JP6659178B2 - Image processing apparatus and image processing method - Google Patents

Description

  The present invention relates to an image processing device and an image processing method.

  In fields such as image production, opportunities for handling image data having a wide dynamic range are increasing. Here, the dynamic range is a range of luminance-related values relating to luminance. A wide dynamic range is called “HDR (High Dynamic Range)” or the like, and a dynamic range narrower than HDR is called “SDR (Standard Dynamic Range)” or the like. The image data having HDR is called “HDR image data” and the like, and the image data having SDR is called “SDR image data” and the like.

  Also, the standardization of HDR image data that can be transmitted using a cable such as an SDI (Serial Digital Interface) cable is in progress. For example, ST2084 standardized by SMPTE (American Movie and Television Engineers Association) has been proposed. A technique for displaying an image (HDR image) based on HDR image data with high luminance has also been proposed.

ST2084 is a gradation characteristic based on human visual characteristics, and defines the luminance of the HDR image data as absolute luminance. In ST2084, the absolute luminance up to 10000 cd / m ² is handled. However, a general display device, only can display luminance to hundreds to thousands cd / ^{m 2,} it is not possible to display the luminance of 10000 cd / ^{m 2.}

Therefore, a part of the dynamic range of the HDR image data can be set as a range suitable for display on a display device (an absolute luminance range up to 1000 cd / m ² , an absolute luminance range up to 2000 cd / m ² , and the like). A display device has been proposed. Hereinafter, such a function is referred to as “HDR setting function”, and the range set by the HDR setting function is referred to as “setting HDR”. In a display device having an HDR setting function, the set HDR is displayed with a gradation characteristic conforming to the standard (gradation characteristics) of the HDR image data. For example, when the standard of the HDR image data is ST2084, the setting HDR is displayed with the absolute luminance defined in ST2084. Then, a luminance-related value that is larger than the maximum value of the plurality of luminance-related values belonging to the set HDR is displayed in whiteout.

  As a method (standard; gradation characteristics) of HDR image data, a method of defining the luminance of HDR image data by relative luminance in addition to the method of defining the luminance of HDR image data by absolute luminance has been proposed.

  In image production and the like, there is a need to check the luminance distribution of input image data. As an assist function for confirming the luminance distribution of the input image data, there is a function of converting the color of the input image data into a color corresponding to the luminance gradation value of the input image data. Color conversion can also be referred to as "color coloring", and such an assist function can be referred to as "color conversion function", "coloring function", and the like. By displaying an image based on the image data whose color has been converted by the color conversion function, the user can confirm the luminance gradation value of the input image data by color.

FIG. 8 shows an example of a correspondence relationship between a luminance gradation value of input image data and a color after conversion by the color conversion function. FIG. 8 shows an example where the luminance gradation value of the input image data is a 10-bit value (0 to 1023). In the example of FIG. 8, six colors are respectively associated with six ranges forming a dynamic range (range of luminance gradation values) of input image data.

  A technique relating to the color conversion function is disclosed in, for example, Patent Document 1. According to the technique disclosed in Patent Literature 1, a zebra pattern is displayed in an image region in which a luminance level (luminance gradation value) is equal to or more than a predetermined value.

JP 2014-167609 A

As described above, in the conventional color conversion function, the color of the input image data is converted into a color corresponding to the luminance gradation value of the input image data. Therefore, even when the conventional color conversion function is used, the user cannot grasp the absolute luminance defined by the gradation characteristics of the input image data, the relative luminance defined by the gradation characteristics of the input image data, and the like. . The ^{user, 100cd / m 2, 200cd /} m 2, can not be grasped plurality of distribution of absolute luminance as a separator and the like.

  In some cases, a luminance-related value close to the maximum value of a plurality of luminance-related values belonging to HDR is not used for display. Process). As a result, it becomes difficult to confirm the distribution of the luminance-related values. As a method for solving such a problem, a method of narrowing the HDR to the set HDR and converting the color of the image data into a color corresponding to the luminance gradation value of the image data having the set HDR can be considered. However, in such a method, the user cannot confirm the distribution of the luminance-related values belonging to the HDR and not belonging to the set HDR.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a technique capable of more appropriately displaying a luminance distribution of input image data.

A first aspect of the present invention provides:
Conversion means for converting the color of the input image data based on information indicating the correspondence between the luminance level and the color to generate converted image data;
Setting means for setting tone characteristics of the input image data;
With
The conversion means,
When the gradation characteristic set by the setting unit is a first gradation characteristic corresponding to a first dynamic range, a first correspondence using a gradation value of the input image data as the luminance level is set. Based on the information shown, convert the color of the input image data,
A second gradation characteristic in which the gradation characteristic set by the setting means corresponds to a second dynamic range wider than the first dynamic range, and the absolute value is associated with a gradation value of the input image data. In the case of, the color of the input image data is converted based on information indicating a second correspondence relationship using the absolute luminance associated with the gradation value of the input image data as the luminance level,
A third gradation characteristic in which the gradation characteristic set by the setting means corresponds to a third dynamic range wider than the first dynamic range, and a relative luminance is associated with a gradation value of the input image data; In the case of, converting the color of the input image data based on information indicating a third correspondence using the relative luminance associated with the gradation value of the input image data as the luminance level. It is an image processing apparatus characterized by the following .

A second aspect of the present invention provides:
A conversion step of converting the color of the input image data based on information indicating the correspondence between the luminance level and the color to generate converted image data;
A setting step of setting a gradation characteristic of the input image data,
Has ,
In the conversion step,
When the gradation characteristic set in the setting step is a first gradation characteristic corresponding to a first dynamic range, a first correspondence relationship using a gradation value of the input image data as the luminance level is set. Based on the information shown, convert the color of the input image data,
A second gradation characteristic in which the gradation characteristic set in the setting step corresponds to a second dynamic range wider than the first dynamic range, and the absolute luminance is associated with a gradation value of the input image data. In the case of, the color of the input image data is converted based on information indicating a second correspondence relationship using the absolute luminance associated with the gradation value of the input image data as the luminance level,
A third gradation characteristic in which the gradation characteristic set in the setting step corresponds to a third dynamic range wider than the first dynamic range, and a relative luminance is associated with a gradation value of the input image data. In the case of, converting the color of the input image data based on information indicating a third correspondence using the relative luminance associated with the gradation value of the input image data as the luminance level. This is a featured image processing method .

A third aspect of the present invention is a program for causing a computer to execute each step of the above-described image processing method.

  According to the present invention, it is possible to more appropriately display the luminance distribution of input image data.

Configuration example of the display device according to the present embodiment Example of range conversion processing according to the present embodiment An example of a processing flow of the color conversion parameter generation unit according to the present embodiment An example of the correspondence (correspondence between absolute luminance and color) according to the present embodiment An example of a processing result of the color conversion processing unit according to the present embodiment An example of the correspondence (correspondence between relative luminance and color) according to the present embodiment An example of the correspondence (correspondence between absolute luminance and color) according to the present embodiment Example of Correspondence (Correspondence between Brightness Tone Value and Color) According to the Present Embodiment

  Hereinafter, embodiments of the present invention will be described. Hereinafter, an example of a display device having the image processing device according to the present embodiment will be described. The display device is, for example, a liquid crystal display device, an organic EL (Electro Luminescence) display device, a plasma display device, a MEMS (Micro Electro Mechanical System) shutter type display device, or the like. Note that the image processing device may be a device separate from the display device. The image processing device separate from the display device is, for example, a personal computer (PC), a reproducing device (for example, a Blu-ray player), a server device, or the like.

  FIG. 1 shows a configuration example of a display device 100 according to the present embodiment. The display device 100 includes an image input unit 101, an image processing unit 102, a color conversion processing unit 103, a display unit 104, a CPU 105, a UI (user interface) unit 106, and a color conversion parameter generation unit 107.

  The image input unit 101 acquires image data (input image data) and outputs the input image data to the image processing unit 102. In the present embodiment, the image input unit 101 acquires input image data from outside the display device 100 (image processing device). Specifically, the image input unit 101 has an SDI input terminal conforming to the SDI standard, and acquires an SDI signal from outside the display device 100 via the SDI input terminal. The image input unit 101 converts the SDI signal into image data having a data format that can be processed inside the display device 100, and outputs the converted image data to the image processing unit 102. In the present embodiment, the gradation value of the input image data is a 10-bit value (0 to 1023).

  Note that a method for acquiring input image data is not particularly limited. For example, the display device 100 (image processing unit) may include a storage unit that stores image data, and the image input unit 101 may read image data (input image data) from the storage unit. The image signal input to the image input unit 101 need not be an SDI signal. The number of bits (bit depth) of the input image data may be more or less than 10 bits.

The image processing unit 102 determines a gradation characteristic of input image data in response to a user operation (an instruction from a user) on the display device 100 (image processing device) (characteristic determination processing). Here, the user operation is, for example, a user operation for specifying a gradation characteristic. The image processing unit 102 performs image processing based on at least the determined gradation characteristic on the input image data output from the image input unit 101. Thereby, processed image data is generated. Then, the image processing unit 102 outputs the processed image data to the color conversion processing unit 103. The gradation characteristic is, for example, a characteristic related to a correspondence between a gradation value before conversion and a gradation value after conversion in a gradation conversion process for converting a gradation value of image data. In the present embodiment, gamma 2.2, SMPTE ST. 2084 (PQ, Perceptual Quantization) and one of three types of Log gradation characteristics are determined as the gradation characteristics of the input image data. Note that the corresponding gradation characteristics are not limited to the above-described gradation characteristics. For example, it may be Hybrid Log-Gamma (HLG) specified in ARIB STD-B67. Hereinafter, “the gradation characteristic is ST2084” means that the gradation characteristic is SMPTE ST. It means the PQ defined in 2084.

  A wide dynamic range is called “HDR (High Dynamic Range)” or the like, and a dynamic range narrower than HDR is called “SDR (Standard Dynamic Range)” or the like. The dynamic range is a range of a luminance-related value (luminance level) relating to luminance. The luminance related value (luminance level) is a luminance gradation value (Y value), an absolute luminance, a relative luminance, or the like. The image data having HDR is called “HDR image data” and the like, and the image data having SDR is called “SDR image data” and the like. Gamma 2.2 is a gradation characteristic corresponding to SDR, and ST2084 and Log are gradation characteristics corresponding to HDR.

  ST2084 is a gradation characteristic in which absolute luminance is associated with a pixel value (tone value) of input image data, and Log is a relative luminance (relative luminance level) associated with a pixel value of input image data. This is the obtained gradation characteristic. In other words, ST2084 is a gradation characteristic that defines the luminance of the input image data by absolute luminance, and Log is a gradation characteristic that defines the luminance of the input image data by relative luminance. HLG is a gradation characteristic that defines the luminance of input image data as relative luminance. The association of the relative luminance with the pixel value can be said to be an indirect association of the luminance level with the pixel value. When HLG is used as the gradation characteristic, the same processing as when the gradation characteristic is Log is performed.

  When luminance (absolute luminance or relative luminance) is associated with the pixel value as in ST2084, Log, etc., the correspondence between the pixel value of the image data and the luminance of the image data is represented as a gradation characteristic. Relevant properties can be used. Specifically, information (function, table, etc.) indicating the correspondence between the pixel value of the image data and the luminance of the image data can be used as the information of the gradation characteristics. Such information is called "EOTF (Electro-optical transfer function)" or the like.

  The image processing performed by the image processing unit 102 includes a gradation conversion process, a range conversion process, and the like. The gradation conversion process is a process of converting the gradation value of the input image data according to the determined gradation characteristics. For example, in the gradation conversion process, the gradation value of the input image data is converted using a predetermined LUT (Look Up Table) corresponding to the determined gradation characteristic. In the gradation conversion processing, a 1DLUT (one-dimensional LUT) or the like is used as a predetermined LUT. A predetermined function may be used instead of the predetermined LUT.

  The range conversion process is a process of correcting the input image data (gradation value of the input image data) so that at least a part of the dynamic range of the input image data can be appropriately displayed. In the present embodiment, range conversion processing is performed when the gradation characteristic of the input image data is ST2084 and when the gradation characteristic of the input image data is Log.

  In the present embodiment, the image processing unit 102 determines at least a part of the dynamic range of the input image data as the designated display range according to a user operation on the display device 100 (image processing device). Specifically, the image processing unit 102 determines the maximum value of a plurality of luminance-related values belonging to the designated display range according to a user operation (first threshold value determination processing). Thereby, the range from the minimum value of the plurality of luminance-related values belonging to the dynamic range of the input image data to the determined maximum value (the maximum value of the plurality of luminance-related values belonging to the designated display range) is set as the designated display range. used. In the range conversion process, the input image data is corrected based on the designated display range (the determined maximum value). As a result, when the later-described color conversion process is not performed, the designated display range is displayed with a gradation characteristic according to the standard (gradation characteristics) of the input image data. Then, the overrange pixels are displayed in a predetermined color. An over-range pixel is a pixel having a luminance-related value higher (greater) than the maximum value of a plurality of luminance-related values belonging to the designated display range. For example, such a luminance-related value is displayed in white (whiteout).

Here, it is assumed that the gradation characteristic of the input image data is ST2084 and the maximum luminance of a plurality of absolute luminances belonging to the designated display range is 1000 cd / m ² . In ST2084, an absolute luminance of 0 to 10000 cd / m ² is defined. In the present embodiment, a display luminance (screen luminance) of 0 to 1000 cd / m ² can be realized. In this case, 1000 cd / ^{m 2} or less of absolute luminance (absolute brightness defined in ST2084) is displayed as it luminance, and the absolute luminance are displayed in 1000 cd / ^{m 2} higher than 1000 cd / ^{m 2} Thus, the input image data is corrected (FIG. 2A). Next, consider a case where the gradation characteristic of the input image data is ST2084 and the maximum luminance of a plurality of absolute luminances belonging to the designated display range is 10000 cd / m ² . In this case, the input is performed such that the range including the absolute luminance of 0 to 10000 cd / m ² (the absolute luminance defined in ST2084) is compressed and displayed in the range including the display luminance of 0 to 1000 cd / m ^2. The image data is corrected (FIG. 2B).

  The method for determining the gradation characteristics of the input image data is not particularly limited. For example, characteristic information related to the gradation characteristics of the input image data may be included in the metadata added to the input image data. Then, the image processing unit 102 may determine the gradation characteristics of the input image data according to the characteristic information acquired from the metadata of the input image data (characteristic determination processing). The image processing unit 102 may automatically determine the gradation characteristics of the input image data according to the type of the input image data (medical image, illustration image, landscape image, etc.). The image processing unit 102 may automatically determine the gradation characteristics of the input image data according to the use environment of the display device 100 (image processing device). The use environment of the display device 100 is the temperature of the display device 100, the brightness around the display device 100, and the like.

  As the characteristic information, for example, information indicating the correspondence between the gradation value before conversion and the gradation value after conversion in the gradation conversion processing can be used. As the characteristic information, it is also possible to use information indicating the correspondence between the gradation value before conversion and the gradation value after conversion in the gradation conversion processing already performed on the input image data. When luminance (absolute luminance or relative luminance) is associated with the pixel value as in ST2084, Log, etc., the correspondence between the pixel value of the image data and the luminance of the image data is indicated as the characteristic information. Information can also be used. In EOTF, an input value is a pixel value, and an output value is luminance. On the other hand, information (a function, a table, or the like) in which the input value is luminance and the output value is a pixel value is called “OETF (Opto-electronic transfer function)” or the like. When the luminance is associated with the pixel value, EOTF, OETF, or the like can be used as the characteristic information.

  Further, the method of determining the designated display range (the maximum value of the plurality of luminance-related values belonging to the designated display range) is not particularly limited. For example, range information indicating the designated display range may be included in the metadata of the input image data. Then, the image processing unit 102 may determine the designated display range according to the range information. The image processing unit 102 may automatically determine the designated display range according to the type of the input image data. The image processing unit 102 may automatically determine the designated display range according to the use environment of the display device 100 (image processing device).

Further, the gradation characteristics of the input image data, the dynamic range of the input image data, the range of the display luminance, the image processing performed by the image processing unit 102, the luminance-related values, and the like are not particularly limited. For example, various proposed gradation characteristics can be used as the gradation characteristics of the input image data. The display luminance range may be narrower or wider than the display luminance range of 0 to 1000 cd / m ² . Range conversion processing may not be performed in at least one of the case where the gradation characteristic of the input image data is ST2084 and the case where the gradation characteristic of the input image data is Log. Range conversion processing may be performed when the gradation characteristic of the input image data is gamma 2.2. The image processing unit 102 may omit the gradation conversion processing. As the input image data, image data that has been subjected to the gradation conversion processing of the image processing unit 102 may be obtained.

  The color conversion processing unit 103 converts the color of the processed image data output from the image processing unit 102 using the color conversion parameters generated by the color conversion parameter generation unit 107 (color conversion processing). Thereby, display image data (converted image data) is generated. The color conversion processing unit 103 outputs display image data to the display unit 104. Color conversion can also be referred to as "color coloring", and color conversion processing can also be referred to as "coloring processing". The color conversion parameter is, for example, a table indicating a conversion color (a color after conversion in the color conversion process) for each pixel of the processed image data. Note that the color conversion processing unit 103 may generate display image data by performing color conversion processing on input image data instead of processed image data.

  The display unit 104 displays an image on a screen based on the display image data output from the color conversion processing unit 103. As the display unit 104, a self-luminous display panel, a combination of a light-emitting unit and a modulation panel, or the like can be used. The self-luminous display panel displays an image on a screen by emitting light based on display image data. The light emitting unit emits light to the modulation panel. The modulation panel displays an image on a screen by modulating (transmitting, reflecting, etc.) the light emitted from the light emitting unit based on the display image data. Light emission (light emission luminance, light emission color, etc.) of the light emitting unit may be controlled based on the display image data. In a transmissive liquid crystal display device, the light emitting unit is called a "backlight unit" or the like, and the modulation panel is called a "liquid crystal panel" or the like. The backlight unit emits light to the back of the liquid crystal panel. The liquid crystal panel displays an image on a screen by transmitting light emitted from the backlight unit.

  The CPU 105 controls the operation of the display device 100 (each functional unit of the display device 100). For example, the display device 100 has a storage unit (such as a non-volatile memory) that stores a program, and the CPU 105 controls the operation of the display device 100 by reading out the program from the storage unit and executing the program.

  The UI unit 106 receives a user operation on the display device 100 (image processing device). Then, the UI unit 106 transmits an operation signal corresponding to the performed user operation to another functional unit of the display device 100 (the image processing unit 102, the color conversion processing unit 103, the CPU 105, the color conversion parameter generation unit 107, and the like). Output to The UI unit 106 is, for example, a button provided on the display device 100, a touch panel provided on the display unit 104, or the like. An operation unit (a controller, a keyboard, a mouse, or the like) detachable from the display device 100 may be used as the UI unit 106.

  The UI unit 106 receives, for example, user operations such as a characteristic setting operation, a range setting operation, and a color conversion setting operation. The characteristic setting operation is a user operation for determining the gradation characteristics of the input image data. For example, the characteristic setting operation is a user operation for specifying a gradation characteristic, a user operation for specifying an operation mode of the display device 100 (image processing device), or the like. The range setting operation is a user operation for determining the designated display range. For example, the range setting operation is a user operation of specifying a specified display range, a user operation of specifying a maximum value of a plurality of luminance-related values belonging to the specified display range, a user operation of specifying an operation mode of the display device 100, and the like. . The color conversion setting operation is a user operation for determining whether to execute a color conversion process. For example, the color conversion setting operation is a user operation for specifying whether or not to execute the color conversion process, a user operation for specifying an operation mode of the display device 100, and the like.

  In the present embodiment, the setting of whether or not to execute the color conversion processing is referred to as “false color setting”. The color conversion parameter generation unit 107 switches the state of the false color setting between the on state and the off state according to the color conversion setting operation. The ON state is a state where the color conversion processing is executed, and the OFF state is a state where the color conversion processing is not executed. Therefore, by selecting the state of the false color setting, it is possible to select whether or not to execute the color conversion processing. For example, the color conversion processing unit 103, the color conversion parameter generation unit 107, or both of them select a false color setting state according to the color conversion setting operation.

  In the range setting operation for specifying the maximum value of the plurality of luminance-related values belonging to the specified display range, the type of the luminance-related value is not particularly limited. For example, a user operation of designating the maximum value as a luminance gradation value regardless of the gradation characteristics of the input image data may be performed as the range setting operation. However, from the viewpoint of convenience or the like, it is preferable that the user operation of designating a type of luminance gradation value according to the gradation characteristics of the input image data is performed as a range setting operation. For example, when the gradation characteristic of the input image data is ST2084, it is preferable that the user operation for specifying the absolute luminance is performed as a range setting operation. When the gradation characteristic of the input image data is Log, it is preferable that the user operation for specifying the relative luminance is performed as a range setting operation.

  The color conversion parameter generation unit 107 generates a color conversion parameter based on the input image data and information indicating the correspondence between the luminance related value (luminance level) of the input image data and the conversion color of the color conversion processing. For example, as described above, a table indicating a conversion color of each pixel is generated as a color conversion parameter. Then, the color conversion parameter generation unit 107 outputs the generated color conversion parameters to the color conversion processing unit 103. Thereby, in the color conversion process, the color of the processed image data is converted based on the correspondence. In the present embodiment, the color conversion parameter generation unit 107 uses the correspondence according to the determined gradation characteristics of the input image data. This makes it possible to more appropriately display the luminance distribution of the input image data. For example, when the gradation characteristic of the input image data is gamma 2.2, a correspondence relationship in which the conversion color is associated with the luminance gradation value of the input image data is used. If the gradation characteristic of the input image data is ST2084, a correspondence relationship in which the conversion color is associated with the absolute luminance of the input image data is used. When the gradation characteristic of the input image data is Log, a correspondence relationship in which the conversion color is associated with the relative luminance of the input image data is used. That is, the color conversion parameter generation unit 107 switches the correspondence between the luminance level and the conversion color according to the gradation characteristics.

Note that the gradation characteristics of the input image data may be determined by the color conversion parameter generation unit 107. The gradation characteristics of the input image data may be determined (determined) in each of the image processing unit 102 and the color conversion parameter generation unit 107. Similarly, the designated display range (the maximum value of the plurality of luminance-related values belonging to the designated display range) may be determined by the color conversion parameter generation unit 107. The designated display range may be determined in each of the image processing unit 102 and the color conversion parameter generation unit 107.

  An example of the processing flow of the color conversion parameter generation unit 107 will be described with reference to the flowchart in FIG.

  First, in S101, the color conversion parameter generation unit 107 determines whether the false color setting state is the ON state. If the false color setting is in the off state (S101: No), the process proceeds to S102. If the false color setting is in the on state (S101: Yes), the process proceeds to S103. Can be

  In S102, color conversion parameter generation section 107 selects “no coloring” as the pattern of the correspondence between the luminance-related value of the input image data and the conversion color.

  In S103, the color conversion parameter generation unit 107 determines whether or not the gradation characteristics of the input image data correspond to HDR. If the gradation characteristics of the input image data do not support HDR (S103: No), the process proceeds to S107, and if the gradation characteristics of the input image data support HDR (S103: Yes), the process proceeds to S104. Specifically, when the gradation characteristic of the input image data is gamma 2.2, it is determined that the gradation characteristic of the input image data corresponds to SDR, and the process proceeds to S107. If the gradation characteristic of the input image data is ST2084 or Log, it is determined that the gradation characteristic of the input image data corresponds to HDR, and the process proceeds to S104.

  In S107, color conversion parameter generation section 107 selects “pattern C” as the pattern of the correspondence between the luminance-related value of the input image data and the converted color.

  In S104, color conversion parameter generation section 107 determines whether or not absolute luminance is defined by the gradation characteristics of the input image data. If the absolute luminance is defined by the gradation characteristics of the input image data (S104: Yes), the process proceeds to S105. If the absolute luminance is not defined by the gradation characteristics of the input image data and the relative luminance is defined by the gradation characteristics of the input image data (S104: No), the process proceeds to S106. Specifically, if the gradation characteristic of the input image data is ST2084, the process proceeds to S105, and if the gradation characteristic of the input image data is Log, the process proceeds to S106.

  In S105, the color conversion parameter generation unit 107 selects “pattern A” as the pattern of the correspondence between the luminance-related value of the input image data and the conversion color. In S106, color conversion parameter generation section 107 selects “pattern B” as the pattern of the correspondence between the luminance-related value of the input image data and the converted color.

  When “no coloring” is selected, the color conversion parameter generation unit 107 generates a color conversion parameter that does not convert the color of the processed image data. As a result, in the color conversion processing unit 103, display image data equal to the processed image data is generated by the color conversion processing. A color conversion parameter that does not convert the color of the processed image data can also be referred to as a “color conversion parameter in which the color after conversion is equal to the color before conversion”. If the false color setting is in the off state, the generation of the color conversion parameter may be omitted. Then, the color conversion processing unit 103 may omit the color conversion processing and output the processed image data as the display image data.

In the present embodiment, the color of the overrange pixel is converted into a predetermined color (for example, white) by the image processing of the image processing unit 102. An over-range pixel is a pixel having a luminance-related value higher (greater) than the maximum value of a plurality of luminance-related values belonging to the designated display range. Then, when "no coloring" is selected, the color of the processed image data is not converted, and the color of the overranged pixel is maintained at the predetermined color. On the other hand, when any one of “pattern A”, “pattern B”, and “pattern C” is selected, the processing image data is processed based on the correspondence between the luminance-related value of the input image data and the conversion color. Is converted. Therefore, the overrange pixels are also converted into colors based on the correspondence between the luminance-related values of the input image data and the conversion colors.

  When “pattern A” is selected, the color conversion parameter generation unit 107 determines whether the color conversion parameter generation unit 107 is in accordance with the designated display range (the maximum luminance of a plurality of absolute luminances belonging to the designated display range). ) Is determined and used.

FIG. 4A shows an example in which the maximum luminance of a plurality of absolute luminances belonging to the designated display range is 10,000 cd / m ² . That is, in the example of FIG. 4A, the designated display range includes all the absolute luminances of 0 to 10000 cd / m ² defined in ST2084.

In the correspondence shown in FIG. 4A, a plurality of conversion colors are respectively associated with a plurality of ranges (color conversion ranges) of the absolute luminance. For example, a monochrome color (gray color) is associated with a color conversion range to which an absolute luminance of 95 to 105 cd / m ² belongs. Therefore, the color of a portion (pixel) having an absolute luminance of 95 to 105 cd / m ² is converted to a monochrome color by a color conversion process. Green is associated with the color conversion range to which the absolute luminance of 999 to 1005 cd / m ² belongs. In the correspondence shown in FIG. 4A, a plurality of color conversion ranges are separated from each other, and a range (a non-color conversion range) to which no conversion color is associated exists between the two color conversion ranges. . In the color conversion processing, the color of the pixel having the absolute luminance belonging to the non-color conversion range is not converted.

  By using the correspondence shown in FIG. 4A, the distribution of the absolute luminance belonging to the color conversion range is displayed in color. As described above, in the correspondence shown in FIG. 4A, a plurality of color conversion ranges are separated from each other. Therefore, the distribution of the absolute luminance belonging to the color conversion range is displayed in a form like a contour line.

FIG. 4B illustrates an example in which the maximum luminance of a plurality of absolute luminances belonging to the designated display range is 1500 cd / m ² . That is, in the example of FIG. 4 (B), the specified display range includes the absolute luminance of 0~1500cd / ^{m 2,} it does not include a high absolute luminance than 1500 cd / ^{m 2.}

  In the correspondence shown in FIG. 4B, the same setting (color conversion range, non-color conversion range, correspondence between color conversion range and conversion color) is made for the designated display range as in FIG. 4A. Therefore, when the correspondence shown in FIG. 4B is used, as a result of the color conversion processing on the pixels having the absolute luminance belonging to the designated display range, the same result as when the correspondence shown in FIG. Is obtained.

In the correspondence shown in FIG. 4B, a conversion color different from the plurality of conversion colors respectively corresponding to the plurality of color conversion ranges is associated with the non-designated display range. Specifically, a red color is associated with the non-designated display range. Therefore, the color of the pixel having the absolute luminance belonging to the non-designated display range is converted to red by the color conversion processing. The non-designated display range is a range outside the designated display range. In the example of FIG. 4B, the non-designated display range is a range of absolute luminance higher than 1500 cd / m ² (the maximum luminance of a plurality of absolute luminances belonging to the designated display range).

As described above, when the pattern A is selected, the correspondence in which the conversion color is associated with the absolute luminance is used, and the color conversion processing based on the absolute luminance is performed. Thereby, the absolute luminance (distribution of the absolute luminance) of the input image data can be suitably displayed in color. As a result, the user can easily grasp the absolute luminance of the input image data by color. For example, FIG.
, (B), the absolute luminance at the center of the color conversion range is a sharp absolute luminance (100 cd / m ² , 200 cd / m ² , 400 cd / m ² , 1000 cd / m ² , 2000 cd / m ² , 4000 cd / m ² , etc.). Therefore, it is possible to preferably display sharp absolute brightness in color. As a result, the user can easily grasp the sharp absolute brightness by color. ^{100cd / m 2, 200cd / m} 2, 400cd / m 2, 1000cd / m 2, 2000cd / m 2 and,, 4000 cd / ^{m 2,} a plurality of division areas constituting the range of absolute luminance may take the input image data Can be called multiple boundaries. The plurality of color conversion ranges can be said to be a plurality of boundary regions each including the plurality of boundaries.

  In the correspondence shown in FIGS. 4A and 4B, a plurality of color conversion ranges are separated from each other, and the distribution of absolute luminance belonging to the color conversion range is displayed in a form like a contour line. This allows the user to check the processed image (the image represented by the processed image data) for the image area in the non-color conversion range. That is, the user can simultaneously check the luminance distribution and the processed image.

  Further, a conversion color different from the plurality of conversion colors respectively corresponding to the plurality of color conversion ranges is associated with the non-designated display range. Therefore, the image area in the non-designated display range is displayed in a different color from the image area in the color conversion range. Thereby, the user can easily distinguish and grasp the image area of the non-designated display range and the image area of the color conversion range.

  In the non-designated display range, the luminance of the converted color may change continuously according to the continuous change of the absolute luminance (luminance-related value). By doing so, the color of the pixel having the absolute luminance belonging to the non-designated display range is converted by the color conversion processing into a color whose luminance changes continuously according to the continuous change of the absolute luminance. As a result, in the image area of the non-designated display range, gradation display in which the luminance of the conversion color continuously changes according to the continuous change of the absolute luminance is performed as the display in the conversion color. According to the gradation display, the user can easily grasp the distribution of the absolute luminance in the image area of the non-designated display range.

Although the color conversion ranges in FIGS. 4A and 4B have a width of 10 cd / m ² , the position of the color conversion range, the width of the color conversion range, the number of the color conversion ranges, and the like are particularly limited. Not done. In addition, colors associated with the color conversion range, the non-designated display range, and the like are not particularly limited. However, it is preferable that a color not used in other color conversion processing is used as a conversion color.

  If a pixel having an absolute luminance belonging to the color conversion range is not included in the input image data, the conversion to the conversion color corresponding to the color conversion range is not performed. Therefore, for each of the plurality of color conversion ranges, the color conversion parameter generation unit 107 performs the plurality of color conversions so that the number of pixels having a luminance-related value belonging to the color conversion range is equal to or greater than a predetermined number. Preferably, the range is determined. For example, the color conversion parameter generation unit 107 determines at least one of the center of the color conversion range, the width of the color conversion range, and the like so that the number of pixels having a luminance-related value belonging to the color conversion range is equal to or greater than a predetermined number. It is preferable to adjust from the initial value.

In addition, a plurality of image areas having the same converted color and each having a size equal to or smaller than a predetermined size may be scattered like noise (FIG. 5A). Therefore, the color conversion processing unit 103 converts the image area between the plurality of image areas so that the color of the linear image area connecting the plurality of scattered image areas becomes the same color as the conversion color of the plurality of image areas. It is preferable to further convert the color (FIG. 5B). In FIG. 5A, a plurality of scattered pixels 301 are a plurality of pixels that have been converted into the same color by the color conversion processing. By further converting the color of the pixel between the plurality of pixels 301, display such as noise can be suppressed, and as an image region of the same color as the pixel 301, the linear region (FIG. 5B) (A linear image area) 302 can be displayed. The predetermined size may be a size for one pixel or a size for a plurality of pixels.

  When “pattern B” is selected, the color conversion parameter generation unit 107 determines whether the color conversion parameter generation unit 107 is in accordance with the designated display range (the maximum luminance of a plurality of relative luminances belonging to the designated display range). ) Is determined.

  FIG. 6A shows an example in which the maximum luminance of a plurality of relative luminances belonging to the designated display range is 1600%. In the Log, a relative luminance of 0 to 1600% is defined. That is, in the example of FIG. 6A, the designated display range includes all the relative luminances of 0 to 1600% defined by Log.

  In the correspondence shown in FIG. 6A, a plurality of conversion colors are respectively associated with a plurality of ranges (color conversion ranges) of relative luminance. For example, a monochrome color is associated with a color conversion range to which a relative luminance of 0 to 100% belongs. In other words, a monochrome color is associated with a range of relative luminance of 100% or less (below a threshold). Green is associated with the color conversion range to which the relative luminance of 400 to 800% belongs.

  FIG. 6B shows an example in which the maximum luminance of a plurality of relative luminances belonging to the designated display range is 400%. That is, in the example of FIG. 6B, the designated display range includes a relative luminance of 0 to 400% and does not include a relative luminance higher than 400%. In the correspondence shown in FIG. 6B, a conversion color different from the plurality of conversion colors respectively corresponding to the plurality of color conversion ranges is associated with the non-designated display range. Specifically, a red color is associated with the non-designated display range. Therefore, the color of the pixel having the absolute luminance belonging to the non-designated display range is converted to red by the color conversion processing. In the example of FIG. 6B, the non-designated display range is a range of relative luminance higher than 400% (maximum luminance of a plurality of relative luminances belonging to the designated display range).

  When the pattern A is selected, as shown in FIGS. 4A and 4B, the position (center) of the color conversion range is fixed without depending on the designated display range. Then, the number of color conversion ranges changes according to the designated display range. On the other hand, even if the color of the relative luminance changes depending on the designated display range, the user can easily grasp the relative luminance. Therefore, when the pattern B is selected, as shown in FIGS. 6A and 6B, the color conversion parameter generation unit 107 sets the designated display range (the maximum of a plurality of relative luminances belonging to the designated display range). At least the position of the color conversion range is changed according to the luminance. 6A and 6B, the number of the plurality of color conversion ranges, the relationship between the plurality of color conversion ranges and the plurality of conversion colors, and the like are maintained according to the designated display range. , The position of the color conversion range and the width of the color conversion range are changed. That is, in the examples of FIGS. 6A and 6B, a plurality of color conversion ranges are compressed or expanded as a whole according to the designated display range.

  In this manner, when the pattern B is selected, the correspondence in which the conversion color is associated with the relative luminance is used, and the color conversion processing based on the relative luminance is performed. Thereby, the relative luminance (distribution of the relative luminance) of the input image data can be suitably displayed in color. As a result, the user can easily grasp the relative luminance of the input image data by color. In the present embodiment, since the number of the plurality of color conversion ranges, the relationship between the plurality of color conversion ranges and the plurality of colors, and the like are maintained, the relative luminance can be more appropriately displayed, and the user can reduce the relative luminance. It can be grasped more suitably. In the image area of the non-designated display range, a different color is displayed than in the image area of the color conversion range. Thereby, the user can easily distinguish and grasp the image area of the non-designated display range and the image area of the color conversion range.

Note that, in the range (at least one of the color conversion range and the non-designated display range), the luminance of the converted color may change continuously according to the continuous change of the relative luminance (luminance-related value). By doing so, a gradation display in which the luminance of the converted color continuously changes according to the continuous change of the relative luminance can be performed as the display of the converted color in the image area of the range. As a result, the user can easily grasp the distribution of the relative luminance in the image area of the range.

  When “pattern C” is selected, the color conversion parameter generation unit 107 determines the correspondence as shown in FIG. In the correspondence shown in FIG. 8, a plurality of conversion colors are respectively associated with a plurality of ranges (color conversion ranges) of luminance gradation values. For example, a monochrome color is associated with a color conversion range to which a luminance gradation value of 0 to 171 belongs. Green is associated with the color conversion range to which the luminance gradation values of 512 to 683 belong.

  As described above, when the pattern C is selected, the correspondence in which the conversion color is associated with the luminance gradation value is used, and the color conversion processing based on the luminance gradation value is performed. Thereby, the luminance gradation value (distribution of the luminance gradation value) of the input image data can be suitably displayed in color. As a result, the user can easily grasp the luminance gradation value of the input image data by color.

  Note that, in a range (such as a color conversion range), the luminance of the converted color may change continuously according to a continuous change in the luminance gradation value (luminance-related value). By doing so, a gradation display in which the luminance of the converted color continuously changes according to the continuous change of the luminance gradation value can be performed as the display of the converted color in the image area of the above range. As a result, the user can easily grasp the distribution of the relative luminance in the image area of the range.

  6A, 6B, and 8, a non-color conversion range is not set and a plurality of continuous color conversion ranges are set, but the present invention is not limited to this. For example, a plurality of color conversion ranges separated from each other are set in at least one of the case where the gradation characteristic of the input image data is gamma 2.2 and the case where the gradation characteristic of the input image data is Log. Good. Further, when the gradation characteristic of the input image data is ST2084, a plurality of continuous color conversion ranges may be set.

  Further, when the gradation characteristic of the input image data is gamma 2.2, the designated display range (the maximum value of a plurality of luminance gradation values belonging to the designated display range) may be determined. Then, a conversion color different from the plurality of conversion colors respectively corresponding to the plurality of color conversion ranges may be associated with the non-designated display range. In the non-designated display range, the luminance of the converted color may continuously change according to the continuous change of the luminance gradation value. In at least one of the case where the gradation characteristic of the input image data is gamma 2.2 and the case where the gradation characteristic of the input image data is ST2084, the position of the color conversion range, the width of the color conversion range, and the like are designated. It may depend on the display range. In at least one of the case where the gradation characteristic of the input image data is gamma 2.2 and the case where the gradation characteristic of the input image data is Log, the position of the color conversion range, the width of the color conversion range, and the like are specified. It does not have to depend on the display range. In at least one of the case where the gradation characteristic of the input image data is gamma 2.2 and the case where the gradation characteristic of the input image data is Log, even if the number of color conversion ranges depends on the designated display range. Good.

Further, a range of a luminance-related value lower than the threshold may be set as the non-color conversion range. For example, the range corresponding to SDR may be set as the non-color conversion range in at least one of the case where the gradation characteristic of the input image data is ST2084 and the case where the gradation characteristic of the input image data is Log. . Specifically, when the gradation characteristic of the input image data is ST2084, the range of the absolute luminance of 0 to 100 cd / m ² may be set as the non-color conversion range corresponding to SDR. When the gradation characteristic of the input image data is Log, a range of 0-100% relative luminance may be set as a non-color conversion range corresponding to SDR.

  Further, the color conversion parameter generation unit 107 may determine a non-color conversion range according to a user operation on the display device 100 (image processing device). For example, the color conversion parameter generation unit 107 may determine the threshold value according to a user operation (second threshold value determination processing). The user operation for determining the non-color conversion range, the threshold, and the like is, for example, a user operation for specifying a luminance-related value. In the user operation of designating the luminance-related value, the type of the luminance-related value is not particularly limited. For example, irrespective of the gradation characteristics of the input image data, a user operation for specifying a luminance gradation value may be performed as the user operation for determining a non-color conversion range, a threshold, and the like. However, from the viewpoint of convenience or the like, a user operation for specifying a luminance gradation value of a type corresponding to the gradation characteristics of input image data is performed as the above-mentioned user operation for determining a non-color conversion range, a threshold, and the like. Preferably.

7A to 7C show another example of the correspondence relationship of the pattern A. FIG. In the example of FIG. 7A, the designated display range includes all the absolute luminances of 0 to 10000 cd / m ² defined in ST2084. In the correspondence shown in FIG. 7A, a plurality of conversion colors are respectively associated with a plurality of ranges (color conversion ranges) of the absolute luminance. In the correspondence shown in FIG. 7A, a conversion color whose luminance changes continuously according to a continuous change of the absolute luminance is associated with a color conversion range. For example, the color conversion range to which the absolute luminance of 0 to 100 cd / m ² belongs is associated with a monochrome color whose luminance changes continuously according to the continuous change of the absolute luminance. The color conversion range to which the absolute luminance of 400 to 1000 cd / m ² belongs is associated with a green color whose luminance changes continuously according to the continuous change of the absolute luminance. For this reason, in the image area of the color conversion range, as the display of the converted color, a gradation display in which the luminance of the converted color continuously changes according to the continuous change of the absolute luminance is performed.

In the example of FIG. 7 (B), the specified display range includes the absolute luminance of 0~1500cd / ^{m 2,} it does not include a high absolute luminance than 1500 cd / ^{m 2.} The non-designated display range is a range having an absolute luminance higher than 1500 cd / m ² . In the correspondence shown in FIG. 7B, the same setting (color conversion range, correspondence between the color conversion range and the converted color) is made for the designated display range as in FIG. 7A. That is, the position of the color conversion range is fixed without depending on the designated display range, and the number of the color conversion ranges changes according to the designated display range. Conversion colors different from the plurality of conversion colors respectively corresponding to the plurality of color conversion ranges are associated with the non-designated display range. The non-designated display range is also associated with a conversion color whose luminance continuously changes according to a continuous change of the absolute luminance. More specifically, the non-designated display range is associated with a red color whose luminance continuously changes according to a continuous change of the absolute luminance.

In the example of FIG. 7C, the range of the absolute luminance of 0 to 100 cd / m ² is set as the non-color conversion range corresponding to SDR. Otherwise, it is the same as FIG. 7 (B). In other words, the position of the color conversion range is fixed without depending on the non-color conversion range which is a range of the luminance-related value lower than the threshold, and the number of the color conversion ranges changes according to the non-color conversion range. I do.

  Note that the correspondence using the relative luminance instead of the absolute luminance in FIGS. 7A to 7C may be used as the correspondence of the pattern B. 7A to 7C may be used as the correspondence of the pattern C instead of using the absolute luminance in FIG.

  As described above, according to the present embodiment, as the correspondence between the luminance-related value and the converted color, the correspondence corresponding to the gradation characteristics of the input image data is used. This makes it possible to more appropriately display the luminance distribution of the input image data.

Note that each functional unit in the above-described embodiment may be individual hardware or may not be. The functions of two or more functional units may be realized by common hardware. Each of a plurality of functions of one functional unit may be realized by individual hardware. Two or more functions of one functional unit may be realized by common hardware. Further, each functional unit may or may not be realized by hardware. For example, the device may have a processor and a memory in which a control program is stored. Then, the functions of at least some of the functional units of the device may be realized by the processor reading out the control program from the memory and executing the control program.

  The above-described embodiment is merely an example, and the present invention includes a configuration obtained by appropriately modifying or changing the configuration of the embodiment within the scope of the present invention.

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

  103: color conversion processing unit 107: color conversion parameter generation unit

Claims (29)

Conversion means for converting the color of the input image data based on information indicating the correspondence between the luminance level and the color to generate converted image data;
Setting means for setting tone characteristics of the input image data;
With
The conversion means,
When the gradation characteristic set by the setting unit is a first gradation characteristic corresponding to a first dynamic range, a first correspondence using a gradation value of the input image data as the luminance level is set. Based on the information shown, convert the color of the input image data,
A second gradation characteristic in which the gradation characteristic set by the setting means corresponds to a second dynamic range wider than the first dynamic range, and the absolute value is associated with a gradation value of the input image data. In the case of, the color of the input image data is converted based on information indicating a second correspondence relationship using the absolute luminance associated with the gradation value of the input image data as the luminance level,
A third gradation characteristic in which the gradation characteristic set by the setting means corresponds to a third dynamic range wider than the first dynamic range, and a relative luminance is associated with a gradation value of the input image data; In the case of, converting the color of the input image data based on information indicating a third correspondence using the relative luminance associated with the gradation value of the input image data as the luminance level. Characteristic image processing device. The image processing apparatus according to claim 1, wherein the setting unit sets a gradation characteristic according to an instruction input by a user. The image processing apparatus according to claim 1, wherein the setting unit sets a gradation characteristic based on metadata added to the input image data. The information indicating the correspondence is information in which different colors are associated with each of a plurality of ranges of luminance levels,
The conversion unit converts, for each of the plurality of ranges, a color of a portion of the input image data having a luminance level of the range into a color associated with the range in the information indicating the correspondence relationship. The image processing apparatus according to claim 1, wherein: The image processing apparatus according to claim 1, wherein the conversion unit converts an area of the input image data whose luminance level is equal to or less than a first threshold to monochrome. The conversion unit converts an area of the input image data whose luminance level is higher than a second threshold into a predetermined color,
The image processing apparatus according to claim 5, wherein the second threshold is higher than the first threshold. The image processing apparatus according to claim 6, wherein the second threshold is a luminance level specified by a user. 5. The image processing apparatus according to claim 1, wherein the conversion unit converts an area of the input image data whose luminance level is higher than a second threshold into a predetermined color. 6. apparatus. The image processing apparatus according to claim 8, wherein the second threshold is a luminance level specified by a user. The image processing apparatus according to claim 1, further comprising: a gradation conversion unit configured to convert the input image data with the set gradation characteristics. At least one of the information indicating the first correspondence, the information indicating the second correspondence, and the information indicating the third correspondence constitutes a range of possible brightness levels of the input image data. The image processing apparatus according to claim 1, wherein a different color is associated with each of the plurality of divided ranges. At least one of the information indicating the first correspondence, the information indicating the second correspondence, and the information indicating the third correspondence constitutes a range of possible brightness levels of the input image data. The image processing according to any one of claims 1 to 10, wherein different colors are associated with a plurality of boundary areas each including a plurality of boundaries of the plurality of divided ranges. apparatus. The second gradation characteristic is described in ST. The image processing apparatus according to claim 1, wherein the image processing apparatus has a PQ characteristic defined in 2084. 14. The image processing apparatus according to claim 1, wherein the third gradation characteristic is an HLG characteristic defined by ARIB STD-B67. A conversion step of converting the color of the input image data based on information indicating the correspondence between the luminance level and the color to generate converted image data;
A setting step of setting a gradation characteristic of the input image data,
Has,
In the conversion step,
When the gradation characteristic set in the setting step is a first gradation characteristic corresponding to a first dynamic range, a first correspondence relationship using a gradation value of the input image data as the luminance level is set. Based on the information shown, convert the color of the input image data,
A second gradation characteristic in which the gradation characteristic set in the setting step corresponds to a second dynamic range wider than the first dynamic range, and the absolute luminance is associated with a gradation value of the input image data. In the case of, the color of the input image data is converted based on information indicating a second correspondence relationship using the absolute luminance associated with the gradation value of the input image data as the luminance level,
A third gradation characteristic in which the gradation characteristic set in the setting step corresponds to a third dynamic range wider than the first dynamic range, and a relative luminance is associated with a gradation value of the input image data. In the case of, converting the color of the input image data based on information indicating a third correspondence using the relative luminance associated with the gradation value of the input image data as the luminance level. Characteristic image processing method. 16. The image processing method according to claim 15, wherein, in the setting step, a gradation characteristic is set according to an instruction input by a user. 16. The image processing method according to claim 15, wherein in the setting step, a gradation characteristic is set based on metadata added to the input image data. The information indicating the correspondence is information in which different colors are associated with each of a plurality of ranges of luminance levels,
In the conversion step, for each of the plurality of ranges, a color of a portion of the input image data having a luminance level of the range is converted into a color associated with the range in the information indicating the correspondence relationship. The image processing method according to any one of claims 15 to 17, wherein: 19. The image processing method according to claim 15, wherein, in the conversion step, an area of the input image data whose luminance level is equal to or less than a first threshold is converted to monochrome. In the conversion step, of the input image data, a region whose luminance level is higher than a second threshold value is converted into a predetermined color,
The image processing method according to claim 19, wherein the second threshold is higher than the first threshold. The image processing method according to claim 20, wherein the second threshold is a luminance level specified by a user. The image processing according to any one of claims 15 to 18, wherein in the conversion step, an area of the input image data having a luminance level higher than a second threshold is converted into a predetermined color. Method. 23. The image processing method according to claim 22, wherein the second threshold is a luminance level specified by a user. 24. The image processing method according to claim 15, further comprising a gradation conversion step of converting the input image data with the set gradation characteristics. At least one of the information indicating the first correspondence, the information indicating the second correspondence, and the information indicating the third correspondence constitutes a range of possible brightness levels of the input image data. 25. The image processing method according to claim 15, wherein different colors are associated with each of the plurality of divided ranges. At least one of the information indicating the first correspondence, the information indicating the second correspondence, and the information indicating the third correspondence constitutes a range of possible brightness levels of the input image data. The image processing according to any one of claims 15 to 24, wherein a different color is associated with each of a plurality of boundary regions including a plurality of boundaries of the plurality of divided ranges. Method. The second gradation characteristic is described in ST. The image processing method according to any one of claims 15 to 26, wherein the PQ characteristic is defined by 2084. The image processing method according to any one of claims 15 to 27, wherein the third gradation characteristic is an HLG characteristic defined by ARIB STD-B67. A program for causing a computer to execute each step of the image processing method according to any one of claims 15 to 28.

Images