TWI822513B - Dynamic contrast adjustment module, display driver chip, display device and information processing device - Google Patents

Abstract

The present invention mainly discloses a dynamic contrast adjustment module, which is integrated into a display device by applying a driving display chip to perform a contrast adjustment process on an input display data to generate an output display data. In particular, the dynamic contrast adjustment module of the present invention performs a dynamic contrast weakening operation within a contrast value range of [0,50], and performs a dynamic contrast enhancement operation within a contrast value range of (50,100], thereby completing the contrast adjustment process. The output display data enables the display driver chip to drive the display device to display an image with both dynamic contrast enhancement and weakening based on the output display data. On the other hand, the display driver chip can be adjusted by adjusting customer parameters (such as: [0, 100 ]) and the internally used algorithm parameters (such as: C, B) make the dynamic contrast adjustment module of the present invention suitable for various display devices.

Description

Dynamic contrast adjustment module, display driver chip, display device and information processing device

The present invention relates to the technical field related to display driving, and in particular, to a dynamic contrast adjustment module used in display driving chips.

Figure 1 is a block diagram of a conventional display device. Electronic engineers who are familiar with the design and manufacturing of display devices must know that the structure of a conventional display device 1a includes: a display panel 11a and at least one display driver IC (Display driver IC, DDI) 12a, where the display driver chip 12a is A host computer 2a (such as an application processor of a smartphone) receives an input display data, preprocesses the input display data into an output display data, and finally performs display driving on the display panel 11a based on the output display data.

In order to drive the display panel 11a to display images with high contrast, as shown in FIG. 1 , the prior art provides a contrast adjustment unit 121a in the display driving chip 12a to perform a contrast adjustment process on the input display data. Electronic engineers who are familiar with the design and manufacturing of the display driver chip 12a must know that the contrast adjustment unit 121a uses histogram equalization (Histogram Equalization, HE) to enhance the image contrast. Its main technical means is to first generate a signal based on the input display data. A first histogram of the number of pixels relative to the gray level (Gray level, 0~255), and the first histogram contains a plurality of histogram bars. Then, a uniform distribution process is performed on the plurality of histograms in the first histogram, so that the plurality of histograms are evenly distributed in the gray scale range of 0 to 255, thereby obtaining a second histogram. Finally, an output display data corresponding to a specific image is generated according to the second histogram, so that the display driver chip 12a drives the display panel 11a to display the specific image according to the output display data.

Practical experience shows that histogram equalization has some defects. For example, after the histogram equalization process, when the display panel 11a displays images, the display screen will be too white. On the other hand, after histogram equalization processing, some details disappear due to the reduction in grayscale levels of the image (disappearance due to excessive whitening). In general, the contrast adjustment unit 121a of the conventional technology uses histogram equalization to enhance image contrast. However, its processing process lacks flexibility and cannot be dynamically adjusted, so it is necessary to improve it.

It can be seen from the above description that a dynamic contrast adjustment module is urgently needed in this field.

The main purpose of the present invention is to provide a dynamic contrast adjustment module that can realize dynamic contrast adjustment of a display device and has the characteristics of high applicability, adjustable maximum adjustment range, dynamic contrast reduction, and dynamic contrast enhancement.

Specifically, the dynamic contrast adjustment module of the present invention performs a dynamic contrast weakening operation within a contrast value range of [0,50], and performs a dynamic contrast enhancement operation within a contrast value range of (50,100], thereby completing the contrast adjustment process. The output display data is generated so that the display driver chip drives the display device to display an image with both dynamic contrast enhancement and weakening based on the output display data. On the other hand, the user parameters (such as: [0, 100]) and the internally used algorithm parameters (such as: C, B), making the dynamic contrast adjustment module of the present invention suitable for various display devices.

In order to achieve the above object, the present invention proposes an embodiment of the dynamic contrast adjustment module, which is integrated into a display device and used to perform a contrast adjustment process on an input display data, and the contrast adjustment process includes the following Steps: Generate a first histogram of the number of pixels relative to the grayscale value based on the input display data, and the first histogram includes K first histograms; Clipping the L first square bars according to a clipping threshold to obtain L clipped parts; where K is a positive integer, and L≦K; Divide the number of pixels contained in the L cropped parts equally into the K first histogram bars to obtain a second histogram including K second histogram bars; Perform a square bar accumulation operation on the K second histogram bars to obtain K accumulation parameters, and calculate K contrast parameters based on the K accumulation parameters and an image length and width parameter; Draw a contrast parameter curve based on the K sampling points and the K contrast parameters; and The contrast parameter curve is used to perform a grayscale value adjustment process on the input display data.

In one embodiment, the dynamic contrast adjustment module of the present invention includes: a histogram generating unit configured to generate the first histogram based on the input display data; A threshold calculation unit for calculating a contrast value of the display device, a contrast intermediate value, a first mapping value obtained from a contrast maximum value mapping, and a second mapping value obtained from the contrast intermediate value mapping. ; A cropping unit, used to crop L first square bars according to the cropping threshold to obtain the L cropped parts, and equally divide the number of pixels contained in the L cropped parts into the K first bar; a cumulative distribution calculation unit, used to perform the histogram accumulation operation on the K second histogram bars to obtain the K accumulation parameters; a parameter calculation unit used to calculate the K contrast parameters; and A processing unit draws the contrast parameter curve based on the K sampling points and the K contrast parameters, and then uses the contrast parameter curve to perform the gray scale value adjustment process on the input display data.

In one embodiment, the threshold calculation unit uses the following mathematical operation formula (1) to calculate the clipping threshold: ……………………(1); Among them, EQ_lim is the clipping threshold, User_coe is the contrast value, 50 is the contrast intermediate value, C is the first mapping value, and B is the second mapping value .

In one embodiment, the cumulative distribution calculation unit calculates and obtains the cumulative parameter using the following mathematical operation formula (2): ………(2); Among them, CDF(i) is the cumulative parameter, i≦K, Hist(1) is the first second histogram, and Hist(i-1) is the i-1th the second histogram, and Hist(i) is the i-th second histogram.

In one embodiment, the parameter calculation unit calculates and obtains the contrast parameter using the following mathematical operation formula (3): …………………………(3); Among them, Dbit is the bit used to represent the data processing accuracy, DRF(i) is the contrast parameter, and W and L are the image length and width parameters .

Furthermore, the present invention also proposes an embodiment of a display device, including at least one display driver chip and a display panel, characterized in that the display driver chip has a dynamic contrast adjustment module, so that the dynamic contrast adjustment module is used to adjust an input The display data undergoes a contrast adjustment process, and the contrast adjustment process includes the following steps: Generate a first histogram of the number of pixels relative to the grayscale value based on the input display data, and the first histogram includes K first histograms; Clipping the L first square bars according to a clipping threshold to obtain L clipped parts; where K is a positive integer, and L≦K; Divide the number of pixels contained in the L cropped parts equally into the K first histogram bars to obtain a second histogram including K second histogram bars; Perform a square bar accumulation operation on the K second histogram bars to obtain K accumulation parameters, and calculate K contrast parameters based on the K accumulation parameters and an image length and width parameter; Draw a contrast parameter curve based on the K sampling points and the K contrast parameters; and The contrast parameter curve is used to perform a grayscale value adjustment process on the input display data.

In one embodiment, the dynamic contrast adjustment module of the present invention includes: a histogram generating unit configured to generate the first histogram based on the input display data; A threshold calculation unit for calculating a contrast value of the display device, a contrast intermediate value, a first mapping value obtained from a contrast maximum value mapping, and a second mapping value obtained from the contrast intermediate value mapping. ; A cropping unit, used to crop L first square bars according to the cropping threshold to obtain the L cropped parts, and equally divide the number of pixels contained in the L cropped parts into the K first bar; a cumulative distribution calculation unit, used to perform the histogram accumulation operation on the K second histogram bars to obtain the K accumulation parameters; a parameter calculation unit used to calculate the K contrast parameters; and A processing unit draws the contrast parameter curve based on the K sampling points and the K contrast parameters, and then uses the contrast parameter curve to perform the gray scale value adjustment process on the input display data.

In one embodiment, the threshold calculation unit uses the following mathematical operation formula (1) to calculate the clipping threshold: ……………(1); Among them, EQ_lim is the clipping threshold, User_coe is the contrast value, 50 is the contrast intermediate value, C is the first mapping value, and B is the second mapping value.

In one embodiment, the cumulative distribution calculation unit calculates and obtains the cumulative parameter using the following mathematical operation formula (2): ...(2); Among them, CDF(i) is the cumulative parameter, i≦K, Hist(1) is the first second histogram, Hist(i-1) is the i-1th all the second histogram bar, and Hist(i) is the i-th second histogram bar.

In one embodiment, the parameter calculation unit calculates and obtains the contrast parameter using the following mathematical operation formula (3): ……………………………(3); Among them, Dbit is the bit used to represent the data processing accuracy, DRF(i) is the contrast parameter, and W and L are the length and width of the image parameters.

Furthermore, the present invention also provides an information processing device, which is characterized in that it includes the display device of the present invention as mentioned above. In one embodiment, the information processing device is selected from a flat display device, a smart TV, a smart phone, a smart watch, a tablet computer, an all-in-one computer, a notebook computer, a car entertainment device, and a video doorway An electronic device in a group of machines.

In order to enable the review committee to further understand the structure, characteristics, purpose, and advantages of the present invention, drawings and detailed descriptions of preferred embodiments are attached below.

FIG. 2 is a block diagram of a display device including a dynamic contrast adjustment module of the present invention. The display device 1 includes: a display panel 11 and at least one display driver chip 12, wherein the display driver chip 12 receives input display data from a host computer 2 (such as an application processor of a smartphone). As shown in FIG. 2 , the dynamic contrast adjustment module 121 of the present invention is integrated in the driving display chip 12 to perform a contrast adjustment process on the input display data to generate an output display data, so that the driving display chip 12 drives the display panel 11 to display an image according to the output display data.

FIG. 3 is a block diagram of the dynamic contrast adjustment module of the present invention shown in FIG. 2 . As shown in Figure 3, the dynamic contrast adjustment module 121 of the present invention includes: a histogram generation unit 1211, a threshold calculation unit 1212, a cropping unit 1213, a cumulative distribution calculation unit 1214, a parameter calculation unit 1215, and a Processing unit 1216. When executing the contrast adjustment process, the dynamic contrast adjustment module 121 of the present invention first starts the histogram generation unit 1211 to generate a first number of pixels relative to the grayscale value based on the input display data. Histogram, and the first histogram contains K first histograms. Figure 4 is a diagram of the first histogram. Next, the dynamic contrast adjustment module 121 starts its threshold calculation unit 1212 to calculate a contrast value based on a contrast value of the display device, a contrast intermediate value, a first mapping value obtained from a contrast maximum value mapping, and a first mapping value obtained from the contrast maximum value mapping. Contrast intermediate value mapping obtains a second mapping value, and then uses the cropping unit 1213 to crop the L first square bars according to the cropping threshold to obtain L cropping parts, and the L cropping parts are The number of pixels contained is evenly divided into the K first histogram bars to obtain a second histogram containing K second histogram bars. Figure 5 is a diagram of the second histogram.

In one embodiment, the threshold calculation unit 1212 calculates and obtains the clipping threshold using the following mathematical operation formula (1): …… (1).

In the above formula (1), EQ_lim is the clipping threshold, User_coe is the contrast value, 50 is the contrast intermediate value, C is the first mapping value, and B is the second mapping value. Specifically, the adjustable range of the contrast value of the display is usually 0 to 100, which can be recorded as [0, 100], and (0-100)/2=50 is the intermediate contrast value. According to the design of the present invention, the dynamic contrast adjustment module 121 performs a dynamic contrast weakening operation within the contrast value range of [0,50], and performs a dynamic contrast enhancement operation within the contrast value range of (50,100]. Among them, 0 is User_coe The minimum value, and 100 is the maximum value of User_coe.

It is worth noting that when making the histogram, 17 sampling points are first selected from the gray scale values 0 to 255. The gray scale values of these sampling points are between 0 and 255. Then, count the number of pixel grayscale values in the image block that are equal to the grayscale values of these 17 sampling points. For example, the 17 grayscale values are G1 to G17 respectively. Among them, in the image block, the number of pixels with a pixel grayscale value equal to G1 is 100,..., pixel grayscale values The number of pixels equal to G17 is 20. After completing the statistics of the number of pixels, a first histogram including K first histograms as shown in Figure 4 can be drawn. Continuing, as shown in Figure 4, the L first square bars are clipped with the clipping threshold EQ_lim to obtain L clipped parts, and then, as shown in Figure 5, the L clipped parts contained The number of pixels is evenly divided into the K first histogram bars to obtain a second histogram including K second histogram bars. Among them, K is a positive integer, and L≦K.

Continuing, the dynamic contrast adjustment module 121 activates its cumulative distribution calculation unit 1214 and parameter calculation unit 1215 to perform a Cumulative Distribution Function (CDF) operation on the K second histograms as shown in Figure 5 to obtain K cumulative parameters are obtained, and then K contrast parameters are calculated based on the K cumulative parameters and an image length and width parameter. Specifically, the cumulative distribution calculation unit 1214 and the parameter calculation unit 1215 respectively use the following mathematical operation formulas (2) and (3) to calculate and obtain the cumulative parameter and the contrast parameter: …············ (2) ………………………………········· (3)

In the above formula (2), CDF(i) is the i-th cumulative parameter, i≦K, Hist(1) is the first second histogram, and Hist(i-1) is the i-th 1 second histogram bar, and Hist(i) is the i-th second histogram bar. In the above formula (3), Dbit is a bit used to represent the data processing accuracy, such as 9 bits. Moreover, DRF(i) is the contrast parameter, and W and L are the image length and width parameters. Specifically, when performing a histogram generation operation on an image corresponding to the input display data, the image is usually divided into a plurality of 512×512 grayscale images. In this case, the data processing accuracy of the algorithm used in the present invention is 9 bits, so =511.

After completing the calculation of the K contrast parameters, the dynamic contrast adjustment module 121 activates its processing unit 1216 to draw the contrast parameter curve based on the K sampling points and the K contrast parameters, and then use the contrast parameter curve The input display data is subjected to the grayscale value adjustment process.

For example, when the contrast value of the display device 1 is 30 (ie, User_coe=30), User_coe=70 can be used to calculate the corresponding cropping threshold EQ_lim, and then use this EQ_lim to adjust the K shown in Figure 4 Cut the first first square bar. It should be understood that since only L first square bars will exceed EQ_lim, only L first square bars can actually be cropped to obtain L cropped parts. Continue to divide the number of pixels contained in the L cropped parts into the K first histograms to obtain a second histogram including K second histograms (as shown in Figure 5), and then Perform a square bar accumulation operation on the K second histogram bars to obtain K accumulation parameters, and calculate K contrast parameters based on the K accumulation parameters and an image length and width parameter.

Finally, the processing unit 1216 draws a contrast parameter curve based on the K sampling points and the K contrast parameters. This contrast parameter curve is called a forward contrast parameter curve here. Figure 6 is a diagram of the forward contrast parameter curve. Next, the (X, Y) values of the 17 data points in Figure 6 are reversed to obtain 17 new data points, and these 17 data points are drawn into another contrast parameter curve. This contrast parameter curve is called here Inverse contrast parameter curve. Figure 7 is a diagram of the forward contrast parameter curve and the reverse contrast parameter curve. As shown in Figure 7, the data symmetry method of (X=Y, Y=X) is used to symmetry the two data points (96, 155) and (128, 192) of the forward contrast parameter curve into the two data points of the reverse contrast parameter curve. Data points (155, 96), (192,128).

Continuing, the 17 data points of the forward contrast parameter curve and the 17 data points of the reverse contrast parameter curve can be expressed in the form of line segment coordinates. Figure 8 is a diagram showing the forward contrast parameter curve and the reverse contrast parameter curve expressed in the form of line segment coordinates. As shown in Figure 8, a 512×512 grayscale image is sampled along the , 256, 288, 320, 352, 384, 416, 448, 480, 511 are the 17 coordinate points of the X-axis. It should be understood that each sampling point has its corresponding DCR. Moreover, after obtaining the inverse contrast parameter curve, the DCR of each sampling point can be further calculated using the interpolation method. Finally, the processing unit 1216 then uses the inverse contrast parameter curve to perform the grayscale value adjustment process on the input display data. Usually, the brightness value corresponding to the DCR of each sampling point can be obtained by using the lookup table method and the interpolation method. This brightness value corresponds to the grayscale value of a pixel, which is the grayscale value of the pixel after contrast adjustment processing. After completing the grayscale value adjustment process, the processing unit 1216 generates an output display data, so that the display driver chip 12 drives the display panel 11 to display an image with both dynamic contrast enhancement and weakening based on the output display data. .

In this way, the above has completely and clearly explained the dynamic contrast adjustment module of the present invention; and from the above, it can be known that the present invention has the following advantages:

(1) The present invention provides a dynamic contrast adjustment module that can realize dynamic contrast adjustment of a display device and has the characteristics of high applicability, adjustable maximum adjustment range, dynamic contrast reduction, and dynamic contrast enhancement. Specifically, the dynamic contrast adjustment module of the present invention performs a dynamic contrast weakening operation within a contrast value range of [0,50], and performs a dynamic contrast enhancement operation within a contrast value range of (50,100], thereby completing the contrast adjustment process. The output display data is generated so that the display driver chip drives the display device to display an image with both dynamic contrast enhancement and weakening based on the output display data. On the other hand, the user parameters (such as: [0, 100]) and the internally used algorithm parameters (such as: C, B), making the dynamic contrast adjustment module of the present invention suitable for various display devices.

(2) Furthermore, the present invention also provides a display device, which includes at least one display driver chip and a display panel. It is characterized in that the display driver chip has the dynamic contrast adjustment module of the present invention as described above, thereby utilizing the dynamic contrast adjustment module. The contrast adjustment module performs a contrast adjustment process on an input display data, so that the display driver chip 12 drives the display panel to display an image with high contrast.

(3) Furthermore, the present invention also provides an information processing device, which is characterized by including the display device of the present invention as described above. In a feasible embodiment, the information processing device is selected from the group consisting of a flat display device, a smart TV, a smart phone, a smart watch, a tablet computer, an all-in-one computer, a notebook computer, an in-vehicle entertainment device, and a video communication device. An electronic device in a group composed of door phones.

It must be emphasized that the foregoing disclosed in this case are preferred embodiments. Any partial changes or modifications derived from the technical ideas of this case and easily inferred by those familiar with the art do not deviate from the patent of this case. category of rights.

To sum up, regardless of the purpose, means and effects of this case, it shows that it is completely different from the conventional technology, and that the invention is practical first, and indeed meets the patent requirements for inventions. I sincerely ask the review committee to take a clear look and grant the patent as soon as possible for your benefit. Society is a prayer for the Supreme Being.

1a:Display device

11a:Display panel

12a: Display driver chip

121a: Contrast adjustment unit

2a: Host computer

1:Display device

11:Display panel

12:Display driver chip

121:Dynamic contrast adjustment module

1211: Histogram generation unit

1212: Threshold calculation unit

1213:Cutting unit

1214: Cumulative distribution calculation unit

1215: Parameter calculation unit

1216:Processing unit

2: Host computer

Figure 1 is a block diagram of a conventional display device; Figure 2 is a block diagram of a display device including a dynamic contrast adjustment module of the present invention; Figure 3 is a block diagram of the dynamic contrast adjustment module of the present invention shown in Figure 2; Figure 4 is a diagram of the first histogram; Figure 5 is a diagram of the second histogram; Figure 6 is a diagram of the forward contrast parameter curve; Figure 7 is a diagram of a forward contrast parameter curve and a reverse contrast parameter curve; and FIG. 8 is a diagram showing the forward contrast parameter curve and the reverse contrast parameter curve expressed in the form of line segment coordinates.

121:Dynamic contrast adjustment module

1211: Histogram generation unit

1212: Threshold calculation unit

1213:Cutting unit

1214: Cumulative distribution calculation unit

1215: Parameter calculation unit

1216:Processing unit

Claims (9)

A dynamic contrast adjustment module is integrated into a display device and includes a histogram generation unit, a threshold calculation unit, a cropping unit, a cumulative distribution calculation unit, a parameter calculation unit and a processing unit, for A contrast adjustment process is performed on an input display data, and the contrast adjustment process includes the following steps: driving the histogram generation unit to generate a first number of pixels (number of pixels) relative to the grayscale value according to the input display data. a histogram, and the first histogram includes K first histograms; driving the threshold calculation unit to map a contrast value obtained from a contrast value of the display device, a contrast intermediate value, and a first contrast maximum value. A mapping value and a second mapping value obtained from the contrast intermediate value mapping determine a clipping threshold; driving the clipping unit to clip L first square bars according to the clipping threshold to obtain L clippings Parts, where K is a positive integer, and L≦K, and the number of pixels contained in the L cropped parts is evenly divided into the K first histograms to obtain a K second histograms. The second histogram; drives the cumulative distribution calculation unit to perform a square bar accumulation operation on the K second histogram bars to obtain K cumulative parameters, and drives the parameter calculation unit to calculate the K second histogram based on the K cumulative parameters and an image length and width. The parameters calculate K contrast parameters; and drive the processing unit to draw a contrast parameter curve based on the K sampling points and the K contrast parameters, and use the contrast parameter curve to perform a grayscale value adjustment process on the input display data. The dynamic contrast adjustment module as described in claim 1, wherein the threshold calculation unit uses the following mathematical operation formula (1) to calculate the cropping threshold:

Among them, EQ_lim is the clipping threshold, User_coe is the contrast value, 50 is the contrast intermediate value, C is the first mapping value, and B is the second mapping value. The dynamic contrast adjustment module as described in claim 2, wherein the cumulative distribution calculation unit uses the following mathematical operation formula (2) to calculate and obtain the cumulative parameter: CDF(i)=Hist(i)+Hist(i-1) +…+Hist(1).... ． ． ． ． ． ． ． ． (2); Among them, CDF(i) is the i-th cumulative parameter, i≦K, Hist(1) is the first second histogram, and Hist(i-1) is the i-1 the second histogram, and Hist(i) is the i-th second histogram. The dynamic contrast adjustment module as described in claim 3, wherein the parameter calculation unit calculates and obtains the contrast parameter using the following mathematical operation formula (3):

Wherein, Dbit is a bit used to represent data processing accuracy, DRF(i) is the contrast parameter, and W and L are the image length and width parameters. A display device, including at least one display driver chip and a display panel, characterized in that the display driver chip has a dynamic contrast adjustment module to perform a contrast adjustment process on an input display data, and the dynamic contrast adjustment module includes a histogram A generation unit, a threshold calculation unit, a cropping unit, a cumulative distribution calculation unit, a parameter calculation unit and a processing unit, and the contrast adjustment process includes the following steps: Driving the histogram generation unit to generate a first histogram of a number of pixels relative to grayscale values based on the input display data, and the first histogram includes K first histogram bars; driving The threshold calculation unit determines a crop according to a contrast value of the display device, a contrast intermediate value, a first mapping value obtained from a contrast maximum value mapping, and a second mapping value obtained from the contrast intermediate value mapping. threshold; driving the cutting unit to cut L first square bars according to a cutting threshold to obtain L cutting parts, where K is a positive integer, and L≦K, and the L cutting parts are The number of pixels contained is evenly divided into the K first histograms to obtain a second histogram including K second histograms; driving the cumulative distribution calculation unit to perform a continuous operation on the K second histograms The square bar accumulation operation obtains K accumulation parameters, and drives the parameter calculation unit to calculate K contrast parameters based on the K accumulation parameters and an image length and width parameter; and drives the processing unit to calculate K contrast parameters based on K sampling points and the K Draw a contrast parameter curve for each contrast parameter, and use the contrast parameter curve to perform a grayscale value adjustment process on the input display data. The display device according to claim 5, wherein the threshold calculation unit calculates and obtains the cropping threshold using the following mathematical operation formula (1):

Among them, EQ_lim is the clipping threshold, User_coe is the contrast value, 50 is the contrast intermediate value, C is the first mapping value, and B is the second mapping value. The display device of claim 6, wherein the cumulative distribution calculation unit calculates and obtains the cumulative parameter using the following mathematical operation formula (2): CDF(i)=Hist(i)+Hist(i-1)+… +Hist(1).... ． ． ． ． ． ． ． ． (2); Among them, CDF(i) is the i-th cumulative parameter, i≦K, Hist(1) is the first second histogram, and Hist(i-1) is the i-1 the second histogram, and Hist(i) is the i-th second histogram. The display device according to claim 7, wherein the parameter calculation unit calculates and obtains the contrast parameter using the following mathematical operation formula (3):

Wherein, Dbit is a bit used to represent data processing accuracy, DRF(i) is the contrast parameter, and W and L are the image length and width parameters. An information processing device, characterized by including the display device described in any one of claims 5 to 8.

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