circuit can apply a corner mask M_corner to a block BLK_corner located at a corner. The corner mask M_corner can be a 3×3 matrix with a center coefficient of 1, a horizontal coefficient of 0, a vertical coefficient of 0, and a corner coefficient of 0. Therefore, a block with a center coefficient of 1 can become a center block, a block with a horizontal coefficient of 0 can become a horizontal block, a block with a vertical coefficient of 0 can become a vertical block, and a block with a corner coefficient of 0 can become a corner block (see [link to documentation]). Figure 13 (The pattern area in the middle).

[0171] The filtering result calculation circuit can calculate the filtered dimming value by performing calculations on the dimming values ​​and coefficients related to the blocks. The filtering result calculation circuit can also calculate the filtered dimming value by performing calculations on the mask coefficients related to the dimming values ​​associated with the central block and the dimming values ​​associated with neighboring blocks. Here, the filtered dimming value can be understood as the result obtained by performing spatial filtering on the central block. To calculate the filtered dimming value related to the central block, the filtering result calculation circuit can reflect the results obtained by performing calculations on the dimming values ​​and coefficients associated with neighboring blocks. Specifically, the filtering result calculation circuit can calculate the filtered dimming value via Equation 3 below.

[0172] [Formula 3]

[0173] PWM new (x, y, n) = α cen (PWM i (x,y,n))+α hor (PWM i (x-1, y, n)+PWM i (x+1, y, n))+α ver (PWM i (x, y-1, n) + PWM i (x, y+1, n))+α cor (PWM i (x-1, y-1, n) + PWM i (x-1, y+1, n)+PWM i (x+1, y-1, n)+PWM i (x+1, y+1, n)

[0174] PWM sf (x, y, n) = max(PWM) i (x, y, n), PWM new (x, y, n))

[0175] The filtering result calculation circuit can calculate the dimming value (PWM). i (x,y,n) and the central coefficient α of the central block cen Multiply, and the dimming value (PWM) will be used. i (x-1, y, n)), (PWM) i (x+1, y, n) and the level coefficient α of the horizontal block hor Multiply, and the dimming value (PWM) will be used. i (x, y-1, n)), (PWM) i (x, y+1, n) and the vertical coefficient α of the vertical block ver Multiply, and combine the dimming value (PWM) i(x-1, y-1, n)), (PWM) i (x-1, y+1, n)), (PWM) i (x+1, y-1, n)), (PWM) i (x+1, y+1, n) and the corner coefficient α of the corner block cor Multiplication. The filtering result calculation circuit can calculate the new dimming value (PWM) by adding all the results of multiplication. new (x,y,n)). Here, x and y represent the coordinates related to the central block, horizontal block, vertical block, and corner block corresponding to the mask, and n can represent the number of blocks to which the mask is applied. In the case of a central mask M_center, the central coefficient α cen It can be 0.36, the level coefficient α hor and vertical coefficient α ver It can be 0.12, and the corner factor α cor It can be 0.04.

[0176] Furthermore, the filtering result calculation circuit compares the calculation result with the dimming value (PWMi(x,y,n)) of the central block. If the calculation result is greater than the dimming value of the central block, the filtering result calculation circuit can output the calculation result as the filtered dimming value. Optionally, if the calculation result is less than the dimming value of the central block, the filtering result calculation circuit can output the dimming value (PWMi(x,y,n)) of the central block. i (x, y, n) is used as the dimming value after filtering. That is, the filtering result calculation circuit can determine and output the new dimming value (PWM) for the central block. new (x,y,n)) and dimming value (PWM) i The dimming value with the maximum value in (x,y,n) is used as the dimming value after filtering.

[0177] On the other hand, the dimming value filtering device can specify the region of interest requiring high contrast. It can apply a basic filter (center mask M_center) to blocks outside the region of interest, and a special filter (mask M_corner or edge mask M_edge) to blocks within the region of interest. Therefore, if the center mask M_center is applied, the difference between the dimming value associated with blocks outside the region of interest and the dimming value associated with adjacent blocks can be reduced. When the corner mask M_corner or the edge mask M_edge is applied, the difference between the dimming value associated with blocks outside the region of interest and the dimming value associated with adjacent blocks can be increased. Furthermore, compared to applying the edge mask M_edge, applying the corner mask M_corner can result in a larger difference between the dimming value associated with blocks outside the region of interest and the dimming value associated with adjacent blocks.

[0178] Figure 14 This is a diagram illustrating the use of a moving mask to apply the mask to a block, according to another exemplary embodiment.

[0179] Reference Figure 14 The mask application circuit can select and apply different masks based on the position or brightness of the blocks in the video image 1 while moving the blocks. The mask application circuit can sequentially detect blocks of the video image 1 in one direction and perform spatial filtering on them.

[0180] For example, the mask application circuit can sequentially detect blocks of video image 1 along a zigzag direction (see dashed lines). The mask application circuit can apply a corner mask M_corner to the block BLK_corner located at the corner while moving near the corner of video image 1. The mask application circuit can apply an edge mask M_edge to the block BLK_edge located at the edge while moving near the edge of video image 1. The mask application circuit can apply a center mask M_center to the block BLK_center located in the center while moving near the center of video image 1.

[0181] Figure 15 This is a flowchart illustrating spatial filtering of an image data processing apparatus according to another embodiment. (Refer to...) Figure 15 The dimming value filtering device of the image data processing apparatus can receive dimming values ​​from the dimming value calculation circuit. The dimming value calculation circuit can calculate the brightness value of a block of the video image and calculate the dimming value based on the brightness value. In operation S1502, the dimming value can be data used to adjust the brightness of the backlight. In operation S1504, the dimming value filtering device can generate multiple masks including coefficients. In operation S1506, the dimming value filtering device can select one of the multiple masks based on the position of the block of the video image. In operation S1508, the dimming value filtering device can apply the selected mask to a block to which spatial filtering is to be performed. In operation S1510, the dimming value filtering device can calculate the filtered dimming value by performing calculations of dimming values ​​and coefficients related to a block and its neighboring blocks.

[0182] Cross-references to related applications

[0183] This application claims priority to Korean Patent Application No. 10-2020-0073002, filed on June 16, 2020, the entire contents of which are incorporated herein by reference.

Claims

1. A dimming value filtering apparatus for spatially filtering dimming values for adjusting luminance of blocks of a backlight, the dimming value filtering apparatus comprising: a mask generating circuit configured to generate a plurality of masks different from each other; a mask applying circuit configured to select one of the plurality of masks according to a position of a block and apply the selected mask to the block; a filtering result calculating circuit configured to calculate a filtered dimming value for the block according to the selected mask; and a transmission / reception circuit configured to transmit the filtered dimming value, wherein the mask includes a plurality of coefficients corresponding to the block and its neighboring blocks, and the filtering result calculating circuit calculates the filtered dimming value by performing an arithmetic operation on dimming values of the block and its neighboring blocks and the plurality of coefficients, and wherein the filtering result calculating circuit compares a result of the arithmetic operation with a dimming value of the block before the arithmetic operation, and outputs the result of the arithmetic operation as the filtered dimming value in a case where the result of the arithmetic operation is greater than the dimming value of the block before the arithmetic operation. Each mask includes a plurality of coefficients, and the filtering result calculating circuit uses the coefficients to calculate a filtered dimming value for the block.

2. The dimming value filtering apparatus according to claim 1, wherein, The position of the block is one of a center, an edge, and a corner of a video image.

3. The dimming value filtering apparatus according to claim 1, wherein, The plurality of masks includes a center mask applied to a block located at a center of the video image, an edge mask applied to a block located at an edge of the video image, and a corner mask applied to a block located at a corner of the video image.

4. The dimming value filtering apparatus according to claim 3, wherein, The neighboring blocks include a horizontal block adjacent to the block in a horizontal direction, a vertical block adjacent to the block in a vertical direction, and a corner block adjacent to the block in a diagonal line.

5. The dimming value filtering apparatus of claim 1, wherein, The plurality of coefficients includes a center coefficient corresponding to the block, a horizontal coefficient corresponding to the horizontal block, a vertical coefficient corresponding to the vertical block, and a corner coefficient corresponding to the corner block.

6. The dimming value filtering device of claim 5, wherein, The mask applying circuit specifies a region in a video image where filtering is to be performed, and applies one of the plurality of masks to blocks included in the region.

7. The dimming value filtering device of claim 1, wherein, The mask applying circuit applies different masks to each block included in the region according to positions of the blocks.

8. The dimming value filtering device of claim 7, wherein, The region is predetermined and stored in advance.

9. The dimming value filtering device of claim 7, wherein, 10. A dimming value filtering apparatus for spatially filtering dimming values for adjusting luminance of blocks of a backlight, the dimming value filtering apparatus comprising: a mask generating circuit configured to generate a plurality of masks different from each other; a mask applying circuit configured to select one of the plurality of masks according to a position of a block and apply the selected mask to the block; a filtering result calculating circuit configured to calculate a filtered dimming value for the block according to the selected mask; and a transmission / reception circuit configured to transmit the filtered dimming value, wherein the mask includes a plurality of coefficients corresponding to the block and its neighboring blocks, and the filtering result calculating circuit calculates the filtered dimming value by performing an arithmetic operation on dimming values of the block and its neighboring blocks and the plurality of coefficients, and wherein the filtering result calculating circuit compares a result of the arithmetic operation with a dimming value of the block before the arithmetic operation, and outputs the result of the arithmetic operation as the filtered dimming value in a case where the result of the arithmetic operation is greater than the dimming value of the block before the arithmetic operation. wherein the mask includes a plurality of coefficients corresponding to the block and its neighboring blocks, and the filter result calculation circuit calculates the filtered dimming value by performing an arithmetic operation on the dimming values of the block and its neighboring blocks and the plurality of coefficients, wherein the filter result calculation circuit compares a result of the arithmetic operation with the dimming value of the block before the arithmetic operation, and outputs the dimming value of the block before the arithmetic operation as the filtered dimming value in a case where the result of the arithmetic operation is smaller than the dimming value of the block before the arithmetic operation.

11. A dimming value filtering apparatus for spatially filtering a dimming value used for adjusting luminance of a block of a backlight, the dimming value filtering apparatus comprising: a mask generation circuit configured to generate a plurality of masks different from each other; a mask application circuit configured to select one of the plurality of masks according to a position of a block, and apply the selected mask to the block; a filter result calculation circuit configured to calculate a filtered dimming value for the block according to the selected mask; and a transmission / reception circuit configured to transmit the filtered dimming value, wherein the mask includes a plurality of coefficients corresponding to the block and its neighboring blocks, and the filter result calculation circuit calculates the filtered dimming value by performing an arithmetic operation on the dimming values of the block and its neighboring blocks and the plurality of coefficients, wherein the neighboring blocks include a horizontal block adjacent to the block in a horizontal direction, a vertical block adjacent to the block in a vertical direction, and a corner block adjacent to the block in a diagonal line, wherein the plurality of coefficients include a central coefficient corresponding to the block, a horizontal coefficient corresponding to the horizontal block, a vertical coefficient corresponding to the vertical block, and a corner coefficient corresponding to the corner block, and wherein the central coefficient has a value greater than the horizontal coefficient, the vertical coefficient, and the corner coefficient.

12. The dimming value filtering device of claim 11, wherein, The filter result calculation circuit calculates the filtered dimming value by multiplying the dimming value of the block by the central coefficient, multiplying the dimming values of the horizontal blocks by the horizontal coefficients respectively, multiplying the dimming values of the vertical blocks by the vertical coefficients respectively, multiplying the dimming values of the corner blocks by the corner coefficients respectively, and then adding all the multiplied results.

13. A dimming value filtering apparatus for spatially filtering a dimming value used for adjusting luminance of a block of a backlight, the dimming value filtering apparatus comprising: a mask generation circuit configured to generate a plurality of masks different from each other; a mask application circuit configured to select one of the plurality of masks according to a position of a block, and apply the selected mask to the block; a filter result calculation circuit configured to calculate a filtered dimming value for the block according to the selected mask; and a transmission / reception circuit configured to transmit the filtered dimming value, wherein the mask includes a plurality of coefficients corresponding to the block and its neighboring blocks, and the filter result calculation circuit calculates the filtered dimming value by performing an arithmetic operation with respect to the dimming values of the block and its neighboring blocks and the plurality of coefficients, wherein the neighboring blocks include a horizontal block adjacent to the block in a horizontal direction, a vertical block adjacent to the block in a vertical direction, and a corner block adjacent to the block in a diagonal line, wherein the plurality of coefficients include a center coefficient corresponding to the block, a horizontal coefficient corresponding to the horizontal block, a vertical coefficient corresponding to the vertical block, and a corner coefficient corresponding to the corner block, wherein the plurality of masks include a center mask applied to a block located at a center of a video image, an edge mask applied to a block located at an edge of the video image, and a corner mask applied to a block located at a corner of the video image, and the center coefficient of the center mask has a value smaller than the center coefficients of the corner mask and the edge mask.

14. A dimming value filtering apparatus for spatially filtering a dimming value used for adjusting brightness of a block of a backlight, the dimming value filtering apparatus comprising: a mask generation circuit configured to generate a plurality of masks different from each other; a mask application circuit configured to select one mask of the plurality of masks in accordance with a position of a block, and apply the selected mask to the block; a filter result calculation circuit configured to calculate a filtered dimming value for the block in accordance with the selected mask; and a transmission / reception circuit configured to transmit the filtered dimming value, wherein the mask includes a plurality of coefficients corresponding to the block and its neighboring blocks, and the filter result calculation circuit calculates the filtered dimming value by performing an arithmetic operation with respect to the dimming values of the block and its neighboring blocks and the plurality of coefficients, wherein the neighboring blocks include a horizontal block adjacent to the block in a horizontal direction, a vertical block adjacent to the block in a vertical direction, and a corner block adjacent to the block in a diagonal line, wherein the plurality of coefficients include a center coefficient corresponding to the block, a horizontal coefficient corresponding to the horizontal block, a vertical coefficient corresponding to the vertical block, and a corner coefficient corresponding to the corner block, wherein the plurality of masks include a center mask applied to a block located at a center of a video image, an edge mask applied to a block located at an edge of the video image, and a corner mask applied to a block located at a corner of the video image, and the center coefficient of the center mask has a value smaller than the center coefficients of the corner mask and the edge mask.

15. An image data processing apparatus comprising: a block acquisition circuit configured to divide a video image into a plurality of regions and designate each region as a block; a dimming value calculation circuit configured to calculate a luminance value of each block, and calculate a dimming value for adjusting luminance of a backlight corresponding to the block according to the luminance value; a dimming value filter configured to receive the dimming value, generate a plurality of masks, select one mask from the plurality of masks according to a position of a block in the video image, and apply the selected mask to the block to calculate a filtered dimming value; and a dimming output circuit configured to output a dimming control signal for driving the backlight according to the dimming value to a backlight driving device, wherein the dimming value filter specifies an area of interest, and filters the dimming value of a block included in the area of interest such that a difference between the dimming value of the block located within the area of interest and the dimming value of an adjacent neighboring block increases.

16. The image data processing apparatus of claim 15, wherein The dimming value filter specifies an area of interest, and filters the dimming value of a block located outside the area of interest such that a difference between the dimming value of the block located outside the area of interest and the dimming value of an adjacent neighboring block decreases.

17. The image data processing apparatus according to claim 15, wherein The mask includes a plurality of coefficients in a matrix form, which are used for arithmetic operations on the dimming values of the block and its neighboring blocks.

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