JP2021148874A - Control apparatus, display device, control program, and control method - Google Patents

Abstract

To reduce power consumed and heat generated by a display device while increasing luminance and contrast of the display device.SOLUTION: A control apparatus (10) includes: a grayscale value calculation unit (12) which calculates a maximum grayscale value and a centroidal grayscale value; a degree-of-emphasis calculation unit (13) which calculates a degree of emphasis (E) by use of the maximum grayscale value and the centroidal grayscale value; a correction unit (14) which generates IMG2 by use of a special tone curve; and a BL control unit (15) which sets luminance values of a plurality of light sources constituting BL (83) in accordance with the degree of emphasis (E).SELECTED DRAWING: Figure 1

Description

The present invention relates to a control device, a display device, a control program, and a control method of the control device.

HDR (High Dynamic Range) technology is one of the functions for improving the image quality of the display device. The HDR signal can have luminance information of about 10000 nit (cd / m ^2). Therefore, by using the HDR technology, it is possible to increase the brightness and contrast of the display device, and it is possible to increase the power of the image. However, if an attempt is made to display the display device according to the brightness indicated by the HDR signal, the display device may consume more power and generate heat depending on the size and type of the display device.

As a technique for adjusting the brightness of a display device to reduce power consumption and heat generation of the display device, for example, Patent Document 1 discloses an image display device provided with a brightness correction unit. The brightness correction unit of the image display device of Patent Document 1 determines the gradation of image data so as to reduce the change in brightness that occurs in the light modulated by the spatial light modulator by controlling the amount of light according to the dimming rate. Control the value.

Japanese Unexamined Patent Publication No. 2006-30863 (published on November 9, 2006)

The brightness correction unit of the image display device of Patent Document 1 calculates the correction amount of the brightness correction based on the difference between the average value of the brightness values of the image data and the brightness value after the level correction. This brightness correction method is for securing the overall display image of the image displayed on the display device, and realizes high brightness in a narrow image area peculiar to HDR technology to realize the image area. It is not possible to emphasize glossiness and glare.

One aspect of the present invention has been made in view of the above problems, and an object of the present invention is to realize a display device or the like that achieves both high brightness and high contrast and reduction of power consumption and heat generation. be.

In order to solve the above problems, the control device according to one aspect of the present invention is a control device that controls a display device having a display panel and is capable of correcting an input image and generating an output image. By analyzing the input image, a histogram showing the distribution of the input gradation value which is the gradation value of a plurality of input pixels constituting the input image is acquired, and is the maximum value of the input gradation value. The input image using the first calculation unit for calculating the maximum gradation value and the center of gravity gradation value which is the input gradation value of the center of gravity of the histogram, and the maximum gradation value and the center of gravity gradation value. Second calculation for calculating the degree of emphasis indicating the degree of emphasis when correcting the input image so that the input-side high-gradation region in which the input gradation value is larger than the other regions is emphasized in the output image. With respect to the gradation change characteristic indicating the correspondence between (i) the input gradation value and the output gradation value which is the gradation value of a plurality of output pixels constituting the output image, the emphasis level The output image is generated by generating a special gradation change characteristic which is the corresponding gradation change characteristic and correcting the input gradation value of the plurality of input pixels by using the special gradation change characteristic. In addition, (ii) includes a processing unit that sets brightness values of a plurality of display elements arranged on the display panel according to the emphasis.

In order to solve the above-mentioned problems, the control method according to one aspect of the present invention is a control method of a control device capable of correcting an input image and generating an output image, which controls a display device having a display panel. By analyzing the input image, a histogram showing the distribution of the input gradation values, which is the gradation values of the plurality of input pixels constituting the input image, is acquired, and the maximum of the input gradation values is obtained. The first calculation step for calculating the maximum gradation value which is a value and the center of gravity gradation value which is the input gradation value of the center of gravity of the histogram, the maximum gradation value calculated in the first calculation step, and the above. Emphasis when correcting the input image by using the center of gravity gradation value so that the input side high gradation region in the input image in which the input gradation value is larger than the other regions is emphasized in the output image. Correspondence between the second calculation step of calculating the emphasis degree indicating the degree of the above, and (i) the input gradation value and the output gradation value which is the gradation value of a plurality of output pixels constituting the output image. With respect to the gradation change characteristic indicating, a special gradation change characteristic which is the gradation change characteristic according to the emphasis calculated in the second calculation step is generated, and the plurality of the special gradation change characteristics are used. The output image is generated by correcting the input gradation value of the input pixel of the above, and (ii) a plurality of images arranged on the display panel according to the emphasis calculated in the second calculation step. It includes a processing step of setting the brightness value of the display element of.

According to one aspect of the present invention, it is possible to realize a control device or the like that reduces power consumption and heat generation of the display device while enabling high brightness and high contrast of the display device.

It is a block diagram which shows the main part structure of the display device which concerns on Embodiment 1-5 of this invention. It is a flowchart which shows the flow of the display process of the display device which concerns on Embodiment 1 of this invention. It is a flowchart which shows the calculation method of the center of gravity gradation value by the gradation value calculation part of the control apparatus which concerns on Embodiment 1 of this invention. It is a graph which shows the relationship between the emphasis degree, the maximum gradation value, and the centroid gradation value. The figure shown by reference numeral 501 is an example of an input image having a relatively high emphasis. The figure indicated by reference numeral 502 is a histogram of the input image indicated by reference numeral 501. The figure shown by reference numeral 601 is an example of an input image having a relatively low emphasis. The figure shown by reference numeral 602 is a histogram of the input image shown by reference numeral 601. The figure shown by reference numeral 701 is a graph showing an example of a first special tone curve applied to an input image having a relatively high emphasis. The figure shown by reference numeral 702 is a graph showing an example of a second special tone curve applied to an input image having a relatively low emphasis. The figure shown by reference numeral 703 is an example of an output image when an input image having a relatively low emphasis is corrected by using the second special tone curve. The figure shown by reference numeral 801 is an example of an output image displayed on the display panel according to the second embodiment of the present invention. The figure shown by reference numeral 802 is a histogram showing the distribution of the output luminance value when the output image indicated by reference numeral 801 is displayed on the display panel. The figure shown by reference numeral 803 is a graph showing the relationship between the input luminance value and the output luminance value before the BL control unit according to the second embodiment of the present invention controls BL. The figure indicated by reference numeral 804 is an output image indicated by reference numeral 801 displayed on the display panel after control of BL by the BL control unit. The figure shown by reference numeral 805 is a histogram showing the distribution of the output luminance value when the output image indicated by reference numeral 804 is displayed on the display panel. The figure shown by reference numeral 806 is a graph showing the relationship between the input luminance value and the output luminance value after the BL control unit controls BL. Reference numeral 901 is an example of a graph showing the relationship between the input gradation value and the output gradation value after the BL control unit controls BL. Reference numeral 902 is another example of a graph showing the relationship between the input gradation value and the output gradation value after the BL control unit controls BL. The figure indicated by reference numeral 111 is an example of an output image displayed on the display panel according to the third embodiment of the present invention. The figure indicated by reference numeral 112 is a histogram showing the distribution of the output luminance value when the output image indicated by reference numeral 111 is displayed on the display panel. The figure indicated by reference numeral 113 is a graph showing the relationship between the output luminance value and the output luminance value correction magnification. The figure indicated by reference numeral 114 is an output image indicated by reference numeral 111, which is displayed on the display panel after BL is controlled by the BL control unit according to the third embodiment of the present invention. The figure indicated by reference numeral 115 is a histogram showing the distribution of the output luminance value when the output image indicated by reference numeral 114 is displayed on the display panel. The figure shown by reference numeral 121 is an example of an input image before being processed by the control device according to the fourth embodiment of the present invention. The figure indicated by reference numeral 122 is a histogram of the input image indicated by reference numeral 121. The figure indicated by reference numeral 123 is a graph showing an example of a third special tone curve applied to the input image indicated by reference numeral 121. The figure indicated by reference numeral 124 is an example of an output image after the input image indicated by reference numeral 121 is corrected by the correction unit according to the fourth embodiment of the present invention. The figure indicated by reference numeral 131 is another example of the input image before being processed by the control device according to the fourth embodiment of the present invention. The figure indicated by reference numeral 132 is a histogram of the input image indicated by reference numeral 131. The figure indicated by reference numeral 133 is a graph showing an example of a fourth special tone curve applied to the input image indicated by reference numeral 131. The figure indicated by reference numeral 134 is an example of an output image after the input image indicated by reference numeral 131 is corrected by the correction unit according to the fourth embodiment of the present invention. The figure shown by reference numeral 141 is an example of an input image before being processed by the control device according to the fifth embodiment of the present invention. The figure shown by reference numeral 142 is another example of the input image before being processed by the control device.

[Embodiment 1]
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 7. For convenience of explanation, the members having the same functions as the members described in the first embodiment are designated by the same reference numerals in the following embodiments, and the description thereof will not be repeated.

<Overview of display device 1>
The outline of the display device 1 according to the first embodiment will be described with reference to FIG. The display device 1 may be a portable display device such as a smartphone, or may be a stationary display device (eg, a television or a desktop PC (Personal Computer)). In the first embodiment, it is assumed that the display device 1 is a smartphone. This also applies to the following embodiments 2 to 5.

As shown in FIG. 1, the display device 1 includes a control device 10, an RGB / illuminance sensor 18, a display panel 80, a BL (Back Light) 83, a BL power supply 84, and a storage unit 90. The details of the storage unit 90 will be described later. The display panel 80 is a TP (Touch Panel: touch panel) in each of the first and subsequent embodiments, and the input unit 81 and the display unit 82 are integrally provided. As an example, the input unit 81 is a known touch sensor. The display unit 82 is, for example, a liquid crystal panel. However, the input unit 81 and the display unit 82 may be provided as separate bodies.

The control device 10 comprehensively controls each part of the display device 1. In each of the following embodiments, the control device 10 also has a role as a display control device for controlling the display unit 82. FIG. 1 illustrates a configuration in which the control device 10 and the display unit 82 are each one (singular). However, at least one of the control device 10 and the display unit 82 may be a plurality (two or more).

The display unit 82 is predetermined with a vertical direction (vertical direction toward the paper surface) and a horizontal direction (horizontal direction toward the paper surface). A plurality of display elements (not shown) are arranged on the display unit 82 along each of the vertical direction and the horizontal direction. That is, a plurality of display elements are arranged in a matrix on the display unit 82. The plurality of display elements may be, for example, organic EL (electroluminescence) display elements. In this case, the display device 1 is not provided with the following BL83, and a plurality of display elements emit light.

The BL83 irradiates the display panel 80 (more specifically, the display unit 82) with light (eg, white light). BL83 has a plurality of light sources (not shown). The light source of BL83 is, for example, an LED (Light Emitting Diode). The BL83 is arranged on the back side of the display panel 80 (the side opposite to the display surface of the display panel 80) so as to overlap the display panel 80. It should be noted that in FIG. 1, for convenience of explanation, the overlap between the display panel 80 and the BL83 is not accurately illustrated.

The BL power supply 84 drives a plurality of light sources constituting the BL 83. As an example, by controlling the current supplied from the BL power supply 84 to the light source, the light emission intensity (example: brightness) of the light emitting surface (the surface facing the back surface of the display panel 80) of the BL 83 can be controlled. This control is performed by the BL control unit 15, which will be described later. An image can be formed by a plurality of display elements on the display surface (display area) of the display panel 80 by the light emitted from the BL83 to the display panel 80. That is, a desired image can be displayed in the display area. The RGB / illuminance sensor 18 detects the illuminance around the display device 1 and the image signals of the red component (R), the green component (G), and the blue component (B) when the IMG1 described later is in the RGB format. Then, it is output to the emphasis calculation unit 13 described later.

<Overview of control device 10>
As shown in FIG. 1, the control device 10 includes an image analysis unit 11 (a part of the "first calculation unit"), a gradation value calculation unit 12 (a part of the "first calculation unit"), and an emphasis degree calculation unit. It includes 13 (second calculation unit), correction unit 14 (processing unit), BL control unit 15 (processing unit), and application execution unit 17. In the present specification, the "application" means an application (application software) that can be executed on the display device 1. The operation of each part of the control device 10 will be described later.

The control device 10 acquires the IMG 1 (input image) from the outside. Embodiment 1 In each of the following embodiments, as IMG1, image data of images of various applications installed in the display device 1 will be described as an example. As images of various applications, in addition to images of game applications, images of SNS (Social Networking Service), cameras, televisions, and the like can be exemplified. Further, the IMG 1 may be image data of a moving image or image data of a still image. Further, as the IMG 1, the control device 10 may acquire image data of various images stored in a VRAM (Video Random Access Memory) (not shown) in the display device 1, for example.

The control device 10 generates an IMG 2 (output image) by correcting the gradation value of each pixel of the IMG 1 (hereinafter, each input pixel) using a LUT (Look Up Table). The LUT is data that stores the gradation value of each pixel of IMG1 and the gradation value of each pixel of IMG2 (hereinafter, each output pixel) to be output corresponding to the gradation value of each pixel of the IMG1. It's a table. In each of the following embodiments, the gradation value of each pixel of the IMG1 is corrected by using a 1D (one-dimensional) LUT. However, a 3D (three-dimensional) LUT may be used instead of the 1D LUT. Further, the graph when the LUT is graphed becomes a tone curve. The control device 10 outputs the generated IMG 2 to the display unit 82, so that the IMG 2 is displayed on the display unit 82.

Hereinafter, "correcting the gradation value of each input pixel of the IMG1 using the LUT" is simply "correcting the gradation value of the IMG1 using the tone curve" (or "using the tone curve," It is also called "correcting IMG1"). Further, the gradation value of each input / output pixel of IMG 1 and 2 is also simply referred to as "gradation value of IMG 1 and 2".

Here, the tone curve used for the correction of the IMG1 is newly conceived based on the inventor's idea of "correcting the IMG1 by using a tone curve different from the conventional tone curve". Hereinafter, the tone curve (newly conceived by the inventor) according to one aspect of the present invention will be referred to as a “special tone curve”. The details of the special tone curve will be described later.

<Input gradation value x and output gradation value y>
In the present specification, the gradation value of one input pixel of IMG1 is referred to as "input gradation value x". Further, the gradation value of one output pixel of IMG2 corresponding to the one input pixel is referred to as "output gradation value y". As a result, the tone curve may be referred to as a function (y = f (x)) indicating the correspondence between the input gradation value x and the output gradation value y, in other words, the “gradation change characteristic”. Further, the special tone curve may be referred to as a "special gradation change characteristic".

In this specification, the case where the input gradation value x and the output gradation value y are standardized gradation values is illustrated. That is, in both IMG1 and IMG2, it is assumed that 0 is the minimum value of the gradation value and 1 is the maximum value of the gradation value. That is, it is assumed that the input gradation value x and the output gradation value y satisfy 0 ≦ x ≦ 1 and 0 ≦ y ≦ 1. The gradation value is an index indicating the brightness (brightness) of a pixel. Specifically, the larger the gradation value (the closer the gradation value is to 1), the higher the brightness of the pixel. Further, the smaller the gradation value (the closer the gradation value is to 0), the lower the brightness of the pixel.

It should be noted that the tone curves in the present specification all pass through the two points (x, y) = (0, 0) and (1, 1). Further, each tone curve in the present specification is a continuous function for all input gradation values x.

Further, the gradation value before standardization is expressed as a digital value having an arbitrary number of bits (N bits) (N is an integer). As an example, N = 8. Therefore, the input gradation value x and the output gradation value y are discrete numbers whose values increase for each predetermined value (example: 1 / 2N).

In the present specification, when y = f (x), the rate of change of the output gradation value y with respect to the input gradation value x is referred to as "gradation change rate" (hereinafter, V). Mathematically, it can be expressed as V = dy / dx = d {f (x)} / dx. As an example, consider the case where x changes as x → x + Δx and then changes from y → y + Δy. Δx is a minute amount. As an example, Δx = 1 / 2N. In the display device 1, the gradation change rate may be calculated with V = Δy / Δx.

In the present specification, the x-axis of the graph of y = f (x) is referred to as "gradation region in input image" (hereinafter, "input side gradation region"). The input-side gradation area is an area indicating the input gradation value x of each pixel in the input image. In the present specification, the input-side gradation region will be described by dividing it into three regions, that is, an input-side low-gradation region, an input-side medium-gradation region, and an input-side high-gradation region.

The input-side low-gradation region means a region in which the input gradation value x is small in the input-side gradation region. Further, the input-side high-gradation region means a region in which the input gradation value x is large in the input-side gradation region. Therefore, the input-side medium gradation region can be defined as an region excluding the input-side low-gradation region and the input-side high-gradation region from the entire range of the input-side gradation region.

As an example, consider arbitrary numbers a and b that satisfy 0 <a <b <1. in this case,
Area of 0 ≦ x <a: Low gradation area on the input side;
Region of a ≦ x ≦ b: Middle gradation region on the input side;
Region of b <x ≦ 1: Input side high gradation region;
Each area can be defined as. The values of a and b may be appropriately set by the designer of the display device 1. As an example, a may be set to a value of about 0.2 or less, and b may be set to a value of about 0.9 or more. However, please note that these numbers are just examples.

In the present specification, the y-axis of the graph of y = f (x) is referred to as a “gradation region in the output image” (hereinafter, “output-side gradation region”). The output-side gradation area is an area indicating the output gradation value y of each pixel in the output image. In the present specification, the output side gradation region will be described by dividing it into three regions, an output side low gradation region, an output side middle gradation region, and an output side high gradation region. The definitions and definitions of the output side low gradation region, the output side middle gradation region, and the output side high gradation region correspond to the input side low gradation region, the input side middle gradation region, and the input side high gradation region. ing.

<Flow of display processing of control device 10>
The flow of the display process of the control device 10 according to the first embodiment will be described with reference to FIGS. 2 to 7. First, the user operates the display panel 80 (more specifically, the input unit 81) in order to execute an arbitrary application pre-installed on the display device 1. The application execution unit 17 activates an application corresponding to the operation. Then, the application execution unit 17 executes the started application (hereinafter referred to as the started application), and outputs the image data of the started application to a decoder (not shown) provided in the control device 10. The decoder converts the image data format of the startup application into the YUV format and outputs it to the image analysis unit 11. As shown in FIG. 2, the image analysis unit 11 acquires the image data converted into the YUV format as IMG1 (S101).

Next, the image analysis unit 11 converts the acquired IMG1 from the YUV format to the HSV format (S102). Since the brightness (hereinafter, V) of the image data in the HSV format is the same as the maximum value of the RGB value, the image analysis unit 11 converts the acquired IMG1 into the RGB format to acquire the maximum value of the RGB value. It may be input in RGB format.

Next, the image analysis unit 11 acquires V data from each input pixel of the IMG1 converted into the HSV format. Then, the image analysis unit 11 standardizes the V data of each input pixel divided into 1024 stages and sets it as the input gradation value x of each input pixel. The input gradation value x of each input pixel is stored in a memory (not shown) built in the image analysis unit 11. The input gradation value x of each input pixel may be stored in the storage unit 90. Then, the image analysis unit 11 acquires a histogram showing the distribution of the input gradation value x of each input pixel (see the figure shown by reference numeral 502 in FIG. 5 and the figure shown by reference numeral 602 in FIG. 6), and obtains the histogram. It is output to the gradation value calculation unit 12 (S103: first calculation step).

Next, the gradation value calculation unit 12 uses the histogram acquired from the image analysis unit 11 to obtain the maximum gradation value xmax, which is the maximum value of the input gradation value x, and the input gradation value x of the center of gravity of the histogram. The centroid gradation value xv is calculated (S104: first calculation step). In the "input gradation value x of the center of gravity of the histogram", when the frequencies are sequentially integrated for each step from the frequencies of the input gradation value x = 0, the integrated values of the frequencies are all the input gradation values x. It is an input gradation value x corresponding to the frequency added when it becomes more than half of the total integrated value obtained by integrating the frequencies of.

As a method of calculating the center of gravity gradation value xv by the gradation value calculation unit 12, a method as shown in the flowchart of FIG. 3 can be exemplified. Specifically, first, the gradation value calculation unit 12 initially sets the value of the first degree integrated value variable sum and the value of the counter i (sum = 0, i = 0) (S201). Next, the gradation value calculation unit 12 adds the frequency of the step i + 1 corresponding to the value of the counter i + 1 to the integrated value of the frequencies up to the step i corresponding to the value of the counter i, and the first frequency integrated value variable. Update sum (S202). The data of the first frequency integrated value variable sum after the update, that is, the integrated value of the updated frequency is stored in the memory of the image analysis unit 11. The integrated value of the updated frequency may be stored in the storage unit 90.

Next, the gradation value calculation unit 12 determines whether or not the value of the counter i is 1024, that is, whether or not all the frequencies up to 1024 steps are added (S203). If the value of the counter i is not 1024 (YES in S203), the gradation value calculation unit 12 executes the process of S202 again.

On the other hand, when the value of the counter i reaches 1024 (NO in S203), the gradation value calculation unit 12 stores the integrated value of the frequencies updated up to that point in the memory as the total integrated value of the frequencies. The total integrated value of the frequency may be stored in the storage unit 90. Further, the gradation value calculation unit 12 initially sets (val = 0, i = 0) the value of the second frequency integrated value variable val and the value of the counter i (S204).

Next, the gradation value calculation unit 12 adds the frequency of step i + 1 corresponding to the value of the counter i + 1 to the integrated value of the frequencies up to the stage i corresponding to the value of the counter i, and sets the second frequency integrated value variable val. Update (S205). The data of the second frequency integrated value variable variable after the update, that is, the integrated value of the updated frequency is stored in the memory. The integrated value of the updated frequency may be stored in the storage unit 90.

Next, the gradation value calculation unit 12 calls the total integrated value of the frequency from the memory, and the data of the updated second integrated value variable variable of the frequency becomes more than half of the total integrated value of the frequency. (Hereinafter, it is determined whether or not it is a reference state) (S206). If the reference state is not reached (NO in S206), the gradation value calculation unit 12 executes the process of S205 again.

On the other hand, when the reference state is reached (YES in S206), the gradation value calculation unit 12 sets the input gradation value x corresponding to the frequency added when the reference state is reached as the center of gravity gradation value xv (YES). S207). When the processing of S207 is completed, the calculation of the center of gravity gradation value xv by the gradation value calculation unit 12 is completed. Then, the gradation value calculation unit 12 outputs the calculated maximum gradation value xmax and the center of gravity gradation value xv to the emphasis calculation unit 13.

Next, as shown in FIG. 2, the emphasis calculation unit 13 includes the maximum gradation value xmax and the center of gravity gradation value xv acquired from the image analysis unit 11, and the periphery of the display device 1 acquired from the RGB / illuminance sensor 18. Emphasis E is calculated using the illuminance of (S105: second calculation step). The emphasis level E indicates the degree of emphasis of the input side high gradation region when the IMG 1 is corrected so that the input side high gradation region of the IMG 1 is emphasized in the IMG 2.

The emphasis level E can be calculated by, for example, the following equation (1).

Emphasis E = h + α × (xmax ^ d- (xv ^ d / xmax ^ d)) ... Equation (1)
h: Emphasis correction value α: Emphasis correction magnification xmax: Maximum gradation value xv: Center of gravity gradation value d: Display panel correction value When, for example, 0.4 is set as the emphasis correction value h, the display device 1 is HLG. If (Hybrid Log Gamma) is set, the emphasis correction value h is the minimum value of the emphasis E. Needless to say, an arbitrary value other than 0.4 may be set as the emphasis correction value h. The emphasis correction magnification α adjusts the ease with which the emphasis E is increased, and can be arbitrarily set by the designer of the display device 1. Unless there are special circumstances, the emphasis correction magnification α is set to 1.0. The display panel correction value d is set to 1 / γ (γ: γ value of the display panel).

When the value calculated by the above equation (1) is larger than 1, the emphasis calculation unit 13 uniformly sets the emphasis E to 1. When the maximum gradation value xmax and the center of gravity gradation value xv are the same, the emphasis calculation unit 13 sets the emphasis E to 0.5. As for the calculated emphasis level E, the emphasis level calculation unit 13 outputs the calculated emphasis level E to the correction unit 14 and the BL control unit 15.

The emphasis E calculated by the above equation (1) becomes higher as the maximum gradation value xmax becomes larger or the center of gravity gradation value xv becomes smaller. Further, the emphasis degree E becomes lower as the maximum gradation value xmax becomes smaller or the center of gravity gradation value xv becomes larger. When the height of the emphasis degree E is represented by the size of a circle, the relationship between the emphasis degree E, the maximum gradation value xmax, and the centroid gradation value xv can be represented by the graph shown in FIG.

Next, the correction unit 14 uses the emphasis degree E obtained from the emphasis degree calculation unit 13 to generate a special tone curve corresponding to the emphasis degree E (S105: processing step). Hereinafter, the generation of the special tone curve by the correction unit 14 will be described with reference to an example.

First, when the IMG1 is, for example, the IMG1A shown by the reference numeral 501 in FIG. 5, the image analysis unit 11 acquires the HIST1 shown by the reference numeral 502 in FIG. 5 as a histogram. Although the brightness of the entire image of the IMG1A is relatively dark, a relatively bright region (a region near the center on the left side of the paper in the figure) is locally present. Therefore, in HIST1, the frequency of the input gradation value x of each input pixel included in the input side high gradation region of IMG1A is generally small, and the frequency of each input pixel included in the input side low gradation region of IMG1A is small. The frequency of the input gradation value x is generally large. In other words, HIST1 has a relatively small center of gravity gradation value xv.

When the emphasis calculation unit 13 calculates the emphasis E for the IMG1A having the above-mentioned characteristics, the emphasis E is relatively high because the center of gravity gradation value xv is relatively small. Therefore, the correction unit 14 acquires a relatively high emphasis degree E from the emphasis degree calculation unit 13.

The correction unit 14 that has acquired the relatively high emphasis E calls the first reference tone curve CV (first reference LUT) stored in the storage unit 90 in advance. Then, the correction unit 14 corrects the first reference tone curve CV to generate the first special tone curve CV1 (first special gradation change characteristic) as shown by reference numeral 701 in FIG. 7.

The first special tone curve CV1 is a form of the special tone curve. The first special tone curve CV1 has an output gradation value y of each output pixel included in the output side high gradation region of the IMG2 as compared with an input gradation value x of each input pixel included in the input side high gradation region of the IMG1. Is larger uniformly. Here, "the output gradation value y of each output pixel is uniformly larger" means that, specifically, the output gradation value y of each output pixel included in the output side high gradation region of the IMG2 is It means that the output gradation value y of the corresponding first reference tone curve CV is uniformly larger than the output gradation value y.

Further, the first special tone curve CV1 is included in a region other than the output side high gradation region in the IMG2, as compared with the input gradation value x of each input pixel included in the region other than the input side high gradation region of the IMG1. The output gradation value y of the output pixel is smaller. Here, "the output gradation value y of each output pixel is smaller" specifically means that the output gradation value y of each output pixel included in a region other than the output side high gradation region in IMG2. However, it means that it is smaller than the output gradation value y of the corresponding first reference tone curve CV. Since the first special tone curve CV1 has the above-mentioned characteristics, if the first special tone curve CV1 is applied, the integrated gradation value of all the input gradation values x and all the output gradation values are applied. The integrated gradation value of y becomes the same.

Further, when the IMG1 is, for example, the IMG1B shown by the reference numeral 601 in FIG. 6, the image analysis unit 11 acquires the HIST2 shown by the reference numeral 602 in FIG. 6 as a histogram. In IMG1B, since the entire image is relatively bright, the contrast of the entire image is relatively low. Therefore, HIST2 inputs the frequency of the input gradation value x of each input pixel included in the input side high gradation area of IMG1B, the frequency of the input gradation value x of each input pixel included in the input side middle gradation area, and the input. The frequency of the input gradation value x of each input pixel included in the side low gradation region is substantially the same. In other words, HIST2 has a relatively large center of gravity gradation value xv.

When the emphasis calculation unit 13 calculates the emphasis E for the IMG1B having the above-mentioned characteristics, the emphasis E is relatively low because the center of gravity gradation value xv is relatively large. Therefore, the correction unit 14 acquires a relatively low emphasis degree E from the emphasis degree calculation unit 13.

The correction unit 14 that has acquired the relatively low emphasis E calls the first reference tone curve CV from the storage unit 90 and corrects the first reference tone curve CV, thereby correcting the first reference tone curve CV in the figure shown by reference numeral 702 in FIG. The second special tone curve CV2 as described above is generated. The second special tone curve CV2 (second special gradation change characteristic) is also a form of the special tone curve.

The second special tone curve CV2 has an output gradation value y of each output pixel included in the output side high gradation region of IMG2 as compared with an input gradation value x of each input pixel included in the input side high gradation region of IMG1. Is larger. Here, "the output gradation value y of each output pixel is larger" specifically means that the output gradation value y of each output pixel included in the output side high gradation region of the IMG2. However, it means that it is larger than the output gradation value y of the corresponding first reference tone curve CV.

Further, the degree to which the output gradation value y of each output pixel included in the output side high gradation region of the IMG2 becomes larger than the output gradation value y of the corresponding first reference tone curve CV is such that the output side high gradation of the IMG2 is large. The larger the output gradation value y of each output pixel included in the region, the larger the output gradation value y. The second special tone curve CV2 of the first embodiment is the output floor of the corresponding first reference tone curve CV continuously from the output gradation value y of each output pixel included in the output side low gradation region of the IMG2. It is larger than the metering y.

Next, the BL control unit 15 sets each luminance value (hereinafter, BL luminance value L) of the plurality of light sources constituting the BL 83 according to the luminance degree E acquired from the emphasis degree calculation unit 13 (S105: processing step). ). The BL luminance value L corresponds to each luminance value of the plurality of display elements arranged on the display surface of the display panel 80. Specifically, when the emphasis degree E is relatively high, the BL control unit 15 sets the maximum value of the brightness value of the IMG 1 corresponding to the maximum gradation value xmax as the BL brightness value L. When the emphasis degree E is relatively low, the BL control unit 15 calculates the attenuation factor according to the difference between the maximum gradation value xmax and the center of gravity gradation value xv, and the brightness of the IMG 1 corresponding to the maximum gradation value xmax. The value obtained by multiplying the maximum value by the attenuation factor is defined as the BL luminance value L.

The actual setting of the BL luminance value L is as described below. When the emphasis level E is relatively high, the value obtained by multiplying the maximum value of the BL brightness value L that can be set by BL83 by the BL level becomes the maximum value of the brightness value of IMG1 corresponding to the maximum gradation value xmax. The BL control unit 15 calculates the level.

When the emphasis level E is relatively low, the value obtained by multiplying the maximum value of the BL brightness value L that can be set by BL83 by the attenuation factor and the BL level becomes the maximum value of the brightness value of IMG1 corresponding to the maximum gradation value xmax. The BL control unit 15 calculates such a BL level. In any of the above cases, the BL control unit 15 sets the calculated BL level as the BL luminance value L by multiplying the maximum value of the BL luminance value L that can be set by the BL 83.

When the BL luminance value L is set as described above, the new BL luminance value L after the setting becomes larger than the BL luminance value L before the setting as a whole if the emphasis degree E is relatively high, and is emphasized. If the degree E is relatively low, it becomes smaller than the BL luminance value L before setting as a whole.

Next, the correction unit 14 corrects IMG1 using the generated special tone curve (first special tone curve or second special tone curve), and generates IMG2 (S106: processing step). For example, when the IMG1B is corrected by using the second special tone curve, the IMG2B as shown by the reference numeral 703 of FIG. 7 is generated. The IMG2B maintains the brightness in the high-luminance region of the IMG1B (see the figure indicated by reference numeral 601 in FIG. 6), and the contrast of the entire image is higher than that of the IMG1B.

Next, the correction unit 14 converts the generated IMG2 from the YUV format to the RGB format (S107). Next, the correction unit 14 and the BL control unit 15 synchronize the RGB format IMG2 and the BL luminance value L and output them to the display panel 80 (S108). Here, the larger the amount of change in the new BL luminance value L after setting from the BL luminance value L before setting, the more there is a risk of giving the user a sense of discomfort such as flickering when the BL83 emits light. Therefore, when the amount of change is large, the BL control unit 15 outputs a new BL brightness value L after setting so that each light source of BL83 quickly changes to a new BL brightness value L after setting and emits light. It is preferable to do so. On the other hand, when the amount of change is small, the BL control unit 15 causes each light source of BL83 to gradually change to a new BL brightness value L after setting and emit light in order to make the change of BL brightness value L inconspicuous. It is preferable to output a new BL luminance value L after setting.

The correction unit 14 may process the generated IMG2 in the YUV format. Specifically, the correction unit 14 acquires a histogram (not shown) showing the distribution of the luminance signal (Y) in the IMG2 (S107), and outputs the YUV format IMG2 to the display panel 80 based on the histogram (S108). You may let me. In this case, for IMG2, it is necessary to synchronize the amount of change in the luminance signal with the amount of change in the difference signal (U) of the blue component and the amount of change in the difference signal (V) of the red component.

The control device 10 repeats the process of S108 until the image display is completed (NO in S109), and when the image display is completed (YES in S109), all the display processes by the control device 10 are completed.

[Embodiment 2]
The display device 2 according to the second embodiment will be described with reference to FIGS. 1, 8 and 9. The display device 2 relates to the display device according to the first embodiment in that the BL control unit 15 of the control device 20 sets the maximum extension luminance value Lmax-1 according to the emphasis degree E when a predetermined condition is satisfied. Different from 1. As shown in FIG. 1, the main components of the display device 2 and the control device 20 are the same as those of the display device 1 and the control device 10. Further, the functions of each device and each part of the display device 2 and the functions of each part other than the BL control unit 15 in the control device 20 are the same as those of the display device 1 and the control device 10.

<Display processing peculiar to the control device 20>
Hereinafter, the display processing peculiar to the control device 20 will be described by taking as an example the case where the IMG2C represented by reference numeral 801 of FIG. 8 is displayed as the IMG2 on the display panel 80 of the display device 2. In the IMG2C displayed on the display panel 80, the contrast between the output side high gradation area (the image area of the fluorescent lamp in the IMG2C) and other areas is relatively low, and the output side high gradation area is blurred. ..

Each luminance value of the plurality of display elements in the display panel 80 in such a display state has a distribution like the histogram (hereinafter, HIST3) shown by reference numeral 802 in FIG. Hereinafter, the luminance value of one display element when the IMG 2 is displayed on the display panel 80 is referred to as an “output luminance value”.

In HIST3, the maximum value of the output luminance value is smaller than the second maximum set value L-4. In other words, the "maximum value of the output luminance value" is the maximum value at each luminance value of the plurality of display elements when the IMG 2 is displayed on the display panel 80. Hereinafter, the maximum value of the output luminance value is referred to as "maximum luminance value L-3". The second maximum set value L-4 is the maximum value of the output luminance value that can be set on the display panel 80.

The relationship between the input luminance value and the output luminance value of the IMG 2C when the maximum luminance value L-3 is smaller than the second maximum set value L-4 is shown in the graph shown by reference numeral 803 in FIG. Will be. The input luminance value is the luminance value of each output pixel in the IMG 2 after being acquired by the display panel 80 and before being displayed on the display panel 80.

For the IMG2C, all the output pixels having an input luminance value larger than the input luminance value corresponding to the maximum luminance value L-3 are actually displayed on the display panel 80 with the brightness of the maximum luminance value L-3. Will be done. This is one of the reasons why the high gradation region on the output side of the IMG2C is displayed blurry.

As in the example of IMG2C, when blurring occurs in the high gradation region on the output side of IMG2, the BL control unit 15 of the control device 20 sets the maximum stretched luminance value according to the emphasis E when a predetermined condition is satisfied. Lmax-1 is set. Specifically, the BL control unit 15 emphasizes the degree E when the integrated luminance value is equal to or less than the first maximum set value or the maximum luminance value L-3 is equal to or less than the second maximum set value L-4. The maximum extension brightness value Lmax-1 is set according to the above. Here, "the BL control unit 15 sets the maximum extension luminance value Lmax-1" means that the BL control unit 15 sets the BL83 so that the maximum value of each output luminance value becomes the maximum extension luminance value Lmax-1. It refers to setting the BL luminance value L of a plurality of constituent light sources.

The integrated luminance value is an integrated value obtained by integrating the luminance values of the plurality of display elements when the IMG 2 is displayed on the display panel 80. The first maximum set value is the maximum value of the integrated luminance value that can be set on the display panel 80. The stretched maximum luminance value Lmax-1 is a value obtained by increasing the maximum luminance value L-3 according to the emphasis degree E.

In the example of IMG2C, the maximum luminance value L-3 is smaller than the second maximum set value L-4. When the maximum luminance value L-3 is equal to or less than the second maximum luminance value L-4, the BL control unit 15 sets the second maximum luminance value L-4 as the extended maximum luminance value Lmax-1. After the extension maximum luminance value Lmax-1 is set, the IMG2C that has been displayed on the display panel 80 up to that point changes to a display mode like the IMG2C-1 indicated by reference numeral 804 in FIG. The IMG2C-1 has a relatively high contrast as compared with the IMG2C, and the output side high gradation region is clearly displayed.

The histogram showing the distribution of the output luminance values of IMG2C-1 is as shown in HIST4 shown by reference numeral 805 in FIG. Further, the relationship between the input luminance value of IMG2C and the output luminance value of IMG2C-1 is as shown in the graph shown by reference numeral 806 in FIG. In the graph shown by reference numeral 806 in FIG. 8, the portion where the input luminance value takes a large value is lifted by setting the extended maximum luminance value Lmax-1. On the other hand, the part other than the part where the input luminance value takes a large value is not lifted. From these facts, it can be seen that the IMG2C-1 has a relatively high contrast as compared with the IMG2C, and the high gradation region on the output side is clearly displayed.

<Variations of display processing peculiar to the control device 20>
The BL control unit 15 of the control device 20 calculates the maximum extension luminance value Lmax-1 by the following formula (2), including the above-mentioned example of IMG2C. However, the following equation (2) is just an example, and the BL control unit 15 can also calculate the maximum extended luminance value Lmax-1 by using another equation. In the following equation (2), the reference numerals are omitted for the purpose of clarifying the equation.

Maximum stretched brightness value = maximum brightness value + emphasis x (upper limit brightness value-maximum brightness value) ... Equation (2)
The emphasis level E used in the above equation (2) takes a value of 0 or more and 1 or less, and the higher the emphasis level, the closer the value approaches 1. The upper limit luminance value is a value obtained by correcting the second maximum set value L-4 according to the illuminance around the display device 2. When the upper limit brightness value is smaller than the maximum brightness value L-3, the maximum brightness value L-3 is set as the upper limit brightness value.

When calculating the stretched maximum luminance value Lmax-1 using the above equation (2), if the emphasis E is very high (very close to 1), the BL control unit 15 sets the second maximum set value L−. A maximum extension luminance value Lmax-1 larger than 4 can be set. When a stretch maximum luminance value Lmax-1 larger than the second maximum set value L-4 is set, the relationship between the input luminance value and the output luminance value is, for example, as shown in the graph shown by reference numeral 901 in FIG.

Further, in the setting of the extension maximum brightness value Lmax-1 larger than the second maximum setting value L-4, the maximum brightness value L-3 is the second maximum setting value L-4 as shown in the graph shown by reference numeral 902 in FIG. It is possible even if you have reached. When a stretch maximum brightness value Lmax-1 larger than the second maximum set value L-4 is set, for example, it is smoother than the IMG2 displayed on the display panel 80 after setting the stretch maximum brightness value Lmax-1. It is preferable to apply a curve that changes to so that the curve change point of the displayed image is not felt.

[Embodiment 3]
The display device 3 according to the third embodiment will be described with reference to FIGS. 1 and 10. In the display device 3, the BL control unit 15 of the control device 30 sets the extended luminance value Lmax-2 according to the illuminance around the display device 3 when a predetermined condition is satisfied. -It is different from the display devices 1 and 2 according to 2. As shown in FIG. 1, the main components of the display device 3 and the control device 30 are the same as those of the display devices 1 and 2 and the control devices 10 and 20. Further, the functions of each device and each part of the display device 3 and the functions of each part other than the BL control unit 15 in the control device 30 are the same as those of the display devices 1 and 2 and the control devices 10 and 20.

In the third embodiment, the image analysis unit 11 of the control device 30 acquires a histogram in which the output luminance value is standardized so as to take a value of 0 to 100 (histograms shown by reference numerals 112 and 115 in FIG. 10). reference). Further, in the following description, the illuminance around the display device 3 is simply referred to as "ambient illuminance".

<Display processing peculiar to the control device 30>
Hereinafter, the display processing peculiar to the control device 30 will be described by taking as an example a case where the IMG2D indicated by reference numeral 111 in FIG. 10 is displayed as the IMG2 on the display panel 80 of the display device 3. It is assumed that the surroundings of the display device 3 are bright (the ambient illuminance is high).

The IMG2D displayed on the display panel 80 is relatively dark over the entire image, coupled with the high ambient illuminance. Therefore, it is difficult for the user to visually recognize the IMG2D. The histogram showing the distribution of the output luminance values on the display panel 80 in such a display state is as shown by HIST5 indicated by reference numeral 112 in FIG. In HIST5, the frequency is relatively high in the portion where the output luminance value is small.

As in the example of this IMG2D, when the IMG2 is displayed relatively dark over the entire image, the BL control unit 15 of the control device 30 determines the extended luminance value Lmax- if the integrated luminance value is equal to or less than the minimum set value. Set 2. The minimum set value is the minimum value of the integrated luminance value that can be set on the display panel 80. The extended luminance value Lmax-2 is a value obtained by increasing each output luminance value when the IMG 2 is displayed on the display panel 80. Here, "the BL control unit 15 sets the extended luminance value Lmax-2" means that the BL control unit 15 comprises a plurality of light sources constituting the BL83 so that each output luminance value becomes the extended luminance value Lmax-2. Refers to setting the BL luminance value L of.

Specifically, the BL control unit 15 calculates the stretched luminance value Lmax-2 by the following equations (3) and (4). However, the following equations (3) and (4) are merely examples, and the BL control unit 15 can also calculate the stretched luminance value Lmax-2 using other equations. In the following equations (3) and (4), the reference numerals are omitted for the purpose of clarifying the equations.

Extended brightness value = output brightness value correction magnification x output brightness value ... Equation (3)
Output brightness value correction magnification = 1 + illuminance coefficient x integrated brightness value coefficient x (ambient illuminance / integrated brightness value) ... Equation (4)
The output luminance value correction magnification takes a value of 0 or more and 1 or less, and is calculated by the above equation (4). Further, the relationship between the output luminance value correction magnification and the output luminance value of IMG2 is as shown in the graph indicated by reference numeral 113 in FIG.

The illuminance coefficient has a proportional relationship with the ambient illuminance so that the value increases as the ambient illuminance increases until the ambient illuminance reaches a certain value. The constant value is an ambient illuminance that does not require the setting of the extended luminance value Lmax-2, and can be arbitrarily designed by the designer of the display device 3. When the ambient illuminance exceeds a certain value, the illuminance coefficient maintains the value when the ambient illuminance becomes a constant value. The integrated luminance value coefficient decreases as the integrated luminance value increases, and becomes 0 when the integrated luminance value increases to the extent that the setting of the extended luminance value Lmax-2 becomes unnecessary.

The relationship between the illuminance coefficient and the ambient illuminance may be as described below, for example. That is, in the first period, the higher the ambient illuminance, the larger the illuminance coefficient, and in the second period after the first period, the higher the ambient illuminance, the gradual increase in the illuminance coefficient than in the first period. .. The first period is the period from 0 to the first constant value of the ambient illuminance, and the second period is the second constant value (> the first constant value) after the ambient illuminance reaches the first constant value. It is the period until it reaches.

In this case, the amount of increase in the illuminance coefficient in the second period (per unit illuminance value of the ambient illuminance) decreases as the ambient illuminance increases, and when the ambient illuminance reaches the second constant value, the amount of increase in the illuminance coefficient increases. It becomes 0. Then, when the ambient illuminance becomes the second constant value or more, the illuminance coefficient may maintain the value when the ambient illuminance becomes the second constant value.

After setting the stretched luminance value Lmax-2, the IMG2D that has been displayed on the display panel 80 up to that point changes to a display mode such as the IMG2D-1 indicated by reference numeral 114 in FIG. Compared to IMG2D, IMG2D-1 has a relatively bright overall image and a relatively high contrast. Therefore, the output side high gradation region of the IMG2D-1 is clearly displayed.

The histogram showing the distribution of the output luminance values of IMG2D-1 is like HIST6 shown by reference numeral 115 in FIG. In HIST6, the frequency is generally lower than that in HIST5 for the portion where the output gradation value is small. On the other hand, the frequency of the portion other than the portion where the output gradation value takes a small value is higher than that of HIST5 as a whole. In particular, the frequency of the portion where the output gradation value is large is significantly higher than that of HIST5. From these facts, it can be seen that IMG2D-1 is relatively brighter than IMG2D and has a relatively high contrast.

<Variations of display processing peculiar to the control device 30>
The setting of the extended luminance value Lmax-2 by the BL control unit 15 of the control device 30 may be executed without considering the ambient illuminance. In this case, the BL control unit 15 calculates the stretched luminance value Lmax-2 by the above equation (3) and the following equation (5).

Output luminance value correction magnification = 1 + integrated luminance value coefficient x integrated luminance value ... Equation (5)
By using the above equations (3) and (5), when the integrated luminance value is equal to or less than the minimum set value, the BL control unit 15 immediately sets the extended luminance value Lmax-2 without considering the ambient rowing degree. Set.

[Embodiment 4]
The display device 4 according to the fourth embodiment will be described with reference to FIGS. 1, 11 and 12. In the display device 4, the correction unit 14 of the control device 40 generates a third special tone curve CV3 (third special gradation change characteristic) according to the occupation ratio of the input side high gradation region with respect to the IMG 1. It is different from the display devices 1 to 3 according to 1 to 3. The display device 4 also has a point that the correction unit 14 of the control device 40 generates the fourth special tone curve CV4 (fourth special gradation change characteristic) according to the occupation ratio of the input side low gradation region with respect to the IMG1. It is different from the display devices 1 to 3 according to the first to third embodiments.

As shown in FIG. 1, the main components of the display device 4 and the control device 40 are the same as those of the display devices 1 to 3 and the control devices 10 to 30. Further, the functions of each device and each part of the display device 4 and the functions of each part other than the correction unit 14 in the control device 40 are the same as those of the display devices 1 to 3 and the control devices 10 to 30.

<Display processing peculiar to the control device 40>
Hereinafter, the display processing peculiar to the control device 40 will be described by taking as an example a case where the correction unit 14 of the control device 40 corrects the IMG1E-1 and the IMG1E-2 as the IMG1.

First, a case where the correction unit 14 of the control device 40 corrects the IMG1E-1 represented by reference numeral 121 in FIG. 11 will be described as an example. The IMG1E-1 has a relatively high occupancy ratio of the input side high gradation region with respect to the IMG1E-1, and there is almost no region other than the input side high gradation region. Therefore, the contrast of IMG1E-1 is relatively very low, and the high gradation region on the input side is blurred. The distribution of the input gradation value x of the IMG1E-1 having such a feature is as shown by HIST7 indicated by reference numeral 122 in FIG.

When the occupancy ratio of the input side high gradation region with respect to the IMG1 is relatively high as in the example of the IMG1E-1, the correction unit 14 uses the reference numeral 123 in FIG. 11 as a special tone curve used for the correction of the IMG1. 3 Generates a special tone curve CV3. Specifically, the correction unit 14 calls the second reference tone curve CVN (second reference LUT) stored in the storage unit 90 of the display device 4 in advance to correct the second reference tone curve CVN, thereby making the second reference tone curve CVN. 3 Generates a special tone curve CV3.

The third special tone curve CV3 has an output gradation value y of each output pixel included in the output side high gradation region of the IMG2 as compared with an input gradation value x of each input pixel included in the input side high gradation region of the IMG1. Is larger uniformly. Here, "the output gradation value y of each output pixel is uniformly larger" means that, specifically, the output gradation value y of each output pixel included in the output side high gradation region of the IMG2 is , It means that it is uniformly larger than the output gradation value y of the corresponding second reference tone curve CVN.

Further, the third special tone curve CV3 is included in a region other than the output side high gradation region in the IMG2, as compared with the input gradation value x of each input pixel included in the region other than the input side high gradation region of the IMG1. The rate of increase of the output gradation value y of the output pixel is smaller. Here, "the rate of increase of the output gradation value y of each output pixel is smaller" specifically means that the output floor of each output pixel included in an area other than the output side high gradation area in IMG2. It means that the slope of the tuning value y is smaller than the slope of the output gradation value y of the corresponding second reference tone curve CVN. Since the third special tone curve CV3 has the above-mentioned characteristics, if the third special tone curve CV3 is applied, IMG2 having a more uniform integrated gradation value than IMG1 can be obtained. Can be done.

The correction unit 14 generates the third special tone curve CV3 having the above-mentioned characteristics and applies it to the IMG1E-1 to generate the IMG2E-1 represented by the reference numeral 124 in FIG. 11 as the IMG2. The contrast of IMG2E-1 is relatively higher than that of IMG1E-1, and the high gradation region on the output side is clearly displayed.

Next, a case where the correction unit 14 of the control device 40 corrects the IMG1E-2 represented by reference numeral 131 in FIG. 12 will be described as an example. The IMG1E-2 occupies a relatively high proportion of the input-side low-gradation region with respect to the IMG1E-2, and there is almost no region other than the input-side low-gradation region. Therefore, the contrast of IMG1E-2 is relatively very low, and the entire image is relatively dark. The distribution of the input gradation value x of the IMG1E-2 having such a feature is as shown by HIST8 indicated by reference numeral 132 in FIG.

When the occupancy ratio of the input side low gradation region with respect to IMG1 is relatively high as in the example of IMG1E-2, the correction unit 14 is indicated by reference numeral 133 in FIG. 12 as a special tone curve used for correction of IMG1. The fourth special tone curve CV4 is generated. The point that the fourth special tone curve CV4 is generated by calling the second reference tone curve CVN from the storage unit 90 and correcting the second reference tone curve CVN is the same as that of the third special tone curve CV3.

The fourth special tone curve CV4 has an output gradation of each output pixel included in the output side low gradation region of the IMG2 as compared with the input gradation value x of each input pixel included in the input side low gradation region of the IMG1. The value y is larger. Here, "the output gradation value y of each output pixel is larger" specifically means that the output gradation value y of each output pixel included in the output side low gradation region of the IMG2. It means that the value is larger than the output gradation value y of the corresponding second reference tone curve CVN.

The correction unit 14 generates the fourth special tone curve CV4 having the above-mentioned characteristics and applies it to the IMG1E-2 to generate the IMG2E-2 represented by the reference numeral 134 in FIG. 12 as the IMG2. The contrast of IMG2E-2 is relatively higher than that of IMG1E-2, and the low gradation region on the output side is clearly displayed.

[Embodiment 5]
The display device 5 according to the fifth embodiment will be described with reference to FIGS. 1 and 13. The display device 5 is different from the display devices 1 to 4 according to the first to fourth embodiments in that the control device 50 includes the determination unit 16. Further, the display device 5 also has a display according to the first to fourth embodiments in that the image analysis unit 11 of the control device 50 analyzes the IMG1 and calculates the occupancy ratio of the object image (hereinafter, IMG1O and IMG1UI) to the IMG1. Different from devices 1 to 4. Further, the display device 5 also relates to the first to fourth embodiments in that the correction unit 14 of the control device 50 sets the color correction degree C and then color-corrects the IMG1O and the IMG1UI according to the color correction degree C. It is different from the display devices 1 to 4.

The main components of the display device 5 and the control device 50 are the same as those of the display devices 1 to 4 and the control devices 10 to 40 as shown in FIG. 1 except that the determination unit 16 is provided. Further, the functions of each device and each part of the display device 4 and the functions of each part other than the image analysis unit 11, the correction unit 14, and the determination unit 16 in the control device 40 are also the functions of the display devices 1 to 4 and the control devices 10 to 40. It is the same.

<Display processing peculiar to the control device 50>
Hereinafter, the display processing peculiar to the control device 50 will be described by taking as an example a case where the control device 50 executes the display processing of the IMG1F-1 and the IMG1F-2 as the IMG1.

First, a case where the control device 50 executes the display process of IMG1F-1 shown by reference numeral 141 in FIG. 13 will be described as an example. The IMG1F-1 is converted into RGB format by the decoder of the control device 50 before being output to the image analysis unit 11 and the determination unit 16 of the control device 50.

The determination unit 16 that has acquired the IMG1F-1 determines the type of a predetermined object projected by the object image (hereinafter, IMG1O) in the IMG1F-1 by using the trained model. The trained model is a training model using teacher data in which correct answer data indicating the target object and input data composed of a large number of images showing each of various types of objects including the target object are associated with each other. It is generated by letting the machine learn.

The target object is an object projected on the target object image in IMG1. The target object image is an image area in the IMG1 to which the correction unit 14 of the control device 50 performs color correction. The target object can be arbitrarily selected by the designer of the display device 5. As the target object, for example, an object whose color should be corrected to the memory color is preferable. Therefore, in the fifth embodiment, it is assumed that a person, a flower, a leaf, and the sky are selected as the target object. Further, in the fifth embodiment, it is assumed that the UI is also selected as the target object. From these things, the target object image in the fifth embodiment is an image in which each of the person, the flower, the leaf, the sky, and the UI is projected alone or in a combination of two or more types.

When the input data is a still image, for example, CNN can be used as the trained model. On the other hand, when the input data is a moving image, it is preferable to use, for example, a trained model in which CNN and RNN (Recurrent Neutal Natwork) or CNN and LSTM (Long Short-Term Memory) are combined as the trained model. The generated trained model may be stored in, for example, a storage unit 90, or may be stored in a server (not shown). When stored in the server, the determination unit 16 of the control device 50 acquires the learned model from the server by performing wireless communication or the like between the server and the display device 5.

A known machine learning algorithm such as multinomial logistic regression analysis may be used to generate the trained model. Alternatively, a trained model may be generated using a known neural network technique (eg, a known deep learning technique).

In this example of IMG1F-1, the determination unit 16 uses the trained model to determine that a person, that is, one type of target object is projected on IMG1O-1 in IMG1F-1 as a predetermined object. do. Further, the determination unit 16 determines that flowers and leaves, that is, two types of target objects different from the target objects of the IMG1O-1, are projected on the IMG1O-2 in the IMG1F-1 as predetermined objects.

Next, the image analysis unit 11 of the control device 50 acquires a determination result indicating that a total of three types (people, flowers, leaves) of target objects are projected in the IMG1F-1 from the determination unit 16. Since the target object is projected in the IMG1F-1, the image analysis unit 11 that has acquired this determination result analyzes the IMG1F-1 and determines the occupancy ratio of the IMG1O-1 and the IMG1O-2 to the IMG1F-1. calculate.

Next, the correction unit 14 of the control device 50 acquires the calculation result from the image analysis unit 11. The correction unit 14 that has acquired the calculation result sets the color correction degree C according to the calculation result. The color correction degree C indicates the degree of color correction when the IMG1O is color-corrected, and is set stepwise with a numerical value between 0 and 1. When the color correction degree C is 0, it indicates that the color correction is not performed, and when the color correction value C is 1, the color correction having the highest degree is performed. The designer of the display device 5 can arbitrarily set how much the color correction degree C is divided into. In the fifth embodiment, the degree of color correction is set according to the occupancy ratio of the target object image with respect to IMG1.

Since both the occupancy ratio of IMG1O-1 to IMG1F-1 and the occupancy ratio of IMG1O-2 to IMG1F-1 are relatively high, the correction unit 14 sets the color correction degree C1 of IMG1O-1 to "1" and IMG1O-2. The color correction degree C2 of is set to "1". On the other hand, in IMG1F-1, for example, there is no target object image in which the sky is reflected. That is, the occupancy ratio of the target object image in which the sky is reflected to IMG1F-1 is 0. Therefore, the color correction degree C of the target object image in which the sky is reflected is "0".

Next, the correction unit 14 in which the color correction degree C is set calls any one of the plurality of 3DLUTs generated for each type of the target object image from, for example, the storage unit 90. As a matter of course, the storage unit 90 calls the 3DLUT corresponding to the target object image that is color-corrected by the correction unit 14. Therefore, the correction unit 14 in which the color correction degrees C1 and C2 are set calls the 3DLUT corresponding to IMG1O-1 and the 3DLUT corresponding to IMG1O-2 from the storage unit 90.

Then, the correction unit 14 has a color correction degree for the target object image in the IMG2 (see S106 and S107 in FIG. 2) that has been converted from the YUV format to the RGB format after being corrected by the first special tone curve or the second special tone curve. Apply 3DLUT to a degree corresponding to C. By applying this 3DLUT, the target object image is color-corrected. Therefore, the correction unit 14 applies 3DLUT to the output image corresponding to the IMG1O-1 to the highest degree corresponding to the color correction degree C1 (= 1) to perform color correction. Further, the correction unit 14 also applies 3DLUT to the output image corresponding to the IMG1O-2 to the highest degree corresponding to the color correction degree C1 (= 1) to perform color correction.

Next, a case where the control device 50 executes the display process of IMG1F-2 shown by reference numeral 142 in FIG. 13 will be described as an example. The IMG1F-2 is also converted into the RGB format in advance by the decoder of the control device 50.

The determination unit 16 that has acquired the IMG1F-2 determines the type of a predetermined object projected by the IMG1O in the IMG1F-2 using the trained model. Specifically, the determination unit 16 determines that a person, that is, one type of target object is projected as a predetermined object on the IMG1O-3 in the IMG1F-2 by using the trained model. Further, the determination unit 16 determines that the UI in the IMG1F-2 in the IMG1F-2, that is, one type of target object different from the target object of the IMG1O-3 is projected as a predetermined object.

Next, the image analysis unit 11 which has acquired the determination result that a total of two types (people, UI) of the target objects are projected in the IMG1F-2 from the determination unit 16 analyzes the IMG1F-2 and the IMG1O-. Calculate the occupancy ratio of 3 and IMG1UI.

Next, the correction unit 14 that has acquired the calculation result from the image analysis unit 11 sets the color correction degree C according to the calculation result. Since the occupancy ratio of IMG1O-3 to IMG1F-1 is not so high, the correction unit 14 sets the color correction degree C3 of IMG1O-3 to "0.5". On the other hand, since the occupancy ratio of the IMG1UI to the IMG1F-1 is relatively high, the correction unit 14 sets the color correction degree C4 of the IMG1UI to “1”. Next, the correction unit 14 in which the color correction degrees C3 and C4 are set calls the 3DLUT corresponding to the IMG1O-3 and the 3DLUT corresponding to the IMG1UI from the storage unit 90.

Then, the correction unit 14 applies 3DLUT to the output image corresponding to the IMG1O-3 to a moderate degree corresponding to the color correction degree C3 (= 0.5) to perform color correction. Further, the correction unit 14 applies 3DLUT to the output image corresponding to the IMG1UI to the highest degree corresponding to the color correction degree C4 (= 1) to perform color correction.

The correction unit 14 may apply, for example, 1DLUT for color temperature correction to the IMG2 after color correction to perform color temperature correction.

[Example of realization by software]
The control block of the control device 10 (particularly the image analysis unit 11, the gradation value calculation unit 12, the emphasis calculation unit 13, the correction unit 14, and the BL control unit 15) is a logic circuit formed in an integrated circuit (IC chip) or the like. It may be realized by (hardware) or by software.

In the latter case, the control device 10 includes a computer that executes instructions of a program that is software that realizes each function. The computer includes, for example, at least one processor (control device) and at least one computer-readable recording medium that stores the program. Then, in the computer, the object of the present invention is achieved by the processor reading the program from the recording medium and executing the program.

As the processor, for example, a CPU (Central Processing Unit) can be used. As the recording medium, a "non-temporary tangible medium", for example, a ROM (Read Only Memory) or the like, a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, a RAM (Random Access Memory) for expanding the program may be further provided. Further, the program may be supplied to the computer via an arbitrary transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program. It should be noted that one aspect of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

〔summary〕
The control device (10, 20, 30, 40, 50) according to the first aspect of the present invention controls an input image (IMG1) that controls a display device (1, 2, 3, 4, 5) having a display panel (80). ) Is corrected to generate an output image (IMG2), and the input floor is a gradation value of a plurality of input pixels constituting the input image by analyzing the input image. A histogram (HIST1, HIST2) showing the distribution of the adjustment value (x) is acquired, and the maximum gradation value (xmax) which is the maximum value of the input gradation value and the input gradation value of the center of gravity of the histogram are obtained. In the input image, the first calculation unit (image analysis unit 11, gradation value calculation unit 12) for calculating the center of gravity gradation value (xv), the maximum gradation value, and the center of gravity gradation value are used. A th-th. 2 Correspondence between the calculation unit (emphasis calculation unit 13) and (i) the input gradation value and the output gradation value (y) which is the gradation value of a plurality of output pixels constituting the output image. With respect to the gradation change characteristic indicating the above, special gradation change characteristics (CV1, CV2, CV3, CV4) which are the gradation change characteristics according to the emphasis are generated, and the plurality of the special gradation change characteristics are used. The output image is generated by correcting the input gradation value of the input pixel of the above, and (ii) the brightness value (BL brightness) of a plurality of display elements arranged on the display panel according to the emphasis degree. It includes a processing unit (correction unit 14, BL control unit 15) for setting the value L).

According to the above configuration, the processing unit generates an output image by correcting the input image using the special gradation change characteristic generated according to the emphasis. Further, the processing unit sets the luminance values of the plurality of display elements according to the degree of emphasis. Therefore, the control device can adjust the emphasis of the high gradation region on the input side by correcting the input image by the special gradation change characteristic and setting according to the enhancement of the luminance values of the plurality of display elements.

Therefore, when the emphasis of the input-side high-gradation region is high, for example, the processing unit emphasizes and displays the region corresponding to the input-side high-gradation region in the output image by setting the luminance values of the plurality of display elements to be high. This makes it possible to increase the brightness and contrast of the display device. Further, in this case, the processing unit can reduce the output gradation value of the output image by correcting the input image using the special gradation change characteristic, so that the power consumption and heat generation of the display device can be reduced.

On the other hand, when the emphasis of the high gradation region on the input side is low, for example, the processing unit can reduce the power consumption and heat generation of the display device by setting the brightness values of the plurality of display elements to be low. Further, in this case, the processing unit can maintain the luminance feeling of the entire display device by increasing the output gradation value of the output image by correcting the input image using the special gradation change characteristic.

In the control device (10) according to the second aspect of the present invention, in the first aspect, the emphasis becomes higher as the maximum gradation value becomes larger or the center of gravity gradation value becomes smaller. As the emphasis level increases, the special gradation change characteristic of the unit is that the input side high gradation region in the output image is compared with the input gradation value of each input pixel included in the input side high gradation region. The output gradation value of each output pixel included in the output-side high-gradation region corresponding to is uniformly increased, and the input gradation value of each input pixel included in the region other than the input-side high-gradation region is set to. By comparing, by making the output gradation value of each output pixel included in the region other than the output side high gradation region in the output image smaller, the integrated gradation value of all the input gradation values and all The first special gradation change characteristic (CV1) that corrects the input image is generated so that the integrated gradation value of the output gradation value of the above is the same, and the brightness value of the plurality of display elements. May be set larger.

According to the above configuration, the higher the emphasis is, the higher the contrast between the input side high gradation region and the other region in the input image. That is, the higher the emphasis, the higher the demand for higher brightness and higher contrast of the display device. Therefore, the control device more effectively realizes high brightness and high contrast of the display device by uniformly increasing the output gradation value of each output pixel included in the output side high gradation region as the emphasis level increases. can do. Further, the control device can more effectively realize high brightness and high contrast of the display device by setting the brightness values of the plurality of display elements to be larger as the emphasis level is higher.

Further, according to the above configuration, the control device reduces the output gradation value of each output pixel included in the region other than the output side high gradation region as the emphasis is increased, thereby reducing the power consumption and heat generation of the display device. Can be reduced. Further, the control device uses the first special gradation change characteristic to correct the input image so that the integrated values of all the input gradation values and the integrated values of all the output gradation values are the same. Therefore, when the user visually recognizes the output image displayed on the display panel, the user can feel that the apparent luminance value of the output image is the same as the luminance value of the input image.

Further, according to the above configuration, when the emphasis of one frame is relatively low, even if the emphasis of the next one frame is relatively high, the brightness values of the plurality of display elements are increased according to the emphasis. The high gradation area on the output side can be emphasized simply by setting to increase. Therefore, the control device can emphasize the high gradation region on the output side in response to a sudden increase in the emphasis.

In the control device according to the third aspect of the present invention, in the first or second aspect, the emphasis becomes lower as the maximum gradation value becomes smaller or the center of gravity gradation value becomes larger. As the special gradation change characteristic, the lower the emphasis is, the higher the input side in the output image (IMG2B) is compared with the input gradation value of each input pixel included in the input side high gradation region. A second special gradation change characteristic (CV2) that corrects the input image so that the output gradation value of each output pixel included in the output side high gradation region corresponding to the adjustment region is larger is generated. Moreover, the brightness values of the plurality of display elements may be set smaller.

According to the above configuration, the lower the emphasis is, the lower the contrast between the input side high gradation region and the other region in the input image. That is, the lower the emphasis, the lower the demand for higher brightness and higher contrast of the display device. Therefore, the control device sets the brightness values of the plurality of display elements to be smaller as the emphasis level is lower. It is possible to reduce the heat generation of the display device due to the waste of electricity and the waste of electric power. Further, the control device can maintain the brightness feeling of the entire display device by increasing the output gradation value of the output image as the emphasis degree is lowered.

In the control device (20) according to the fourth aspect of the present invention, in any one of the first to third aspects, the processing unit displays the integrated luminance value obtained by integrating the luminance values of the plurality of display elements on the display panel. The maximum luminance value (1-3), which is equal to or less than the first maximum set value which is the maximum value of the integrated luminance value that can be set, or the maximum value of the luminance values of the plurality of display elements, is set on the display panel. In any case of the second maximum set value (L-4) or less, which is the maximum value of the luminance values of the plurality of display elements, the maximum elongation value is increased according to the emphasis degree. The brightness value (Lmax-1) may be set.

According to the above configuration, the control device sets the extended maximum luminance value when the integrated luminance value is equal to or less than the first maximum set value and the maximum luminance value is equal to or less than the second maximum set value, so that the input image in the output image The area corresponding to the high gradation area on the input side can be highlighted and displayed on the display panel.

In the control device (30) according to the fifth aspect of the present invention, in any one of the first to fourth aspects, the processing unit displays the integrated luminance value obtained by integrating the luminance values of the plurality of display elements on the display panel. When it is equal to or less than the minimum set value which is the minimum value of the integrated luminance value that can be set, the extended luminance value (Lmax-2) in which the luminance values of the plurality of display elements are increased may be set.

According to the above configuration, when the integrated luminance value is equal to or less than the minimum set value, the control apparatus sets the stretched luminance value for each of the plurality of display elements to set the input side high gradation region of the input image in the output image. The corresponding area can be highlighted on the display panel.

In any of the fifth aspects of the control device according to the sixth aspect of the present invention, when the integrated luminance value is equal to or less than the minimum set value, the processing unit may use the control device according to the illuminance around the display device. The stretched luminance value may be set.

According to the above configuration, the control device can not set the extended luminance value depending on the illuminance around the display device even when the integrated luminance value is equal to or less than the minimum set value. Alternatively, the control device can appropriately adjust the magnitude of the stretched luminance value according to the illuminance around the display device. Therefore, the control device can display the region corresponding to the input side high gradation region of the input image in the output image with an appropriate degree of enhancement according to the illuminance around the display device.

In the control device (40) according to the seventh aspect of the present invention, in any one of the first to sixth aspects, the processing unit increases the occupancy ratio of the input side high gradation region with respect to the input image (IMG1E-2). As the special gradation change characteristic, the output gradation value of each output pixel included in the output side high gradation region corresponding to the input side high gradation region in the output image (IMG2E-2) is uniformly increased. At the same time, by increasing the inclination of the output gradation value of each output pixel included in the region other than the output side high gradation region in the output image, the input gradation value is more than the integrated gradation value distribution. The third special gradation change characteristic (CV3) is generated so that the integrated gradation value distribution of the output gradation value is relatively uniform, and the input gradation value is smaller than that of other regions. Regarding the gradation region, the higher the occupancy ratio of the input side low gradation region with respect to the input image (IMG1E-1), the higher the input side lower floor in the output image (IMG2E-1) as the special gradation change characteristic. The fourth special gradation change characteristic (CV4) included in the output side low gradation region corresponding to the adjustment region may be generated so that the output gradation value of each output pixel becomes larger.

The higher the ratio of the high gradation region on the input side to the input image, the higher the demand for higher brightness and higher contrast of the display device. In that respect, according to the above configuration, as the occupancy ratio becomes higher, the output gradation value of each output pixel included in the output side high gradation region is uniformly increased by using the third special gradation change characteristic. It is possible to more effectively realize high brightness and high contrast of the device. Further, the control device uses the third special gradation change characteristic to input so that the integrated gradation value distribution of the output gradation value is relatively uniform than the integrated gradation value distribution of the input gradation value. Correct the image. Therefore, when the user visually recognizes the output image displayed on the display panel, the user can feel that the apparent luminance value of the output image is the same as the luminance value of the input image.

On the other hand, the higher the occupancy ratio of the low gradation region on the input side with respect to the input image, the higher the demand for optimizing the contrast in the display device. In that respect, according to the above configuration, as the occupancy ratio becomes higher, the output gradation value of each output pixel included in the output side low gradation region is uniformly increased by using the fourth special gradation change characteristic. It is possible to optimize the contrast of the display device.

The control device (50) according to the eighth aspect of the present invention has been trained, in any one of the first to seventh aspects, generated by machine learning using a predetermined object and an image of the predetermined object as teacher data. Using the model, the first The calculation unit (image analysis unit 11) calculates the occupancy ratio of the object image with respect to the input image by analyzing the input image according to the determination result of the determination unit, and the processing unit is the determination unit. Based on the determination result of the above and the calculation result of the first calculation unit, a color correction degree (C) indicating the degree of color correction when the object image is color-corrected is set, and the object is set according to the color correction degree. The output image may be generated by color-correcting the image.

According to the above configuration, the determination unit can determine the type of a predetermined object on which the object image in the input image is projected with high determination accuracy. Further, the control device can appropriately color-correct the object image according to the occupancy ratio of the object image with respect to the input image and the type of the predetermined object.

The display device (1, 2, 3, 4, 5) according to the ninth aspect of the present invention includes the control device (10, 20, 30, 40, 50) according to any one of the first to eighth aspects. According to the above configuration, it is possible to realize a display device having the same effect as the control device according to the first aspect of the present invention.

In the control method according to the tenth aspect of the present invention, the input image (IMG1) is corrected to control the display device (1, 2, 3, 4, 5) having the display panel (80), and the output image (IMG2) is obtained. It is a control method of a control device (10, 20, 30, 40, 50) that can be generated, and by analyzing the input image, the gradation values of a plurality of input pixels constituting the input image are used. A histogram (HIST1, HIST2) showing the distribution of a certain input gradation value (x) is acquired, and the maximum gradation value (xmax) which is the maximum value of the input gradation value and the input gradation of the center of gravity of the histogram are obtained. Using the first calculation step (S103, S104) for calculating the center of gravity gradation value (xv), which is a value, and the maximum gradation value and the center of gravity gradation value calculated in the first calculation step, Emphasis (E) indicating the degree of enhancement when the input image is corrected so that the input side high gradation region in which the input gradation value in the input image is larger than the other regions is emphasized in the output image. Correspondence between the second calculation step (S105) for calculating the above, and (i) the input gradation value and the output gradation value (y) which is the gradation value of a plurality of output pixels constituting the output image. With respect to the gradation change characteristic indicating the above, special gradation change characteristics (CV1, CV2, CV3, CV4) which are the gradation change characteristics according to the emphasis calculated in the second calculation step are generated, and the special The output image is generated by correcting the input gradation values of the plurality of input pixels using the gradation change characteristic, and (ii) according to the emphasis calculated in the second calculation step. A processing step (S105, S106) for setting a brightness value (BL brightness value L) of a plurality of display elements arranged on the display panel is included. According to the above configuration, it is possible to realize a control method having the same effect as the control device according to the first aspect of the present invention.

The control device according to each aspect of the present invention may be realized by a computer. In this case, the control program of the control device that realizes the control device by the computer by operating the computer as each part (software element) included in the device also falls within the scope of the present invention. A computer-readable recording medium on which the control program is recorded also falls within the scope of the present invention.

[Additional notes]
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

1, 2, 3, 4, 5 Display device 10, 20, 30, 40, 50 Control device 11 Image analysis unit (part of "1st calculation unit")
12 Gradation value calculation unit (part of "1st calculation unit")
13 Emphasis calculation unit (second calculation unit)
14 Correction unit (processing unit)
15 BL control unit (processing unit)
16 Judgment unit 17 Application execution unit 18 RGB / Illuminance sensor 80 Display panel C Color correction degree CV1 Tone curve (1st special gradation change characteristic)
CV2 tone curve (second special gradation change characteristic)
CV3 tone curve (third special gradation change characteristic)
CV4 tone curve (4th special gradation change characteristic)
E Emphasis HIST1, HIST2 Histogram IMG1, IMG1A, IMG1B, IMG1E-1, IMG1E-2, IMG1F-1, IMG1F-2 Input images IMG2, IMG2B, IMG2C, IMG2C-1, IMG2D, IMG2D-1, IMG2E-1, IMG2E-2 output image IMG1O, IMG1O-1, IMG1O-2, IMG1O-3, IMG1UI Object image L BL luminance value (luminance value)
L-3 Maximum brightness value L-4 Second maximum setting value Lmax-1 Extended maximum brightness value Lmax-2 Extended brightness value x Input gradation value y Output gradation value xmax Maximum gradation value xv Center of gravity gradation value

Claims (11)

A control device that controls a display device having a display panel and is capable of correcting an input image and generating an output image.
By analyzing the input image, a histogram showing the distribution of the input gradation value which is the gradation value of a plurality of input pixels constituting the input image is acquired, and the maximum value which is the maximum value of the input gradation value is obtained. A first calculation unit that calculates the gradation value and the center of gravity gradation value that is the input gradation value of the center of gravity of the histogram, and
Using the maximum gradation value and the center of gravity gradation value, the input is such that an input-side high gradation region in which the input gradation value in the input image is larger than other regions is emphasized in the output image. A second calculation unit that calculates the degree of emphasis, which indicates the degree of emphasis when correcting an image,
(I) The gradation change characteristic showing a correspondence relationship between the input gradation value and the output gradation value which is the gradation value of a plurality of output pixels constituting the output image is described according to the emphasis. The output image is generated by generating a special gradation change characteristic which is a gradation change characteristic and correcting the input gradation values of the plurality of input pixels by using the special gradation change characteristic, and ( ii) A control device including a processing unit that sets brightness values of a plurality of display elements arranged on the display panel according to the emphasis. The emphasis becomes higher as the maximum gradation value becomes larger or as the center of gravity gradation value becomes smaller.
The higher the emphasis of the processing unit, the higher the emphasis.
As the special gradation change characteristic,
The output of each output pixel included in the output side high gradation region corresponding to the input side high gradation region in the output image as compared with the input gradation value of each input pixel included in the input side high gradation region. In addition to increasing the gradation value uniformly
The output gradation of each output pixel included in the region other than the output side high gradation region in the output image as compared with the input gradation value of each input pixel included in the region other than the input side high gradation region. The first special that corrects the input image so that the integrated gradation value of all the input gradation values and the integrated gradation value of all the output gradation values become the same by making the value smaller. Generates gradation change characteristics and
The control device according to claim 1, wherein the brightness values of the plurality of display elements are set larger. The emphasis becomes lower as the maximum gradation value becomes smaller or the center of gravity gradation value becomes larger.
In the processing unit, the lower the emphasis is, the more
As the special gradation change characteristic, it is included in the output side high gradation region corresponding to the input side high gradation region in the output image as compared with the input gradation value of each input pixel included in the input side high gradation region. A second special gradation change characteristic that corrects the input image so that the output gradation value of each output pixel becomes larger is generated.
The control device according to claim 1 or 2, wherein the brightness values of the plurality of display elements are set smaller. In the processing unit, the integrated luminance value obtained by integrating the luminance values of the plurality of display elements is equal to or less than the first maximum set value which is the maximum value of the integrated luminance value that can be set on the display panel, or the plurality of such integrated luminance values. When the maximum brightness value, which is the maximum value of the brightness value of the display element, is equal to or less than the second maximum setting value, which is the maximum value of the brightness value of the plurality of display elements that can be set on the display panel. The control device according to any one of claims 1 to 3, wherein the extended maximum luminance value in which the maximum luminance value is increased according to the emphasis degree is set. When the integrated luminance value obtained by integrating the luminance values of the plurality of display elements is equal to or less than the minimum set value which is the minimum value of the integrated luminance value that can be set on the display panel, the processing unit may perform the plurality of integrated luminance values. The control device according to any one of claims 1 to 4, wherein an extended luminance value in which the luminance value of the display element is increased is set. The control device according to claim 5, wherein the processing unit sets the extended luminance value according to the illuminance around the display device when the integrated luminance value is equal to or less than the minimum set value. The processing unit
The higher the occupancy ratio of the input side high gradation region with respect to the input image, the more each output pixel included in the output side high gradation region corresponding to the input side high gradation region in the output image as the special gradation change characteristic. By uniformly increasing the output gradation value of the above and increasing the slope of the output gradation value of each output pixel included in a region other than the output side high gradation region in the output image, the input floor A third special gradation change characteristic is generated so that the integrated gradation value distribution of the output gradation value is relatively more uniform than the integrated gradation value distribution of the adjustment value.
With respect to the input-side low-gradation region in which the input gradation value is smaller than the other regions, the higher the occupancy ratio of the input-side low-gradation region with respect to the input image, the higher the special gradation change characteristic in the output image. From claim 1, the fourth special gradation change characteristic, which is included in the output side low gradation region corresponding to the input side low gradation region, is generated so that the output gradation value of each output pixel becomes larger. The control device according to any one of 6. Using a trained model generated by machine learning using a predetermined object and an image showing the predetermined object as teacher data, the type of the predetermined object projected by the object image in the input image is determined. Equipped with a judgment unit
The first calculation unit calculates the occupancy ratio of the object image to the input image by analyzing the input image according to the determination result of the determination unit.
Based on the determination result of the determination unit and the calculation result of the first calculation unit, the processing unit sets a color correction degree indicating the degree of color correction when the object image is color-corrected, and the color correction degree The control device according to any one of claims 1 to 7, wherein the output image is generated by color-correcting the object image according to the above. A display device including the control device according to any one of claims 1 to 8. A control program for operating a computer as the control device according to any one of claims 1 to 8, for operating the computer as the first calculation unit, the second calculation unit, and the processing unit. Control program. It is a control method of a control device that controls a display device having a display panel and can generate an output image by correcting an input image.
By analyzing the input image, a histogram showing the distribution of the input gradation value which is the gradation value of a plurality of input pixels constituting the input image is acquired, and the maximum value which is the maximum value of the input gradation value is obtained. The first calculation step of calculating the gradation value and the center of gravity gradation value which is the input gradation value of the center of gravity of the histogram, and
Using the maximum gradation value calculated in the first calculation step and the center of gravity gradation value, an input-side high gradation region in which the input gradation value in the input image is larger than other regions is the output image. In the second calculation step of calculating the degree of emphasis indicating the degree of emphasis when correcting the input image, as emphasized in
(I) In the second calculation step, the gradation change characteristic showing the correspondence relationship between the input gradation value and the output gradation value which is the gradation value of a plurality of output pixels constituting the output image is obtained. The special gradation change characteristic, which is the gradation change characteristic according to the calculated emphasis, is generated, and the input gradation value of the plurality of input pixels is corrected by using the special gradation change characteristic. A processing step of generating an output image and (ii) setting brightness values of a plurality of display elements arranged on the display panel according to the emphasis calculated in the second calculation step is included. But the control method.

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