Image processing apparatus and image processing method

Abstract

To provide an image processing apparatus that makes a parameter related to a HDR signal of a PQ system applicable to an HDR signal obtained by converting the PQ system into an HLG system.SOLUTION: An image processing apparatus acquires a PQ image that is an HDR signal of a perceptual quantization (PQ) system, and information associated with the PQ image and related to the maximum luminance value of the PQ image. The image processing apparatus converts the PQ image into an HLG image that is an HDR signal of a hybrid log gamma (HLG) system. The image processing apparatus converts the information related to the maximum luminance value similarly to the conversion of the PQ image and the HLG image. The image processing apparatus associates the HLG image and the converted information related to the maximum luminance value with each other.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an image processing device and an image processing method, and more particularly to an image processing device and an image processing method that use a high dynamic range (HDR) signal. [Background technology]

[0002] The Hybrid Log Gamma (HLG) and Perceptual Quantization (PQ) methods have been standardized for video signals that support a wider dynamic range than conventional video signals. The HLG method specifies the Opto-Electronic Transfer Function (OETF), which indicates the relationship between display luminance and video signal level, i.e., the characteristics of the imaging device. On the other hand, the PQ method specifies the Electro-Optical Transfer Function (EOTF), which indicates the relationship between video signal level and display luminance, i.e., the characteristics of the display device. Also, while the LHG method treats luminance as a relative value, the PQ method treats luminance as an absolute value.

[0003] Patent Document 1 discloses that the maximum luminance value [nits or cd / m2] of the output dynamic range or a gradation value (signal level) corresponding to the maximum luminance value is recorded as a parameter called maxDRL in association with a PQ HDR signal. By using maxDRL, it becomes possible to appropriately map the luminance of the PQ HDR signal to the luminance of the HLG HDR signal or SDR signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-90109 [Non-patent literature]

[0005] [Non-Patent Document 1] Report ITU-R BT.2408-5, "Guidance for operational practices in HDR television production", [online], March 2022, ITU-R, [Retrieved December 26, 1992], Internet<https: / / www.itu.int / dms_pub / itu-r / opb / rep / R-REP-BT.2408-5-2022-PDF-E.pdf> Summary of the Invention [Problem to be solved by the invention]

[0006] The PQ HDR signal can be converted into the HLG HDR signal by the method described in Non-Patent Document 1. In this case, the maxDRL recorded for the PQ HDR signal before conversion cannot be applied to the HLG HDR signal after conversion. However, there is no proposal on how to handle associated parameters other than the HDR signal when converting from the PQ format to the HLG format.

[0007] In one aspect, the present invention provides an image processing device and an image processing method that enable parameters related to a PQ HDR signal to be applied to an HDR signal converted from the PQ format to the HLG format. [Means for solving the problem]

[0008] In one aspect, the present invention provides an image processing device comprising: an acquisition means for acquiring a PQ image, which is an HDR signal of a Perceptual Quantization (PQ) method, and information related to the maximum luminance value of the PQ image, which is associated with the PQ image; a conversion means for converting the PQ image into an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) method, and converting the information related to the maximum luminance value in a manner similar to the conversion of the PQ image and the HLG image; and a recording means for recording the HLG image and the information related to the converted maximum luminance value in association with each other. Effect of the Invention

[0009] According to one aspect of the present invention, it is possible to provide an image processing device and an image processing method that enable parameters related to a PQ HDR signal to be applied to an HDR signal converted from the PQ format to the HLG format. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of an image processing apparatus according to an embodiment of the present invention. [Diagram 2] A diagram showing the conversion model from PQ to HLG. [Diagram 3] A flowchart showing an example of image processing according to an embodiment of the present invention. [Figure 4] A diagram showing the EOTF characteristics of the ITU-R BT.2100 (PQ) standard and the OETF characteristics of the ITU-R BT.2100 (HLG) standard. [Diagram 5] Diagram showing another conversion model from PQ to HLG. [Figure 6] FIG. 1 is a diagram showing an example of a data file structure used in a first embodiment of the present invention. [Figure 7] An example of a histogram of a PQ image and a shaded display of the saturated area [Figure 8] An example of a histogram of a PQ image and a shaded display of the saturated area [Figure 9] An example of a GUI for setting up HEIF(PQ) → HEIF(HLG) conversion [Figure 10] 11 is a flowchart showing an example of image processing according to a second embodiment of the present invention. [Figure 11] FIG. 13 is a diagram showing a conversion model from the PQ format to the HLG format in the second embodiment of the present invention. [Figure 12] A table showing the relationship between brightness and display gamma [Figure 13] FIG. 13 is a diagram showing an example of a data file structure used in a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below based on its exemplary embodiments with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. In addition, although multiple features are described in the embodiments, not all of them are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numbers are used for the same or similar configurations, and duplicated explanations are omitted.

[0012] In the following embodiment, the present invention will be described with respect to a case where the present invention is implemented in a computer device (personal computer, tablet computer, media player, PDA, etc.) as an example of an image processing device. However, the present invention can be implemented in any electronic device capable of handling HDR signals. Such electronic devices include imaging devices, smartphones, game consoles, display devices, robots, drones, and drive recorders. These are merely examples, and the present invention can also be implemented in other electronic devices.

[0013] ●(First embodiment) The present invention is applicable to image data composed of pixel data having multiple color components. For example, the image data may be generated by an imaging device using an imaging element having a color filter. Note that the HDR signal of the PQ method requires a depth of 10 bits or more per component. Therefore, a data format corresponding to a depth of 10 bits or more is used.

[0014] As an example, a data format conforming to the High Efficiency Image File Format (HEIF) standardized by ISO / IEC 23008-12 is used here. HIEF can store data of related images other than the main image and its thumbnail in one data file. For example, data of still images or videos with a depth of 10 bits that are encoded using an encoding method conforming to the H. 265 or High Efficiency Video Codec (HEVC) standard can be stored as data of related images.

[0015] In the following, unless otherwise specified, we will refer to HIEF format data files in which a PQ format HDR signal is recorded as the main image data and the maxDRL for the main image is recorded in the metadata.

[0016] 1 is a block diagram showing an example of the functional configuration of an image processing device 10 according to an embodiment. The image processing device 10 includes a CPU 1, a ROM 2, a RAM 3, an external storage device 4, an operation unit 5, a display unit 6, and a system bus .

[0017] The CPU 1 performs the operation of the image processing device 10 described below by loading programs stored in the ROM 2 and the external storage device 4 into the RAM 3 and executing them. Although one CPU 1 is shown in FIG. 1, multiple CPUs may actually work together.

[0018] The ROM 2 is an electrically rewritable non-volatile memory that stores control programs such as a BIOS required to start up the image processing apparatus 10, as well as programs, parameters, and data that do not require modification.

[0019] The RAM 3 has a work area for the CPU 1, a primary storage area for temporarily storing various data, an area for loading various programs, a video memory area for the display unit 6, and the like.

[0020] The external storage device 4 stores operating system (OS), various control programs, various application programs executable on the OS, various data, etc. The external storage device 4 is, for example, a hard disk drive (HDD), a solid state drive (SSD), a storage device using removable media, etc. The external storage device 4 may be removable.

[0021] The external storage device 4 stores a plurality of application programs including, for example, the following application programs. An application program that applies so-called development processing to RAW format image data in which pixels have one color component -Application program to convert HDR signal format from PQ to HLG format

[0022] The operation unit 5 is one or more input devices that can be operated by a user, such as a keyboard, a mouse, a touch panel, etc. The CPU 1 detects an operation on the operation unit 5, and executes a process according to the detected operation.

[0023] The display unit 6 is, for example, a liquid crystal display (LCD) or an organic EL display. The display unit 6 may be an external device. The display unit 6 displays various information through a user interface of the OS and application programs running on the image processing device 10.

[0024] The system bus 7 connects the above-mentioned functional blocks so that they can communicate with each other.

[0025] FIG. 2 shows a conversion model from the PQ format to the HLG format described in Non-Patent Document 1. Hereinafter, a PQ format HDR signal will be referred to as a PQ image, and a HLG format HDR signal will be referred to as an HLG image. A PQ image 31 is generated based on the EOTF of the PQ format. -1 Therefore, the signal value is converted to display light by applying the PQ EOTF (PQ EOTF) 32. -1is the inverse function of the Electro-Optical Transfer Function (EOTF). The same is true for the Opto-Optical Transfer Function (OOTF) and the Optical-Electric Transfer Function (OETF). The Optical-Optical Transfer Function (OOTF) is a transfer function that converts scene light to display light.

[0026] The display brightness reflects the production intent, so the HLG OOTF -1 (HLG OOTF -1 ) 34 is applied to convert the display luminance to scene luminance (Scene Light). Then, an HLG image 36 is obtained by applying an OETF (HLG OETF) 35 in the HLG format. -1 The combination of 34 and HLG OETF35 is the EOTF of the HLG system. -1 (EOTF -1 )

[0027] In Non-Patent Document 1, the standard parameter values ​​are γ=1.2, maximum display luminance L W = 1000 [nit] is the black display luminance L B =0[nit] is listed. These parameter values ​​are HLG OOTF -1 34. In this conversion method, the maximum luminance of the PQ image is set to the maximum luminance of the HLG image (here, 1000 [nit]), thereby making it possible to avoid changes in luminance due to conversion.

[0028] However, the signal value corresponding to the maximum luminance differs between the PQ image before conversion and the HLG image after conversion. For example, if the maximum luminance of the PQ image is 650 [nit] and the signal value is 721, the corresponding signal value in the HLG image after conversion is 955. Therefore, if the signal level corresponding to the maximum luminance of the PQ image is recorded as maxDRL, it cannot be used for the HLG image after conversion.

[0029] Therefore, in this embodiment, when a PQ image is converted into an HLG image, the maxDRL for the PQ image is also converted into a value suitable for HLG images.

[0030] FIG. 3 is a flowchart showing a process of converting a PQ image into an HLG image, which is carried out by the CPU 1 executing a PQ-HLG conversion application program stored in the external storage device 4, for example, in this embodiment.

[0031] Here, it is assumed that a PQ image in HEIF format is generated by an imaging device, and the optical image of the subject is converted into a signal value according to the OETF of the imaging device. It is also assumed that a parameter maxDRL relating to the maximum brightness of the PQ image is recorded as metadata in a data file that stores the PQ image.

[0032] Information on the transfer functions of the PQ and HLG systems (OOTF, OETF, EOTF and their inverse functions) can be stored in the ROM 2 or in the external storage device 4. If the PQ EOTF, PQ OOTF, HLG OETF and HLG OOTF are stored, other transfer functions can be obtained. For example, the PQ OETF is the sum of the PQ OOTF and the PQ EOTF. -1 It can be found from the following.

[0033] In S1, the CPU 1 acquires the PQ image 31 and reads it into the RAM 3. Here, the PQ image 31 is acquired from a data file in HEIF format stored in the external storage device 4, but it may also be acquired from an external device with which the image processing device 10 can communicate via an external interface.

[0034] In S2, the CPU 1 obtains the maxDRL for the PQ image 31 from the data file that stores the PQ image 31, and stores it in the RAM 3.

[0035] In S3, the CPU 1 converts the signal value of the PQ image 31 into a display luminance (Display Light) by applying the PQ EOTF 32 shown in Fig. 4(a) to the signal values ​​of the pixels that make up the PQ image 31. By applying the PQ EOTF 32, the nonlinearity of the OETF applied when generating the PQ image 31 is removed, so that the Display Light is a linear signal.

[0036] S4 CPU1, HLG OOTF on Display Light33 -1 By applying the above, the Display Light 33 is converted to Scene Light. Scene Light is a signal that corresponds to the subject luminance. -1 EOTF -1 and OETF -1 However, it may be stored in the ROM 2 or the external storage device 4 in advance. -1 The system parameters (γ, L W , L B ) may be as described above.

[0037] Then, the CPU 1 converts the Scene Light into a signal value of an HLG image 36 by applying an HLG OETF 35 as shown in FIG. 4( b ) to the Scene Light.

[0038] In addition, in S4, OOTF -1 Alternatively, instead of converting the Display Light 33 into the Scene Light using the HLG OETF 35, the Display Light 33 may be regarded as the Scene Light and the HLG OETF 35 may be applied. In this case, the HLG image 36 is obtained by a conversion procedure as shown in FIG.

[0039] In S5 and S6, the CPU 1 converts the maxDRL of the PQ image into the maxDRL of the HLG image in the same manner as in S3 and S4. Specifically, in S5, the CPU 1 applies the PQ EOTF32 to the maxDRL of the PQ image acquired in S2 to convert it into a Display Light value.

[0040] Then, in S6, CPU1 converts the maxDRL to the Display Light value and converts it to HLG OOTF -1 The maxDRL converted to the value of Display Light is converted to the maxDRL of the HLG image 36 by applying the HLG OETF 35 to the maxDRL converted to the value of Scene Light. In this case, the maxDRL converted to the value of Display Light may be converted to the maxDRL of the HLG image 36 by directly applying the HLG OETF 35.

[0041] In S7, the CPU 1 generates a data file in HEIF format that stores the HLG image 36 obtained in S4, and includes the maxDRL obtained in S6 as metadata.

[0042] In S8, the CPU 1 records the data file of the HLG image in the external storage device 4. Here, the HLG image and the converted maxDRL are recorded in the same data file, but they do not have to be recorded. For example, the CPU 1 may associate the HLG image with the converted maxDRL and store them in the RAM 3, without recording them in the external storage device 4.

[0043] 6A is a diagram showing an example of the file structure of a data file in the HEIF format used for PQ images and HLG images in this embodiment. ftype 802 is a container (area) that stores header information. MetaData 805 stores metadata such as maxDRL. ImageData 809 stores image data.

[0044] 6B is a diagram showing details of ImageData 809. Various image data can be stored in ImageData 809. Here, it is assumed that ImageData 809 has a thumbnail area 821, a Multi Picture Format image area 822, and a main image area 823.

[0045] In this way, in this embodiment, when a PQ image is converted into an HLG image, the maxDRL is also converted in the same way as the image and associated with the HLG image. Therefore, even if the maximum signal value (1023 for 10-bit depth) available in the HLG image does not correspond to the maximum luminance value, appropriate processing can be performed based on the maxDRL.

[0046] For example, consider the case where a PQ image having a histogram as shown in Fig. 7 is converted into an HLG image. In the brightness histogram 21 of the PQ image shown in Fig. 7, a brightness range 23 exceeding a maximum brightness value 22 corresponding to maxDRL is shaded, so that the user can easily grasp the brightness saturation level of the PQ image.

[0047] In an HLG image that handles luminance values ​​relatively, the saturation luminance level is usually equal to the maximum signal value corresponding to the bit depth (1023 in the case of 10-bit depth). However, when a PG image is converted into an HLG image, the signal value corresponding to the saturation luminance level of the HLG image becomes smaller than the maximum signal value according to the maximum luminance of the PG image. According to this embodiment, since the maxDRL corresponding to the converted HLG image can be associated, the signal level corresponding to the maximum luminance value of the HLG image can be correctly grasped based on the maxDRL. Therefore, as shown in FIG. 8, in a luminance histogram 81 of an HLG image converted from a PQ image, a luminance range 83 exceeding a maximum luminance value 82 corresponding to the maxDRL can be clearly indicated to inform the user.

[0048] Note that the use of maxDRL for the converted HLG image is not limited to displaying a luminance histogram, but can be used for any processing that depends on maximum luminance, such as displaying highlight areas of an HLG image.

[0049] According to this embodiment, when a PQ image is converted into an HLG image, the parameters recorded for the PQ image are converted so as to be applicable to the converted HLG image. Therefore, even if the signal value corresponding to the maximum luminance of the HLG image is not the maximum signal value, processing dependent on the maximum luminance of the HLG image can be appropriately executed.

[0050] ●(Second embodiment) Next, a second embodiment of the present invention will be described. -1 In the above description, the maximum luminance of the HLG image used is set to 1000 [nit] and the system gamma γ is set to 1.2. This embodiment relates to a configuration in which these values ​​can be selected by the user.

[0051] 9 shows an example of a setting screen 101 that is displayed on the display unit 6 by the CPU 1 executing a PQ-HLG conversion application program. A user of the image processing device 10 can set the system gamma 102 or the maximum luminance value of HLG [nit or cd / m2] by operating the setting screen via the operation unit 5. These values ​​may be set from among predetermined options, or may be set by the user directly inputting values.

[0052] When the setting screen 101 is closed, the CPU 1 obtains the setting value of the system gamma (or the maximum luminance value) and stores it in the ROM 2, for example.

[0053] 10 is a flowchart relating to the conversion process from a PQ image to an HLG image, which is carried out in this embodiment by the CPU 1 executing a PQ-HLG conversion application program stored in, for example, the external storage device 4. Steps that perform the same operations as in the first embodiment are given the same reference numerals as in FIG. 3 and will not be described further. This embodiment also handles PQ image data files in the HEIF format described in the first embodiment.

[0054] Hereinafter, the PQ-HLG conversion process in this embodiment will be described with reference to the conversion model shown in FIG.

[0055] In S11, the CPU 1 refers to the ROM 2 and obtains the system gamma setting value (or the maximum brightness value).

[0056] In S12, the CPU 1 applies the PQ EOTF 102 to the PQ image 101 stored in the RAM 3 in the same manner as in the first embodiment. Next, the CPU 1 applies the HLG OOTF -1 In this manner, in this embodiment, the PQ EOTF 102 and the HLG OOTF 103 are applied to the PQ image 101. -1 103 to convert the PQ image 101 into the Display Light 105.

[0057] And HLG OOTF -1 For the system gamma (or maximum display luminance L W ) is applied to the system parameters 104. Note that the black display luminance L B is also set to 0 here.

[0058] Thereafter, S4 and subsequent steps are the same as those in the first embodiment. That is, as described with reference to Fig. 5, the CPU 1 regards the Display Light 105 as the Scene Light and applies the HLG OETF 106 to generate an HLG image 107. The maxDRL is also converted in the same way as the PQ image, and then recorded as metadata of the HLG image.

[0059] According to this embodiment, it is possible to execute PQ-HLG conversion taking into consideration the gamma of the display device that displays the converted HLG image, and it is possible to display the HLG image appropriately according to the gamma of the display device. Also, as in the first embodiment, it is possible to achieve the effect of obtaining an appropriate maxDRL for the converted HLG image.

[0060] ●(Third embodiment) Next, a third embodiment of the present invention will be described. In the second embodiment, PQ-HLG conversion is performed taking into account the set system gamma. In this embodiment, an HLG image is generated for each of a plurality of predetermined system parameters.

[0061] 12 shows an example of maximum display luminance and gamma value for a typical display device described in Non-Patent Document 1. In this embodiment, in the conversion model shown in FIG. 11, each of a plurality of system parameters 104 with different values, as shown in FIG. 12, is converted into HLG OOTF -1 The other operations are the same as those in the second embodiment.

[0062] However, in this embodiment, an HLG image and maxDRL equal to the number of system parameter types are generated from a PQ image of one frame, so the configurations of MetaData 805 and Image Data 809 in the data file that stores the HLG image are different. Since a data file in HEIF format can store multiple images in one file, the number of data files does not increase.

[0063] 13 is a diagram showing the data structure of Image Data 809 in an HLG image data file in HEIF format recorded in this embodiment. Three items, thumbnail, Multi Picture Format, and main image, are stored in sequence corresponding to each system parameter. For example, images related to system parameters of maximum display luminance 400 [nit] and display gamma 1.03 are stored in areas 821-823. Images related to system parameters of maximum display luminance 600 [nit] and display gamma 1.11 are stored in areas 824-826. Similarly, images related to system parameters up to maximum display luminance 200 [nit] and display gamma 1.33 are stored in areas 827-832.

[0064] Similarly, in MetaData 805, maxDRL corresponding to each system parameter is stored in sequence.

[0065] When displaying an HLG image from an HLG image data file generated in this embodiment, for example, the display program obtains HLG image data that matches the gamma or maximum display brightness of the display device from Image Data 809 and uses it for display. Also, when maxDRL is used, maxDRL that matches the gamma or maximum display brightness of the display device is obtained from MetaData 805 and used. Note that the display program may be, for example, an application program that runs on a computer device. Alternatively, when the HLG image data file is recorded on a recording medium such as an optical disc, it may be a program that runs on a drive that plays the recording medium.

[0066] In this embodiment, when converting a PQ image into an HLG image, an HLG image corresponding to each of a plurality of system parameters with different values ​​is generated. Therefore, it is possible to display an HLG image suitable for the system parameters of the environment in which the HLG image is displayed. In addition, the maxDRL is also generated and recorded for each system parameter value, so that a maxDRL suitable for the HLG image to be used for display can be used.

[0067] (Other embodiments) Instead of applying the transfer function, a lookup table in which discrete signal values ​​of a PQ image and values ​​of Display Light correspond to each other, and a lookup table in which discrete values ​​of Scene Light correspond to signal values ​​of an HLG image may be used. For example, instead of applying the PQ EOTF, the value of Display Light corresponding to the signal value of each pixel constituting the PQ image is obtained by referring to the lookup table. Signal values ​​that are not stored in the lookup table can be obtained by interpolating the value of Display Light according to the difference with the stored signal value. Similarly, instead of applying the HLG OETF, the value of each pixel of Scene Light (Display Light) can be converted to the signal value of the pixel of the HLG image using the lookup table. The maxDRL can be converted in the same manner. For example, a lookup table can be used when processing speed is more important than conversion accuracy.

[0068] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0069] The disclosure of the present embodiment includes the following image processing device, image processing method, and program. (Item 1) An acquisition means for acquiring a PQ image which is an HDR signal of a Perceptual Quantization (PQ) method and information related to the maximum luminance value of the PQ image, the information being associated with the PQ image; A conversion means for converting the PQ image into an HLG image which is an HDR signal of a Hybrid Log Gamma (HLG) format, and converting information regarding the maximum luminance value in the same manner as the conversion between the PQ image and the HLG image; an association means for associating the HLG image with information regarding the converted maximum luminance value; 13. An image processing device comprising: (Item 2) The image processing device described in item 1, characterized in that the conversion means applies a transfer function including an electro-optical transfer function (EOTF) of a PQ system, and then applies a transfer function including an optical-electrical transfer function (OETF) of an HLG system, thereby converting the PQ image into the HLG image and converting information regarding the maximum luminance value. (Item 3) A transfer function including the EOTF of the PQ system converts the PQ image to a display luminance; 3. The image processing device according to item 2, characterized in that the transfer function including the OETF of the HLG method includes an inverse function of an optical-to-optical transfer function (OOTF) of the HLG method that converts the display luminance to subject luminance, and the OETF of the HLG method. (Item 4) The transfer function including the EOTF of the PQ method includes an inverse function of the optical optical transfer function (OOTF) of the HLG method applied after the EOTF of the PQ method, The user can set system parameters to be applied to the OOTF of the HLG format. 3. The image processing device according to item 2, (Item 5) The transfer function including the EOTF of the PQ method includes an inverse function of the optical optical transfer function (OOTF) of the HLG method applied after the EOTF of the PQ method, the conversion means applies a plurality of system parameters having different values ​​to the OOTF of the HLG format to generate a plurality of the HLG images from the PQ image and information on the maximum luminance value corresponding to each of the plurality of the HLG images; 3. The image processing device according to item 2, (Item 6) 6. The image processing device according to item 5, wherein the associating means records the plurality of HLG images and information regarding the maximum luminance value corresponding to each of the plurality of HLG images in one data file. (Item 7) 7. The image processing device according to item 5 or 6, wherein the system parameter is a gamma value applied when displaying the HLG image, or a maximum luminance value of the HLG image. (Item 8) A transfer function including the EOTF of the PQ system converts the PQ image to a display luminance; 3. The image processing device according to item 2, wherein the transfer function including the OETF of the HLG system is the OETF of the HLG system applied to the display luminance. (Item 9) A transfer function including the EOTF of the PQ system converts the PQ image to a display luminance; 3. The image processing device according to item 2, characterized in that the transfer function including the OETF of the HLG method includes an inverse function of an optical-to-optical transfer function (OOTF) of the HLG method that converts the display luminance to subject luminance, and the OETF of the HLG method. (Item 10) The image processing device described in item 1, characterized in that the conversion means converts the PQ image into the HLG image and converts the information using a pre-stored relationship between discrete signal values ​​of a PQ image and corresponding luminance, and a pre-stored relationship between discrete luminance values ​​and corresponding signal values ​​of an HLG image. (Item 11) An image processing method executed by an image processing device, comprising: Acquire a PQ image, which is an HDR signal using the Perceptual Quantization (PQ) method, obtaining information associated with said PQ image regarding a maximum luminance value of said PQ image; Converting the PQ image into an HLG image, which is an HDR signal in a Hybrid Log Gamma (HLG) format; converting the information about the maximum luminance value in a manner similar to the conversion of the PQ image and the HLG image; Associating the HLG image with information regarding the transformed maximum luminance value; 13. An image processing method comprising: (Item 12) 11. A program for causing a computer to function as the image processing device according to any one of items 1 to 10.

[0070] The present invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, the following claims are appended to disclose the scope of the invention. [Explanation of symbols]

[0071] 1...CPU, 2...ROM, 3...RAM, 4...external storage device, 5...operation unit, 6...display unit, 10...image processing device

Claims

1. An acquisition means for acquiring a PQ image, which is an HDR signal of a Perceptual Quantization (PQ) method, and information related to the maximum luminance value of the PQ image, which is associated with the PQ image; a conversion means for converting the PQ image into an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) format, and converting information about the maximum luminance value in the same manner as the conversion between the PQ image and the HLG image; and associating means for associating the HLG image with information relating to the converted maximum luminance value, the converting means converts the PQ image into the HLG image and converts information about the maximum luminance value by applying a transfer function including an electro-optical transfer function (EOTF) of the PQ system and then applying a transfer function including an optical-electrical transfer function (OETF) of the HLG system; 1. An image processing device comprising:

2. A transfer function including the EOTF of the PQ system converts the PQ image into display luminance; 2. The image processing device according to claim 1, wherein the transfer function including the HLG OETF includes an inverse function of an HLG OETF that converts the display luminance into subject luminance, and the HLG OETF.

3. the transfer function including the EOTF of the PQ system includes an inverse function of the optical transfer function (OOTF) of the HLG system applied after the EOTF of the PQ system; The user can set the system parameters to be applied to the OOTF of the HLG format.

2. The image processing device according to claim 1, wherein:

4. the transfer function including the EOTF of the PQ system includes an inverse function of the optical transfer function (OOTF) of the HLG system applied after the EOTF of the PQ system; the conversion means applies a plurality of system parameters with different values ​​to the OOTF of the HLG format to generate a plurality of the HLG images from the PQ image and information on the maximum luminance value corresponding to each of the plurality of the HLG images; 2. The image processing device according to claim 1, wherein:

5. 5. The image processing device according to claim 4, wherein the associating means associates the HLG images with the information regarding the converted maximum luminance values ​​by recording the plurality of HLG images and the information regarding the converted maximum luminance values ​​corresponding to each of the plurality of HLG images in a single data file.

6. 5. The image processing device according to claim 4, wherein the system parameter is a gamma value applied when the HLG image is displayed, or a maximum luminance value of the HLG image.

7. A transfer function including the EOTF of the PQ system converts the PQ image into display luminance; 2. The image processing device according to claim 1, wherein the transfer function including the OETF of the HLG system is the OETF of the HLG system that is applied to the display luminance.

8. An image processing method executed by an image processing device, Acquire a PQ image, which is an HDR signal using the Perceptual Quantization (PQ) method, obtaining information associated with the PQ image about a maximum luminance value of the PQ image; Applying a transfer function including an electro-optical transfer function (EOTF) of a PQ system, and then applying a transfer function including an optical-electrical transfer function (OETF) of an HLG system, thereby converting the PQ image into an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) system, and converting information about the maximum luminance value; Associating the HLG image with information about the transformed maximum luminance value; An image processing method comprising:

9. A program for causing a computer to function as the image processing device according to any one of claims 1 to 7.

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