JP2017072754A - Display device and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a user with information on an area displayed in a color different from a color based on image data, in a display device equipped with a plurality of light sources having different emission characteristics and capable of controlling lighting independently for each light source.SOLUTION: There is provided a display device comprising: light emission means constituted of a plurality of control areas in which light emission is independently controllable, each control area having a plurality of light sources having different emission characteristics; control means for controlling the light emission of light sources in each control area on the basis of image data; display means for adjusting transmissivity of incident light made incident from the light emission means on the basis of the image data and thereby displaying an image; determination means for calculating, for each region of the display means, the characteristics of an incident light made incident on the display means from the light emission means on the basis of control information on the light source by the control means, and determining, on the basis of the calculated characteristics of the incident light, a caution region in which a color based on image data is not included in a color gamut displayable by the display means; and display control means for making the display means display information on the caution region determined by the determination means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a display device and a control method thereof.

  A display device that includes a light source and light modulation means such as a liquid crystal panel that modulates the transmittance of light incident from the light source for each pixel in accordance with image data, and displays an image based on the image data has become widespread. In such a display device, there is a technique that includes a plurality of types of light sources having different characteristics and controls the light source to be turned on according to a display image.

  For example, Patent Document 1 includes a backlight having a broadband light source having a wide emission spectrum and a narrow narrow band light source. The broadband light source is turned on in a region displaying a low saturation image, and the narrow band is displayed in a region displaying a high saturation image. A technique for lighting a light source is disclosed. Since human visual characteristics have individual differences that are modeled by color matching functions, even if calibration is performed so that the colorimetric values measured by the sensors match the target values, different colors are perceived by the observer There is. The shift in perceived color due to individual differences is particularly likely to occur when observing low saturation images. However, it is known that when a broadband light source is used, the perceived color is less susceptible to variations in the color matching function. In the technique of Patent Document 1, a perceptual color shift caused by individual differences in color matching functions is suppressed by turning on a broadband light source in a display area of a low saturation image.

  Patent Document 2 discloses a technology that includes a backlight having RGB three-color light sources and performs control to turn on only the R light source in an area displaying R with high color purity, for example. In the technique of Patent Document 2, wide color gamut display is enabled by controlling the luminance ratio of the three color light sources according to the image for each area of the screen.

Special table 2012-515948 gazette JP 2007-322944 A

  In a display device having a backlight composed of a plurality of light sources that can be controlled independently as in the above prior art, the light that irradiates the area of the display panel corresponding to each light source corresponds to an adjacent area. It is affected by the light from the light source. For example, in Patent Document 1, when an image in which a high saturation image and a low saturation image are mixed is displayed, the light of the broadband light source in the display area of the adjacent low saturation image is added to the light of the narrow band light source in the display area of the high saturation image. Are mixed, and the displayable color gamut in the display area of the high saturation image is narrowed. Then, in the display area of the high saturation image, the actually displayed image is displayed in a color different from the original color. Also in Patent Document 2, for example, when displaying an image in which an image having a high color purity and an image having an intermediate color are mixed, the same problem may occur. However, the observer cannot know which pixel is displayed in the original color and which pixel is displayed in a color different from the original color. This is because the observer has no means to judge the lighting state of the light source for each region and the influence of light from the adjacent light source. For this reason, the conventional display device may not be able to accurately perform color configuration and editing.

The present invention provides a viewer with information on a region displayed in a color different from a color based on image data in a display device including a plurality of light sources having different light emission characteristics and capable of controlling lighting for each light source independently. With the goal.

The present invention comprises a plurality of control areas that can independently control light emission, each control area having a plurality of light sources having different light emission characteristics,
Control means for controlling light emission of the light source in each control area based on image data;
Display means for displaying an image by adjusting the transmittance of incident light incident from the light emitting means based on the image data;
Based on the control information of the light source by the control means, a characteristic of incident light incident on the display means from the light emitting means is calculated for each area of the display means, and the image data is calculated based on the calculated characteristic of the incident light. Determining means for determining a caution area that is not included in a color gamut that can be displayed by the display means;
Display control means for causing the display means to display information on the attention area determined by the determination means;
It is a display apparatus provided with.

The present invention comprises a plurality of control areas that can independently control light emission, each control area having a plurality of light sources having different light emission characteristics,
Control means for controlling light emission of the light source in each control area based on image data;
Display means for displaying an image by adjusting the transmittance of incident light incident from the light emitting means based on the image data;
Based on the control information of the light source by the control means, the characteristics of the incident light incident on the display means from the light emitting means are calculated for each area of the display means, and the color based on the image data and the characteristics of the incident light From the relationship, a determination means for determining an attention area where a perceptual color shift caused by an individual difference in the color matching function occurs,
Display control means for causing the display means to display information on the attention area determined by the determination means;
It is a display apparatus provided with.

The present invention comprises a plurality of control areas that can independently control light emission, each control area having a plurality of light sources having different light emission characteristics,
Display means for displaying an image by adjusting the transmittance of incident light incident from the light emitting means based on image data;
A display device control method comprising:
Controlling light emission of the light source of each control area based on the image data;
Based on the control information of the light source, the characteristics of the incident light incident on the display means from the light emitting means are calculated for each area of the display means, and the color based on the image data is calculated based on the calculated characteristics of the incident light. Determining a caution area not included in the color gamut that can be displayed by the display means;
Displaying the information on the attention area on the display means;
It is the control method of the display apparatus which has this.

The present invention comprises a plurality of control areas that can independently control light emission, each control area having a plurality of light sources having different light emission characteristics,
Display means for displaying an image by adjusting the transmittance of incident light incident from the light emitting means based on image data;
A display device control method comprising:
Controlling light emission of the light source of each control area based on the image data;
Based on the control information of the light source, the characteristics of the incident light incident on the display means from the light emitting means is calculated for each area of the display means, and from the relationship between the color based on the image data and the characteristics of the incident light, Determining a region of attention where a shift in perceived color due to individual differences in color matching functions occurs;
Displaying the information on the attention area on the display means;
It is the control method of the display apparatus which has this.

  According to the present invention, in a display device including a plurality of light sources having different light emission characteristics and capable of independently controlling lighting for each light source, information on a region displayed in a color different from a color based on image data is presented to an observer. can do.

1 is a configuration diagram of a display device 100 according to a first embodiment. The figure which shows an example of the image data 1010 of Example 1. FIG. The figure which shows an example of the division | segmentation of the image data by the image block of Example 1. The figure which shows an example of the low-saturation area | region of Example 1, 3. The figure which shows an example of the statistic information 1020 of Example 1. FIG. Configuration diagram of a backlight controlled by the display device 100 according to the first and third embodiments. The figure which shows an example of the lighting parameter 1030 of Example 1. FIG. The figure which shows an example of the light intensity from each light source in the control area of Example 1 The figure which shows an example of the intensity | strength of the synthetic | combination light of the light of the narrow band light source of Example 1, and the light of a broadband light source The figure which shows an example of the incident light information 1040 of Example 1. FIG. Displayable color gamut when only the narrow-band light source or broadband light source of Example 1 is turned on FIG. 10 is a diagram illustrating an example of color gamut information 1050 according to the first embodiment. The figure which shows an example of the determination information 1060 of Example 1. FIG. FIG. 10 is a diagram illustrating an example of first pixel value information 1070 according to the first embodiment. The figure which shows an example of the warning superimposition process of Example 1. FIG. 7 is a flowchart illustrating a processing procedure of the display device according to the first embodiment. The flowchart which shows the process sequence of the determination part 106 of Example 1. FIG. The flowchart which shows the process sequence of the correction | amendment part 107 of Example 1. FIG. The flowchart which shows the process sequence of the superimposition part 108 of Example 1. FIG. Configuration diagram of display device 1600 of Embodiment 2 The figure which shows an example of the statistics information 16010 of Example 2. FIG. Configuration diagram of backlight controlled by display device 1600 of Example 2 The figure which shows an example of the lighting parameter 16020 of Example 2. FIG. The figure which shows an example of the intensity | strength of the light from each color light source of Example 2. The figure which shows an example of the intensity | strength of the synthetic | combination light of the light from each color light source of Example 2. The figure which shows an example of the incident light information 16030 of Example 2. FIG. FIG. 10 is a diagram illustrating an example of color gamut information 16040 according to the second embodiment. Configuration diagram of display device of embodiment 3 10 is a flowchart illustrating a processing procedure of the display device according to the third embodiment. The figure showing the spreading | diffusion of the light of the light source of the display apparatus of Example 3. 10 is a flowchart illustrating a processing procedure for calculating a warning area of the display device according to the third embodiment. The figure which shows the process example of the display apparatus of Example 3. The figure which shows the example of a warning display of the display apparatus of Example 3. The figure which shows the positional relationship of the light source of a display apparatus of Example 3, and a pixel. The figure which shows the structural example of the display apparatus of Example 4. FIG. The figure showing the structural example of the backlight of the display apparatus of Example 4. FIG. 10 is a flowchart illustrating a processing procedure of the display device according to the fourth embodiment.

Example 1
FIG. 1 shows the configuration of the display device 100 according to the first embodiment of the present invention.
The display device 100 according to the first embodiment includes an input unit 101, a detection unit 102, a light source determination unit 103, an estimation unit 104, a color gamut calculation unit 105, a determination unit 106, a correction unit 107, a superimposition unit 108, a drive unit 109, and a display unit. 110.

  The input unit 101 inputs image data 1000 from the outside of the display device 100. The input unit 101 includes terminals of communication standards such as DVI (Digital Visual Interface) and HDMI (registered trademark) (High-Definition Multimedia Interface), and processing circuits thereof. The input unit 101 may be a USB (Universal Serial Bus), a LAN (Local Area Network), or the like.

  The input unit 101 converts the image data 1000 into image data 1010 in a format suitable for internal processing of the display device 100 and outputs the image data 1010 to the detection unit 102, the determination unit 106, and the correction unit 107. Here, in the first embodiment, the image size (number of pixels) of the image data 1010 is 1920 pixels wide and 1080 pixels high, and each pixel is raster data expressed by 8 bits for each of RGB. The color system of the image data 1010 is a CIE RGB color system. The image size, the number of bits, and the like are examples and are not limited thereto.

  FIG. 2A shows an example of the image data 1010 according to the first embodiment. In FIG. 2 (A), the part without the central shading is an area composed of pixels of low saturation color, and the part with the shading of the peripheral part is composed of pixels of non-low saturation color. It is an area. Here, the color with low saturation is white, and the color with non-low saturation is red. In FIG. 2A, the coordinates of the four vertices P1, P2, P3, and P4 of the low saturation color pixel region are (640, 270), (1280, 270), (640, 810), (1280, 810).

  The detection unit 102 divides the input image data 1010 into image blocks, and acquires feature amounts or statistical amounts for each image block. Here, the statistic of each image block is information indicating whether or not there is a low-saturation color pixel in the image block.

  FIG. 3 is a diagram illustrating an example of image data division by image blocks. The detection unit 102 divides the image data 1010 into X × Y image blocks in total X in the horizontal direction and Y in the vertical direction. In the first embodiment, an example will be described in which the number of image blocks in the horizontal direction is six and the number of image blocks in the vertical direction is four, and the image data is divided by a total of 24 image blocks. In the first embodiment, the size of each image block is equal to 320 pixels horizontally and 270 pixels vertically. The number of divisions of image data by image blocks is an example and is not limited to this.

The detection unit 102 converts the pixel value of each pixel of the image data 1010 into a value of the xy color system (xy chromaticity coordinate value). The image data 1010 of the first embodiment is a CIE RGB color system. The detection unit 102 calculates xy chromaticity coordinates corresponding to the pixel value of each pixel according to the following formulas 1 to 5.

X = 0.4898R + 0.3101G + 0.2001B (Formula 1)
Y = 0.1769R + 0.8124G + 0.0107B (Formula 2)
Z = 0.0000R + 0.0100G + 0.9903B (Formula 3)

x = X / (X + Y + Z) (Formula 4)
y = Y / (X + Y + Z) (Formula 5)

FIG. 4 is a diagram illustrating a white point and a low saturation region in the xy chromaticity plane. The detection unit 102
In the xy chromaticity plane, a color range in which the distance from the xy chromaticity coordinates (WPx, WPy) of the white point is smaller than a predetermined value r is defined as a low saturation region, and the xy chromaticity coordinates included in the low saturation region are included. The pixel is determined as a low saturation pixel. The predetermined value r represents a low-saturation chromaticity range close to white in which individual differences due to color matching functions tend to appear in color vision, and is determined in advance based on the emission spectrum of the light source provided in the backlight. The detection unit 102 determines a pixel having xy chromaticity coordinates outside the low saturation region as a non-low saturation pixel. In the first embodiment, the value of the xy chromaticity coordinates (WPx, WPy) of the white point is (0.33, 0.33), and the value of r is 0.08. Note that the value of the predetermined value r may be arbitrarily designated by the user.

  Based on the determination result of whether or not each pixel acquired by the above-described method is a low saturation pixel, the detection unit 102 outputs information on the presence or absence of the low saturation pixel for each image block as the statistic information 1020. FIG. 5 is a diagram illustrating an example of the statistic information 1020. The statistic information 1020 is data composed of image block coordinates and low chroma pixel presence / absence information (0 is no low chroma pixel and 1 is a low chroma pixel). FIG. 2B shows the detection result of the statistic for each image block when the statistic is obtained as described above for the image data of FIG. In FIG. 2B, one rectangle surrounded by a solid line represents one image block.

  The light source determination unit 103 generates a lighting parameter 1030 that is information on the light emission control of the light source that constitutes the backlight based on the input statistical information 1020.

  The configuration of the backlight of the display device 100 of Example 1 is shown in FIG. The backlight of the display device 100 includes a plurality of control areas that can independently control light emission. The number of control areas constituting the backlight is a total of X × Y, X in the horizontal direction and Y in the vertical direction. In the first embodiment, the number of control areas constituting the backlight is the same as the number of image data 1010 divided by the image block in order for the detection unit 102 to acquire the statistics, and six in the horizontal direction and four in the vertical direction. 24 in total. As shown in FIG. 6, the control areas are arranged at predetermined intervals. In the first embodiment, the boundary between the control areas in the backlight and the boundary between the image blocks in the image data are the same, and one control area corresponds to one image block.

  Each control area of the backlight has a plurality of light sources having different light emission characteristics. Specifically, R (red), G (green), B (blue), and W (white) LEDs are arranged. The W LED is a first light source having a broad emission spectrum, and the R, G, and B LEDs are second light sources having a narrow emission spectrum.

  Based on the statistic information 1020, the light source determination unit 103 generates a lighting parameter indicating control information indicating which of the narrow band light source and the broadband light source is turned on for each control area. The light source determination unit 103 generates a lighting parameter for turning on only the broadband light source (W) for the control area corresponding to the image block having the low saturation pixel in the statistic information 1020. The light source determination unit 103 generates a lighting parameter for lighting only the narrow-band light source (RGB) for the control area corresponding to the image block having no low saturation pixel in the statistic information 1020.

FIG. 7 is a diagram illustrating an example of the lighting parameter 1030 generated and output by the light source determination unit 103. In the example of FIG. 7, the narrow-band light source is turned on in the control area (0, 0), and the broadband light source is turned on in the control area (2, 1). The lighting parameter 1030 is data including control area coordinates, narrow-band light source lighting information (0 is not lit, 1 is lit), and broadband light source lighting information (0 is not lit, 1 is lit). . FIG. 2C shows the calculation results of the narrow band light source lighting information and the broadband light source lighting information for each control area when the lighting parameters are obtained as described above for the image data of FIG. In FIG. 2C, one rectangle surrounded by a solid line indicates one control area. In FIG. 2C, for example, “narrow: 1, wide: 0” means that the narrowband light source lighting information is 1 and the broadband light source lighting information is 0.

  The estimation unit 104 estimates the distribution of the characteristics of the backlight light incident on the display unit 110 based on the lighting parameter 1030. Specifically, the estimation unit 104 calculates the intensity of narrowband light and the intensity of broadband light incident from the backlight for each pixel of the display unit 110 and outputs the calculated light as incident light information 1040. Narrowband light is light derived from a narrowband light source, and broadband light is light derived from a broadband light source.

Here, in general, the light from the LED has a spread rather than only directly above the LED. Therefore, in the first embodiment, the description will be made assuming that the light of the LED in a certain control area spreads to a control area diagonally adjacent to the left and right of the control area. An example of how the LED light spreads is shown in FIG. FIG. 8 is a diagram showing the narrowband light intensity and the broadband light intensity in the control areas (0, 1) to (5, 1). In FIG. 8, only the narrow-band light source is lit in the control area (0, 1), the control area (1, 1), the control area (4, 1), and the control area (5, 1). In the control area (2, 1) and the control area (3, 1), only the broadband light source is lit.
As shown in FIG. 8, only the narrow-band light source is lit in the control area (1, 1) and the control area (4, 1), but the light from the broadband light source in the surrounding control area enters. Similarly, in the control area (2, 1) and the control area (3, 1), only the broadband light source is lit, but the light of the narrow band light source in the surrounding control area enters.

  FIG. 9 is a diagram showing the light intensity of the combined light of the broadband light source and the combined light of the narrow band light source in each control area shown in FIG. FIG. 8 and FIG. 9 are simplified for explanation, and only the influence of the light from the light source of each control area on the adjacent control area in the horizontal direction is considered, but originally only in the horizontal direction. In addition, it is necessary to consider the influence on the control areas adjacent in the vertical and diagonal directions. The estimation unit 104 considers the influence of narrowband light and broadband light incident from the control area adjacent to the control area to which the target pixel for calculating the incident light intensity from the backlight belongs in the horizontal and vertical directions as follows. Narrowband light intensity and broadband light intensity incident on the target pixel are calculated.

式６、式７において、座標（ｐ，ｑ）の画素が属する制御エリアの座標（Ｘ，Ｙ）とする。
係数ＫＮ_{ｐｑ（Ｘ＋ｉ）（Ｙ＋ｊ）}、ＫＢ_{ｐｑ（Ｘ＋ｉ）（Ｙ＋ｊ）}は、制御エリア（Ｘ＋ｉ，Ｙ＋ｊ）のＬＥＤ由来の光の座標（ｐ，ｑ）の画素における強度を示す係数である。
Ｂ_{（Ｘ＋ｉ）（Ｙ＋ｊ）}は、制御エリア（Ｘ＋ｉ，Ｙ＋ｊ）の広帯域光源の点灯情報である。
Ｎ_{（Ｘ＋ｉ）（Ｙ＋ｊ）}は、制御エリア（Ｘ＋ｉ，Ｙ＋ｊ）の狭帯域光源の点灯情報である。
これら点灯情報の値は点灯パラメータ１０３０として算出された値である。 The estimation unit 104 calculates the light intensity NE _pq derived from the narrow-band light source and the light intensity BE _pq derived from the broadband light source incident on the pixel at the coordinates (p, q) from the backlight by the following expressions 6 and 7.

In Expressions 6 and 7, the coordinates (X, Y) of the control area to which the pixel with the coordinates (p, q) belongs are set.
The coefficients _{KNpq (X + i) (Y + j)} and _{KBpq (X + i) (Y + j)} are coefficients indicating the intensity at the pixel of the coordinate (p, q) of the light derived from the LED in the control area (X + i, Y + j).
B _{(X + i) (Y + j)} is lighting information of the broadband light source in the control area (X + i, Y + j).
N _{(X + i) (Y + j)} is lighting information of the narrow-band light source in the control area (X + i, Y + j).
These lighting information values are values calculated as the lighting parameter 1030.

  In the first embodiment, the backlight that is incident on the target pixel by superimposing the light intensity derived from the narrow-band light source and the light intensity derived from the broadband light source in the control area that is adjacent to the control area to which the target pixel belongs in the diagonal direction. Find the light intensity. Therefore, in Expression 6 and Expression 7, -1 ≦ i ≦ 1 and −1 ≦ j ≦ 1. Thereby, the estimation unit 104 calculates the characteristics of the incident light on the display unit based on the diffusion characteristics of the light from the light source.

The estimation unit 104 outputs the calculated information on the narrowband light intensity NE _pq and the broadband light intensity BE _pq of the backlight light incident on each pixel as incident light information 1040.
FIG. 10 is a diagram illustrating an example of incident light information 1040. Here, the backlight light incident on the pixel at coordinates (0, 0) is only a narrow-band light source, and the backlight light incident on the pixel at coordinates (960, 590) is only broadband light. The backlight light incident on the pixel at the coordinates (630, 540) is a pixel located in the control area (1, 2), and both narrowband light and broadband light are incident from the backlight. The incident light information 1040 is data including information on pixel coordinates, narrowband light intensity, and broadband light intensity.

The color gamut calculation unit 105 calculates the displayable color gamut of each pixel based on the input incident light information 1040 and outputs the calculated color gamut information 1050. The displayable color gamut is represented by a triangle connecting three vertices on the xy chromaticity plane.
FIG. 11 shows the displayable color gamut when only the narrow-band light source is lit, the displayable color gamut when only the broadband light source is lit, and the displayable color gamut when both are lit in the xy chromaticity system. FIG. In the first embodiment, the xy chromaticity coordinates of the three vertices representing the displayable color gamut when only the narrow-band light source is turned on have the following values.

Vertex NR (NRx, NRy) = (0.65, 0.33)
Vertex NG (NGx, NGy) = (0.21, 0.71)
Vertex NB (NBx, NBy) = (0.15, 0.06)

In addition, the xy chromaticity coordinates of the three vertices representing the displayable color gamut when only the broadband light source is turned on have the following values.

Vertex BR (BRx, BRy) = (0.52, 0.33)
Vertex BG (BGx, BGy) = (0.28, 0.56)
Vertex BB (BBx, BBy) = (0.23, 0.17)

  In addition, said value is an example. In the first embodiment, the values of the xy chromaticity coordinates of the three vertices representing the displayable color gamut of the pixel only incident with the narrowband light and the xy chromaticities of the three vertices representing the displayable color gamut of the pixel only incident with the broadband light are input. The coordinate value is stored in advance in a storage device provided in the display device 100. Each processing unit can appropriately read the information from the storage device.

ここで、ＮＥ_ｐｑは座標（ｐ，ｑ）の画素に入射する狭帯域光強度であり、ＢＥ_ｐｑは座標（ｐ，ｑ）の画素に入射する広帯域光強度である。これらの値は推定部１０４で算出
され入射光情報１０４０として出力されたものである。 Based on the incident light information 1040, the color gamut calculation unit 105 calculates the ratio NEP _pq of narrowband light and the ratio BEP _{pq of} broadband light incident on each pixel (p, q) by the following formulas 8 and 9.

Here, NE _pq is the narrow band light intensity incident on the pixel at coordinates (p, q), and BE _pq is the broadband light intensity incident on the pixel at coordinates (p, q). These values are calculated by the estimation unit 104 and output as incident light information 1040.

Next, the color gamut calculation unit 105 calculates a displayable color gamut for each pixel. Expressions 10 to 15 show calculation formulas for the displayable color gamut. Displayable color gamut is a region inside the triangle defined by the chromaticity point _{CS R, CS G, CS B} . The color gamut calculation unit 105 obtains xy chromaticity coordinates of three chromaticity points that define a displayable color gamut for each pixel. Xy chromaticity coordinates of the _{CS R (CS Rx, CS Ry} ), xy chromaticity coordinates of the _{CS G (CS Gx, CS Gy} ), xy chromaticity coordinates _(CS Bx, CS _By) of CS _B has the formula 10 below Calculated by Equation 15.

The color gamut calculation unit 105 outputs the narrowband light intensity, the broadband light intensity, and the calculated displayable color gamut information of each pixel to the determination unit 106 and the correction unit 107 as color gamut information 1050.
FIG. 12 is a diagram illustrating an example of the color gamut information 1050. The color gamut information 1050 includes pixel coordinates, light intensity derived from a narrow band light source, light intensity of a broadband light source, and a displayable color gamut (xy chromaticity coordinate values of three vertices representing a displayable color gamut). It is data.

  In the example of FIG. 12, the backlight light incident on the pixel at coordinates (0,0) is only narrowband light, so the displayable color gamut of the pixel at coordinates (0,0) is the narrowband light source of FIG. This is the same as the displayable color gamut when only the light is on. Further, since the backlight light incident on the pixel at coordinates (960, 590) is only broadband light, the displayable color gamut of the pixel at coordinates (960, 590) can be displayed when only the broadband light source in FIG. 11 is lit. Similar to the color gamut. Since both the narrow-band light and the broadband light are incident on the pixel at the coordinates (630, 540), the displayable color gamut of the pixel at the coordinates (630, 540) has a narrow-band light intensity and a wide-band light intensity. The color gamut can be displayed according to the ratio.

Based on the input image data 1010 and color gamut information 1050, the determination unit 106 is information regarding whether or not the color (target display chromaticity) to be displayed on each pixel is included in the displayable color gamut of the pixel. Some determination information 1060 is output. When the target display chromaticity is not included in the displayable color gamut, the color assumed from the image data is different from the actually displayed color. In such a pixel, there is a possibility that a deviation occurs between the color assumed from the image data and the actually observed color.
The determination unit 106 first calculates the target display chromaticity CLxy of each pixel based on the image data 1010. The calculation formula of the target display chromaticity CLxy is the same as the formulas 1 to 5 used in the processing of the detection unit 102, and the xy chromaticity coordinate value is calculated from the pixel value (RGB).
Next, the determination unit 106 determines whether or not the calculated display target chromaticity CLxy of each pixel is included in the displayable color gamut (output as the color gamut information 1050) of each pixel. The determination unit 106 collectively outputs information as to whether or not the target display chromaticity CLxy is included in the displayable color gamut as determination information 1060.

  FIG. 13 is a diagram illustrating an example of the determination information 1060. The determination information 1060 is data including pixel coordinates (p, q) and information indicating whether the target display chromaticity of each pixel is included in the displayable color gamut of each pixel (hereinafter, display enable / disable information). It is. The display availability information represents 0 (display is possible) if the target display chromaticity is included in the displayable color gamut, and 1 (cannot be displayed) if the target display chromaticity is not included in the displayable color gamut.

Here, the pixel at the coordinate (0, 0) is a non-low saturation pixel, and the target display chromaticity is a color with high saturation, but the displayable color gamut is a displayable color when only a narrow-band light source is lit. Wide color gamut can be displayed in the same color gamut as the color gamut. Therefore, the target display chromaticity is within the displayable color gamut, and the display enable / disable information is 0.
Further, the pixel at the coordinates (960, 590) is a low saturation pixel, the color of the target display chromaticity is low, and the displayable color gamut is the same color as the displayable color gamut when only the broadband light source is lit. Narrow in the area. Therefore, the target display chromaticity is within the displayable color gamut, and the display enable / disable information is 0.
In addition, the pixel with coordinates (630, 540) has the same target display chromaticity as the pixel with coordinates (0, 0), but the incident light from the backlight includes both narrowband light and broadband light. The possible color gamut is narrower than the displayable color gamut of the pixel at coordinates (0, 0). Here, it is assumed that the target display chromaticity of the pixel at coordinates (630, 540) is outside the displayable color gamut. In this case, the display availability information is 1.

The correction unit 107 calculates a pixel value used for transmittance control of each pixel of the display unit 110 based on the input image data 1010, color gamut information 1050, and determination information 1060.
First, the correction unit 107 calculates a target display chromaticity of a processing target pixel (coordinates (p, q)) based on the image data 1010. Here, the calculation formula of the target display chromaticity is the same as the formulas 1 to 5 used in the processing of the detection unit 102.
Next, the correction unit 107 determines whether the target display chromaticity of the target pixel is outside the displayable color gamut based on the determination information 1060. If the target display chromaticity is out of the displayable color gamut, Correct the degree. Specifically, the correction unit 107 selects one chromaticity within the displayable color gamut that is closest to the target display chromaticity on the xy chromaticity plane, and uses that chromaticity as the new target display color of the target pixel. Degree. The correction unit 107 converts the new target display chromaticity from a coordinate value on the xy chromaticity plane to an XYZ value for calculation described later. The new target display chromaticity XYZ values obtained by the conversion are defined as HSX _pq , HSY _pq , and HSZ _pq . When the target display chromaticity of the target pixel is within the displayable color gamut of the pixel, the target display chromaticity is not corrected.

ここでＫＮＲＸ、ＫＮＲＹ、ＫＮＲＺはそれぞれ対象画素に入射する狭帯域光強度の比率ＮＥＰ_ｐｑから入射光のＸＹＺ値を求めるための係数である。またＫＢＲＸ、ＫＢＲＹ、ＫＢＲＺはそれぞれ対象画素に入射する広帯域光強度の比率ＢＥＰ_ｐｑから入射光のＸＹＺ値を求めるための係数である。補正部１０７は、対象画素に入射するバックライト光のＧ色、Ｂ色のＸＹＺ値についても同様の方法で算出する。 Next, the correction unit 107 calculates the chromaticity of the backlight light incident on the target pixel as an XYZ value. The correction unit 107 calculates the R value X value RL _pq . Of the backlight light incident on the pixel at coordinates (p, q). X, Y values RL _pq . Y, Z value RL _pq . Z is calculated by Equation 16 below.

Here, KRRX, KRRY, and KNRZ are coefficients for obtaining the XYZ value of incident light from the ratio NEP _pq of the narrow-band light intensity incident on the target pixel. KBRX, KBRY, and KBRZ are coefficients for obtaining the XYZ value of the incident light from the ratio BEP _pq of the broadband light intensity incident on the target pixel. The correcting unit 107 calculates the XYZ values of the G and B colors of the backlight light incident on the target pixel by the same method.

補正部１０７は、対象画素の補正後のＲＧＢ値（ＧＲ_ｐｑ、ＧＧ_ｐｑ、ＧＢ_ｐｑ）を式１８で算出する。

なお、補正部１０７は、対象画素の当初の目標表示色度が当該画素の表示可能色域内である場合、対象画素のＲＧＢ値を補正せずそのまま補正後のＲＧＢ値（ＧＲ_ｐｑ、ＧＧ_ｐｑ、ＧＢ_ｐｑ）として出力する。
最後に、補正部１０７は、上記のように算出した全ての画素の画素値を第１画素値情報１０７０として出力する。 Next, the correction unit 107 calculates a pixel value used for transmittance control of the target pixel based on the calculated XYZ value of the incident light of the target pixel and the new target display chromaticity of the target pixel. Specifically, the correction unit 107 uses the R color and the G color of the backlight light incident on the target pixel with respect to the XYZ values (HSX _pq , HSY _pq , HSZ _pq ) of the new target display chromaticity of the target pixel. The inverse matrix of the matrix composed of XYZ values of chromaticity for each of the B colors is multiplied. An inverse matrix iG of a matrix composed of XYZ values of the chromaticities of the R color, the G color, and the B color of the backlight light is expressed by Expression 17.

The correction unit 107 calculates the corrected RGB values (GR _pq , GG _pq , GB _pq ) of the target pixel using Expression 18.

In addition, when the initial target display chromaticity of the target pixel is within the displayable color gamut of the target pixel, the correction unit 107 does not correct the RGB value of the target pixel and corrects the corrected RGB values (GR _pq , GG _pq , GB _pq ).
Finally, the correction unit 107 outputs the pixel values of all the pixels calculated as described above as the first pixel value information 1070.

FIG. 14 is a diagram illustrating an example of the first pixel value information 1070. The first pixel value information 1070 is data composed of pixel coordinates and pixel values (GR _pq , GG _pq , GB _pq ) calculated by the correction unit 107. Here, as shown in FIG. 2C, the pixel at coordinates (960, 590) is a low saturation pixel (white), and the pixel at coordinates (630, 540) and the pixel at coordinates (0, 0) are Non-low saturation pixel (red). The pixel at coordinates (630, 540) and the pixel at coordinates (0, 0) are the same red pixels in the input image, but have different pixel values in the first pixel value information 1070. This is because the chromaticity of the incident backlight is different between the pixel at coordinates (630, 540) and the pixel at coordinates (0, 0). Since the pixel at the coordinates (630, 540) receives both narrowband light and broadband light as shown in the incident light information 1040 in FIG. 10, the displayable color gamut as shown in the color gamut information 1050 in FIG. Is narrower than when only broadband light is used. Therefore, as shown in the determination information 1060 in FIG. 13, the initial target display chromaticity based on the pixel value of the input image is out of the displayable color gamut. Thus, if the light source that emits light in the control area corresponding to the pixel to be determined is a narrow-band light source and the light source that emits light in at least one control area adjacent to the control area is a broadband light source, the pixel is warned. The target pixel can be determined. Therefore, the initial target display chromaticity of this pixel is changed to a new target display chromaticity having a chromaticity within the displayable color gamut of the pixel and closest to the initial target display chromaticity by correction. The Then, as shown in the first pixel value information 1070 of FIG. 14, a pixel value for displaying a new target display chromaticity is set as a pixel value (new pixel value) used for transmittance control of this pixel. .

  Based on the input determination information 1060 and the first pixel value information 1070, the superimposing unit 108 displays a warning for presenting information on a caution area including pixels whose original target display chromaticity is outside the displayable color gamut to the user. The image is superimposed on the input image corrected by the correction unit 107. In the first embodiment, as the warning display image, an image in which an area composed of pixels whose original target display chromaticity is outside the displayable color gamut is emphasized with diagonal lines is displayed. Thereby, the superimposing unit 108 performs display control for displaying information on the attention area on the display unit.

  First, based on the determination information 1060, the superimposing unit 108 calculates the pixel value of a pixel whose original target display chromaticity is not included in the displayable color gamut (a pixel whose display availability information of the determination information 1060 is 1) as a pixel of the warning display image Replace with value. Specifically, the superimposing unit 108 acquires display permission / prohibition information of the pixel to be processed based on the determination information 1060. The superimposing unit 108 stores the pixel value of the pixel whose display enable / disable information is 1 (the pixel that cannot display the original target display chromaticity) among the pixel values of the first pixel value information 1070 in advance. The pixel value is replaced and output as second pixel value information. The superimposing unit 108 outputs the pixel value of the pixel whose display enable / disable information is 0 among the pixels of the first pixel value information 1070 (the pixel that can display the original target display chromaticity) as the second pixel value information.

FIG. 15 is a diagram illustrating an example of a warning image superimposing process of the superimposing unit 108. Here, the image 151 indicates an image represented by the pixel value of the first pixel value information 1070. The shaded portion of the image 152 indicates a region of pixels whose original target display chromaticity acquired from the determination information 1060 is not included in the displayable color gamut (pixels whose displayability information of the determination information 1060 is 1). An image 153 shows a predetermined warning display image held in advance by the superimposing unit 108. An image 154 shows an area of the first pixel value information 1070 that the superimposing unit 108 replaces with a warning display image. An image 155 shows an image represented by pixel values after the superposition unit 108 completes the replacement of the pixel values.
The superimposing unit 108 outputs, as second pixel value information 1080, pixel value information for which pixel value replacement processing has been completed for the first pixel value information 1070.

  In the first embodiment, an example has been described in which diagonal lines are displayed as a warning display image in a region of pixels (referred to as pixels outside the display color gamut) whose original target display chromaticity is not included in the displayable color gamut. In this case, since all the pixels outside the display color gamut are finally replaced with the warning display image, display based on the pixel value corrected by the correction unit 107 is not performed. Therefore, when such a warning display is performed, the correction processing of the pixel values of the pixels outside the display color gamut by the correction unit 107 may be omitted.

  However, various methods other than the above-described method of painting out the display color gamut pixels with the warning display image can be considered as methods for presenting information such as the presence of the display color gamut pixels and their positions to the user. For example, text display such as “cannot display the color to be displayed” on the screen may be performed, or the outer frame (boundary line) of the pixel outside the display color gamut may be highlighted with a high saturation pixel or the like. . Thus, when highlighting the boundary line of the region outside the display color gamut, the pixels inside the boundary line are not replaced with the warning display image, so that the pixel value is corrected by the correction unit 107 to obtain the corrected pixel value. Display based on.

The drive unit 109 generates and outputs a drive signal 1090 for driving the backlight based on the input lighting parameter 1030.
The display unit 110 is a liquid crystal display device including a liquid crystal panel, a backlight, and respective controllers. The liquid crystal panel displays an image by adjusting the transmittance of light incident from the backlight based on the image data. The display unit 110 controls the transmittance of the liquid crystal element of each pixel of the liquid crystal panel based on the input second pixel value information 1080, and controls the lighting of each light source in each control area of the backlight based on the drive signal 1090. . Thereby, an image based on the second pixel value information 1080 is displayed on the display unit 110.

A processing procedure of the display device according to the first embodiment will be described with reference to a flowchart of FIG.
In step S <b> 101, image data 1000 is input from the input unit 101.
In step S <b> 102, the detection unit 102 calculates statistic information 1020 for each image block based on the image data 1010 acquired from the input unit 101. The statistic information 1020 is information on the presence or absence of low-saturation pixels in the image block.
In step S <b> 103, the light source determination unit 103 determines a lighting parameter 1030 for each backlight control area based on the statistic information 1020 acquired from the detection unit 102. The lighting parameter 1030 is information indicating which of the narrow band light source and the broadband light source is turned on in the control area.

In step S <b> 104, the estimation unit 104 calculates incident light information 1040 for each pixel based on the lighting parameter acquired from the light source determination unit 103. The incident light information 1040 is information on the intensity of narrowband light and the intensity of broadband light incident on the pixel.
In step S105, the color gamut calculation unit 105 calculates color gamut information 1050 for each pixel based on the incident light information 1040. The color gamut information 1050 is information on the color gamut that can be displayed on the pixel under the condition of backlight light incident on the pixel.
In step S <b> 106, the determination unit 106 calculates determination information 1060 for each pixel based on the color gamut information 1050 and the image data 1010. The determination information 1060 is information indicating whether or not the initial target display chromaticity of the pixel based on the image data 1010 can be displayed on the pixel. The processing procedure of step S106 will be described later based on the flowchart of FIG.

In step S107, the correction unit 107 calculates first pixel value information 1070 for each pixel based on the determination information 1060 and the image data 1010. The first pixel value information 1070 is a pixel value obtained by correcting the pixel value of a pixel whose initial target display chromaticity is outside the displayable color gamut so that the display chromaticity falls within the displayable color gamut. The processing procedure of step S107 will be described later based on the flowchart of FIG.
In step S108, the superimposing unit 108 calculates second pixel value information for each pixel based on the determination information 1060 and the first pixel value information 1070. The second pixel value information 1080 is image data obtained by superimposing a warning display image that presents information on pixels whose initial target display chromaticity is outside the displayable color gamut to the original image. The processing procedure of step S108 will be described later based on the flowchart of FIG.
In step S109, the backlight of the display unit 110 emits light based on the drive signal 1090 output from the drive unit 109, and the liquid crystal panel of the display unit 110 is controlled for transmittance based on the second pixel value information 1080, thereby generating an image. Display is performed.

The processing procedure of step S106 will be described based on the flowchart of FIG.
In step S <b> 110, the determination unit 106 acquires a displayable color gamut of the processing target pixel based on the color gamut information 1050.
In step S111, the determination unit 106 acquires the initial target display chromaticity of the processing target pixel based on the image data 1010.
In step S112, the determination unit 106 determines whether the initial target display chromaticity of the processing target pixel is within the displayable color gamut. If the initial target display chromaticity is within the displayable color gamut, the process proceeds to step S113. If the initial target display chromaticity is outside the displayable color gamut, the process proceeds to step S114.
In step S113, the determination unit 106 sets the display availability information of the processing target pixel to 0.
In step S <b> 114, the determination unit 106 sets the display availability information of the processing target pixel to 1.
In step S115, the determination unit 106 repeats the above processing for all the pixels, and outputs display enable / disable information for all the pixels as the determination information 1060.

The processing procedure of step S107 will be described based on the flowchart of FIG.
In step S116, the correction unit 107 acquires the initial target display chromaticity of the processing target pixel based on the image data 1010.
In step S117, the correction unit 107 acquires display enable / disable information of the processing target pixel based on the determination information 1060.
In step S118, the correction unit 107 determines whether the display availability information of the processing target pixel is 0 or 1. When the display availability information is 1 (when the initial target display chromaticity is outside the displayable color gamut), the process proceeds to step S119. When the display availability information is 0 (when the initial target display chromaticity is within the displayable color gamut), the process proceeds to step S121.

In step S119, the correction unit 107 acquires the chromaticity within the displayable color gamut of the processing target pixel and closest to the original target display chromaticity as a new target display chromaticity (HSX _pq , HSY _pq , HSZ _pq ).
In step S120, the correction unit 107 calculates the corrected pixel value of the pixel (GR _pq , GG _pq , GB _pq ) based on the new target display chromaticity of the processing target pixel.
In step S121, the correction unit 107 outputs the pixel value based on the image data of the processing target pixel as the corrected pixel value as it is.
In step S122, the correction unit 107 repeats the above processing for all the pixels, and outputs the pixel values after correction of all the pixels as the first pixel value information 1070.

The processing procedure of step S108 is demonstrated based on the flowchart of FIG.
In step S123, the superimposition unit 108 acquires display enable / disable information of the processing target pixel based on the determination information 1060.
In step S <b> 124, the superimposing unit 108 determines whether the display availability information of the processing target pixel is 0 or 1. When the display availability information is 1 (when the initial target display chromaticity is outside the displayable color gamut), the process proceeds to step S125. When the display availability information is 0 (when the initial target display chromaticity is within the displayable color gamut), the process proceeds to step S126.

In step S125, the superimposing unit 108 replaces the pixel value of the processing target pixel in the first pixel value information 1070 with the pixel value of the warning display image.
In step S126, the superimposing unit 108 outputs the pixel value of the processing target pixel in the first pixel value information 1070 as it is.
In step S127, the superimposing unit 108 repeats the above process for all the pixels, and outputs the corrected pixel values of all the pixels as the second pixel value information 1080.

  According to the first embodiment, light emission control values of a plurality of light sources are obtained based on input image data, a displayable color gamut is calculated for each pixel, and whether or not the original target display chromaticity can be displayed is determined for each pixel. When there is a pixel that cannot be displayed, a display for presenting information on the pixel to the user is performed. The user can easily know that there is a pixel that cannot display the color that should be displayed in the displayed image. As a result, for example, it is possible to suppress a situation in which the user knows that the calibration or image editing work has been performed in a state where the display color is not correct, and restarts the work, thereby improving convenience.

(Example 2)
In the first embodiment, the embodiment in which the present invention is applied to a display device including a narrow band light source and a broadband light source in the backlight has been described. In the second embodiment, an embodiment in which the present invention is applied to a display device that includes R, G, and B LEDs in a backlight and controls the light emission amount of each color LED according to an image will be described.

FIG. 20 shows the configuration of the display device 1600 according to the second embodiment.
Here, elements given the same reference numerals as those in FIG. 1 in FIG. 20 are elements that perform the same processing as the elements described in the first embodiment, and thus description thereof is omitted.
A display device 1600 according to the second embodiment includes an input unit 101, a detection unit 1601, a light source determination unit 1602, an estimation unit 1603, a color gamut calculation unit 1604, a determination unit 1605, a correction unit 1606, a superimposition unit 1607, a drive unit 1608, and a display unit. 1609.

The detection unit 1601 divides the input image data 1010 into image blocks, and acquires statistics for each image block. The statistic acquired by the detection unit 1601 in the second embodiment is the maximum pixel value of each RGB color of the pixels in the image block (hereinafter referred to as the maximum pixel value).
First, the detection unit 1601 divides the image data 1010 into a total of X × Y image blocks of X in the horizontal direction and Y in the vertical direction. In the second embodiment, the number of divisions is 24 in total, 6 in the horizontal direction and 4 in the vertical direction.
Next, the detection unit 1601 acquires the pixel value of each pixel of the image data 1010 in order to calculate the statistic, and calculates the maximum pixel value of each color of RGB in the image block for each image block.
The detection unit 1601 outputs, as statistical information 16010, information on the maximum pixel value of each RGB color for each image block acquired as described above.

  Here, it is assumed that the image data input to the display device 1600 of the second embodiment is the same as the image data (see FIG. 2A) shown in the first embodiment. In other words, the central area of the image is composed of low-saturation colors, and the peripheral area shown by shading is composed of non-low-saturation colors. In the second embodiment, the low saturation color is assumed to be white, and the non-low saturation color is assumed to be red.

  FIG. 21 is a diagram showing an example of the statistic information 16010. In FIG. 21, since the pixel in the image block (0, 0) is only red, only the maximum pixel value (R) has a value. Since the pixels in the image block (2, 1) are only white, the maximum pixel value (R), the maximum pixel value (G), and the maximum pixel value (B) all have large values. The statistic information 16010 is data including image block coordinates and RGB maximum pixel values.

The light source determination unit 1602 calculates the light emission amount of each light source of the backlight based on the input statistical information 16010 and outputs it as the lighting parameter 16020.
The configuration of the backlight of the display device 1600 of Example 2 is shown in FIG. The backlight according to the second embodiment includes a plurality of control areas that can individually control light emission. The number of control areas constituting the backlight is a total of X × Y, X in the horizontal direction and Y in the vertical direction. In the second embodiment, the number of control areas constituting the backlight is the same as the number of image data 1010 divided by the image block in order for the detection unit 1601 to obtain statistics, which is six in the horizontal direction and four in the vertical direction. 24 in total. In each control area of the backlight, LEDs of R (red), G (green), and B (blue) are arranged as light sources. In the second embodiment, the boundary between the control areas in the backlight and the boundary between the image blocks in the image data are the same, and one control area corresponds to one image block.

ここでＲＨＶ_ＸＹ、ＧＨＶ_ＸＹ、ＢＨＶ_ＸＹは、それぞれ制御エリア（Ｘ，Ｙ）に対応する画像ブロック（Ｘ，Ｙ）のＲ色、Ｇ色、Ｂ色の最大画素値である。またＨＶは画素値の最大階調であり、８ビットの画像データであれば２５５である。 The light source determination unit 1602 first obtains the maximum pixel value of each RGB color of the image block corresponding to each control area based on the statistic information 16010. Next, the light source determination unit 1602 calculates the light emission amounts of the RGB LEDs in each control area. Source determination unit 1602, a control area (X, Y) of the R color LED light emission amount RLED _XY, G color LED light emission amount GLED _XY, B color LED light emission amount BLED the _XY Formula 19, Formula 20, Calculated according to Equation 21.

Here, RHV _XY , GHV _XY , and BHV _XY are the maximum pixel values of the R, G, and B colors of the image block (X, Y) corresponding to the control area (X, Y), respectively. HV is the maximum gradation of the pixel value, and is 255 for 8-bit image data.

The light source determination unit 1602 outputs the light emission amount information of the LEDs of each RGB color in each control area calculated as described above as the lighting parameter 16020.
FIG. 23 is a diagram illustrating an example of the lighting parameter 16020. The lighting parameter 16020 is data composed of information on the coordinates of the control area and the light emission amounts of the LEDs of each RGB color.

The estimation unit 1603 calculates the light intensity of each RGB color LED incident from the backlight for each pixel of the display unit 1609 based on the lighting parameter 16020, and outputs it as incident light information 16030.
Here, in general, the light from the LED has a spread rather than only directly above the LED. Therefore, in the second embodiment, the description will be made assuming that the light of the LED in a certain control area spreads to the control area diagonally adjacent to the control area. An example of how the LED light spreads is shown in FIG. FIG. 24 is a diagram illustrating an example of light emission amounts of the RGB color LEDs in the control areas (0, 1) to (5, 1). In the example of FIG. 24A, a state in which an R color LED emits light in each of the control areas (0, 1) to (5, 1) is shown. FIGS. 24B and 24C show a state in which the G color and B color LEDs are lit in the control area (2, 1) and the control area (3, 1). Note that the light emission amounts of the R, G, and B LEDs shown in FIG. 24 are an example obtained according to the display image shown in FIG. 2A, and have different values depending on the display image.

FIG. 25 is a diagram showing the intensity of the combined light from the LEDs in the respective control areas shown in FIG. 24 for each color of RGB.
FIG. 24 and FIG. 25 are simplified for explanation, and only the influence of the light from the light source of each control area on the adjacent control area in the horizontal direction is considered, but originally only in the horizontal direction. In addition, it is necessary to consider the influence on the control areas adjacent in the vertical and diagonal directions. The estimation unit 1603 considers the influence of the light of each RGB color LED incident from the control area adjacent to the control area to which the target pixel for calculating the incident light intensity from the backlight belongs in the horizontal and vertical directions as follows. The intensity of each RGB color LED incident on the target pixel is calculated.

式２２，式２３，式２４において、座標（ｐ，ｑ）の画素が属する制御エリアの座標（Ｘ，Ｙ）とする。
係数ＫＲ_{ｐｑ（Ｘ＋ｉ）（Ｙ＋ｉ）}、ＫＧ_{ｐｑ（Ｘ＋ｉ）（Ｙ＋ｉ）}、ＫＢ_{ｐｑ（Ｘ＋ｉ）（Ｙ＋ｉ）}は、制御エリア（Ｘ＋ｉ，Ｙ＋ｊ）のＲＧＢ各色ＬＥＤ由来の光の座標（ｐ，ｑ）の画素における強度を示す係数である。
Ｒ_{（Ｘ＋ｉ）（Ｙ＋ｊ）}は、制御エリア（Ｘ＋ｉ，Ｙ＋ｊ）のＲ色ＬＥＤの発光量（０〜１）である。
Ｇ_{（Ｘ＋ｉ）（Ｙ＋ｊ）}は、制御エリア（Ｘ＋ｉ，Ｙ＋ｊ）のＧ色ＬＥＤの発光量（０
〜１）である。
Ｂ_{（Ｘ＋ｉ）（Ｙ＋ｊ）}は、制御エリア（Ｘ＋ｉ，Ｙ＋ｊ）のＢ色ＬＥＤの発光量（０〜１）である。
これら発光量の値は点灯パラメータ１６０２０として算出された値である。 The estimation unit 1603 calculates the light intensity RE _pq derived from the R color LED, the light intensity GE _pq derived from the G color LED, and the light intensity BE _pq derived from the B color LED incident on the coordinates (p, q) of the target pixel from the backlight. It calculates with the following formula 22, formula 23, and formula 24.

In Expression 22, Expression 23, and Expression 24, the coordinates (X, Y) of the control area to which the pixel with the coordinates (p, q) belongs are set.
The coefficients _{KRpq (X + i) (Y + i)} , _{KGpq (X + i) (Y + i)} , and _{KBpq (X + i) (Y + i)} are the coordinates (p, q) of the light derived from the RGB color LEDs in the control area (X + i, Y + j). It is a coefficient which shows the intensity | strength in this pixel.
R _{(X + i) (Y + j)} is the light emission amount (0 to 1) of the R color LED in the control area (X + i, Y + j).
G _{(X + i) (Y + j)} is the light emission amount (0 of the G color LED in the control area (X + i, Y + j)).
To 1).
B _{(X + i) (Y + j)} is the light emission amount (0 to 1) of the B color LED in the control area (X + i, Y + j).
These light emission amount values are values calculated as the lighting parameter 16020.

  In Example 2, the intensity of light derived from each color LED of RGB in a control area adjacent to the control area to which the target pixel belongs in the left-right and up-down diagonal directions is superimposed to obtain the intensity of the backlight light incident on the target pixel. Therefore, in Expression 22, Expression 23, and Expression 24, −1 ≦ i ≦ 1 and −1 ≦ j ≦ 1.

The estimation unit 1603 outputs information on the calculated light intensities RE _pq , GE _pq , and BE _pq derived from the RGB LEDs incident on each pixel as incident light information 16030.
FIG. 26 is a diagram showing an example of incident light information 16030. Here, the backlight light incident on the pixel at the coordinates (0, 0) is only light derived from the LED (R). The backlight light incident on the pixel at coordinates (960, 590) is light derived from LED (R), LED (G), and LED (B). The backlight light incident on the pixel at the coordinate (1, 0) is only light derived from the LED (R) as in the pixel at the coordinate (0, 0). However, depending on the positional relationship between the LED and the pixel, 0,0) is different in light intensity. The incident light information 16030 is data composed of pixel coordinates and light intensity derived from RGB color LEDs.

  The color gamut calculation unit 1604 calculates the displayable color gamut of each pixel based on the input incident light information 16030 and outputs the color gamut information 16040. The displayable color gamut is represented by a triangle connecting three vertices on the xy chromaticity plane.

次に、色域算出部１６０４は、算出した各画素におけるＲＧＢ各色ＬＥＤ由来の光強度の比率に基づき、各画素の表示可能色域を算出する。表示可能色域は色度点ＣＳ_Ｒ、ＣＳ_Ｇ、ＣＳ_Ｂで定義される三角形内部の領域である。色域算出部１６０４は、画素毎に、表示可能色域を定義する３つの色度点ＣＳ_Ｒ、ＣＳ_Ｇ、ＣＳ_Ｂのｘｙ色度座標を求める。ＣＳ_Ｒのｘｙ色度座標（ＣＳ_Ｒｘ，ＣＳ_Ｒｙ）、ＣＳ_Ｇのｘｙ色度座標（ＣＳ_Ｇｘ，ＣＳ_Ｇｙ）、ＣＳ_Ｂのｘｙ色度座標（ＣＳ_Ｂｘ，ＣＳ_Ｂｙ）は、以下の式２８により算出される。

式２８で、係数Ｋ１１からＫ６３は表示装置１６００に予め設定されている係数である。 The color gamut calculation unit 1604, based on the incident light information 16030, the light intensity ratio REP _pq derived from the R color LED incident on each pixel (p, q), the light intensity ratio GEP _pq derived from the G color LED, and the B color LED. The derived light intensity ratio BEP _pq is calculated by the following formula 25, formula 26, and formula 27. However, when the light intensities derived from the RGB LEDs are all 0, the ratios of the light intensities derived from the RGB LEDs are all 0.

Next, the color gamut calculation unit 1604 calculates the displayable color gamut of each pixel based on the ratio of the light intensity derived from each RGB color LED in each calculated pixel. Displayable color gamut is a region inside the triangle defined by the chromaticity point _{CS R, CS G, CS B} . The color gamut calculation unit 1604 obtains xy chromaticity coordinates of three chromaticity points CS _R , CS _G , and CS _B that define a displayable color gamut for each pixel. Xy chromaticity coordinates of the _{CS R (CS Rx, CS Ry} ), xy chromaticity coordinates of the _{CS G (CS Gx, CS Gy} ), xy chromaticity coordinates _(CS Bx, CS _By) of CS _B has the following formula 28 Is calculated by

In Equation 28, coefficients K11 to K63 are coefficients preset in the display device 1600.

The color gamut calculation unit 1604 outputs, as color gamut information 16040, the light intensity derived from each RGB color LED and the calculated displayable color gamut of each pixel.
FIG. 27 is a diagram illustrating an example of the color gamut information 16040. The color gamut information 16040 is data composed of pixel coordinates, light intensity derived from each RGB LED, and displayable color gamut (xy chromaticity coordinate values of three vertices representing the displayable color gamut).

  In the example of FIG. 27, the backlight light incident on the pixel with coordinates (0, 0) and the pixel with coordinates (1, 0) have different light intensities, but both are only LEDs (R). The areas are the same. Further, since light derived from LEDs of all RGB colors is incident on the pixel at coordinates (960, 590), the displayable color gamut is a displayable color corresponding to the ratio of the light intensity of each RGB color LED of incident light. It becomes an area. Generally, when light derived from a plurality of color LEDs is incident, the displayable color gamut is narrower than when only light derived from one color LED is incident. Therefore, the displayable color gamut of the pixel at coordinates (960, 590) is narrower than the pixel at coordinates (0, 0) and the pixel at coordinates (1, 0).

Based on the input image data 1010 and color gamut information 16040, the determination unit 1605 outputs determination information 16050 that is information indicating whether or not the target display chromaticity of each pixel is included in the displayable color gamut of the pixel. .
The determination unit 1605 first calculates the target display chromaticity of the target pixel based on the image data 1010. Here, the calculation formula of the target display chromaticity is the same as the formulas 1 to 5. The determination unit 1605 determines whether or not the target display chromaticity of the target pixel is included in the displayable color gamut of the target pixel (the area inside the triangle on the xy chromaticity plane defined by the three vertices in the color gamut information 16040). Determine.

  The determination unit 1605 outputs information as to whether or not the calculated target display chromaticity of each pixel is included in the displayable color gamut (display enable / disable information) as the determination information 16050. When the target display chromaticity is included in the displayable color gamut, the display availability information is 0. When the target display chromaticity is not included in the displayable color gamut, the display availability information is 1. When the display enable / disable information is 1, it means that the color to be originally displayed cannot be actually displayed based on the input image data.

The correction unit 1606 calculates a pixel value used for transmittance control of each pixel of the display unit 1609 based on the input image data 1010, color gamut information 16040, and determination information 16050.
First, the correcting unit 1606 calculates the target display chromaticity of each pixel based on the image data 1010. Here, the calculation formula of the target display chromaticity is the same as the formulas 1 to 5.

  Next, based on the determination information 16050, the correction unit 1606 changes the display chromaticity for pixels for which the target display chromaticity is determined to be outside the displayable color gamut. Specifically, the correction unit 1606 selects one chromaticity within the displayable color gamut that is closest to the target display chromaticity on the xy chromaticity plane, and uses that chromaticity as the new target display color of the pixel. Degree.

ここでＫＲＲＸ、ＫＲＲＹ、ＫＲＲＺはそれぞれ対象画素に入射するＬＥＤ（Ｒ）の光強度の比率ＲＥＰ_ｐｑから入射光のＸＹＺ値を求めるための係数である。またＫＧＲＸ、ＫＧＲＹ、ＫＧＲＺはそれぞれ対象画素に入射するＬＥＤ（Ｇ）の光強度の比率ＧＥＰ_ｐｑから入射光のＸＹＺ値を求めるための係数である。またＫＢＲＸ、ＫＢＲＹ、ＫＢＲＺはそれぞれ対象画素に入射するＬＥＤ（Ｂ）の光強度の比率ＢＥＰ_ｐｑから入射光のＸＹＺ値を求めるための係数である。
補正部１６０６は、対象画素に入射するバックライト光のＧ色、Ｂ色のＸＹＺ値についても同様の方法で算出する。 Next, the correction unit 1606 calculates a pixel value used for transmittance control of each pixel. Specifically, the correction unit 1606 calculates the color of the backlight light that is incident on the target pixel (coordinates (p, q)) for calculating the pixel value used for transmittance control, as an XYZ value. The correction unit 1606 calculates the R value X value RLxy. Of the backlight light incident on the pixel at the coordinates (p, q). X, Y value RLxy. Y, Z value RLxy. Z is calculated by the following equation 29.

Here, KRRX, KRRY, and KRRZ are coefficients for obtaining the XYZ value of incident light from the ratio REP _pq of the light intensity of the LED (R) incident on the target pixel. KGRX, KGRY, and KGRZ are coefficients for obtaining the XYZ value of the incident light from the ratio GEP _pq of the light intensity of the LED (G) incident on the target pixel. KBRX, KBRY, and KBRZ are coefficients for obtaining the XYZ value of the incident light from the ratio BEP _pq of the light intensity of the LED (B) incident on the target pixel.
The correction unit 1606 calculates the G and B XYZ values of the backlight light incident on the target pixel by the same method.

補正部１６０６は、座標（ｐ，ｑ）の対象画素の画素値（ＲＧＢ値）（ＧＲ_ｐｑ、ＧＧ_ｐｑ、ＧＢ_ｐｑ）を式３１で算出する。

ここで、ＨＳＸ_ｐｑ、ＨＳＹ_ｐｑ、ＨＳＺ_ｐｑはそれぞれ座標（ｐ，ｑ）の画素の目標表示色度のＸ値、Ｙ値、Ｚ値である。
補正部１６０６は、算出した全ての画素の透過率制御に用いる画素値を第１画素値情報１６０６０として出力する。 Next, the correction unit 1606 calculates a pixel value used for transmittance control of the target pixel based on the calculated XYZ value of the incident light of the target pixel and the new target display chromaticity of the target pixel. The correction unit 1606 is the inverse of the matrix composed of the XYZ values of the R, G, and B colors of the backlight light incident on the target pixel with respect to the XYZ values of the new target display chromaticity of the target pixel. By multiplying the matrix, a pixel value used for transmittance control of the target pixel is calculated.
Here, an inverse matrix iG of a matrix composed of XYZ values of the chromaticities of the R color, the G color, and the B color of the backlight light is expressed by Expression 30.

The correction unit 1606 calculates the pixel value (RGB value) (GR _pq , GG _pq , GB _pq ) of the target pixel at the coordinates (p, q) using Equation 31.

Here, HSX _pq , HSY _pq , and HSZ _pq are the X value, Y value, and Z value of the target display chromaticity of the pixel at coordinates (p, q), respectively.
The correction unit 1606 outputs the calculated pixel values used for transmittance control of all the pixels as first pixel value information 16060.

  Based on the input determination information 16050 and first pixel value information 16060, the superimposing unit 1607 corrects a warning display image for presenting information about pixels whose original target display chromaticity is outside the displayable color gamut to the user. The image is superimposed on the input image corrected by the unit 1606.

  In the second embodiment, as the warning display image, an image in which an area composed of pixels whose original target display chromaticity is outside the displayable color gamut is emphasized with diagonal lines is displayed.

First, based on the determination information 16050, the superimposing unit 1607 acquires the coordinates of pixels whose original target display chromaticity is not included in the displayable color gamut (pixels whose displayability information of the determination information 16050 is 1). Next, the superimposing unit 1607 replaces the pixel value of the pixel whose display enable / disable information is 1 among the pixel values of the first pixel value information 16060 with the pixel value of the warning display image held in advance by the superimposing unit 1607.
The superimposing unit 1607 outputs, as second pixel value information 16070, pixel value information for which the pixel value replacement processing has been completed for the pixel values of the first pixel value information 16060.

In the second embodiment, an example in which diagonal lines are displayed as a warning display image in a pixel area where the original target display chromaticity is not included in the displayable color gamut has been described. However, the method of presenting information to the user that there is a pixel whose original target display chromaticity is not included in the displayable color gamut and where such a pixel is located is not limited to this. For example, information such as “cannot display the color that should be displayed” may be displayed on the screen, or the outer periphery of the pixel area where the original target display chromaticity is not included in the displayable color gamut is surrounded by a line. It may be highlighted.
The driving unit 1608 generates and outputs a driving signal 16080 for driving the backlight based on the input lighting parameter 16020.

  A display unit 1609 is a liquid crystal display device including a liquid crystal panel, a backlight, and respective controllers. The display unit 1609 controls the transmittance of the liquid crystal element of each pixel of the liquid crystal panel based on the input second pixel value information 16070, and controls the lighting of each light source in each control area of the backlight based on the drive signal 16080. . Accordingly, an image is displayed on the display unit 1609 based on the second pixel value information 16070.

  According to the second embodiment, the light emission control values of a plurality of light sources are obtained based on the input image data, the displayable color gamut is calculated for each pixel, and whether or not the original target display chromaticity can be displayed for each pixel is determined. When there is a pixel that cannot be displayed, a display for presenting information on the pixel to the user is performed. The user can easily know that there is a pixel that cannot display the color that should be displayed in the displayed image. As a result, for example, it is possible to suppress a situation in which the user knows that the calibration or image editing work has been performed in a state where the display color is not correct, and restarts the work, thereby improving convenience.

(Example 3)
Embodiment 3 of the display device according to the present invention will be described below.
FIG. 28 is a diagram illustrating a configuration example of the display device according to the third embodiment. The display device 200 according to the third embodiment includes an input unit 201, a detection unit 202, a light source determination unit 203, an estimation unit 204, a correction unit 205, a determination unit 206, a superimposition unit 207, a drive unit 208, and a display unit 209.

  Here, components and general functions will be described. Detailed processing contents will be described later with a flowchart. Unless otherwise stated, each component is assumed to be configured by hardware or software inside an arithmetic device such as a microcomputer.

  The display unit 209 includes a backlight and a liquid crystal panel. The configuration of the backlight is the same as that of the first embodiment. That is, as shown in FIG. 6, the backlight is composed of a plurality of control areas that can individually control light emission (in the third embodiment, a total of 24 in the horizontal direction and 4 in the vertical direction). A plurality of light sources having different light emission characteristics are arranged in each control area. Specifically, in each control area, R (red), G (green), and B (blue) LEDs that are narrow-band light sources and W (white) LEDs that are broadband light sources are arranged.

  The input unit 201 inputs image data from the outside of the display device 200. The input unit 201 transmits image data to the detection unit 202, the correction unit 205, and the determination unit 206. In the third embodiment, description will be made assuming that the image data is data represented by the CIE RGB color system.

  The detection unit 202 divides the input image data into image blocks, calculates a statistic for each image block, and transmits it to the light source determination unit 203 as statistic information. To do. Here, the statistic of each image block is information indicating whether or not the image block has a pixel having a chromaticity that does not fall within a predetermined color gamut or more. The predetermined color gamut is a color gamut that can be displayed by a broadband light source (white LED) of the backlight, and is, for example, sRGB. The predetermined threshold is 30%, for example. The method for dividing image data by image blocks is the same as in the first embodiment. That is, as shown in FIG. 3, the detection unit 202 divides image data into a total of 24 image blocks, with the number of horizontal image blocks being 6 and the number of vertical image blocks being 4. Each image block corresponds to each control area of the backlight. The detection unit 202 converts the pixel value (CIE RGB color system) of each pixel of the image data into a CIE xy color system value. The conversion formula is the same as Formula 1 to Formula 5 of Example 1. The detection unit 202 determines whether or not the xy chromaticity coordinate value obtained by conversion falls within a predetermined color gamut, counts the number of pixels that do not fall within the predetermined color gamut for each image block, and determines a predetermined color. It is determined whether or not the number of pixels that do not fall within the range is greater than or equal to a threshold value.

The light source determination unit 203 acquires statistical information from the detection unit 202, determines a lighting parameter that is information on light emission control of the light source that constitutes the backlight based on the statistical information, and transmits the lighting parameter to the estimation unit 204 and the driving unit 208. To do.
The light source determination unit 203 is a lighting parameter that causes the red LED, the green LED, and the blue LED that are narrow band light sources to emit light in a control area corresponding to an image block that includes a pixel whose chromaticity is out of a predetermined color gamut or more. To decide. On the other hand, in a control area corresponding to an image block in which pixels whose chromaticity is outside a predetermined color gamut are not included in a predetermined threshold value or more, a lighting parameter for emitting a white LED as a broadband light source is determined. Thereby, for example, for a control area corresponding to an image block in which the ratio of pixels outside the sRGB color gamut is 30% or more, a lighting parameter for lighting the red LED, the green LED, and the blue LED is determined. In the control area corresponding to the image block in which the ratio of pixels outside the sRGB color gamut is less than 30%, a lighting parameter for lighting only the white LED is determined.

The estimation unit 204 acquires the lighting parameter from the light source determination unit 203, estimates the distribution of the characteristics of the backlight light incident on the display unit 209 based on the lighting parameter, and transmits the incident light information to the correction unit 205 and the determination unit 206. Send.
Light from the light source of the backlight diffuses before reaching the liquid crystal panel. Therefore, not only light from the light source nearest to the pixel but also light from a light source around the light source is incident on each pixel of the liquid crystal panel. In the third embodiment, the backlight includes a plurality of types of light sources (narrow band light source and broadband light source) having different emission characteristics, and the light source that emits light for each control area is controlled according to the input image. Therefore, depending on the input image, there may be a pixel on which a combined light of light derived from light sources having different light emission characteristics is incident due to adjacent control areas where different light sources emit light.

FIG. 30 schematically shows how light from the light source is diffused. FIG. 30 is a one-dimensional representation of the light diffusion state of the narrow-band light source arranged on the left side and the broadband light source arranged on the right side. Vertical broken lines in the figure indicate boundaries between control areas in FIG. As shown in FIG. 30, when light sources having different light emission characteristics emit light in the control areas adjacent to each other, the backlight light incident on each pixel can be classified into the following three types.
(1) Only narrowband light is incident (2) Both narrowband light and broadband light are incident (3) Only broadband light is incident Here, narrowband light is a red LED, green LED, and blue LED that are narrowband light sources The broadband light is light derived from a white LED that is a broadband light source.

Furthermore, as shown in FIG. 32, when considered two-dimensionally, the backlight light incident on each pixel depends on whether the four light sources located at the vertices of the rectangle are narrow-band light sources or broadband light sources, respectively. Thus, it is classified into the above three types.
The estimation unit 204 estimates, for each pixel of the display unit 209, whether the incident backlight light is only narrowband light, only broadband light, or both narrowband light and broadband light. Output as optical information.

  The correction unit 205 acquires image data from the input unit 201 and acquires incident light information from the estimation unit 204. Based on the incident light information, the correction unit 205 corrects the image data so that the display chromaticity of each pixel becomes the chromaticity within the color gamut that can be displayed under the backlight light incident on the pixel. For example, the correction unit 205 calculates the initial target display chromaticity based on the pixel value in the input image data of the pixel to be processed, and the initial target display chromaticity must be included in the color gamut that can be displayed in the processing target pixel. For example, the pixel value of the processing target pixel is corrected. Specifically, the chromaticity based on the corrected pixel value is a chromaticity within the displayable color gamut, and is the closest chromaticity on the xy chromaticity plane to the initial target display chromaticity. Then, make corrections.

  The correction unit 205 has a conversion table corresponding to incident backlight light in advance, and corrects image data using the conversion table corresponding to incident light information of each pixel. The correcting unit 205 transmits the corrected image data to the superimposing unit 207. For example, it is assumed that the color gamut that can be displayed when the incident backlight light is only broadband light is sRGB. In this case, the correction unit 205 corrects the image data so that the display chromaticity is the chromaticity within sRGB for the pixel in which the incident light is only broadband light in the incident light information.

  The determination unit 206 acquires image data from the input unit 201, acquires incident light information from the estimation unit 204, and determines whether there is a possibility that individual differences in color vision may occur for each pixel based on the incident light information. The determination result is output to the superimposing unit 207 as determination information.

  The determination unit 206 may cause individual differences in color perception in pixels where the incident backlight includes narrowband light and the chromaticity based on the image data falls within the low saturation region shown in FIG. This is determined as a pixel that should warn the user. In such a pixel, there may be a difference in perceived color due to individual differences in the color matching function between the color assumed from the image data and the actually observed color. Based on the incident light information, the determination unit 206 determines that the backlight light incident on the determination target pixel is (1) or (2) in the above classification, and the determination target pixel has a low chromaticity in FIG. If it is included in the saturation area, it is determined that the pixel is a pixel to be warned.

  On the other hand, the determination unit 206 has the classification (1) or (2) of the backlight light incident on the determination target pixel, and the chromaticity of the determination target pixel is included in the low saturation region of FIG. If not, it is determined that the pixel is not to be warned. In addition, when the backlight light incident on the determination target pixel is classified as (3), the determination unit 206 issues the warning regardless of whether the chromaticity of the pixel is included in the low saturation region. It is determined that the pixel is not a power pixel.

  The superimposing unit 207 acquires the corrected image data from the correction unit 205 and acquires determination information from the determination unit 206. The superimposing unit 207 superimposes on the input image corrected by the correcting unit 205 a warning display image for presenting information on a caution area including pixels that may cause individual differences in color vision based on the determination information. To do. In Example 3, as shown in FIG. 32D, a shaded image is displayed as a warning display image. The superimposing unit 207 transmits the image data on which the warning display image is superimposed to the display unit 209. In addition, the superimposing unit 207 transmits a lighting parameter corresponding to the image data on which the warning display image is superimposed to the driving unit 208.

The driving unit 208 acquires lighting parameters from the light source determination unit 203 and the superimposing unit 207, generates a driving signal for controlling the backlight based on the lighting parameters, and transmits the driving signal to the display unit 209.
The display unit 209 includes a backlight and a liquid crystal panel that is an optical modulator (filter) that modulates the transmittance of light from the backlight for each pixel in accordance with a drive signal. The display unit 209 acquires a backlight driving signal from the driving unit 208 and controls the backlight. The display unit 209 acquires image data from the superimposing unit 207 and adjusts the light transmittance of each pixel of the liquid crystal panel based on the image data.

A processing procedure of the display device according to the third embodiment will be described with reference to a flowchart of FIG.
In step S <b> 301, image data is input from the input unit 201.
In step S <b> 302, the detection unit 202 calculates a statistic for each image block of the image data input from the input unit 201, and transmits the statistic information to the light source determination unit 203.
In step S <b> 303, the light source determination unit 203 determines a backlight lighting parameter based on the statistic information acquired from the detection unit 202, and transmits the backlight lighting parameter to the estimation unit 204 and the drive unit 208.

In step S <b> 304, the estimation unit 204 calculates incident light information based on the lighting parameter acquired from the light source determination unit 203 and transmits the incident light information to the correction unit 205 and the determination unit 206.
In step S <b> 305, the correction unit 205 corrects the image data based on the image data acquired from the input unit 201 and the incident light information acquired from the estimation unit 204, and transmits the corrected image data to the superimposition unit 207. As described above, this correction is performed based on incident light information so that the chromaticity of each pixel of the image data becomes the chromaticity within the color gamut that can be displayed by the backlight light incident on the pixel.

In step S <b> 306, the determination unit 206 calculates determination information based on the image data acquired from the input unit 201 and the incident light information acquired from the estimation unit 204, and transmits the determination information to the superimposition unit 207.
In step S307, the superimposing unit 207 acquires corrected image data from the correcting unit 205, acquires determination information from the determining unit 206, generates warning display image data based on them, and generates corrected image data. Superimpose on. The display unit 209 displays an image on which the warning display image is superimposed.

FIG. 31 is a flowchart showing determination information calculation processing in step S306. The determination unit 206 performs the processing of this flowchart.
In step S <b> 501, the determination unit 206 selects one pixel to be determined from the image data acquired from the input unit 201.
In step S <b> 502, the determination unit 206 determines whether or not the narrowband light is included in the backlight light incident on the position of the determination target pixel based on the incident light information acquired from the estimation unit 204.
When narrowband light is included in the incident light of the determination target pixel (classification (1) or classification (2)), the process proceeds to step S503.
When narrowband light is not included in the incident light of the determination target pixel (classification (3)), the process proceeds to step S504.

In step S503, the determination unit 206 determines whether or not the chromaticity of the determination target pixel is within the low saturation region of FIG.
When the chromaticity of the determination target pixel is within the low saturation region, the process proceeds to step S505.
When the chromaticity of the determination target pixel is not within the low saturation region, the process proceeds to step S504.
In step S <b> 504, the determination unit 206 determines that the determination target pixel is not a pixel that should warn the user that there is a possibility that an individual difference in color vision may occur, stores the position, and ends the process of the flowchart. .

In step S505, the determination unit 206 determines that the determination target pixel is a pixel that should warn the user that there is a possibility that an individual difference in color vision may occur, stores the position, and ends the process of the flowchart. .
The determination unit 206 performs the processes in steps S501 to S505 in the above flowchart for all the pixels constituting the image data. The determination unit 206 outputs, as determination information, the position of the pixel that has been determined as the pixel to be warned.

  Although an example of determining whether or not to warn for each pixel has been described here, the above determination may be performed for each image region having a certain size in order to reduce the processing load. In this case, the process in step S503 may be a process for determining whether or not the average value of chromaticity of pixels in the image area is in the low saturation area. Or it is good also as a process which determines whether the pixel in a low saturation area | region beyond a fixed level exists in an image area. Further, in step S505, the entire image area may be determined as a target to warn the user as an area that may cause individual differences in color vision.

An example of processing of the display device according to the third embodiment will be described with reference to FIG.
FIG. 32A shows an example of an input image. In this example, an object image 281 composed of low-saturation pixels is present in the right region of the image, and the other part is a background image 282 composed of high-saturation pixels.

  FIG. 32B shows backlight lighting parameters determined by the light source determination unit 203 for the input image of FIG. In this example, as described above, the backlight is composed of 4 vertical × 6 horizontal control blocks, and a light source group including a broadband light source and a narrow band light source is arranged in each control block. As described above, the lighting parameter is determined according to the number of low saturation pixels in the image block. In the control area corresponding to the area of the object image 281 composed of low saturation pixels, the broadband light source is turned on. In the control area corresponding to the area of the background image 282 composed of high saturation pixels, the narrow band light source is turned on.

  FIG. 32C is a diagram illustrating the incident light information estimated by the estimation unit 204 based on the lighting parameters of FIG. As described above, in the third embodiment, the light from each light source is diffused to the position of the adjacent light source. As shown in FIG. 32C, the incident light in the region of the low-saturation object image 281 is only broadband light, and the incident light in the region of the high-saturation background image 282 is only narrow-band light, and its boundary region Both broadband light and narrowband light are incident on.

  FIG. 32D shows a calculation example of a pixel area (warning area) determined to be warned. As shown in FIG. 32D, the warning area is an area of pixels in which narrowband light is incident and the chromaticity is included in the low saturation area. As shown in FIG. 32D, among the low-saturation pixels constituting the object image 281, pixels near the boundary with the high-saturation background image 282 are derived from the narrow-band light source that is lit in the region of the background image 282. Light diffuses and enters. Therefore, it becomes a warning area in which there is a possibility that individual differences in color vision may occur.

FIG. 33 is a diagram illustrating an example of a warning display image of the display device according to the third embodiment. As a method for displaying the warning display image, for example, the following various methods are conceivable.
In FIG. 33A, a warning is given with characters and graphics by OSD (On-Screen Display). In this example, a character string “Warning: A color vision difference has occurred” is displayed, and the user is notified that there is a pixel that may cause a color vision individual difference (color vision difference). . In addition, a graphic (shaded image) is superimposed on the warning area to notify the user of information on the position of a pixel that may cause a color vision difference.

When the size of the warning area is small, the warning area and its surrounding area may be enlarged and displayed by a method such as PinP (Picture in Picture) as shown in FIG. In addition, the superimposing unit 207 may calculate a lighting parameter such that only broadband light is incident on a PinP portion that enlarges and displays a warning area as illustrated in FIG. Thereby, since only the broadband light is incident on the PinP portion, the user can confirm the difference in display color between the case where the narrowband light is incident and the case where the narrowband light is not incident.
Since the influence of the color vision difference increases as the saturation of the pixel becomes closer to white, the warning display may be emphasized by making the display color brighter by the OSD as the saturation of the pixel is closer to white.
As mentioned above, although several warning display methods were illustrated, you may combine these suitably.

In the above description, the estimation unit 204 has described an example of outputting three kinds of values (classification 1, classification 2, classification 3) of only narrowband light, only broadband light, and a mixture of both as incident light information. The intensity ratio may be considered when both are present. For example, as shown in FIG. 34, the estimation unit 204, based on the distance from four light source groups existing around the target pixel for calculating incident light information, the intensity ratio A (= (Broadband light intensity / narrowband light intensity) is calculated. It is known that the intensity of light is inversely proportional to the square of the distance. In the example of FIG. 34, two narrow-band light sources (distances a and b from the target pixel) and two broadband light sources (distances c and d from the target pixel) are lit around the target pixel. If the light emission amount (brightness) of the narrow-band light source and the broadband light source is the same, the intensity ratio A can be calculated as follows.

A = (1 / c ² + 1 / d ² ) / (1 / a ² + 1 / b ² )

  As described above, when the incident light information includes information on the light intensity ratio between the broadband light source and the narrow band light source, the determination unit 206 determines a predetermined value that defines the range of the low saturation region in FIG. 4 in the determination process of step S503. r may be decreased as the value of the intensity ratio A increases.

  As the value of the intensity ratio A is larger, the proportion of the broadband light in the backlight light incident on the pixel is larger. As the proportion of broadband light increases, individual differences in color perception are less likely to occur, so the chromaticity range that is determined to be a warning target (the range that is determined to be a low saturation pixel) can be reduced. By adjusting the condition to be determined as a warning target according to the intensity ratio of the broadband light, it is possible to suppress a warning that there is a possibility that an individual difference in color vision may occur in a wider range than necessary.

  According to the third embodiment, in a display device that controls light emission of a plurality of types of light sources having different light emission characteristics for each control area, it is possible to perform a warning display that notifies a user of pixel information that is likely to cause individual differences in color vision. . Thus, the user can easily determine pixels in the displayed image that may have individual differences in color vision, so that work efficiency such as color calibration work is improved.

Example 4
Embodiment 4 of the display device according to the present invention will be described.
In the fourth embodiment, detailed description of the same parts as those in the third embodiment will be omitted, and description will be made focusing on differences from the third embodiment. In Example 3, the backlight has two types of light sources, a narrow-band light source and a broadband light source. In Example 4, the backlight has only a narrow-band light source.

FIG. 35 is a diagram illustrating a configuration example of the display device according to the fourth embodiment. 35, elements denoted by the same reference numerals as those in FIG. 28 are elements that perform the same processing as in the third embodiment, and thus description thereof is omitted. A display device 2000 according to the fourth embodiment includes an input unit 201, a correction unit 205, a determination unit 206, a superimposition unit 207, a drive unit 208, and a display unit 1006. In the case of the fourth embodiment, the light source is only a narrow-band light source, and the incident light information and the lighting parameters are the same on all screens. The display unit 1006 includes a liquid crystal panel and a backlight, and the backlight has only a narrow-band light source as a light source.

FIG. 36 shows some configuration examples of the backlight in the fourth embodiment.
The backlight in FIG. 36A has a configuration in which narrow-band light sources including three color light sources of a red light source (R), a green light source (G), and a blue light source (B) are arranged at predetermined intervals.
The backlight in FIG. 36B has a structure in which white light sources (W) are arranged at predetermined intervals. This white light source is assumed to be a white LED (Light Emitting Diode) having a narrow spectrum width.
The backlight in FIG. 36C has a structure in which narrow-band light sources (L) are arranged at both ends and a light guide plate that guides light emitted from the light sources into the screen. The light source (L) is assumed to be a red light source, a green light source, a set of blue light sources, or a white light source. In the case of the configuration using the light guide plate, the light sources may be arranged at the left and right ends of the screen or at the upper and lower ends.

FIG. 37 is a flowchart illustrating a processing procedure of the display device according to the fourth embodiment.
The difference from the flowchart of FIG. 29 is that the processing of step S302, step S303, and step S304 in FIG. 29 is not performed. In FIG. 37, the processing contents of the steps denoted by the same reference numerals as those in FIG. 29 are the same as those described in the third embodiment, and thus detailed description thereof is omitted.

The other flow in FIG. 37 is basically the same as that in FIG. 29, so only the differences will be described.
In step S1202, as in step S305, the correction unit 205 performs image data processing so that the display chromaticity of each pixel becomes a chromaticity within a color gamut that can be displayed under the backlight incident on the pixel. Correction is performed using a conversion table corresponding to incident light information. In the fourth embodiment, since the type of light source is one narrow-band light source, the incident light information is classified as (1) described in the third embodiment for all pixels. Therefore, the conversion table stored in advance is one type of conversion table that is applied when the incident light is only narrowband light.

In step S306, the incident light information is only a narrow-band light source on the entire screen. In the process of the flowchart of FIG. 31 executed by the determination unit 206, step S502 is determined to be Yes on the entire screen, and the process proceeds to step S503. Become. The value of the distance r in FIG. 4 used in the determination in step S503 is a value determined in advance based on the spectrum of the narrow band light source that constitutes the backlight.
When step S307 is executed, FIG. 33 (A) or FIG. 33 (B) is performed as a warning display.

  As described above, according to the fourth embodiment, the pixel belonging to the low chroma region is determined as a pixel that may cause individual differences in color vision, and a warning display that notifies the user of information on the pixel is displayed. Done. Thereby, the user can easily determine a pixel in the display image to determine whether there is a possibility of individual differences in color vision, so that work efficiency such as color calibration work is improved.

(Other examples)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

100: Display device 103: Light source determination unit 106: Determination unit 108: Superimposition unit 110: Display unit

Claims (13)

A plurality of control areas that can independently control light emission, each control area having a plurality of light sources having different light emission characteristics,
Control means for controlling light emission of the light source in each control area based on image data;
Display means for displaying an image by adjusting the transmittance of incident light incident from the light emitting means based on the image data;
Based on the control information of the light source by the control means, a characteristic of incident light incident on the display means from the light emitting means is calculated for each area of the display means, and the image data is calculated based on the calculated characteristic of the incident light. Determining means for determining a caution area that is not included in a color gamut that can be displayed by the display means;
Display control means for causing the display means to display information on the attention area determined by the determination means;
A display device comprising: A plurality of control areas that can independently control light emission, each control area having a plurality of light sources having different light emission characteristics,
Control means for controlling light emission of the light source in each control area based on image data;
Display means for displaying an image by adjusting the transmittance of incident light incident from the light emitting means based on the image data;
Based on the control information of the light source by the control means, the characteristics of the incident light incident on the display means from the light emitting means are calculated for each area of the display means, and the color based on the image data and the characteristics of the incident light From the relationship, a determination means for determining an attention area where a perceptual color shift caused by an individual difference in the color matching function occurs,
Display control means for causing the display means to display information on the attention area determined by the determination means;
A display device comprising:   The display device according to claim 1, wherein the display control unit replaces a portion corresponding to the attention area in the image data with predetermined image data.   The display device according to claim 1, wherein the display control unit replaces a portion of the image data corresponding to a boundary of the attention area with predetermined image data.   The determination unit is configured to display characteristics of incident light incident on each region of the display unit, control information of a light source of the control area corresponding to the region, and a light source of a control area adjacent to the control area corresponding to the region. The display device according to claim 1, which is calculated based on the control information of the light source and the light diffusion characteristics of the light source. The plurality of light sources includes a first light source having a broadband emission spectrum and a second light source having a narrow band emission spectrum,
The determination unit includes a region in which a light source that emits light in a corresponding control area is the second light source, and a light source that emits light in at least one control area adjacent to the corresponding control area is the first light source. The display device according to claim 1, wherein the display device is determined as a caution area. A correction means for correcting a pixel value of a pixel included in the attention area of the image data;
The display device according to claim 1, wherein the correction unit performs correction so that a color based on the corrected image data is included in the displayable color gamut. The plurality of light sources includes a first light source having a broadband emission spectrum and a second light source having a narrow band emission spectrum,
The determination unit is a region in which a color based on the image data is a color whose saturation is lower than a threshold value, and the characteristic of the incident light is a characteristic indicating that light from the second light source is incident. The display device according to claim 2, wherein the display area is determined as the attention area. The plurality of light sources includes only a light source having a narrow-band emission spectrum,
The display device according to claim 2, wherein the determination unit determines an area in which a color based on the image data is a color whose saturation is lower than a threshold as the attention area.   The display device according to claim 1, wherein the determination unit determines the attention area for each pixel of the display unit.   The said control means divides | segments the said image data into the image block corresponding to the said control area, and controls light emission of the light source of a corresponding control area based on the feature-value of each image block. The display device described in 1. A plurality of control areas that can independently control light emission, each control area having a plurality of light sources having different light emission characteristics,
Display means for displaying an image by adjusting the transmittance of incident light incident from the light emitting means based on image data;
A display device control method comprising:
Controlling light emission of the light source of each control area based on the image data;
Based on the control information of the light source, the characteristics of the incident light incident on the display means from the light emitting means are calculated for each area of the display means, and the color based on the image data is calculated based on the calculated characteristics of the incident light. Determining a caution area not included in the color gamut that can be displayed by the display means;
Displaying the information on the attention area on the display means;
A method for controlling a display device. A plurality of control areas that can independently control light emission, each control area having a plurality of light sources having different light emission characteristics,
Display means for displaying an image by adjusting the transmittance of incident light incident from the light emitting means based on image data;
A display device control method comprising:
Controlling light emission of the light source of each control area based on the image data;
Based on the control information of the light source, the characteristics of the incident light incident on the display means from the light emitting means is calculated for each area of the display means, and from the relationship between the color based on the image data and the characteristics of the incident light, Determining a region of attention where a shift in perceived color due to individual differences in color matching functions occurs;
Displaying the information on the attention area on the display means;
A method for controlling a display device.

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