Device and method for processing image data for driving a display panel

Abstract

The present disclosure relates to an apparatus and method for processing image data for driving a display panel, and more particularly, to an apparatus and method for changing the brightness of each pixel according to a representative brightness value of an image.

Description

Background Art

[0001] The present disclosure relates to an apparatus and method for processing image data for driving a display panel. Technical Field

[0002] As society becomes more information-oriented, the demand for products requiring display devices has increased in various ways. Recently, various display devices such as liquid crystal display (LCD) devices, plasma display panels (PDP), organic light emitting diode display (OLED) devices, etc. are used.

[0003] The display device displays an image on a panel by controlling the brightness of each pixel according to image data received from a host device. A display device including pixels that emit light by themselves without using a backlight (e.g., an organic light-emitting display device) can generally control the brightness of each pixel by controlling the level of a driving current supplied to the pixel.

[0004] In this display device, the level of the driving current supplied to the pixel is controlled by an analog voltage converted from image data, that is, a so-called data voltage. Therefore, the display device can control the brightness of the pixel according to the image data.

[0005] Here, as the brightness of each pixel becomes higher, the power consumption of the display device increases.

[0006] In other words, since the image includes more white or off-white, each pixel has a higher brightness, and this will lead to an increase in power consumption of the display device. In addition, this may generate glare on the display device.

[0007] In order to solve these problems, conventionally, a brightness value included in image data in a display device is uniformly lowered so that power consumption can be reduced and glare can be prevented.

[0008] However, when the brightness value included in the image data is uniformly lowered, the brightness of the image which is not desired to be lowered may also be lowered, and this may result in degradation of image quality.

[0009] For example, in the case where an image includes a lot of dark colors, since the brightness values ​​included in the image data are uniformly lowered, this may result in degradation of the image quality of such an image including a lot of dark colors. Summary of the invention

[0010] In this context, an aspect of the present disclosure is to provide a technique for changing the brightness of each pixel according to a representative brightness value of an image.

[0011] To this end, in one aspect, the present disclosure provides a method for processing image data by a processing device, the method for processing image data comprising the following steps: calculating a representative brightness value for an input pixel brightness value included in the input image data; calculating N X-axis point values ​​using N set values, where N is a natural value greater than 2; generating a first reference curve using N first Y-axis point values ​​and the X-axis point values, and generating a second reference curve using N second Y-axis point values ​​and the X-axis point values; generating a brightness adjustment curve using the first reference curve, the second reference curve, and the representative brightness value; and converting the input pixel brightness value into an output pixel brightness value using the brightness adjustment curve.

[0012] The method may further include the step of sending output image data including output pixel brightness values ​​to the panel driving device.

[0013] The input pixel brightness value, the X-axis point value, the first Y-axis point value, the second Y-axis point value, and the output pixel brightness value may be grayscale values.

[0014] The X-axis coordinate value of the brightness adjustment curve may include the input pixel brightness value, and the Y-axis coordinate value of the brightness adjustment curve may include the output pixel brightness value.

[0015] The steps of generating the first reference curve and the second reference curve may include: generating the first reference curve by matching the X-axis point value with the first Y-axis point value and calculating the value between the X-axis point values ​​by data interpolation; and generating the second reference curve by matching the X-axis point value with the second Y-axis point value and calculating the value between the X-axis point values ​​by data interpolation.

[0016] The set value may include an exponent that is a power of 2.

[0017] The step of calculating the X-axis point value may include: calculating the Nth power value by shifting the Nth set value bit number as the last set value, and calculating the Nth X-axis point value as the maximum X-axis point value by subtracting the Nth power value from the highest brightness value of the pixel, wherein the Nth power value is a value raised to the power of 2 with the Nth set value as the exponent.

[0018] The representative brightness value may be less than or equal to a first representative brightness value identified in the first reference curve, and equal to or greater than a second representative brightness value identified in the second reference curve.

[0019] In the step of generating the brightness adjustment curve, the brightness adjustment curve can be generated through data interpolation using the first representative brightness value, the second representative brightness value, and the representative brightness value.

[0020] In another aspect, the present disclosure provides an image data processing device, comprising: a representative brightness value calculation circuit, which is used to calculate a representative brightness value for an input pixel brightness value included in input image data; a curve generation circuit, which is used to generate a first reference curve by calculating N X-axis point values ​​using N set values ​​and using N first Y-axis point values ​​and the N X-axis point values, wherein N is a natural number greater than 2, and the curve generation circuit is used to generate a second reference curve using N second Y-axis point values ​​and the N X-axis point values, and to generate a brightness adjustment curve using the first reference curve, the second reference curve and the representative brightness value; and an image data conversion circuit, which is used to convert the input pixel brightness value into an output pixel brightness value using the brightness adjustment curve.

[0021] The image data processing device may further include an image data transmission circuit that transmits output image data including output pixel brightness values ​​to the panel driving device.

[0022] The curve generating circuit includes: a shift operation circuit for calculating a value raised to a power of 2 with the N set values ​​as exponents by a shift operation; a subtraction circuit for calculating an Nth X-axis point value by subtracting the Nth power value from the highest brightness value of the pixel, and calculating an N-1th X-axis point value by subtracting the Nth power value from the Nth X-axis point value, wherein the Nth X-axis point value is a maximum X-axis point value, the Nth power value is a value raised to a power of 2 with the Nth set value as an exponent, and the Nth set value is the last set value among the N set values; and a data interpolation circuit for generating the first reference curve by matching the X-axis point value with the first Y-axis point value and calculating a value between the X-axis point values, and for generating the second reference curve by matching the X-axis point value with the second Y-axis point value and calculating a value between the X-axis point values.

[0023] The data interpolation circuit may generate the brightness adjustment curve through data interpolation using a first representative brightness value identified in the first reference curve, a second representative brightness value identified in the second reference curve, and the representative brightness value.

[0024] The image data processing device may further include a storage circuit configured to store the N set values, the N first Y-axis point values, and the N second Y-axis point values.

[0025] The storage circuit may also store a lookup table including a plurality of representative brightness ranges, a plurality of weighted average brightness ranges, and a plurality of representative brightness levels corresponding to the plurality of representative brightness ranges and the plurality of weighted average brightness ranges.

[0026] The input pixel brightness value may include an R grayscale value, a G grayscale value and a B grayscale value, the R grayscale value being the grayscale value of a red sub-pixel, i.e., an R sub-pixel, the G grayscale value being the grayscale value of a green sub-pixel, i.e., a G sub-pixel, and the B grayscale value being the grayscale value of a blue sub-pixel, i.e., a B sub-pixel, and the representative brightness value calculation circuit may calculate a weighted average brightness value by dividing a maximum value of a first square sum value obtained by summing the square values ​​of the R grayscale values, a second square sum value obtained by summing the square values ​​of the G grayscale values, and a third square sum value obtained by summing the square values ​​of the B grayscale values ​​by a maximum value of a first sum value obtained by summing the R grayscale values, a second sum value obtained by summing the G grayscale values, and a third sum value obtained by summing the B grayscale values.

[0027] The curve generating circuit may extract a representative brightness level corresponding to a representative brightness range including the representative brightness value and a weighted average brightness range including the weighted average brightness value from the lookup table, and generate a brightness adjustment curve using the first reference curve, the second reference curve and the representative brightness level.

[0028] As described above, according to the present disclosure, the image data processing device generates a brightness adjustment curve appropriately adjusted according to the representative brightness value of the image, and uses the brightness adjustment curve to adjust the brightness of each pixel corresponding to the image. This allows eliminating the degradation of image quality caused by conventional uniform brightness adjustment.

[0029] In addition, according to the present disclosure, the image data processing device generates a brightness adjustment curve through simple calculations, which allows the circuit forming the image data processing device to be simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and other aspects, features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0031] Figure 1 is a configuration diagram of a display device according to an embodiment;

[0032] Figure 2 is a configuration diagram of an image data processing apparatus according to an embodiment;

[0033] Figure 3 is a configuration diagram of a curve generating circuit according to an embodiment;

[0034] Figure 4 are examples of setting values ​​according to the implementation mode;

[0035] Figure 5 and Figure 6is a diagram showing calculation of an X-axis point value according to an embodiment;

[0036] Figure 7 is an example of a lookup table according to an embodiment;

[0037] Figure 8 is a diagram illustrating generation of a first reference curve according to an embodiment;

[0038] Fig. 9 is a diagram illustrating generation of a second reference curve according to an embodiment;

[0039] Fig.10 is a diagram showing generation of a brightness adjustment curve according to an embodiment;

[0040] Fig.11 is a diagram showing conversion of input pixel brightness values ​​using a brightness adjustment curve; and

[0041] Fig.12 is a flowchart showing a procedure of processing image data in the image data processing apparatus. DETAILED DESCRIPTION

[0042] Figure 1 is a configuration diagram of a display device according to an embodiment.

[0043] Reference Figure 1 The display device 100 may include an image data processing device 110 , a panel driving device 120 , a gate driving device 130 and a display panel 140 .

[0044] The image data processing device 110 may receive input image data RGB from an external device (eg, a host device), convert the input image data RGB into output image data RGB′, and transmit the output image data RGB′ to the panel driving device 120 .

[0045] The panel driving device 120 may receive the output image data RGB′ from the image data processing device 110 and generate an analog voltage, so-called data voltage, using the output image data RGB′.

[0046] The panel driving device 120 may transmit an analog voltage to each pixel arranged in the display panel 140 through the data lines DL.

[0047] On the display panel 140, a plurality of pixels may be arranged and each of the plurality of pixels may emit light by itself. For example, each pixel may include an organic light emitting diode (OLED) and may emit light by itself by a driving current supplied to the organic light emitting diode. The brightness of each pixel may be controlled by an analog voltage supplied from the panel driving device 120.

[0048] The gate driving device 130 may supply a scan signal to the display panel 140 through the gate lines GL.

[0049] According to the scan signal, a specific row of the display panel 140 may be selected, and the analog voltage supplied from the panel driving device 120 may be supplied only to the selected row.

[0050] The image data processing device 110 may supply a synchronization signal and / or a control signal to the panel driving device 120 and the gate driving device 130 in order to control a timing for supplying a scanning signal and a timing for supplying an analog voltage.

[0051] The image data processing device 110 may be referred to as a timing controller, the panel driving device 120 may be referred to as a source driver or a column driver, and the gate driving device 130 may be referred to as a gate driver. Each device may be formed in the form of an independent integrated circuit, or at least two devices may be formed in the form of one integrated circuit.

[0052] According to an embodiment, the image data processing device 110 can analyze the brightness of an image corresponding to the input image data RGB received from an external device (e.g., a host device), adjust the input pixel brightness value of the input image data RGB corresponding to the brightness of the image according to the brightness of the image, and send the output image data RGB' including the output pixel brightness value obtained by adjusting the input pixel brightness value to the panel driving device 120.

[0053] For this process, the image data processing device 110 may use ACL (adaptive current limit or automotive current limit) technology.

[0054] This is described in detail below.

[0055] Figure 2 is a configuration diagram of an image data processing device according to an embodiment.

[0056] Reference Figure 2 The image data processing device 110 may include a representative brightness value calculation circuit 210 , a storage circuit 220 , a curve generation circuit 230 , an image data conversion circuit 240 , and an image data transmission circuit 250 .

[0057] The representative brightness value calculation circuit 210 can calculate a representative brightness value for the input pixel brightness value included in the input image data RGB. The representative brightness value, which can be called the average picture level (APL), can be calculated by the following formula. Here, the input pixel brightness value can include an R grayscale value as a grayscale value of a red (R) sub-pixel, a G grayscale value as a grayscale value of a green (G) sub-pixel, and a B grayscale value as a grayscale value of a blue (B) sub-pixel.

[0058] [Formula 1]

[0059] Y=a×R grayscale value+b×G grayscale value+c×B grayscale value

[0060]

[0061] Here, Y may be a pixel grayscale value, which is a brightness component for each of a plurality of pixels arranged in the display panel 140, an R grayscale value may be a grayscale value of a red (R) sub-pixel, a G grayscale value may be a grayscale value of a green (G) sub-pixel, a B grayscale value may be a grayscale value of a blue (B) sub-pixel, and n may be the number of pixels. a may be a weight of an R grayscale value, b may be a weight of a G grayscale value, and c may be a weight of a B grayscale value. Here, a+b+c=1.

[0062] The representative brightness value calculation circuit 210 may also calculate a weighted average brightness value for the input pixel brightness values.

[0063] Specifically, the representative brightness value calculation circuit 210 can calculate a weighted average brightness value for the input pixel brightness value by dividing the maximum value among the first square sum value obtained by summing the squares of the R grayscale values, the second square sum value obtained by summing the squares of the G grayscale values, and the third square sum value obtained by summing the squares of the B grayscale values ​​by the maximum value among the first sum value obtained by summing the R grayscale values, the second sum value obtained by summing the G grayscale values, and the third sum value obtained by summing the B grayscale values. The weighted average brightness value may be referred to as a weighted average picture level (WAPL).

[0064] The storage circuit 220 may store data for generating a brightness adjustment curve in the curve generating circuit 230 which will be described later.

[0065] Specifically, the storage circuit 220 can store N set values, N first Y-axis point values, and N second Y-axis point values ​​for generating a brightness adjustment curve. The X-axis coordinate value of the brightness adjustment curve can be the input brightness value, and its Y-axis coordinate value can be the output brightness value.

[0066] According to an embodiment, in order to minimize the size, the storage circuit 220 may not store all X-coordinate values ​​and Y-coordinate values ​​of points forming the brightness adjustment curve, but may store only N set values, N first Y-axis point values, and N second Y-axis point values, which are basic data required for generating the brightness adjustment curve in the curve generation circuit 230.

[0067] Here, the N set values ​​may mean data for calculating N X-axis point values ​​required to generate the brightness adjustment curve in the curve generating circuit 230 .

[0068] The settings can include Figure 4 and Figure 5 The exponents shown are powers of 2. The reason why the N set values ​​include exponents of powers of 2 will be described later when the curve generating circuit 230 is described.

[0069] Meanwhile, in the case where the representative brightness value calculation circuit 210 calculates the weighted average brightness value for the input pixel brightness value, the storage circuit 220 may further store the weighted average brightness value as shown in FIG. Figure 7 The lookup table shown includes a plurality of representative brightness ranges, a plurality of weighted average brightness ranges, and a plurality of representative brightness levels corresponding to the plurality of representative brightness ranges and the plurality of weighted average brightness ranges.

[0070] The curve generating circuit 230 may generate a brightness adjustment curve for adjusting the brightness value of an input pixel of the input image data.

[0071] Specifically, the curve generating circuit 230 may use N set values ​​to calculate N X-axis point values.

[0072] According to an embodiment, the curve generating circuit 230 may calculate the first power value to the Nth power value, which are values ​​raised to a power of 2 using N set values ​​as exponents, through a shift operation.

[0073] For example, Figure 4 As shown, when there are eight set values ​​from point 1 set value to point 8 set value, and the point 8 set value is 5, the curve generating circuit 230 can obtain the binary number "00010000" corresponding to the decimal number "32" which is 2 raised to the fifth power by shifting 1 in the binary number "00000001" to the left by 5 bits.

[0074] After calculating the first power value to the Nth power value, first, as Figure 5 As shown, the curve generation circuit 230 may calculate the Nth X-axis point value by subtracting the Nth power value from the predetermined maximum brightness value of the pixel.

[0075] Next, the curve generation circuit 230 may calculate the N-1th X-axis point value by subtracting the Nth power value from the Nth X-axis point value.

[0076] In this manner, the curve generating circuit 230 can then calculate the N-2th X-axis point value to the first X-axis point value.

[0077] In other words, the curve generating circuit 230 may calculate the N X-axis point values ​​in the following order: first calculate the X-axis point value corresponding to the highest brightness value, and finally calculate the X-axis point value corresponding to the lowest brightness value.

[0078] For example, in N settings such as Figure 4 In the case shown, the curve generating circuit 230 may first calculate the 8th X-axis point value "991" corresponding to the highest brightness value, and then calculate other X-axis point values ​​in the order of the corresponding brightness values.

[0079] According to the embodiment, the curve generation circuit 230 calculates the X-axis point value using a shift operation and a subtraction operation. This allows the circuit forming the curve generation circuit 230 to be simplified.

[0080] At the same time, the curve generating circuit 230 can compare the N X-axis point values ​​calculated as described above with the N first Y-axis point values ​​( Figure 8 Min1 to Min8 in Figure 8 points in the rectangle).

[0081] After matching, the curve generation circuit 230 can calculate the value between each two adjacent X-axis point values ​​in the N X-axis point values ​​through data interpolation to generate Figure 8 The first reference curve is shown.

[0082] In addition, the curve generating circuit 230 can compare the N X-axis point values ​​with the N second Y-axis point values ​​( Fig. 9 Max1 to Max8 in (see Fig. 9 The diamond point in the middle).

[0083] After matching, the curve generation circuit 230 can calculate the value between the N X-axis point values ​​by data interpolation to generate Fig. 9 The second reference curve is shown.

[0084] Here, the first reference curve and the second reference curve may be a minimum adjustment reference and a maximum adjustment reference required for generating a brightness adjustment curve reflecting a representative brightness value.

[0085] After generating the first reference curve and the second reference curve, the curve generating circuit 230 may generate a brightness adjustment curve by data interpolation using the first representative brightness value identified in the first reference curve, the second representative brightness value identified in the second reference curve, and the representative brightness value. The first representative brightness value and the second representative brightness value may be stored in the storage circuit 220. Here, the representative brightness value may be less than or equal to the first representative brightness value and equal to or greater than the second representative brightness value.

[0086] In an implementation, the Nth Y-axis point value matching the Nth X-axis point value of the brightness adjustment curve may be calculated by the following interpolation formula.

[0087] [Formula 2]

[0088]

[0089] Here, Max.N may be the Nth second Y-axis point value, Rv.B may be the representative brightness value, Rv.B1 may be the first representative brightness value, Min.N may be the Nth first Y-axis point value, and Rv.B2 may be the second representative brightness value.

[0090] The curve generating circuit 230 can use the aforementioned interpolation formula to calculate the N Y-axis point values ​​of the brightness adjustment curve. Subsequently, the N X-axis point values ​​(which match the N Y-axis point values ​​(see Fig.10 to generate the values ​​between the circular points in Fig.10 The brightness adjustment curve shown.

[0091] At the same time, the representative brightness value calculation circuit 210 calculates the weighted average brightness value for the input pixel brightness value, and the storage circuit 220 further stores the weighted average brightness value corresponding to the input pixel brightness value. Figure 7 In the case of a lookup table similar to the one shown in FIG. 1 , the curve generation circuit 230 can extract a representative brightness level corresponding to a representative brightness range and a weighted average brightness range. Here, a representative brightness range can be a representative brightness range including representative brightness values, and a weighted average brightness range can be a weighted average brightness range including weighted average brightness values.

[0092] The curve generating circuit 230 may also generate a brightness adjustment curve using the first reference curve, the second reference curve, and an average brightness level.

[0093] In other words, the first representative brightness level may be applied to the first reference curve, the second representative brightness level may be applied to the second reference curve, and the curve generating circuit 230 may generate a brightness adjustment curve by data interpolation using the first representative brightness level, the second representative brightness level and an average brightness level.

[0094] As described above, according to the embodiment, the curve generation circuit 230 may appropriately adjust the brightness adjustment curve according to the representative brightness value of the input image data RGB, that is, the representative brightness value for the input pixel brightness value included in the input image data RGB.

[0095] The image data conversion circuit 240 may convert the input pixel brightness value into the output pixel brightness value using the brightness adjustment curve.

[0096] For example, if the input pixel brightness value included in the input image data RGB is 831, the image data conversion circuit 240 may convert the input pixel brightness value 831 into the image data RGB. Fig.11 The brightness adjustment curve shown is used to convert the input pixel brightness value 831 into the output pixel brightness value 728.

[0097] After converting all input pixel brightness values ​​included in the input image data RGB into output pixel brightness values, the image data conversion circuit 240 may transmit output image data RGB′ including the output pixel brightness values ​​to the image data transmission circuit 250 .

[0098] The image data transmitting circuit 250 may transmit the output image data RGB′ to the panel driving device 120 .

[0099] According to an embodiment, calculation of representative brightness values ​​and generation of brightness adjustment curves obtained from the representative brightness values ​​may be performed using frames of a data image.

[0100] In other words, whenever the input image data RGB is received frame by frame from the image data processing device 110 , the representative brightness value calculation circuit 210 may calculate the representative brightness value, and thus, the curve generation circuit 230 may generate the brightness adjustment curve.

[0101] Here, if the representative brightness value in the current frame changes greatly compared to the representative brightness value in the previous frame, the brightness of the display device 100 may change greatly, and this may cause discomfort to the user who is viewing the display device 100 .

[0102] To eliminate this problem, a dimming method for mitigating sudden changes may be applied.

[0103] Hereinafter, a detailed configuration of the curve generating circuit 230 will be described.

[0104] Figure 3 is a configuration diagram of a curve generating circuit according to an embodiment.

[0105] Reference Figure 3The curve generating circuit 230 may include a shift operation circuit 310 , a subtraction circuit 320 , and a data interpolation circuit 330 .

[0106] The shift operation circuit 310 may calculate the first power value to the Nth power value, which are values ​​raised to the power of 2 with N set values ​​as exponents, through the shift operation.

[0107] For example, Figure 4 As shown, when the N set values ​​include 8 set values ​​from point 1 set value to point 8 set value, and the point 8 set value is 5, the shift operation circuit 310 can shift 1 in the binary number "00000001" to the left by 5 bits to obtain the binary number "00010000" corresponding to the decimal number "32" which is 2 to the power of 5.

[0108] The subtraction circuit 320 may calculate an Nth X-axis point value by subtracting an Nth power value from a predetermined maximum brightness value of the pixel, and may calculate an N-1th X-axis point value by subtracting an N-1th power value from the Nth X-axis point value.

[0109] In other words, when N X-axis point values ​​are calculated, the subtraction circuit 320 may sequentially calculate the point value corresponding to the highest brightness value to the point value corresponding to the lowest brightness value through subtraction operations.

[0110] The data interpolation circuit 330 can match the N X-axis point values ​​with the N first Y-axis point values ​​stored in the storage circuit 220, and then calculate the value between the N X-axis point values ​​by data interpolation. In this way, the data interpolation circuit 330 can generate Figure 8 The first reference curve is shown.

[0111] In addition, the data interpolation circuit 330 can match the N X-axis point values ​​with the N second Y-axis point values ​​stored in the storage circuit 220, and then calculate the value between the N X-axis point values ​​by data interpolation. In this way, the data interpolation circuit 330 can generate Fig. 9 The second reference curve is shown.

[0112] After generating the first reference curve and the second reference curve, the data interpolation circuit 330 may generate a brightness adjustment curve by data interpolation using the first representative brightness value identified in the first reference curve, the second representative brightness value identified in the second reference curve, and the representative brightness value. The first representative brightness value and the second representative brightness value may be stored in the storage circuit 220. Here, the representative value may be less than or equal to the first representative brightness value and equal to or greater than the second representative brightness value.

[0113] The data interpolation circuit 330 can use the aforementioned interpolation formula (Formula 2) to calculate the N Y-axis point values ​​of the brightness adjustment curve. In addition, the data interpolation circuit 330 can calculate the N X-axis point values ​​(matched with the N Y-axis point values ​​(see Fig.10 to generate the values ​​between the circular points in Fig.10 The brightness adjustment curve shown.

[0114] At the same time, the representative brightness value calculation circuit 210 calculates the weighted average brightness value for the input pixel brightness value, and the storage circuit 220 further stores the weighted average brightness value corresponding to the input pixel brightness value. Figure 7 In the case of a lookup table similar to the one shown in FIG. 1 , the data interpolation circuit 330 can extract a representative brightness level corresponding to a representative brightness range and a weighted average brightness range. Here, a representative brightness range can be a representative brightness range including representative brightness values, and a weighted average brightness range can be a weighted average brightness range including weighted average brightness values.

[0115] The data interpolation circuit 330 may also generate a brightness adjustment curve using the first reference curve, the second reference curve, and an average brightness level.

[0116] In other words, the first representative brightness level may be applied to the first reference curve, the second representative brightness level may be applied to the second reference curve, and the data interpolation circuit 330 may generate a brightness adjustment curve through data interpolation using the first representative brightness level, the second representative brightness level and an average brightness level.

[0117] Hereinafter, a process of processing image data in the image data processing apparatus 110 will be described.

[0118] Fig.12 is a flowchart showing a procedure of processing image data in the image data processing apparatus.

[0119] Reference Fig.12 , the image data processing device 110 may receive input image data RGB from the host device, and calculate a representative brightness value for an input pixel brightness value included in the input image data RGB (S1210). Here, the representative brightness value may be referred to as an average picture level (APL), and the input pixel brightness value may include an R grayscale value as a grayscale value of a red (R) sub-pixel, a G grayscale value as a grayscale value of a green (G) sub-pixel, and a B grayscale value as a grayscale value of a blue (B) sub-pixel. The image data processing device 110 may calculate the representative brightness value using the aforementioned formula 1.

[0120] After calculating the representative brightness value, the image data processing device 110 can use the previously stored N set values ​​to calculate N X-axis point values ​​(S1220). Here, the image data processing device 110 can use the N set values ​​to calculate the N X-axis point values ​​starting from the Nth X-axis point value through shift operation and subtraction operation.

[0121] Subsequently, the image data processing apparatus 110 may match the N X-axis point values ​​with the previously stored N first Y-axis point values, and calculate a value between the N X-axis point values ​​to generate a first reference curve ( S1230 ).

[0122] The image data processing device 110 may match the N X-axis point values ​​with the previously stored N second Y-axis point values, and calculate the value between the N X-axis point values ​​to generate a second reference curve (S1240). Here, the order of generating the first reference curve and the second reference curve may be determined by the designer of the image data processing device 110.

[0123] Subsequently, the image data processing device 110 may generate a brightness adjustment curve by data interpolation using the first representative brightness value identified in the first reference curve, the second representative brightness value identified in the second reference curve, and the representative brightness value (S1250). Here, the representative brightness value may be less than or equal to the first representative brightness value and equal to or greater than the second representative brightness value.

[0124] The image data processing device 110 may convert the input pixel brightness value into an output pixel brightness value using the brightness adjustment curve, and may transmit output image data RGB′ including the output pixel brightness value to the panel driving device ( S1260 , S1270 ).

[0125] In S1210 , the image data processing device 110 may further calculate a weighted average brightness value for the input pixel brightness values.

[0126] In this case, the image data processing device 110 may further store Figure 7 After S1240, the image data processing device 110 may extract from the lookup table a representative brightness level corresponding to a representative brightness range including the representative brightness value and a weighted average brightness range including the weighted average brightness value.

[0127] The image data processing device 110 may also generate a brightness adjustment curve using the first reference curve, the second reference curve, and a representative brightness level.

[0128] As described above, according to the present disclosure, the image data processing device 110 generates a brightness adjustment curve appropriately adjusted according to the representative brightness value of the image, and adjusts the brightness of each pixel included in the image. This allows eliminating the degradation of image quality caused by conventional uniform brightness adjustment.

[0129] In addition, since the image data processing device 110 generates the brightness adjustment curve using a shift operation, a subtraction operation, and data interpolation, a circuit forming the image data processing device 110 can be simplified.

[0130] CROSS-REFERENCE TO RELATED APPLICATIONS

[0131] This application claims priority to Korean Patent Application No. 10-2020-0028030, filed on Mar. 6, 2020, which is hereby incorporated by reference in its entirety.

Claims

1. A method for processing image data by a processing device, the method for processing image data comprising the following steps: calculating a representative brightness value for input pixel brightness values ​​included in the input image data; Calculate N X-axis point values ​​using N set values, where N is a natural number greater than 2; Generate a first reference curve using N first Y-axis point values ​​and the X-axis point value, and generate a second reference curve using N second Y-axis point values ​​and the X-axis point value; generating a brightness adjustment curve using the first reference curve, the second reference curve and the representative brightness value; as well as Converting the input pixel brightness value into an output pixel brightness value using the brightness adjustment curve, wherein the setting value includes an exponent of a power of 2, and Among them, the step of calculating the X-axis point value includes: calculating the Nth power value by shifting the Nth set value bit number as the last set value, and calculating the Nth X-axis point value as the maximum X-axis point value by subtracting the Nth power value from the highest brightness value of the pixel, wherein the Nth power value is a value raised to the power of 2 with the Nth set value as the exponent.

2. The method for processing image data according to claim 1, further comprising the step of sending output image data including the output pixel brightness value to a panel driving device.

3. The method for processing image data according to claim 1, wherein: The input pixel brightness value, the X-axis point value, the first Y-axis point value, the second Y-axis point value, and the output pixel brightness value are grayscale values.

4. The method for processing image data according to claim 1, wherein: The X-axis coordinate value of the brightness adjustment curve includes the input pixel brightness value, and the Y-axis coordinate value of the brightness adjustment curve includes the output pixel brightness value.

5. The method for processing image data according to claim 1, wherein: The steps of generating a first reference curve and a second reference curve include: generating a first reference curve by matching the X-axis point value with the first Y-axis point value and calculating the value between the X-axis point values ​​by data interpolation; and generating a second reference curve by matching the X-axis point value with the second Y-axis point value and calculating the value between the X-axis point values ​​by data interpolation.

6. The method for processing image data according to claim 1, wherein: The representative brightness value is less than or equal to a first representative brightness value identified in the first reference curve, and is equal to or greater than a second representative brightness value identified in the second reference curve.

7. The method for processing image data according to claim 6, wherein: In the step of generating the brightness adjustment curve, the brightness adjustment curve can be generated by data interpolation using the first representative brightness value, the second representative brightness value, and the representative brightness value.

8. An image data processing device, comprising: a representative brightness value calculation circuit for calculating a representative brightness value for an input pixel brightness value included in the input image data; a curve generating circuit for generating a first reference curve by calculating N X-axis point values ​​using N set values ​​and using N first Y-axis point values ​​and the N X-axis point values, wherein N is a natural number greater than or equal to 2, and for generating a second reference curve using N second Y-axis point values ​​and the N X-axis point values, and generating a brightness adjustment curve using the first reference curve, the second reference curve and the representative brightness value; as well as an image data conversion circuit, which is used to convert the input pixel brightness value into an output pixel brightness value using the brightness adjustment curve, Wherein, the curve generating circuit comprises: a shift operation circuit for calculating a value raised to a power of 2 with the N set values ​​as exponents by a shift operation; a subtraction circuit for calculating an Nth X-axis point value by subtracting an Nth power value from a maximum brightness value of a pixel, and calculating an N-1th X-axis point value by subtracting an Nth power value from the Nth X-axis point value, wherein the Nth X-axis point value is a maximum X-axis point value, the Nth power value is a value raised to a power of 2 with an Nth set value as an exponent, and the Nth set value is a last set value among the N set values; and A data interpolation circuit is used to generate the first reference curve by matching the X-axis point value with the first Y-axis point value and calculating the value between the X-axis point values, and to generate the second reference curve by matching the X-axis point value with the second Y-axis point value and calculating the value between the X-axis point values.

9. The image data processing device according to claim 8, further comprising an image data sending circuit for sending the output image data including the output pixel brightness value to the panel driving device.

10. The image data processing device according to claim 8, wherein: The data interpolation circuit generates the brightness adjustment curve through data interpolation using a first representative brightness value identified in the first reference curve, a second representative brightness value identified in the second reference curve, and the representative brightness value.

11. An image data processing device, comprising: a representative brightness value calculation circuit for calculating a representative brightness value for an input pixel brightness value included in the input image data; a curve generating circuit for generating a first reference curve by calculating N X-axis point values ​​using N set values ​​and using N first Y-axis point values ​​and the N X-axis point values, wherein N is a natural number greater than or equal to 2, and for generating a second reference curve using N second Y-axis point values ​​and the N X-axis point values, and generating a brightness adjustment curve using the first reference curve, the second reference curve and the representative brightness value; An image data conversion circuit, configured to convert the input pixel brightness value into an output pixel brightness value using the brightness adjustment curve; as well as a storage circuit, which is used to store the N set values, the N first Y-axis point values ​​and the N second Y-axis point values, The storage circuit further stores a lookup table, the lookup table comprising a plurality of representative brightness ranges, a plurality of weighted average brightness ranges, and a plurality of representative brightness levels corresponding to the plurality of representative brightness ranges and the plurality of weighted average brightness ranges. The input pixel brightness value includes an R grayscale value, a G grayscale value, and a B grayscale value, wherein the R grayscale value is the grayscale value of a red sub-pixel, i.e., an R sub-pixel, the G grayscale value is the grayscale value of a green sub-pixel, i.e., a G sub-pixel, and the B grayscale value is the grayscale value of a blue sub-pixel, i.e., a B sub-pixel, and The representative brightness value calculation circuit calculates a weighted average brightness value by dividing the maximum value of a first square sum value obtained by summing the square values ​​of the R grayscale values, a second square sum value obtained by summing the square values ​​of the G grayscale values, and a third square sum value obtained by summing the square values ​​of the B grayscale values ​​by the maximum value of a first sum value obtained by summing the R grayscale values, a second sum value obtained by summing the G grayscale values, and a third sum value obtained by summing the B grayscale values.

12. The image data processing device according to claim 11, wherein: The curve generating circuit extracts a representative brightness level corresponding to a representative brightness range including the representative brightness value and a weighted average brightness range including the weighted average brightness value from the lookup table, and generates a brightness adjustment curve using the first reference curve, the second reference curve and the representative brightness level.

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