Image processing apparatus and image processing method

Abstract

To provide an image processing apparatus and an image processing method that can appropriately execute, on HDR signals converted from a perceptual quantization (PQ) system into a hybrid log gamma (HLG) system, processing based on luminance information before the conversion.SOLUTION: An image processing apparatus executes processing based on a parameter determined with reference to information on the maximum luminance of a PQ image, on an HLG image formed from HDR signals of an HLG system converted from the PQ image formed from HDR signals of a PQ system. The image processing apparatus converts the value of the parameter into a value corresponding to the HLG image. The image processing apparatus executes processing on the HLG image by using the parameter after the conversion.SELECTED DRAWING: Figure 7

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) formats have been standardized for video signals that support a wider dynamic range than conventional video signals. The HLG format 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 format 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. Furthermore, the HLG format treats luminance as a relative value, while the PQ format 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 the gradation value (signal level) corresponding to the maximum luminance value is recorded as a parameter 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 an HLG HDR signal or an 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] A PQ HDR signal can be converted into an HLG HDR signal using a method such as that described in Non-Patent Document 1. However, the maxDRL recorded for the PQ HDR signal before conversion cannot be applied to the HLG HDR signal after conversion. This makes it difficult to appropriately perform processing based on the luminance information before conversion (such as highlight warning) on ​​an HDR signal converted from PQ to HDR.

[0007] In one aspect, the present invention provides an image processing device and an image processing method that can appropriately perform processing on an HDR signal converted from the PQ format to the HLG format based on the luminance information before conversion. [Means for solving the problem]

[0008] In one aspect, the present invention provides an image processing device that performs processing on an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) system converted from a PQ image, which is an HDR signal of a Perceptual Quantization (PQ) system, based on parameters determined using information regarding the maximum luminance of the PQ image as a reference, and is characterized by having a conversion means that converts the value of the parameter into a value corresponding to the HLG image, and a processing means that processes the HLG image using the converted parameters. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an image processing device and an image processing method that can appropriately perform processing on an HDR signal converted from the PQ format to the HLG format based on the luminance information before conversion. [Brief explanation 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. [Figure 2] Diagram showing the conversion model from PQ to HLG [Figure 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. [Figure 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] Flowchart for highlight warning processing in the first embodiment [Figure 8] FIG. 10 is a diagram schematically illustrating the effect of the first embodiment. [Figure 9] Flowchart for LUT generation processing and highlight warning processing in the second embodiment [Figure 10] FIG. 10 is a diagram showing an example of an LUT used in the second embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below based on exemplary embodiments with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claimed invention. Furthermore, 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 numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0012] In the following embodiments, the present invention will be described with respect to a case where the present invention is implemented in a computer device (such as a personal computer, tablet computer, media player, or PDA) 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 with a color filter. Note that a PQ HDR signal requires a depth of 10 bits or more per component. Therefore, a data format compatible with a depth of 10 bits or more is used.

[0014] As an example, we will use a data format that complies with the High Efficiency Image File Format (HEIF) standardized in ISO / IEC 23008-12. HIIF can store data for related images other than the main image and its thumbnail in a single data file. For example, related image data can include still image or video data with 10-bit depth that has been encoded using an encoding method compliant with the H.265 or High Efficiency Video Codec (HEVC) standards.

[0015] Unless otherwise specified, the following discussion will refer to HIEF-format data files in which a PQ-format HDR signal is recorded as the main image data and maxDRL for the main image is recorded in the metadata. maxDRL is information indicating the maximum luminance value (nits or cd / m2) of the output dynamic range or the gradation value (signal level) corresponding to the maximum luminance value. In the following discussion, maxDRL will be assumed to indicate a luminance value. Although not explained separately, if maxDRL and other values ​​calculated with maxDRL are expressed in different units, one unit is converted to the other unit, and the calculation is performed after the value is converted to the same unit.

[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 operations 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, in practice, multiple CPUs may work together.

[0018] The ROM 2 is an electrically rewritable non-volatile memory that stores control programs such as 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 detachable.

[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 format 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 processing 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 the 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] Figure 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 an HLG format HDR signal will be referred to as an HLG image. A PQ image 31 is generated using 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 opto-electrical transfer function (OETF). The optical-optical transfer function (OOTF) is a transfer function that converts scene light into display light.

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

[0027] Non-Patent Document 1 states that 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 nits and the signal value is 721, the corresponding signal value in the HLG image after conversion will be 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] FIG. 3 is a flowchart showing the process of converting a PQ image into an HLG image, which is carried out by the CPU 1 in this embodiment by executing a PQ-HLG conversion application program stored in the external storage device 4, for example.

[0030] Here, we assume that a PQ image in HEIF format is generated by an imaging device, and that the optical image of the subject is converted into a signal value according to the OETF of the imaging device. We also assume that the parameter maxDRL relating to the maximum brightness of the PQ image is recorded as metadata in the data file that stores the PQ image.

[0031] Furthermore, information on the transfer functions (OOTF, OETF, EOTF and their inverse functions) of the PQ and HLG systems can be stored in the ROM 2 or an external storage device 4. Note that if the PQ EOTF, PQ OOTF, HLG OETF and HLG OOTF are stored, other transfer functions can be found. For example, the PQ OETF can be calculated by dividing the PQ OOTF and the PQ EOTF. -1 It can be found from the following.

[0032] In S1, the CPU 1 acquires the PQ image 31 and loads 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.

[0033] In S2, the CPU 1 obtains the maxDRL for the PQ image 31 from the data file storing the PQ image 31, and stores it in the RAM 3.

[0034] In S3, the CPU 1 converts the signal values ​​of the PQ image 31 into 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 the Display Light is a linear signal.

[0035] In S4, CPU1 is HLG OOTF on Display Light 33. -1 By applying the above, the Display Light 33 is converted into Scene Light. Scene Light is a signal that corresponds to the luminance of the subject. -1 is EOTF -1 and OETF -1 It may be stored in advance in the ROM 2 or the external storage device 4. -1 The system parameters (γ, L W , L B ) may be as described above.

[0036] Then, the CPU 1 converts the Scene Light into signal values ​​of an HLG image 36 by applying an HLG OETF 35 as shown in FIG. 4(b) to the Scene Light.

[0037] In addition, in S4, OOTF -1 Instead of converting the Display Light 33 to Scene Light using the HLG OETF 35, the Display Light 33 may be regarded as Scene Light and the HLG OETF 35 may be applied. In this case, an HLG image 36 is obtained by the conversion procedure shown in FIG.

[0038] In S5 and S6, the CPU 1 converts the maxDRL of the PQ image into the maxDRL of the HLG image in the same way as in S3 and S4. Specifically, in S5, the CPU 1 applies PQ EOTF32 to the maxDRL of the PQ image acquired in S2 to convert it into a Display Light value.

[0039] Then, in S6, CPU1 converts the maxDRL converted to the Display Light value into HLG OOTF -1Then, the CPU 1 applies the HLG OETF 35 to the maxDRL converted to the Scene Light value to convert it to the maxDRL of the HLG image 36. Again, the maxDRL converted to the Display Light value may be converted to the maxDRL of the HLG image 36 by directly applying the HLG OETF 35.

[0040] In S7, the CPU 1 generates a data file in HEIF format that stores the HLG image 36 obtained in S4, and includes the converted maxDRL (for the HLG image) obtained in S6 as metadata. Note that the CPU 1 can also include the pre-conversion maxDRL (for the PG image) as metadata in the data file.

[0041] If the highlight threshold to be applied to the PQ image is specified as a brightness value, the CPU 1 converts it into a highlight threshold for the HLG image 36, as with maxDRL. Then, in S7, the CPU 1 also includes the highlight threshold for the HLG image as metadata in the HEIF-format data file that stores the HLG image 36. If a highlight warning amount is specified instead of the highlight threshold to be applied to the PQ image, the CPU 1 calculates the highlight threshold and then converts it into a highlight threshold for the HLG image.

[0042] Highlight warning is a function that allows the user to identify areas of an image where brightness is saturated (overexposed) or areas that are almost overexposed. Pixels with values ​​exceeding the highlight threshold are subject to a highlight warning. The amount of highlight warning corresponds to the difference between maxDRL and the highlight threshold. Highlight threshold = maxDRL - highlight warning amount The following relationship is satisfied. The highlight warning threshold and the highlight warning amount are both parameters determined based on maxDRL.

[0043] For example, if the highlight warning amount ΔPQ is defined by the I value (luminance value) in the ICtCp color space, which is one of the perceptually uniform color spaces and is defined in ITU-R-BT.2100, the CPU 1 determines the highlight warning threshold value as follows.

[0044] The RGB values ​​(Xr, Xg, Xb) of a pixel X are converted to values ​​in the ICtCp color space, and the resulting I value (brightness value) is denoted as I(X). The highlight warning threshold for the RGB values ​​of the PQ HDR image is PQ thrH, and the maxHDR of the PQ image is PQ maxHDR. In this case, the following relationship holds: I (PQ thrH)=I (PQ maxHDR) -ΔPQ Equation 2

[0045] Therefore, the CPU 1 converts the maxDRL for the PQ image 31 into an I value and subtracts the highlight warning amount to determine the I value (I (PQ thrH)) of the highlight threshold to be applied to the PQ image 31. The CPU 1 then converts the I value into a luminance value in the same color space as maxHDR, and then converts it into a highlight threshold for the HLG image 36 in the same manner as maxHDR.

[0046] In S8, the CPU 1 records the data file of the HLG image in the external storage device 4. Here, the HLG image, the converted maxDRL, and the highlight warning threshold are recorded in the same data file, but this does not have to be done. For example, the CPU 1 may associate the HLG image with the converted maxDRL and the highlight warning threshold and store them in the RAM 3, without recording them in the external storage device 4.

[0047] 6A shows 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 and highlight warning threshold. ImageData 809 stores image data.

[0048] 6(b) 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.

[0049] In this manner, in this embodiment, when a PQ image is converted into an HLG image, the maxDRL and highlight warning threshold are also converted in the same way as the image, and are associated with the HLG image.

[0050] <Highlight warning action> Next, highlight warning processing for an HLG image converted from a PQ image will be described using the flowchart shown in Fig. 7. Highlight warning processing can be performed on a still image or a video frame.

[0051] In S21, the CPU 1 acquires an HLG image and loads it into the RAM 3. Here, the HLG image 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. The HLG image acquired here has been converted from a PG image, and as described above, has at least maxHDR converted for the HLG image.

[0052] In S22, the CPU 1 determines whether a highlight warning threshold is associated with the acquired HLG image, for example by referring to the metadata of the data file. If it is determined that a highlight warning threshold is associated, the CPU 1 executes S23; if not, the CPU 1 executes S24.

[0053] In S23, the CPU 1 obtains the highlight warning threshold associated with the HLG image and stores it in RAM 3. Note that if the highlight warning threshold associated with the HLG image is the highlight warning threshold for the PQ image before conversion, the CPU 1 converts it to the highlight warning threshold for the HLG image using the method described with reference to FIG.

[0054] At S24, CPU 1 obtains the maxDRL associated with the HLG image and stores it in RAM 3. CPU 1 also obtains the highlight warning amount, for example, from ROM 2. CPU 1 obtains the maxDRL and highlight warning amount for the same HDR format. That is, if the highlight warning amount stored in ROM 2 is for an HLG image, CPU 1 obtains the maxDRL after conversion. If the highlight warning amount stored in ROM 2 is for a PQ image, CPU 1 obtains the maxDRL before conversion.

[0055] Then, CPU 1 calculates a highlight warning threshold to be applied to the HLG image from the acquired maxDRL and highlight warning amount. When the highlight warning amount for the HLG image and the converted maxDRL are acquired, CPU 1 can calculate the highlight warning threshold by subtracting the highlight warning amount from maxDRL. On the other hand, when the highlight warning amount for the PQ image and the unconverted maxDRL are acquired, CPU 1 can calculate the highlight warning threshold using the method described with reference to FIG. 3. CPU 1 stores the calculated highlight warning threshold in RAM 3.

[0056] In S25, CPU 1 applies a highlight warning threshold to the HLG image. For example, CPU 1 compares the value of each pixel that makes up the HLG image with the highlight warning threshold, and detects pixels with values ​​that exceed the highlight warning threshold as pixels that require a warning. When comparing pixel values ​​with the highlight warning threshold, CPU 1 converts the format of the pixel values ​​or highlight warning threshold as necessary so that both have the same format (for example, RGB values ​​or luminance values). Note that when comparing RGB values, pixels that exceed the highlight warning threshold for all RGB components are subject to a highlight warning.

[0057] In S26, the CPU 1 displays a highlight warning. There are no particular limitations on the method of displaying the highlight warning, but it is possible to superimpose (constantly or periodically) a specific pattern such as a zebra pattern on the area of ​​the original image (the HLG image acquired in S21) made up of pixels detected as targets for a highlight warning in S25. Alternatively, it is possible to change the value of the pixels in the original image that are targets for a warning to a specific value (constantly or periodically), or to display the pixels that are targets for a warning in a blinking manner. These are merely examples, and any display method that allows the pixels that are targets for a warning to be visually distinguished from other pixels can be used.

[0058] As described above, according to this embodiment, it is possible to appropriately perform processing based on the luminance information before conversion on an HDR signal converted from the PQ format to the HLG format.

[0059] Specifically, it is now possible to display highlight warnings for HLG images converted from PQ images based on the BT.2408 standard in the same way as for PQ images before conversion. For example, if the original image is a PQ image with a peak brightness of 649 nits, the maxDRL will be 721 in 10-bit notation. When converted to an HLG image based on the BT.2408 standard, the maxDRL after conversion will be 957 in 10-bit notation.

[0060] Also, if the highlight warning amount for a PQ image is set to 6 in 10-bit notation, the highlight warning threshold for the PQ image is 715 in 10-bit notation. The highlight warning threshold applied to the converted HLG image is 948 in 10-bit notation. The maxDRL after conversion is 957 in 10-bit notation, so the highlight warning amount for the HLG image is 9.

[0061] 8A shows an example of a highlight warning display when the highlight warning threshold for a PQ image is converted to the highlight warning threshold for an HLG image according to this embodiment. That is, FIG. 8A is the same as the highlight warning display for a PQ image before conversion. In FIG. 8A, pixels subject to the warning are shown as black pixels.

[0062] On the other hand, Fig. 8(b) shows an example of a highlight warning display in which the highlight warning amount for the PQ image is used as is for the converted HLG image for the same original image as Fig. 8(a). When conversion according to this embodiment is applied, if the highlight warning amount for the PQ image is set to 6 in 10-bit notation, the highlight warning amount for the HLG image becomes 9. However, if the highlight warning amount of 6 for the original image is used as is, the highlight warning threshold becomes higher, and the number of pixels subject to warning decreases.

[0063] ●(Second embodiment) Next, a second embodiment of the present invention will be described. In the first embodiment, the highlight warning threshold and highlight warning amount for the converted HLG image were calculated sequentially using calculation formulas based on the BT.2408 standard. In this embodiment, the calculation results are stored in advance in ROM2 as a lookup table (LUT).

[0064] A method for generating an LUT will be described using the flowchart shown in Fig. 9. As described above, the peak luminance of a PQ image may differ depending on, for example, the shooting mode, so in S31 the CPU 1 sets the shooting mode. The shooting mode may be set based on a user setting, or may be set automatically by the CPU 1 using any method.

[0065] In S32, CPU 1 determines the maxDRL and highlight warning threshold according to the shooting mode. There are no particular limitations on the method of determination, and CPU 1 may obtain maxDRL and highlight warning threshold values ​​pre-stored in ROM 2 according to the shooting mode. Alternatively, CPU 1 may calculate them by applying a predetermined coefficient or the like pre-defined according to the shooting mode to a predetermined standard maxDRL and highlight warning threshold value.

[0066] In S33, the CPU 1 converts the maxDRL and highlight warning threshold determined in S32 into values ​​for an HLG image using the method described in the first embodiment.

[0067] In S34 (optional), the CPU 1 subtracts the converted highlight warning threshold value from the converted maxDRL, as necessary, to calculate the highlight warning amount for the HLG image.

[0068] In S35, the CPU 1 generates an LUT that stores the maxDRL for HLG images and the highlight warning threshold (and a highlight warning amount, if necessary) in association with the shooting mode set in S31. If there are multiple settable shooting modes, the processes of S31 to S34 may be repeated for each shooting mode to generate LUTs that correspond to multiple shooting modes.

[0069] In S36, the CPU1 stores the generated LUT in the ROM2.

[0070] FIG. 10 shows an example of an LUT generated by the processing in FIG. 9(a). This example shows examples of LUTs that support three shooting modes (standard DR mode, high-brightness DR priority mode, and a mode that expands DR by combining multiple frames). The LUT stores the maxDRL, highlight warning threshold, and highlight warning amount for PQ and HLG images, associated with the shooting mode. All of these are expressed in 10-bit notation. While a system gamma of 1.2 is assumed here, a separate LUT may be generated for each system gamma.

[0071] A method for referencing the generated LUT will be described using the flowchart shown in FIG. 9(b).

[0072] In S41, the CPU 1 acquires the shooting mode that was set when the original image (PQ image) of the HLG image for which the highlight warning display is to be displayed is captured, for example, from the operation unit 5. The shooting mode may be acquired from another location, such as from the metadata of the data file that stores the target image.

[0073] In S42, the CPU 1 reads out the LUT corresponding to the shooting mode acquired in S41 from the ROM 2 to the RAM 3.

[0074] In S43, the CPU 1 refers to the LUT and acquires a highlight warning threshold value corresponding to the HLG image for which a highlight warning display is to be performed (or acquires the maxDRL and the highlight warning amount).

[0075] In S44, the CPU 1 uses the acquired highlight warning threshold (or the highlight warning threshold calculated from the maxDRL and the highlight warning amount) to display a highlight warning for the HLG image in the same manner as in S26.

[0076] This embodiment can also achieve the same effects as the first embodiment. Furthermore, by calculating the parameters required for highlight warning processing (maxDRL and highlight warning amount, or highlight warning threshold) in advance and storing them as an LUT, high-speed processing becomes possible. Therefore, this embodiment is suitable for applications requiring high-speed processing, such as when highlight warning processing is performed on moving images used for live view display.

[0077] (Other embodiments) In the above embodiment, the highlight warning process has been described as an example of a process based on the luminance information of the PQ image before conversion. However, the present invention is equally applicable to a process that uses any parameter defined based on the luminance information of the PQ image before conversion, such as maxDRL.

[0078] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the 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 realizes one or more functions.

[0079] The disclosure of the present embodiment includes the following image processing device, image processing method, and program. (Item 1) An image processing device that performs processing on an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) method converted from a PQ image, which is an HDR signal of a Perceptual Quantization (PQ) method, based on parameters defined using information regarding the maximum luminance of the PQ image as a reference, a conversion means for converting the values ​​of the parameters into values ​​corresponding to the HLG image; a processing means for performing the processing on the HLG image using the parameters after the conversion; 1. An image processing device comprising: (Item 2) 2. The image processing device according to item 1, wherein the parameter is a threshold value related to brightness. (Item 3) If the parameter is a value representing the difference between the maximum brightness and another parameter, the conversion means converts information about the maximum luminance in addition to the parameter values ​​into values ​​corresponding to the HLG image; the processing means performs the processing on the HLG image using the parameters after the conversion and information about the maximum luminance after the conversion. 2. The image processing device according to item 1, (Item 4) 4. The image processing device according to item 3, wherein the processing means performs the processing on the HLG image using a value obtained by subtracting the parameter after the conversion from information about the maximum brightness after the conversion as a threshold value. (Item 5) 5. The image processing device according to any one of items 1 to 4, wherein the parameters are associated with the HLG image. (Item 6) 6. The image processing device according to any one of items 1 to 5, wherein the conversion means performs the conversion by referring to a lookup table stored in advance. (Item 7) 7. The image processing device according to item 6, wherein the lookup table has the converted values ​​of the parameters for each shooting mode that was set when the PQ image was shot. (Item 8) An image processing device having a conversion means for converting a PQ image, which is an HDR signal of a Perceptual Quantization (PQ) method, into an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) method, The image processing device is characterized in that the conversion means converts parameters determined based on information relating to the maximum luminance of the PQ image to correspond to the HLG image and associates the parameters with the HLG image. (Item 9) 9. The image processing device according to item 8, wherein the parameter is a threshold value related to brightness. (Item 10) Item 9. The image processing device according to item 8, characterized in that, when the parameter is a value representing the difference between the maximum brightness and another parameter, the conversion means converts information about the maximum brightness in addition to the value of the parameter into a value corresponding to the HLG image and associates it with the HLG image. (Item 11) An image processing method executed by an image processing device to perform processing on an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) method converted from a PQ image, which is an HDR signal of a Perceptual Quantization (PQ) method, based on parameters determined using information related to the maximum luminance of the PQ image as a reference, converting the values ​​of the parameters into values ​​corresponding to the HLG image; performing the processing on the HLG image using the transformed parameters; An image processing method comprising: (Item 12) An image processing method executed by an image processing device for converting a PQ image, which is an HDR signal of a Perceptual Quantization (PQ) method, into an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) method, converting parameters determined based on information about the maximum luminance of the PQ image to correspond to the HLG image; Associating the transformed parameters with the HLG image; An image processing method comprising: (Item 13) 11. A program for causing a computer to function as each of the means possessed by the image processing device according to any one of items 1 to 10.

[0080] 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 clarify the scope of the invention. [Explanation of symbols]

[0081] 1...CPU, 2...ROM, 3...RAM, 4...external storage device, 5...operation unit, 6...display unit, 10...image processing device

Claims

1. An image processing device that performs processing on an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) method converted from a PQ image, which is an HDR signal of a Perceptual Quantization (PQ) method, based on parameters defined using information regarding the maximum luminance of the PQ image as a reference, a conversion means for converting the values ​​of the parameters into values ​​corresponding to the HLG image; a processing means for performing the processing on the HLG image using the parameters after the conversion; 1. An image processing device comprising:

2. 2. The image processing device according to claim 1, wherein the parameter is a threshold value related to brightness.

3. If the parameter is a value representing the difference between the maximum brightness and another parameter, the conversion means converts information about the maximum luminance in addition to the parameter values ​​into values ​​corresponding to the HLG image; the processing means performs the processing on the HLG image using the parameters after the conversion and information about the maximum luminance after the conversion.

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

4. 4. The image processing device according to claim 3, wherein the processing means performs the processing on the HLG image using a value obtained by subtracting the parameter after the conversion from information about the maximum luminance after the conversion as a threshold value.

5. The image processing device according to claim 1 , wherein the parameters are associated with the HLG image.

6. 2. The image processing apparatus according to claim 1, wherein said conversion means performs said conversion by referring to a lookup table stored in advance.

7. 7. The image processing device according to claim 6, wherein the lookup table has the converted values ​​of the parameters for each shooting mode that was set when the PQ image was shot.

8. An image processing device having a conversion means for converting a PQ image, which is an HDR signal of a Perceptual Quantization (PQ) method, into an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) method, The image processing device is characterized in that the conversion means converts parameters determined based on information relating to the maximum luminance of the PQ image to correspond to the HLG image and associates the parameters with the HLG image.

9. 9. The image processing device according to claim 8, wherein the parameter is a threshold value related to brightness.

10. 9. The image processing device according to claim 8, wherein, when the parameter is a value representing a difference between the maximum brightness and another parameter, the conversion means converts information about the maximum brightness, in addition to the value of the parameter, into a value corresponding to the HLG image and associates the information with the HLG image.

11. An image processing method executed by an image processing device to perform processing on an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) method converted from a PQ image, which is an HDR signal of a Perceptual Quantization (PQ) method, based on parameters determined using information related to the maximum luminance of the PQ image as a reference, converting the values ​​of the parameters into values ​​corresponding to the HLG image; performing the processing on the HLG image using the transformed parameters; An image processing method comprising:

12. An image processing method executed by an image processing device for converting a PQ image, which is an HDR signal of a Perceptual Quantization (PQ) method, into an HLG image, which is an HDR signal of a Hybrid Log Gamma (HLG) method, converting parameters determined based on information about the maximum luminance of the PQ image to correspond to the HLG image; Associating the transformed parameters with the HLG image; An image processing method comprising:

13. A program for causing a computer to function as each of the means included in the image processing device according to any one of claims 1 to 10.

Images