JP6525511B2 - Image processing apparatus and control method thereof - Google Patents

Description

  The present invention relates to an image processing apparatus and a control method thereof.

  Display unevenness exists in display devices including liquid crystal displays. There is a method of measuring display unevenness with a measuring device and correcting display unevenness by signal processing based on the result. The display unevenness is roughly classified into brightness unevenness, which is uneven brightness, and color unevenness, which is uneven display color. The brightness depends on the light emission intensity of the display screen, and the brightness unevenness is caused by the unevenness of the light emission intensity of the display screen. There is brightness as an indicator that represents brightness. In addition, there are various chromaticity coordinates in the index indicating the display color.

  In the method of correcting unevenness by signal processing, when the white of the maximum gradation is displayed on the entire screen, the display gradation of the screen is made uniform by lowering the signal gradation in the high luminance area. Therefore, in order to realize equalization for all areas of the screen, it is necessary to match the luminance to the darkest area of the screen at the time of maximum gradation display, and as a result, the luminance of the entire screen is reduced. Therefore, it becomes an issue how to eliminate display unevenness while maintaining high luminance. This problem is particularly noticeable when unevenness correction is performed on a display device in which the brightness of the screen is reduced due to driving for a long time or a display device in which display unevenness is increased.

  There are methods shown in Patent Literatures 1 and 2 as methods of reducing display unevenness without lowering the screen luminance as much as possible. According to the method disclosed in Patent Document 1, the display screen is obtained by correcting the luminance and the chromaticity in the area where all the color components are equal to or more than the target luminance and correcting only the chromaticity in the area where any of the color components becomes less than the target luminance. It is intended to eliminate color unevenness without causing a decrease in the overall luminance. Further, in the method disclosed in Patent Document 2, as the intensity of the color component of the image signal is larger, the amount of correction of the unevenness is reduced to perform the unevenness correction while maintaining the luminance.

JP 2007-171527 A JP, 2008-310261, A

  In the method shown in Patent Document 1, when the variation in color components is large, the uneven brightness after correction may be large. Also, conversely, there is a possibility that the target luminance may be a value lower than the luminance necessary to eliminate unevenness from the entire screen, and the luminance of the entire screen may be unnecessarily lowered. As an easy solution, first set the target brightness higher to perform correction, determine whether the uneven brightness after correction exceeds the preset allowable level, and if it exceeds, correct the target brightness again It is conceivable to make a correction. However, in this method, it takes time for adjustment because the process is repeated. Further, according to the method disclosed in Patent Document 2, when an image is displayed so that the signal gradation is maximized uniformly on the screen, the display unevenness is not corrected and remains nonuniform.

  An object of the present invention is to correct display unevenness in a short time and to suppress a decrease in luminance due to the unevenness correction in an image display device.

The present invention is an image processing apparatus for performing correction on image data input to an image display apparatus ,
Acquisition means for acquiring measured values of luminance and chromaticity in a state in which each of a plurality of single-color image data is displayed on the screen for each of the plurality of areas into which the screen of the image display device is divided ;
First determining means for determining a target chromaticity to be displayed in each area of the screen based on the measured value;
A second determination unit configured to calculate the maximum luminance that can be displayed with the target chromaticity in each area of the screen based on the measurement value, and determine the target luminance to be displayed in each area of the screen based on the maximum luminance;
A correction unit configured to correct image data input to the image display apparatus based on the target chromaticity and the target luminance;
Equipped with
The target brightness is a value larger than the minimum value of the maximum brightness that can be displayed with the target chromaticity in each area of the screen, and the maximum brightness is the target among the plurality of areas of the screen. When the display in the area smaller than the luminance is performed at the maximum luminance in the area and the display in the area where the maximum luminance is the target luminance or more is performed at the target luminance does not exceed the predetermined allowable level , determined is an image processing apparatus according to claim Rukoto.

The present invention is a control method of an image processing apparatus that performs correction on image data input to an image display apparatus .
An acquiring step of acquiring measured values of luminance and chromaticity in a state where each of a plurality of single-color image data is displayed on the screen, for each of the plurality of areas into which the screen of the image display device is divided ;
A first determining step of determining a target chromaticity to be displayed in each area of the screen based on the measured value;
A second determination step of calculating the maximum luminance that can be displayed with the target chromaticity in each area of the screen based on the measurement value, and determining the target luminance to be displayed in each area of the screen based on the maximum luminance;
Correcting the image data input to the image display device based on the target chromaticity and the target luminance;
I have a,
The target brightness is a value larger than the minimum value of the maximum brightness that can be displayed with the target chromaticity in each area of the screen, and the maximum brightness is the target among the plurality of areas of the screen. When the display in the area smaller than the luminance is performed at the maximum luminance in the area and the display in the area where the maximum luminance is the target luminance or more is performed at the target luminance does not exceed the predetermined allowable level it is determined a control method for an image processing apparatus according to claim Rukoto.

  According to the present invention, in the image display device, it is possible to correct display unevenness in a short time and to suppress a decrease in luminance due to the unevenness correction.

The figure which shows schematic structure of the processing apparatus of an Example, and a display apparatus Flow chart showing the flow of display unevenness correction A diagram showing an example of measurement results of luminance for each area of the display screen A diagram showing an example of the result of calculating the maximum displayable luminance for each area of the display screen A diagram showing an example of the result of calculating the relationship between the first target luminance and the post-correction unevenness level A diagram showing an example of change in luminance for each area before and after display unevenness correction

  Hereinafter, an embodiment of an image processing apparatus and a control method thereof according to the present invention will be described. This embodiment is an example, and the present invention is not limited to this embodiment. Hereinafter, the image processing apparatus according to the present invention and the unevenness correction method by the control method thereof will be specifically described with reference to the drawings. The image processing apparatus corrects image data input to the image display apparatus. In this embodiment, an example in which the image processing apparatus is configured separately from the image display apparatus will be described, but a configuration in which the image display apparatus has the image processing apparatus described below is also included in the scope of the present invention. In the present embodiment, luminance is used as an index indicating brightness. Further, as an index representing a display color, stimulus values XYZ and chromaticity coordinates xy according to a color matching function of CIE (International Commission on Illumination) are used. In addition, the index which shows brightness and chromaticity is not limited to these. Any index corresponding to the brightness and any index corresponding to the display color may be used. For example, an indicator such as CIELUV may be used. The output signal level from the measuring device may be used as an index corresponding to the brightness, and the output signal level from a measuring device having different spectral characteristics may be used as an index corresponding to the display color.

  FIG. 1 shows an example of a basic configuration for implementing the correction method according to the present invention. In FIG. 1, a display device 101 is a display device such as a liquid crystal display or an organic EL (Electro-Luminescence) display. The display device 101 is connected to a processing device 102 such as a personal computer. The display device 101 receives image data (image signal) output from the processing device 102. The display unit 104 of the display device 101 displays an image based on the image data by performing display at a luminance according to the gradation value of the image data received by the display device 101. The image data includes tone values of a plurality of color components, that is, R (red) component, G (green) component, and B (blue) component.

  The measuring device 105 measures the luminance and the chromaticity for each of the divided areas of the display unit 104. The measuring device 105 outputs tristimulus values X, Y, Z as measurement results for each area. The measuring device 105 outputs the measurement result to the processing device 102. The measuring device 105 is configured to output the measurement result to the processing device 102 by, for example, wired or wireless communication means. Alternatively, the measuring instrument 105 can be configured to acquire the measurement result by the processing device 102 by writing the measurement result on a storage medium such as a memory card and causing the processing device 102 to read the storage medium.

  In the present embodiment, the luminance and the chromaticity of the display unit 104 of the display device 101 are handled for each of a plurality of divided regions. Display unevenness is treated as variation in luminance and chromaticity for each area when the same image data is input and image display is performed. In this case, a state in which the luminance and the chromaticity of a plurality of regions are all the same is referred to as a state in which there is no display unevenness. Note that the method for determining the presence or absence of display unevenness is not limited to this. When the variation in luminance among the regions falls within a predetermined range, it may be determined that the luminances of the plurality of regions are the same.

<Flow chart of unevenness correction>
The flow of unevenness correction in the present embodiment will be described using the flowchart shown in FIG.
In step S201, the measuring device 105 measures the luminance and the chromaticity of each area of the display device 101 in a state where the display device 101 displays each color component.
In step S202, the processing device 102 acquires the measurement value acquired from the measuring device 105, and sets the target chromaticity based on the acquired measurement value.
In step S203, the processing apparatus 102 calculates the maximum displayable luminance when the image data is corrected to become the target chromaticity for each area from the luminance measured in step S201 and the target chromaticity set in step S202. Do. This is the maximum luminance that can be displayed at the target chromaticity in each area.
In step S204, the processing apparatus 102 calculates the relationship between the first target luminance and the post-correction unevenness level, based on the maximum displayable luminance for each area calculated in step S203. The first target brightness is a target value of the brightness of the entire display screen after unevenness correction, and is one value on the entire display screen.
In step S205, the processing apparatus 102 determines a second target luminance for each area based on the relationship between the first target luminance and the corrected unevenness level calculated in step S204 and the unevenness allowable level set in advance. The second target luminance is a target value of luminance for each of the plurality of areas into which the display screen is divided, and is a value for each of the areas.
In step S206, the processing device 102 determines that the luminance of each region is the second target luminance and the chromaticity is the target chromaticity, based on the target chromaticity set in step S202 and the second target luminance determined in step S205. Correct the image data to become The processing apparatus 102 performs unevenness correction by the above process.
Hereinafter, each step will be specifically described.

<Step S201: Measurement of Luminance of Each Color Component>
In step S201, the measuring instrument 105 measures the luminance and the chromaticity of each area of the display device 101 in a state where the display device 101 displays a single color image of each color of RGB.

Here, in a state where an image of the same gradation value is displayed on the entire screen of the display unit 104, the measuring instrument 105 measures the luminance and chromaticity for each of the plurality of areas into which the screen of the display unit 104 is divided. Images of the same gradation value to be displayed are RGBW single color images, that is, red (R) single color images, green (G) single color images, blue (B) single color images, and white (W) images. is there. The measuring instrument 105 outputs tristimulus values X, Y, Z for each area of the display unit 104 to the processing device 102 as a measurement result. In the present embodiment, obtaining the tristimulus values X, Y, Z corresponds to measuring the luminance and the chromaticity. An example of a measurement result is shown in FIG. Fig.3 (a)-FIG.3 (c) are measurement values of tristimulus value X, Y, Z in the state which displayed the white image. FIG.3 (d)-FIG.3 (f) are the measurement values of tristimulus value X, Y, Z in the state which displayed the monochrome image of red (R). FIG.3 (g)-FIG.3 (i) are the measurement values of tristimulus value X, Y, Z in the state which displayed the monochrome image of green (G). FIGS. 3 (j) to 3 (l) are measurement values of tristimulus values X, Y, Z in a state where a monochromatic image of blue (B) is displayed. FIG. 3 shows an example of measurement values for each area when the display screen is divided into eight horizontally and five vertically. The unit of each measured value in FIG. 3 is cd / m ² . The number of areas into which the screen is divided is an example, and is not limited to this example.

<Step S202: Setting Target Chromaticity>
In step S202, the processing device 102 sets a target chromaticity.
The target chromaticity may be set according to the measurement result in step S201, in addition to the method of setting the predetermined value such as the color temperature 6500 K and the value of the specification of the display device 101. For example, a method of setting the measurement value of the chromaticity of the central region of the screen as the target chromaticity can be exemplified. The setting method of the target chromaticity based on the measurement value is not limited to this. You may set based on an average value, a mode value, etc. The target chromaticity can be appropriately set in accordance with the application of the display device 101 and the like. The processing device 102 sets the target chromaticity by the value of the chromaticity xy.

<Step S203: Calculation Processing (1) Calculation of Maximum Displayable Luminance at Color Correction of Each Region>
In step S203, based on the luminance measured in step S201 and the target chromaticity set in step S202, the processing apparatus 102 corrects the image data for each area so as to achieve the target chromaticity, and the maximum displayable luminance can be obtained. Calculate That is, the processing device 102 calculates the maximum luminance that each area can be displayed at the target chromaticity.

A method of calculating the maximum displayable luminance will be described. The target chromaticity set in step S202 and as (x, y), the measurement result of the measured white image display tristimulus value at Step _{S201 (X W, Y W,} Z W), the target chromaticity vector c and white luminance vector w are defined by Equations 1 and 2, respectively.

The measurement results of tristimulus values at the time of displaying each of R, G, B single-color images measured in step S201 are respectively (X _R , Y _R , Z _R ), (X _G , Y _G , Z _G ), (X _B , Y _B , Z _B ), and the matrix m is defined by Equation 3.

なお、表示装置１０１に色のクロストークがない場合は、修正係数はいずれも１となる。修正係数を用いて、三刺激値と色成分の変換行列Ｍは、式５で表される。

このとき、目標色度に調整するためのＲＧＢ成分の調整値ベクトルｄは式６となる。

Here, the correction coefficients cR, cG and cB of the R, G and B colors are calculated by the equation 4. The correction coefficients cR, cG, cB are coefficients for correcting the deviation between the value obtained by adding the tristimulus values when displaying the R, G, B color monochrome images and the tristimulus value of white.

When there is no color crosstalk in the display device 101, the correction coefficient is 1 in all cases. The transformation matrix M of tristimulus values and color components is expressed by Equation 5 using the correction coefficients.

At this time, the adjustment value vector d of the RGB component for adjusting to the target chromaticity is expressed by Equation 6.

式７中の除算記号（／）はベクトル要素ごとの除算、ｍｉｎはベクトル要素のうち最小値を選択する処理を意味する。ここから、色度補正後の最大表示可能輝度ベクトルｔは式８で算出される。

In order to make correction in signal processing, the component of d needs to be less than or equal to zero. Therefore, the maximum value of k is calculated by Equation 7.

The division symbol (/) in Equation 7 is division for each vector element, and min is a process of selecting the minimum value of the vector elements. From here, the maximum displayable luminance vector t after the chromaticity correction is calculated by Expression 8.

Of the maximum displayable luminance vector t, the numerical value of the element corresponding to the stimulation value Y is the maximum displayable luminance . The processing device 102 performs the above calculation for each area to calculate the maximum displayable luminance of each area. FIG. 4 shows an example of the result of calculating the maximum displayable luminance with the target chromaticity as (0.304, 0.346) based on the measurement result of FIG. The units of the numerical values in FIG. 4 are all cd / m ² .

<Step S204: Calculation Process (2) Calculation of Relationship between Target Luminance and Correction Unevenness Evaluation Value>
In step S204, the processing apparatus 102 calculates the relationship between the first target luminance and the post-correction unevenness level based on the maximum displayable luminance for each area calculated in step S203.

  Specifically, the relationship between the first target brightness and the post-correction unevenness level is calculated as a LUT (look-up table) in which the first target brightness and the post-correction unevenness level are associated. The processing apparatus 102 selects the first target luminance for calculating the corrected non-uniformity level from the predetermined luminance range, and performs the non-uniformity correction with the selected first target luminance as the target luminance (correction level (correction Calculate the post unevenness level). The processing apparatus 102 performs this process on various luminances within a predetermined luminance range, thereby obtaining a post-correction unevenness level corresponding to various possible values of the first target luminance, and generates a LUT. Here, it is preferable to determine the predetermined luminance range based on the maximum value and the minimum value in the screen of the maximum displayable luminance for each area calculated in step S203.

  A method of calculating the post-correction unevenness level corresponding to the first target luminance will be described. The processing device 102 calculates the luminance (luminance after correction) for each region which is realized when the unevenness correction is performed with the selected first target luminance as the target luminance. The processing device 102 sets the first target luminance as the post-correction luminance in a region where the maximum displayable luminance is equal to or higher than the first target luminance, and the maximum displayable luminance in the region where the maximum displayable luminance is smaller than the first target luminance. As the post-correction luminance. In other words, the processing device 102 corrects for each area by replacing the value that is equal to or greater than the selected first target luminance among the maximum displayable luminance for each area obtained in step S203 with the first target luminance. Find the brightness. Thus, the processing apparatus 102 obtains the corrected luminance distribution in the screen, evaluates the luminance unevenness based on the corrected luminance distribution, and calculates the corrected unevenness level.

Various methods can be considered as a method of calculating the post-correction unevenness level based on the post-correction luminance distribution. For example, the processing device 102 evaluates the uneven brightness on the basis of the area ratio of the area where the corrected brightness is smaller than the first target brightness to the entire screen area. In this case, the processing apparatus 102 calculates the post-correction unevenness level by Expression 9.

Uneven level after correction = (the number of areas where the luminance after correction is smaller than the first target luminance) / (the number of all areas) Equation 9

As another method of evaluation of the luminance unevenness, there is also a method of evaluating based on the degree of deviation of luminance (difference between the maximum value and the minimum value of luminance after correction). In that case, the processing apparatus 102 calculates the post-correction unevenness level by Expression 10.

Unevenness level after correction = (maximum value of luminance after correction−minimum value of luminance after correction) / (average value of luminance after correction) formula 10

Further, as another method of evaluating the uneven brightness, there is also a method of evaluating based on a color difference formula. In that case, the processing device 102 converts the corrected luminance for each region into the lightness L * in CIELAB. Thereafter, the processing device 102 calculates the color difference in the display screen by calculating the difference between the lightness of each area and the average lightness of the entire screen, and calculates the post-correction unevenness level by Expression 11 based thereon.

Uneven level after correction = MAX (ABS (brightness for each area-average brightness for all areas)) Equation 11

  MAX in equation 11 is a function that selects the maximum value of the arguments, and ABS is a function that converts the arguments to absolute values. FIG. 5 shows an example of the result of calculating the post-correction unevenness level with respect to various first target luminances. FIG. 5A shows the case where the post-correction unevenness level is calculated based on the area ratio shown in Expression 9. FIG. 5B shows the case where the post-correction unevenness level is calculated based on the luminance deviation degree shown in Expression 10. FIG. 5C shows the case where the post-correction unevenness level is calculated based on the maximum value of the lightness deviation shown in Expression 11.

<Step S205: Calculation Processing (3) Determine Target Luminance of Each Region>
In step S205, the second target luminance for each area is determined based on the relationship between the first target luminance and the corrected unevenness level calculated in step S204, and the unevenness allowable level set in advance.

A specific determination method will be described using the relationship between the first target luminance and the post-correction unevenness level shown in FIG. 5A. The allowable level of unevenness is, for example, based on experiments or empirical rules to set the level of luminance unevenness such that the sense of discomfort given to the observer is within an allowable range, or based on specification requirements etc. determined from conditions such as the purpose of use of the display device 101. Set up. Here, the unevenness allowable level is assumed to be the area ratio 0.1 (10%). In this case, in FIG. 5A, 56.3 cd / m ² is selected as the first target luminance at which the corrected unevenness level is 0.1 or less. The processing device 102 sets the first target luminance as the second target luminance and the region where the maximum displayable luminance is smaller than the selected first target luminance, in a region where the maximum displayable luminance is equal to or higher than the selected first target luminance. The maximum displayable luminance is set as the second target luminance. In other words, the processing device 102 performs the second process for each area by replacing the value higher than the selected first target luminance among the maximum displayable luminance for each area determined in step S203 with the first target luminance. Calculate the target brightness.

<Step S206: Correction of unevenness by signal processing>
In step S206, on the basis of the target chromaticity set in step S202 and the second target luminance determined in step S205, nonuniformity correction is performed on each area by signal processing so that the target luminance and chromaticity are obtained.
The target vector Wt is defined by equation 12 with the tristimulus values for each area based on the target luminance and chromaticity as (Xwt, Ywt, Zwt).

At this time, the adjustment value vector d of the RGB component for adjusting to the target chromaticity is as follows.

The vector w in Equation 13 is the equation 2 and the matrix M is the equation 5.
In the nonuniformity correction by signal processing, an adjustment value vector is selected or interpolated and calculated based on the in-screen position coordinates of the image data and the gradation level, and the calculated value is added to the input signal and output to the display device 101. This signal processing is performed by the processing device 102 or by the signal processing unit 103 provided in the display device 101.

FIG. 6 shows an example of the change in luminance unevenness according to the method of the present invention. In FIG. 6, the horizontal position of the divided area is x0 to x7, and the vertical position is y0 to y4, and the luminance of each area is shown. The luminance D in the case where the correction to make the entire display area uniform with respect to the luminance A before correction in FIG. 6 is 55.6 cd / m ^{2 in} all the areas. On the other hand, as shown in the luminance C when corrected according to the present invention, by allowing part of the unevenness according to the unevenness allowable level set in advance, the luminance unevenness is allowed to be an acceptable level while suppressing the reduction in luminance compared to the prior art. It can be suppressed to the following. In the example of FIG. 6, the brightness of the area other than the area where the unevenness below the allowable level occurs is 56.4 cd / m ² , and the brightness can be improved by about 1.4% compared to the conventional 55.6 cd / m ² It has become.

  According to the present embodiment, in the image processing apparatus that performs correction on image data input to the display device having display unevenness, measurement values of luminance and chromaticity are acquired for each of the plurality of areas into which the screen is divided. A target chromaticity is determined for each area based on the value (first determination means). Then, the maximum luminance that can be displayed with the target chromaticity in each area is calculated, and the target luminance to be displayed in each area is determined based on the calculated maximum luminance (second determination means). The target luminance is set to a value larger than the minimum value of the maximum luminance that can be displayed at the target chromaticity in each region. Therefore, as described above, compared to the case where the chromaticity unevenness correction is performed in accordance with the minimum value of the maximum luminance that can be displayed with the target chromaticity in each region, the luminance decrease due to the chromaticity unevenness correction is suppressed it can. When the display in the region where the maximum brightness is smaller than the target brightness among the plurality of regions is performed in the maximum region in the region and the display in the region where the maximum brightness is the target brightness or more is performed with the target brightness The target brightness is determined so as not to exceed the level. Therefore, although some luminance unevenness remains, the level of the luminance unevenness is equal to or less than the allowable level according to the characteristics of the viewer's appearance and the specification application of the image display apparatus, and hence good display can be performed. is there. As described above, according to the present embodiment, it is possible to correct the chromaticity nonuniformity in a short time and to suppress the luminance decrease due to the chromaticity nonuniformity correction, so that a good display can be realized.

  In the above-described embodiment, various types of processing described as processing to be executed by the processing device 102 which is an external device of the display device 101 can be configured to be executed by the signal processing unit 103 provided in the display device 101. In that case, the display device 101 acquires a measurement value from the measuring instrument 105, and performs signal processing for each area based on the acquired measurement value.

101: Display device 102: Processing device 105: Measuring device

Claims (21)

An image processing apparatus for performing correction on image data input to an image display apparatus, comprising:
Acquisition means for acquiring measured values of luminance and chromaticity in a state in which each of a plurality of single-color image data is displayed on the screen for each of the plurality of areas into which the screen of the image display device is divided;
First determining means for determining a target chromaticity to be displayed in each area of the screen based on the measured value;
A second determination unit configured to calculate the maximum luminance that can be displayed with the target chromaticity in each area of the screen based on the measurement value, and determine the target luminance to be displayed in each area of the screen based on the maximum luminance;
A correction unit configured to correct image data input to the image display apparatus based on the target chromaticity and the target luminance;
Equipped with
The target brightness is a value larger than the minimum value of the maximum brightness that can be displayed with the target chromaticity in each area of the screen, and the maximum brightness is the target among the plurality of areas of the screen. When the display in the area smaller than the luminance is performed at the maximum luminance in the area and the display in the area where the maximum luminance is the target luminance or more is performed at the target luminance does not exceed the predetermined allowable level An image processing apparatus characterized in that it is determined.   The correction means performs display in the region where the maximum brightness is smaller than the target brightness among the plurality of regions of the screen at the maximum brightness, and displays the region where the maximum brightness is the target brightness or more. The image processing apparatus according to claim 1, wherein the image data is corrected such that is performed at the target luminance.   The image processing apparatus according to claim 1, wherein the target brightness is a value selected from a brightness range defined by a minimum value and a maximum value of the maximum brightness in each area of the screen. The second determination means calculates, for a plurality of luminances included in the luminance range, the level of the luminance unevenness which is realized when the one luminance included in the luminance range is temporarily set as the target luminance, The image processing apparatus according to claim 3, wherein a luminance at which the calculated level of luminance unevenness does not exceed the allowable level among the plurality of luminances included in the range is determined as the target luminance. The second determination means calculates the luminance in each area of the screen which is realized when the one luminance included in the luminance range is temporarily set as the target luminance, and the calculation among the plurality of areas of the screen is performed. the image processing apparatus according to claim 4, luminance to calculate the level of the luminance unevenness on the basis of the ratio against the area of the whole screen area of the area smaller than the target luminance.   The second determination means calculates the luminance in each area of the screen which is realized when one luminance included in the luminance range is temporarily set as the target luminance, and the maximum value and the minimum value of the calculated luminance The image processing apparatus according to claim 4, wherein the level of the uneven brightness is calculated based on a difference between   The second determination means calculates the luminance in each area of the screen which is realized when the one luminance included in the luminance range is temporarily set as the target luminance, and each of the screens is calculated based on the calculated luminance. 5. The image processing apparatus according to claim 4, wherein the lightness in the area is calculated, and the level of the uneven brightness is calculated based on the maximum value of the difference between the lightness of each area and the average lightness of the entire screen.   The image processing apparatus according to any one of claims 1 to 7, wherein the target chromaticity is a predetermined value.   The image processing apparatus according to any one of claims 1 to 7, wherein the target chromaticity is determined based on a measurement value of chromaticity in a central region of the screen.   The acquisition means acquires measured values of luminance and chromaticity for each of the regions in a state in which the red monochrome image, the green monochrome image, the blue monochrome image, and the white image are displayed on the screen. The image processing apparatus of any one of 1-9. A control method of an image processing apparatus for performing correction on image data input to an image display apparatus, comprising:
An acquiring step of acquiring measured values of luminance and chromaticity in a state where each of a plurality of single-color image data is displayed on the screen, for each of the plurality of areas into which the screen of the image display device is divided;
A first determining step of determining a target chromaticity to be displayed in each area of the screen based on the measured value;
A second determination step of calculating the maximum luminance that can be displayed with the target chromaticity in each area of the screen based on the measurement value, and determining the target luminance to be displayed in each area of the screen based on the maximum luminance;
Correcting the image data input to the image display device based on the target chromaticity and the target luminance;
Have
The target brightness is a value larger than the minimum value of the maximum brightness that can be displayed with the target chromaticity in each area of the screen, and the maximum brightness is the target among the plurality of areas of the screen. When the display in the area smaller than the luminance is performed at the maximum luminance in the area and the display in the area where the maximum luminance is the target luminance or more is performed at the target luminance does not exceed the predetermined allowable level And a control method of an image processing apparatus characterized by being determined.   In the correction step, among a plurality of areas of the screen, the display in the area where the maximum luminance is smaller than the target luminance is performed at the maximum luminance in the area, and the display in the area where the maximum luminance is the target luminance or more The control method of the image processing apparatus according to claim 11, wherein the correction of the image data is performed so that the correction is performed at the target luminance.   The control method of the image processing apparatus according to claim 11, wherein the target brightness is a value selected from a brightness range defined by a minimum value and a maximum value of the maximum brightness in each area of the screen.   In the second determination step, the level of the luminance unevenness realized when the one luminance included in the luminance range is temporarily set as the target luminance is calculated for a plurality of luminances included in the luminance range, and the luminance is calculated. The control method of the image processing apparatus according to claim 13, wherein the target luminance is determined as a luminance at which the calculated level of the luminance unevenness does not exceed the allowable level among the plurality of luminances included in the range. In the second determination step, the luminance in each area of the screen, which is realized when one luminance included in the luminance range is temporarily set as the target luminance, is calculated, and the calculation among the plurality of areas of the screen is performed. method of controlling an image processing apparatus according to claim 14, the brightness calculating the level of the luminance unevenness on the basis of the ratio against the area of the whole screen area of the area smaller than the target luminance.   In the second determination step, the luminance in each area of the screen, which is realized when one luminance included in the luminance range is temporarily set as the target luminance, is calculated, and the calculated maximum and minimum values of the luminance The control method of the image processing apparatus according to claim 14, wherein the level of the uneven brightness is calculated based on a difference between   In the second determination step, the luminance in each area of the screen, which is realized when one luminance included in the luminance range is temporarily set as the target luminance, is calculated, and each of the screens is calculated based on the calculated luminance. The control method of the image processing apparatus according to claim 14, wherein the lightness in the area is calculated, and the level of the luminance unevenness is calculated based on the maximum value of the difference between the lightness of each area and the average lightness of the entire screen.   The control method of the image processing apparatus according to any one of claims 11 to 17, wherein the target chromaticity is a predetermined value.   The control method of the image processing apparatus according to any one of claims 11 to 17, wherein the target chromaticity is determined based on a measurement value of chromaticity in a central region of the screen.   In the acquisition step, measurement values of luminance and chromaticity are acquired for each of the regions in a state in which the red monochrome image, the green monochrome image, the blue monochrome image, and the white image are displayed on the screen. A control method of an image processing apparatus according to any one of 11 to 19.   The image display apparatus provided with the image processing apparatus of any one of Claims 1-10.

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