JP5338019B2 - Image display device - Google Patents

Description

The present invention relates to an image display device, a luminance decompression processing of an image signal in particular the image display.

In the conventional dimming processing of the image display device, the luminance is expanded according to the image feature amount (white peak, APL (average luminance), etc.) of the input image, and the dimmed portion is reduced by the dimming element. It has been proposed to improve the contrast of an image by illuminating (for example, Patent Documents 1 and 2). However, when the luminance expansion processing is performed, the highlight portion may be emphasized or the overexposure may be reduced. When such a phenomenon occurs in a display portion such as human skin, the user may feel uncomfortable and the subjective image quality may deteriorate. For this reason, a technique for reducing the expansion rate of the skin color portion has been proposed (for example, Patent Document 3).
JP 2002-366121 A JP 2005-200570 A Japanese Patent Laid-Open No. 10-285607

  However, according to the above-described conventional method (Patent Document 3), since the expansion rate is greatly different between the skin color portion and the other portions, only the skin color portion becomes an image that deviates from the entire screen, giving a sense of incongruity. there were.

The present invention has been made to solve such problems, and eliminates a state in which only a portion of a noticeable color such as skin color deviates from the entire screen, and improves the contrast of the image. It is an object of the present invention to provide an image display device .

An image display device according to the present invention includes an attention color region detection unit that detects a region ratio of an attention color in an image, an image feature amount detection unit that detects an image feature amount in an image, the image feature amount, and the attention An expansion processing unit that obtains a correction expansion rate based on the color area ratio, expands the lightness of the image signal based on the correction expansion rate, the lightness of the image signal expanded based on the correction expansion rate, and the image signal And an image signal processing unit that performs signal processing for displaying an image based on the hue and saturation . In the present invention, the decompression processing unit obtains the correction decompression rate based on the image feature amount and the region ratio of the target color, and the brightness of the image signal is decompressed based on the correction decompression rate. This avoids a state in which only the portion is deviated from the entire screen, and it is possible to improve the contrast of the image.

In the image display device according to the present invention, when there are a plurality of colors of interest, the target color area detection unit collects the plurality of colors and obtains the area ratio of the target color as one target color.

In the image display device according to the present invention, when there are a plurality of colors of interest, the target color region detection unit obtains a region ratio in the image of each color, and determines the region ratio that is the maximum value among the regions. The area ratio of the target color.

In the image display device according to the present invention, when there are a plurality of colors of interest, the target color region detection unit obtains a region ratio in the image of each color, and the decompression processing unit detects the color of each color. A correction expansion rate based on the area ratio in the image is obtained, and the maximum correction expansion rate is used as the correction expansion rate.

In the image display device according to the present invention, when there are a plurality of colors of interest, the target color area detection unit obtains areas in the image by assigning priorities to the respective colors, and based on the sum of the areas. The area ratio of the target color is obtained.

The image display device according to the present invention includes a light modulation element that displays an image based on the brightness of the image signal expanded based on the correction expansion rate, and the hue and saturation of the image signal, and the correction expansion rate. based seek dimming of the light control element, further comprising a light control unit that controls the luminance value of the light control device based on the reduced light rate, the noticeable color area detection unit, the color of interest is When there are a plurality of colors, the area ratio in the image of each color is obtained, and the dimming processing unit obtains a dimming rate correction coefficient based on the area ratio in the image of each color, and the maximum of them is obtained. Is used as the dimming rate correction coefficient.
The image display device according to the present invention includes a light modulation element that displays an image based on the brightness of the image signal expanded based on the corrected expansion rate, and the hue and saturation of the image signal, and the image feature. And a dimming processing unit for obtaining a corrected dimming rate based on the amount and the region ratio of the target color, and controlling a luminance value of the dimming element based on the corrected dimming rate, and the target color region detecting unit When there are a plurality of colors of interest, the area ratio in the image of each color is obtained, and the dimming processing unit calculates a dimming rate correction coefficient based on the area ratio in the image of each color. The maximum extinction rate correction coefficient is obtained and used as the extinction rate correction coefficient.

  In the image display device according to the present invention, the image feature amount detection unit obtains an image feature amount based on a white peak value and / or an average luminance value of the image.

  In the image display device according to the present invention, the expansion processing unit includes a table in which an ideal expansion rate corresponding to discrete white peak values and average luminance is set, and the white peak detected by the image feature amount detection unit. Based on the value, the average luminance value, and the table, an ideal expansion rate is obtained. In the present invention, both the white peak value and the average luminance value are taken into consideration in order to obtain the ideal expansion ratio, and thus the characteristics of the image are appropriately reflected.

In the image display device according to the present invention, the dimming processing unit includes a table in which ideal dimming rates corresponding to discrete white peak values and average luminance are set, and is detected by the image feature amount detecting unit. An ideal dimming rate is obtained based on the white peak value and average luminance value and the table. In the present invention, in order to obtain the ideal dimming rate, both the white peak value and the average luminance value are taken into consideration, so that the characteristics of the image are appropriately reflected.

Embodiment 1. FIG.
FIG. 1 is a block diagram showing a configuration of a main part of an image display apparatus according to Embodiment 1 of the present invention. This image display device includes an RGB / HSV conversion unit 11, a skin color region detection unit 12, an image feature amount detection unit 13, an expansion processing unit 14, an HSV / RGB conversion unit 15, an image processing unit 16, a light valve (light modulation element). 17, a light control processing unit 18 and a light control element 19 are provided.

The RGB / HSV conversion unit 11 converts R (red), G (green), and B (blue) video signals into H (hue), S (saturation), and V (lightness) video signals. The following conversion process is performed.
(A) How to obtain V (0-1) V = Max (R, G, B) / 255
(B) How to obtain S (0-1) When V = 0, S = 0
When V ≠ 0, S = {Max (R, G, B) −Min (R, G, B)} / Max (R, G, B)
The Max function is a function that outputs the largest one among a plurality of arguments, and the Min function is a function that outputs the smallest one among a plurality of arguments. The same applies to the following.

(C) How to obtain H (0-359) When S = 0, H = 0
When S ≠ 0, d = Max (R, G, B) −Min (R, G, B)
When R is maximum, H = 60 × (GB) / d
When G is maximum, H = 60 × {2+ (BR) / d}
When B is maximum, H = 60 × {4+ (RG) / d}
When H <0, 360 is added to H. When H = 360, H = 0.

  The skin color area detection unit 12 shows an example of the target color area detection unit of the present invention. In this example, the number of skin color pixels in the image signal is counted and the ratio is detected. The detection range may be the entire screen or only the center portion. Or you may weight by a center part and a peripheral part. Here, the skin color is assumed to have a hue (H) in the range of 6 to 38. The image feature amount detection unit 13 detects a white peak, APL, black peak, histogram, or the like in the video signal as a feature amount.

  The decompression processing unit 14 calculates the decompression rate (ideal decompression rate) from the image feature amount obtained by the image feature amount detection unit 13, and the stretch rate is in accordance with the ratio of the skin color region obtained by the skin color region detection unit 12. To correct (correction expansion rate). Then, the expansion processing unit 14 outputs a value V ′ (lightness) obtained by multiplying the correction expansion rate by V (lightness) of the image signal. When V 'exceeds "1", clipping is performed to "1".

The ideal elongation rate is obtained by the following equation, for example.
K = 255 / WP
Here, K is an ideal expansion rate and WP is a white peak value. For example, when WP = 200,
K = 255/200 = 1.75
It becomes. Next, the ideal extension rate is corrected according to the skin color ratio. For example, K ′ = 1 + (K−1) * M
Here, K ′ is a correction expansion rate, and M is an expansion rate correction coefficient. The expansion rate correction coefficient M takes a value corresponding to the skin color area ratio.

  FIG. 2 is a diagram showing the relationship between the skin color area ratio and the expansion rate correction coefficient M. When the skin color area ratio is less than Th1 (for example, 10%), since the skin color area ratio is small, it is considered that the influence on the subjective image quality is small. Therefore, the expansion rate correction coefficient M is set to “1”. In the case between Th1 and Th2 (for example, 60 to 70%), the skin color area ratio is large, and it is considered that the influence on the subjective image quality becomes large. Therefore, the expansion rate correction coefficient M is decreased as the skin color area ratio increases. In FIG. 2, an example of linear decrease is shown, but any shape may be used as long as it decreases monotonically between Th1 and Th2. When the skin color area ratio exceeds Th2, the expansion rate correction coefficient M is kept constant at Mmin. Not all of the skin color area ratios are human skin, and there is a possibility of misjudgment. For this reason, there is a possibility that the expansion rate is lowered even for an image in which the expansion rate is increased and the user does not feel uncomfortable. Therefore, Mmin is constant in order to increase the contrast feeling even a little. However, Mmin = 0 may be used. Further, if Mmin = 1, the film is always stretched at the ideal stretch rate.

The HSV / RGB conversion unit 15 uses S (saturation) and H (hue) obtained by the RGB / HSV conversion unit 11 and V ′ (brightness) after luminance expansion obtained by the expansion processing unit 14 as R ′. , G ′, B ′ signals and output to the image signal processing unit 16. The image signal processing unit 16 performs predetermined image processing and outputs the image signal to the light valve 17 to generate an image on the light valve 17. The conversion formula at that time is as follows.
(A) When S = 0 R ′ = G ′ = B ′ = V ′ * 255
(B) When S ≠ 0 h = integer part of H / 60 f = V ′ (1-S)
q = V ′ (1-Sf)
t = V ′ (1−S (1−f))
Then,
When h = 0 R ′ = V ′ * 255
G ′ = t * 255
B '= p * 255
When h = 1 R ′ = q * 255
G '= V' * 255
B '= p * 255
When h = 2 R ′ = p * 255
G '= V' * 255
B ′ = t * 255

When h = 3 R ′ = p * 255
G ′ = q * 255
B '= V' * 255
When h = 4 R ′ = t * 255
G ′ = p * 255
B '= V' * 255
When h = 5 R ′ = V ′ * 255
G ′ = p * 255
B ′ = q * 255

The dimming processing unit 18 calculates a dimming rate from the corrected expansion rate, and calculates a dimming parameter for driving the dimming element 19 according to the dimming rate. When the relationship between the luminance value and the brightness is the power of 2.2, the light attenuation rate A is obtained from the following equation.
A = K ' ^-2.2
For example, when K ′ = 1.2, the light attenuation rate A is A = ^1.2−2.2 = 0.670
It becomes. Then, a dimming parameter for driving the dimming element 19 to be 0.670 times the maximum light amount is calculated. It should be noted that the processing of the dimming processing unit 18 includes a change in the corrected expansion rate K ′ and the light amount of the dimming element 19 in order to suppress adverse effects caused by a sudden change in the corrected expansion rate K ′ and the light amount of the dimming element 19. A time delay process may be added by regulating the width or weighted average. Then, the light from the light control element 19 whose light control is controlled by the above light control parameter is transmitted to the light valve 17 through the optical system (not shown), and the image generated in the light valve 17 is synthesized. The image is magnified by a projection lens (not shown) and displayed on the screen.

  As described above, according to the first embodiment, when the decompression processing unit 14 obtains the decompression rate, not only the image feature amount but also the region ratio of the target color is obtained to obtain the corrected decompression rate. Since the dimming processing unit 18 obtains the dimming rate based on the corrected decompression rate, a state where only the skin color (attention color) part deviates from the entire screen is avoided. Therefore, it is possible to improve the contrast of the image.

  Further, the decompression processing unit 14 obtains an ideal decompression rate based on the image feature amount, and obtains a correction decompression rate based on the ideal decompression rate and a predetermined decompression rate correction coefficient. In relation to the color area ratio, the skin color area ratio decreases within the predetermined range (Th1 to Th2) as the skin color area ratio increases, and below the predetermined range, the constant maximum value (Mmax When the specified range is exceeded, a certain minimum value (Mmin) is taken. The larger the skin color area ratio is, the smaller the expansion rate correction coefficient is set. The influence of is reduced.

Embodiment 2. FIG.
FIG. 3 is a block diagram showing the configuration of the main part of the image display apparatus according to Embodiment 2 of the present invention. In the first embodiment, the light reduction rate is obtained from the corrected expansion rate. In the second embodiment, the light attenuation rate is calculated from the image feature amount and the skin color area ratio, and is calculated independently from the corrected expansion rate. The details will be described below with a focus on the differences.

  In the image display apparatus of FIG. 3, the dimming processing unit 18 a calculates the dimming rate A ′ based on the image feature amount and the skin color area ratio. For example, the white peak value WP is used as an example of the image feature amount. When the WP is large, the light control is performed so that the amount of light is increased, and when the WP is small, the light control element 19 is controlled so that the amount of light is decreased.

First, the dimming processing unit 18a obtains an ideal dimming rate A from the image feature amount by, for example, the following equation.
A = (255 / WP) ^-2.2
Next, the ideal dimming rate is corrected according to the skin color area ratio. For example, A '= Min (AN, 1)
Here, A ′ is a correction dimming rate, and N is a dimming rate correction coefficient.

FIG. 4 is a diagram showing the relationship between the skin color area ratio and the dimming rate correction coefficient N. In the figure, Th1 and Th2 use the same value as the expansion rate correction coefficient. In addition, N takes a value of 1 or more and N _max or less.

  As described above, according to the second embodiment, the dimming processing unit 18 obtains a corrected dimming rate based on the image feature amount and the skin color (attention color) area ratio, and the dimming is performed based on the corrected dimming rate. The luminance value of the element 19 is controlled, and not only the image feature amount but also the skin color (attention color) area ratio is directly taken into account, so that the contrast of the image can be improved. It is possible.

Embodiment 3. FIG.
In the first and second embodiments, the example in which the luminance expansion rate is corrected by focusing on one skin color has been described. For example, when there are a plurality of colors of interest, the colors of interest are represented as C1... Cn. If so, proceed as follows.

(Example 1) The attention color area detection unit (skin color area detection unit 12) counts all the pixels corresponding to C1... Cn, and calculates the attention color area ratio from the collectively counted values. Based on the target color area ratio, the expansion processing unit 14 calculates the expansion rate correction coefficient M, and the dimming processing unit 18a calculates the light reduction rate correction coefficient N. In this case, each of the graphs (tables) for obtaining the expansion rate correction coefficient M and the dimming rate correction coefficient N is sufficient.

(Example 2) The target color area detection unit (skin color area detection unit 12) counts C1... Cn separately, and calculates the ratios S1 to Sn of the respective color areas. Then, the largest ratio S in the region is obtained.
S = Max (S1,..., Sn)
Based on S thus obtained, the expansion processing unit 14 calculates the expansion rate correction coefficient M, and the dimming processing unit 18 calculates the light reduction rate correction coefficient N. Even in this case, each of the graphs (tables) for obtaining the expansion rate correction coefficient and the dimming rate correction coefficient is sufficient.

(Example 3) The attention color area detection unit (skin color area detection unit 12) counts C1... Cn separately, the expansion processing unit 14 sets the respective expansion rate correction coefficients Mc1. The dimming rate correction coefficients Nc1... Ncn are calculated. Then, the maximum one of the expansion rate correction coefficients and the maximum one of the dimming rate correction coefficients are obtained.
M = Max (Mc1,..., Mcn)
N = Max (Nc1,..., Ncn)
The expansion processing unit 14 corrects the ideal expansion rate using the expansion rate correction coefficient M determined in this way, and determines the corrected expansion rate. The dimming processing unit 18a also corrects the ideal dimming rate using the dimming rate correction coefficient N obtained in this way, and obtains the corrected dimming rate. In this case, the graphs (tables) for obtaining the expansion rate correction coefficient M and the dimming rate correction coefficient N are required as many as the number of colors of interest.

(Example 4)
The target color region detection unit (skin color region detection unit 12) counts all the pixels corresponding to C1. At this time, priority is given to the color of interest, and if the priority is low, the color is counted with a small value. For example, the priority of C1 is 1, and the priority of C2 is 0.5. In this case, if the color of C2 is 10 pixels, the value to be counted is 10 (pixels) × 0.5 (priority) = 5 (pixels). If the color of C1 is 5 pixels, the value to be counted is 5 (pixels) × 1 (priority) = 5 (pixels). The priority is 1 as the maximum, and the value is decreased as the priority is decreased. The possible range of priority is 1 to 0. When the priority is 0, it can be considered as a non-focused color. The ratio of the color area of interest is calculated from the values counted in this way, the expansion processing unit 14 calculates the expansion rate correction coefficient M, and the dimming processing unit 18 calculates the dimming rate correction coefficient N. In this case, each of the graphs (tables) for obtaining the expansion rate correction coefficient M and the dimming rate correction coefficient N is sufficient.

Embodiment 4 FIG.
In the first to third embodiments, the example in which the white peak value WP is detected as the image feature amount has been described. Here, an example in which APL is used as the image feature amount will be described.
The ideal elongation rate K is calculated by the following equation, for example.
K = Mid (1,128 / APL, 2)
Here, APL is the average picture level (Average Picture Level), and the Mid function is a function that outputs a central value from a plurality of arguments. That is, the ideal elongation rate K varies between 1 and 2 in this example. The method for obtaining the expansion rate correction coefficient M and the method for correcting the expansion rate are the same as in the example using the white peak value described above.

Moreover, the ideal light attenuation rate A is calculated by the following equation, for example.
A = Min (1, (128 / APL) ^-2.2 )
In the case of APL = 0, A = 0.

  The method for obtaining the light attenuation rate correction coefficient N and the method for correcting the light attenuation rate are the same as in the example using the white peak.

Embodiment 5. FIG.
Next, an example in which a white peak value and APL are combined as an image feature amount will be described. In order to calculate the ideal extension rate and the ideal light attenuation rate, for example, a 2DLUT (two-dimensional lookup table) is used here.

  FIG. 5 shows an example of this 2DLUT, where the horizontal axis is APL and the vertical axis is the white peak value. The ideal elongation rate and the ideal dimming rate are defined in the circles in FIG. n1 to n7 are arbitrary constants (however, a monotonically increasing value exceeding 0 and not exceeding 255, and the same value is used for both the x-axis and the y-axis). Since APL does not exceed the white peak value, it is not necessary to define the lower right half of the 2DLUT, and the memory capacity can be reduced. The ideal elongation rate and ideal dimming rate are values at the intersection of the 2DLUTs. For example, when focusing on the ideal expansion rate, the ideal expansion rate is defined from the white peak value and the APL. The ideal stretch rate obtained from the white peak value differs from the ideal stretch rate obtained from the APL. For example, the ideal stretch rate obtained from the white peak value is corrected by the ideal stretch rate obtained from the APL, and the correction is made. The obtained value is stored as the ideal expansion rate at the above intersection. Alternatively, the ideal expansion rate obtained from the white peak value is corrected while actually viewing the image by experiment or the like, and stored as the ideal expansion rate at the intersection point. This also applies to the ideal dimming rate. Further, when the ideal extension rate (or ideal dimming rate) is not defined at the intersection between the detected white peak value and APL, interpolation calculation is performed using the values of the surrounding points. The method for obtaining the expansion rate correction coefficient and the light attenuation rate correction coefficient and the method for correcting the expansion rate and the light attenuation rate are the same as in the example using the white peak.

  As described above, according to the fifth embodiment, both the white peak value and the average luminance value are taken into account in order to obtain the ideal expansion rate or the ideal dimming rate. Therefore, the image characteristics are appropriately reflected. It has become.

1 is a block diagram of a configuration of a main part of an image display device according to Embodiment 1 of the present invention. The figure which showed the relationship between the skin color area | region ratio and the expansion rate correction coefficient M. The block diagram of the structure of the principal part of the image display apparatus which concerns on Embodiment 2 of this invention. The figure which showed the relationship between the skin color area | region ratio and the light reduction rate correction coefficient N. FIG. The figure which showed the example of 2DLUT.

Explanation of symbols

  11 RGB / HSV conversion unit, 12 skin color area detection unit, 13 image feature amount detection unit, 14 decompression processing unit, 15 HSV / RGB conversion unit, 16 image signal processing unit, 17 light valve, 18, 18a dimming processing unit, 19 Dimming element.

Claims (9)

An attention color area detection unit for detecting the area ratio of the attention color in the image;
An image feature amount detection unit for detecting an image feature amount in the image;
An expansion processing unit that obtains a correction expansion rate based on the image feature amount and the region ratio of the target color, and expands the brightness of the image signal based on the correction expansion rate;
An image signal processing unit that performs signal processing for displaying an image based on the brightness of the image signal expanded based on the correction expansion rate and the hue and saturation of the image signal;
When there are a plurality of colors of interest, the target color area detection unit collects the plurality of colors and obtains the area ratio of the target color as one target color . An attention color area detection unit for detecting the area ratio of the attention color in the image;
An image feature amount detection unit for detecting an image feature amount in the image;
An expansion processing unit that obtains a correction expansion rate based on the image feature amount and the region ratio of the target color, and expands the brightness of the image signal based on the correction expansion rate;
An image signal processing unit that performs signal processing for displaying an image based on the brightness of the image signal expanded based on the correction expansion rate and the hue and saturation of the image signal;
When there are a plurality of colors of interest, the target color area detection unit obtains the area ratio in the image of each color, and sets the area ratio of the maximum value as the area ratio of the target color. A characteristic image display device. An attention color area detection unit for detecting the area ratio of the attention color in the image;
An image feature amount detection unit for detecting an image feature amount in the image;
An expansion processing unit that obtains a correction expansion rate based on the image feature amount and the region ratio of the target color, and expands the brightness of the image signal based on the correction expansion rate;
An image signal processing unit that performs signal processing for displaying an image based on the brightness of the image signal expanded based on the correction expansion rate and the hue and saturation of the image signal;
When there are a plurality of colors of interest, the target color area detection unit obtains the area ratio in the image of each color,
The expansion processing unit obtains a correction expansion rate based on a region ratio in the image of each color, and uses the maximum correction expansion rate as the correction expansion rate. Display device. An attention color area detection unit for detecting the area ratio of the attention color in the image;
An image feature amount detection unit for detecting an image feature amount in the image;
An expansion processing unit that obtains a correction expansion rate based on the image feature amount and the region ratio of the target color, and expands the brightness of the image signal based on the correction expansion rate;
An image signal processing unit that performs signal processing for displaying an image based on the brightness of the image signal expanded based on the correction expansion rate and the hue and saturation of the image signal;
When there are a plurality of colors of interest, the attention color area detection unit obtains areas in the image by assigning priorities to the respective colors, and obtains the area ratio of the attention color based on the sum of these areas. An image display device characterized by that. An attention color area detection unit for detecting the area ratio of the attention color in the image;
An image feature amount detection unit for detecting an image feature amount in the image;
An expansion processing unit that obtains a correction expansion rate based on the image feature amount and the region ratio of the target color, and expands the brightness of the image signal based on the correction expansion rate;
An image signal processing unit that performs signal processing for displaying an image based on the brightness of the image signal expanded based on the correction expansion rate, and the hue and saturation of the image signal ;
A light modulation element that displays an image based on the brightness of the image signal expanded based on the corrected expansion rate and the hue and saturation of the image signal;
A dimming processing unit that obtains a dimming rate of the dimming element based on the corrected extension rate, and controls a luminance value of the dimming element based on the dimming rate ;
When there are a plurality of colors of interest, the target color area detection unit obtains the area ratio in the image of each color,
The dimming processing unit obtains a dimming rate correction coefficient based on a region ratio in the image of each color, and uses the maximum dimming rate correction coefficient as the dimming rate correction coefficient. > An image display device characterized by that. An attention color area detection unit for detecting the area ratio of the attention color in the image;
An image feature amount detection unit for detecting an image feature amount in the image;
An expansion processing unit that obtains a correction expansion rate based on the image feature amount and the region ratio of the target color, and expands the brightness of the image signal based on the correction expansion rate;
An image signal processing unit that performs signal processing for displaying an image based on the brightness of the image signal expanded based on the correction expansion rate, and the hue and saturation of the image signal ;
A light modulation element that displays an image based on the brightness of the image signal expanded based on the corrected expansion rate and the hue and saturation of the image signal;
A dimming processing unit that obtains a corrected dimming rate based on the image feature amount and the region ratio of the target color, and that controls a luminance value of the dimming element based on the corrected dimming rate ;
When there are a plurality of colors of interest, the target color area detection unit obtains the area ratio in the image of each color,
The dimming processing unit obtains a dimming rate correction coefficient based on a region ratio in the image of each color, and uses the maximum dimming rate correction coefficient as the dimming rate correction coefficient. > An image display device characterized by that. The image display device according to claim 1 , wherein the image feature amount detection unit obtains an image feature amount based on a white peak value and / or an average luminance value of the image. The expansion processing unit includes a table in which an ideal expansion rate corresponding to discrete white peak values and average luminance is set, and the white peak value and average luminance value detected by the image feature amount detection unit and the table The image display apparatus according to claim 7 , wherein an ideal expansion ratio is obtained based on the above. The dimming processing unit includes a table in which ideal dimming rates corresponding to discrete white peak values and average luminance are set, and the white peak value and average luminance value detected by the image feature amount detection unit and the the image display apparatus according to claim 5, wherein the determination of the ideal dimming ratio based on the table.

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