Information processing device, information processing method, and program

Abstract

To provide an information processing device for suppressing a difference in the appearance to a user between an image displayed on a display on the basis of image data and an image on printed matter based on the image data.SOLUTION: An information processing device acquires display luminance information including the maximum luminance value and the minimum luminance value of a display device, and print luminance information including the maximum luminance value and the minimum luminance value to be reproduced in printed matter. It converts a first luminance range of input image data into a second luminance range smaller than the first luminance range to cause a printer to perform output on the basis of the input image data displayed on the display device, and generates output image data having the second luminance range. A luminance value of a dark area of the input image data is converted into a luminance value of the dark area of the output image data such that the minimum luminance value of the display luminance information is larger than the minimum luminance value of the print luminance information and that in conversion, the contrast of the dark area including the minimum luminance value of the print luminance information comes close to the contrast of the dark area including the minimum luminance value of the display luminance information.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an information processing device, an information processing method, and a program for converting a dynamic range of luminance. [Background technology]

[0002] In recent years, improvements in the performance of imaging devices have made it possible to acquire high dynamic range (HDR) image data (HDR image data) as imaging data for videos, still images, and the like. Non-Patent Document 1 specifies two methods for the video transfer function of HDR image data. The maximum displayable brightness of displays that display HDR images based on HDR image data has also improved, making it possible to simultaneously display images from extremely bright highlights to shadows with high image quality.

[0003] In contrast, the luminance range expressed in conventional sRGB and AdobeRGB is a luminance unit defined by the International System of Units, which is approximately 80 to 120 nits. Content expressed in this conventional luminance range is called SDR (Standard Dynamic Range). SDR content can be viewed by displaying it on an SDR display that supports sRGB or AdobeRGB. It is also possible to display SDR content in the SDR luminance range on an HDR display.

[0004] Patent Document 1 describes image processing that corrects the decrease in contrast that occurs when a dynamic range is converted using a single tone curve. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-86976 [Non-patent literature]

[0006] [Non-Patent Document 1] Recommendation ITU-R BT.2100-2(07 / 2018)Image parameter values ​​for high dynamic range television for use in production and international program exchange Summary of the Invention [Problem to be solved by the invention]

[0007] When displaying an image based on HDR data on a display, depending on the minimum luminance of the display, for example, the image displayed on the display and the image on a printed material based on the HDR data may appear different to the user.

[0008] The present invention aims to provide an information processing device, an information processing method, and a program that suppress the difference in appearance to the user between an image displayed on a display based on image data and an image on a printed material based on that image data. [Means for solving the problem]

[0009] In order to solve the above problem, an information processing device according to the present invention comprises a first acquisition means for acquiring input image data, a second acquisition means for acquiring display luminance information including a maximum luminance value and a minimum luminance value for display on a display device, and print luminance information including a maximum luminance value and a minimum luminance value to be reproduced in a printed matter output by a printing device, and a conversion means for generating output image data having the second luminance range by converting a first luminance range for display by the display device, which is included in the input image data, into a second luminance range for printing by the printing device, which is smaller than the first luminance range, wherein the minimum luminance value of the display luminance information is greater than the minimum luminance value of the print luminance information, and the conversion means: The luminance values ​​of the input image data and the luminance values ​​of the output image data are associated with each other, and the luminance values ​​of the input image data are converted into the luminance values ​​of the output image data using a conversion curve generated with a point darker than a reference point where the input luminance and the output luminance match as an inflection point. It is characterized by: [Effects of the Invention]

[0010] According to the present invention, it is possible to reduce the difference in appearance to the user between an image displayed on a display based on image data and an image on a printed material based on that image data. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating a system configuration. [Figure 2] FIG. 2 is a diagram showing the display luminance characteristics of a display. [Figure 3] FIG. 2 is a diagram illustrating a configuration of an image processing unit. [Figure 4] 10 is a flowchart showing the process up to recording by the recording device. [Figure 5] FIG. 10 is a diagram for explaining the creation of a dynamic range conversion table. [Figure 6] 10 is a flowchart illustrating a dynamic range conversion process. [Figure 7] FIG. 10 is a diagram for explaining the creation of a dynamic range conversion table. [Figure 8] FIG. 10 is a diagram showing the display luminance characteristics of a display when bright light is applied. [Figure 9] FIG. 10 is a diagram showing a user interface screen for acquiring display luminance information. [Figure 10] FIG. 10 is a diagram illustrating a dynamic range conversion of luminance. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features 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.

[0013] [First embodiment] FIG. 1 is a diagram showing an example of the configuration of a system in this embodiment. This system is configured to include, for example, an image processing device 101, an HDR display (display device) 108, and a recording device 110. Note that this configuration is just an example, and devices other than those shown in FIG. 1 may be included. Also, for example, the multiple devices in FIG. 1 may be integrated into a single device, such as by incorporating the image processing device 101 into the recording device 110. Also, additional blocks may be included in the blocks included in each device in FIG. 1. Also, each block included in each device may be divided into multiple blocks, or a single block including multiple blocks may be used.

[0014] For example, a host PC or the like serving as an information processing device is used as the image processing device 101. The image processing device 101 includes a CPU 102, a RAM 103, a HDD 104, a display interface (I / F) 105, an input I / F 106, a data transfer I / F 107, and an image processing unit 111. Each unit is connected to each other via an internal bus so as to be able to communicate with each other.

[0015] The CPU 102 executes various processes, such as processes related to the operation of this embodiment, using the RAM 103 as a work area in accordance with programs stored in the HDD 104. The CPU 102 is an example of a processor, and other types of processors may be used. For example, other types of processors, such as a GPU (Graphics Processing Unit) or a DSP (Digital Signal Processor), may be used in addition or instead. Furthermore, some or all of the processes executed by the CPU 102 may be executed by hardware capable of executing those processes, such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The RAM 103 is a volatile storage area and is used, for example, as a work memory. The HDD 104 is a non-volatile storage area and stores the programs and data related to this embodiment, the OS (Operating System), and the like.

[0016] The display I / F 105 is an interface for transmitting and receiving data to and from the HDR display 108. The display I / F 105 can be connected via, for example, HDMI (registered trademark: High-Definition Multimedia Interface) or DisplayPort. The HDR display 108 is capable of displaying high dynamic range (HDR) image data (HDR image data), and can simultaneously display a wide range from the highlight side to the shadow side of an image in high image quality.

[0017] For example, the International Telecommunication Union-R (ITU-R) Recommendation BT.2100 specifies two transfer functions for HDR image data. These transfer functions are Hybrid Log Gamma (HLG) and Perceptual Quantization (PQ). The transfer function and bit rate are defined so that discontinuities in gradation are not visually detectable during image transmission. Video formats are specified by three transfer functions. One is the image capture side transfer function, the Opto-Electronic Transfer Function (OETF). Another is the display side transfer function, the Electro-Optical Transfer Function (EOTF). And the third is the Opto-Optical Transfer Function (OOTF), which represents the overall characteristics of the transition from scene light to display light. The OOTF is a transfer function that corrects for differences in appearance due to differences between the image capture environment and the display environment. The HLG method defines the OETF on the image capture side, treating the range from black to white as a relative gradation. The EOTF on the display side is composed of the inverse function of the OETF and the OOTF, which represents the overall characteristics of the display light from the scene light. In the HLG method, the system gamma, which determines the characteristics of the OOTF, is applied only to the luminance component. The system gamma is determined according to the luminance of the display, taking into account differences in appearance on displays with different maximum displayable luminance values. The PQ method defines the EOTF on the display side, expressing the luminance on the display side as an absolute value up to 10,000 cd / m2 (hereinafter referred to as nit). The OETF on the image capture side is composed of the OOTF and the inverse function of the EOTF.

[0018] When displaying HDR image data on an SDR display or recording it on a recording device, dynamic range conversion must be performed using a tone curve or other method to match the dynamic range of brightness that each device can reproduce. For example, as shown in Figure 10, dynamic range conversion is performed using a tone curve that reduces the contrast in high-brightness areas.

[0019] The input I / F 106 is an interface for inputting information from a device that accepts user operations, such as a keyboard, pointing device, or touch panel (not shown). The above devices may be external to the image processing apparatus 101 or may be included in the image processing apparatus 101. The data transfer I / F 107 is an interface for transmitting and receiving data to and from the recording device 110. The data transfer I / F 107 may be connected via, for example, a universal serial bus (USB) or IEEE 1394. For example, the CPU 102 generates print data that can be processed by the recording device 110 from image data in accordance with instructions (such as commands) from a user using the operation unit 109 or a program stored in the HDD 104, and transfers the print data to the recording device 110. The recording device 110 may use, for example, an inkjet printing method. In this embodiment, the printing method is not limited to this; for example, an electrophotographic printing device may be used. Furthermore, the media of each interface in FIG. 1 may be either wired or wireless.

[0020] Fig. 2 is a diagram showing the display luminance characteristics of a display. The following explanation will be given using an LCD display with a contrast ratio of 1300:1 as an example. In Fig. 2, luminance characteristics 201 show the display luminance characteristics of the display. Luminance characteristics 202 show the reproduced luminance characteristics of a printed matter. The horizontal axis shows the luminance value of the input image data, and the vertical axis shows the output luminance value.

[0021] If a monitor displays at a maximum brightness of 1,000 nits, the contrast ratio is 1,300:1, meaning the minimum brightness is 0.77 nits. On the other hand, when printing on glossy paper with an inkjet printer used for photo printing, there is a printer-paper combination that produces a black density of 2.6. A density of 2.6 converts to a reflectance of 0.25%. Illuminating this black with 100 nits of light, the brightness used to view typical prints, results in a reflectance of 0.25 nits. In this environment, the black displayed on the monitor is brighter than the black on the print, so the user will see a lower contrast in dark areas on the monitor. In other words, the user will see a difference between the image displayed on the monitor and the print.

[0022] In this embodiment, when output image data is generated by converting the brightness range of input image data displayed on a display, and when a printout is output based on the output image data, the minimum brightness value of the output image data is set based on the minimum brightness value of the input image data. With this configuration, it is possible to reduce the difference in appearance to the user between the image displayed on the display and the printout.

[0023] FIG. 3 is a diagram showing the configuration of the image processing unit 111. In the image processing unit 111, HDR image data, display luminance information of a display that performs display based on the HDR image data, and print luminance information are input to the dynamic range conversion unit 112. The display luminance information and print luminance information will be described later. The dynamic range conversion unit 112 uses the input information to convert the data into image data with a luminance dynamic range (hereinafter simply referred to as dynamic range) that can be input to the output image generation unit 113. The dynamic range of the image data input to the output image generation unit 113 is narrower than the dynamic range of the input HDR image data. The dynamic range that can be input to the output image generation unit 113 is, for example, a dynamic range with a maximum luminance value of 100 cd / m2 in SDR data, such as that input to a general printer. Alternatively, it may be the dynamic range when lighting is applied to the printed matter. In this embodiment, the dynamic range conversion unit 112 generates image data converted from a dynamic range of 1,000 nit to a dynamic range of 100 nit. The output image generation unit 113 generates data that can be printed by the print head of an inkjet printer from the image data output from the dynamic range conversion unit 112. The image data output from the dynamic range conversion unit 112 is, for example, RGB image data expressed in a red, green, and blue color space.

[0024] 4 is a flowchart showing a dynamic range conversion process for recording HDR image data to be displayed on a display in recording device 110. The process in FIG. 4 is realized, for example, by CPU 102 reading and executing a program stored in HDD 104.

[0025] In S101, the image processing unit 111 acquires HDR image data to be displayed on the HDR display 108 as input image data. In S101, the HDR image data may be acquired from the HDD 104, or may be acquired from an external device via the data transfer I / F 107. In this embodiment, RGB image data with a maximum luminance value of the dynamic range of 1,000 nit will be described as an example of HDR image data.

[0026] In S102, the image processing unit 111 acquires display luminance information of the HDR display 108 that is currently displaying the image. The display luminance information includes, for example, the maximum luminance value, minimum luminance value, and contrast ratio of the HDR display 108. This display luminance information is acquired from the HDR display 108 via the display I / F 105. Alternatively, the display luminance information may be stored in advance in the HDD 104 and acquired from the HDD 104. In this embodiment, the display luminance information is acquired from the HDR display 108, and the display luminance information has, for example, a maximum luminance value of 1,000 nits and a minimum luminance value of 0.77 nits. The minimum luminance value may be calculated from the maximum luminance value and the contrast ratio. For example, when the contrast ratio is 1300:1, the minimum luminance can be calculated using equation (1).

[0027] Minimum luminance value = Maximum luminance value × (1 / 1300) (1) In S103, the image processing unit 111 acquires the maximum luminance value and minimum luminance value that can be reproduced by the recording device 110 as print luminance information to be recorded by the recording device 110. The print luminance information is acquired from the recording device 110 via the data transfer I / F 107. Alternatively, the print luminance information may be stored in advance in the HDD 104 and acquired from the HDD 104. The print luminance information may be L*, which represents lightness, in addition to luminance, or may be saved as an ICC profile. In other words, any format that can be converted into luminance information is sufficient. In this embodiment, the print luminance information has, for example, a maximum luminance value of 100 nit and a minimum luminance value of 0.25 nit.

[0028] In S104, the image processing unit 111 generates a dynamic range conversion table for luminance. The dynamic range conversion table is a table in the form of a look-up table (LUT) that is used when performing dynamic range conversion on the luminance component in S105.

[0029] The method for creating the dynamic range conversion table in S104 will be described with reference to Fig. 5. The horizontal axis of Fig. 5 represents the luminance of the input image, and the vertical axis represents the luminance of the output image. Dotted line 501 represents the line where the input luminance and the output luminance match. Solid line 502 represents the correspondence relationship between the input luminance and the output luminance when performing dynamic range conversion.

[0030] Dimax is the maximum brightness value of the input image, and is set to, for example, 1,000 nit. Domax is the maximum brightness value of the output image, and is set to, for example, 100 nit, which is the maximum brightness value of the print brightness information acquired in S103. 18 nit, for example, is set as the reference points Dia and Dio where the input brightness and output brightness match. Dia and Dio are set based on a predetermined reference reflectance. When photographing, the exposure is set to 18% reflectance gray, so 18% reflectance is the reference brightness. If the brightness corresponding to 100% reflectance is 100 nit, then 18% reflectance is 18 nit.

[0031] Domin is the minimum luminance value of the output image. In this embodiment, for example, the minimum luminance value of the display luminance information acquired in S102 is 0.77 nit, and the minimum luminance value of the print luminance information of the recording device 110 acquired in S103 is 0.25 nit. In this case, because the black displayed on the HDR display 108 is brighter than the black reproduced by the recording device 110, 0.77 nit is set as Domin so that the black on the printed matter matches the display on the display. Here, if the minimum luminance value of the display luminance information is smaller than the minimum luminance value of the print luminance information of the recording device 110, 0 nit is set as Domin.

[0032] The image processing unit 111 generates a dynamic range conversion curve by performing spline interpolation between Domin, the intersection of Dia and Doa, and the intersection of Dimax and Domax to form a smooth curve. The curve generated by spline interpolation is converted into a one-dimensional LUT format. Although spline interpolation is used in this embodiment, other configurations, such as histogram smoothing processing that smooths the histogram of an image, may also be used.

[0033] In S105, the image processing unit 111 uses the dynamic range conversion table generated in S104 to perform dynamic range conversion of luminance from the input image data acquired in S101 to generate output image data to be recorded by the recording device 110. The dynamic range conversion in S105 will be described with reference to the flowchart in FIG.

[0034] In S201 of Fig. 6, the image processing unit 111 separates the input image data into a luminance component and a color difference component. For example, if the input image data is in the RGB color space, the image processing unit 111 converts it to the YCbCr color space using equations (2) to (4). Here, Y is the luminance component and CbCr are the color difference components. Furthermore, the color space to which the image data is converted is not limited to the YCbCr color space, and it may also be converted to, for example, the ICtCp color space.

[0035] Y=0.299×R+0.587×G+0.114×B (2) Cb=-0.169×R-0.331×G+0.5×B (3) Cr=0.5×R-0.419×G-0.081×B (4) In S202, the image processing unit 111 performs frequency separation processing to separate the luminance components generated in S201 into low-frequency components and high-frequency components. This is because processing is switched between low-frequency components and high-frequency components based on the Retinex theory. The Retinex theory is a model of how the human brain perceives color and light. This theory states that the intensity of light entering the eye is expressed as the product of the reflectance of an object and the illuminating light illuminating the object, and that the brightness and color perceived by humans depend more heavily on the amount of relative variation from the surroundings than on absolute optical quantities. The absolute optical quantity is the illuminating light illuminating the object, and the relative variation is the reflectance of the object.

[0036] In S202, low-frequency components of the image are separated and extracted as illumination light components illuminating the object. A low-pass filter is applied to separate the low-frequency components. The processing method may involve applying a spatial filter, or converting the data into spatial frequencies using an FFT (Fast Fourier Transform) and then filtering and then converting them back using an IFFT (Inverse Fast Fourier Transform). The target frequencies may be determined taking into account the paper size and viewing distance of the printed material and human visual characteristics. High-frequency components may be extracted using a high-pass filter, or they may be obtained by dividing the obtained low-frequency components by the original image.

[0037] In S203, the image processing unit 111 performs dynamic range conversion processing on the low frequency components separated in S202. The image processing unit 111 converts the luminance components using the dynamic range conversion table generated in S104.

[0038] In S204, the image processing unit 111 performs contrast correction processing on the high frequency components. The contrast correction processing is processing in which the value of the high frequency components is multiplied by a coefficient k. To closely approximate the input data, k is set to about 1. To further take into consideration degradation such as ink bleeding on printed materials, k is set to a value greater than or equal to 1.

[0039] In S205, the image processing unit 111 recombines the data that has undergone dynamic range conversion in S203 and the data that has undergone contrast correction processing in S204. In S206, the image processing unit 111 combines the luminance component and the color difference component, and converts the result into RGB color space using equations (5) to (7).

[0040] R=Y+1.402×Cr (5) G=Y-0.344×Cb-0.714×Cr...(6) B=Y+1.772×Cb (7) After S206, the processing in Fig. 6 ends, and the process proceeds to S106 in Fig. 4. In S106, the output image generation unit 113 converts the image data that has undergone dynamic range conversion in S105 into data that can be processed by the recording device 110, for example, recording data that corresponds to the ejection of ink from the recording head, and outputs the converted data.

[0041] As described above, in this embodiment, as shown in Fig. 5, the minimum luminance value of the display luminance information is set as the minimum luminance value of the output image. With this configuration, dynamic range conversion is performed so that the contrast of dark areas of the printed material approaches the contrast of dark areas of the display. As a result, it is possible to control so as to reduce the difference between how the image appears on the display and how it appears on the printed material recorded by the recording device.

[0042] [Second embodiment] The second embodiment will be described below, focusing on the differences from the first embodiment. The method for generating the dynamic range conversion table in S104 of FIG. 4 in this embodiment will be described with reference to FIG. 7. The solid line 703 in FIG. 7 represents the correspondence between input luminance and output luminance when performing dynamic range conversion. Dis is a point in the shadow part of the input luminance, and Dos is the corresponding output luminance. In the first embodiment, the minimum luminance value of the output image was set based on the display luminance information and the print luminance information. In this embodiment, the luminance conversion line for the shadow part is set based on the display luminance information and the print luminance information.

[0043] 7, Dis is set to a luminance that is smaller than Dia and brighter than the minimum luminance value. In this embodiment, for example, Dis=9, which is half the value of Dia=18, is set. Then, Dos corresponding to Dis is set using equation (8), where m is a coefficient.

[0044] Dos = Dis + m × (minimum luminance value of display luminance - minimum luminance value of recording device) (8) Assume that the minimum luminance value of the display luminance information acquired in S102 is 0.77 nit, and the minimum luminance value of the printing luminance information of the recording device 110 acquired in S103 is 0.25 nit. In this case, if m=4, Dos=9+4×(0.77−0.25)=11.08 is calculated from equation (8). Here, if the minimum luminance value of the display luminance information is smaller than the minimum luminance value of the printing luminance information of the recording device 110, Dos will be a negative value, in which case Dos=Dis. Dimax, Domax, Dia, and Doa are the same as those described in the first embodiment.

[0045] The image processing unit 111 performs spline interpolation so as to generate a smooth curve passing through the control points determined as described above and the origin. The curve generated by spline interpolation is a curve in which Dos is an inflection point as shown in FIG. 7, and is converted into a one-dimensional LUT format. While spline interpolation is used in this embodiment, other configurations, such as histogram smoothing processing that smooths the histogram of an image, may also be used.

[0046] As described above, according to this embodiment, the shadow areas of the dynamic range conversion table are controlled to become brighter as the minimum luminance value of the display luminance information becomes brighter than the minimum luminance value of the print luminance information of the recording device. By controlling the shadow areas to become brighter through the dynamic range conversion process, the difference in contrast between dark areas displayed on the display and on the printed matter is reduced. As a result, it is possible to control the image so that the difference between how it appears on the display and how it appears on the printed matter recorded by the recording device is reduced.

[0047] The following describes a case where a printout output from the recording device 110 is observed under illumination brighter than that of the printout's reproduction luminance characteristics shown in FIG. 2. FIG. 8 shows the display luminance characteristics of the display and the reproduction luminance characteristics of the printout. The display luminance characteristics 801 are the same as the display luminance characteristics 201 of the display in FIG. 2. The luminance characteristics 802 are the reproduction luminance characteristics when illumination is applied to the printout. However, this assumes a case where illumination brighter than that shown in FIG. 2 is applied to the printout. The black on the printout, which is 0.25 nit when illuminated with 100 nit of light, proportionally becomes 0.5 nit when illuminated with 200 nit of light. In other words, the luminance characteristics 802 show the luminance characteristics when illuminated with 200 nit of light.

[0048] In this case, a luminance dynamic range conversion table is created in the same way as in the first and second embodiments. The processing of S103 in Fig. 4 in this case will be described below. Note that S101 and S102 are the same as those in the first and second embodiments, and therefore their description will be omitted.

[0049] In S103, the image processing unit 111 acquires, as print brightness information, the maximum and minimum brightness values ​​reproduced by the recording device 110 when illuminated with illumination brighter than the reference, for example, 200 nits of light. The maximum and minimum brightness values ​​when illuminated with illumination brighter than the reference can be calculated from the brightness value when illuminated with illumination of the reference brightness and the illumination conditions. In other words, since brightness values ​​are proportional to the brightness of the illumination, the maximum and minimum brightness values ​​when illuminated with illumination brighter than the reference can be calculated by multiplying the maximum and minimum brightness values ​​when illuminated with the reference illumination by the ratio of the illumination conditions. S104 to S106 after S103 are processed in the same manner as described in the first and second embodiments.

[0050] In this way, it is possible to calculate print luminance information corresponding to any lighting condition based on print luminance information corresponding to a reference lighting condition, and create a luminance dynamic range conversion table.

[0051] In each of the above embodiments, in S102, the image processing unit 111 may acquire display luminance information of the HDR display 108 via a user interface screen. FIG. 9 shows a screen 901 for acquiring display luminance information. A text box 902 is an input area for inputting a minimum luminance value of the HDR display 108, and a text box 903 is an input area for inputting a maximum luminance value of the HDR display 108. The user operates the operation unit 109 to input luminance values ​​into the text boxes 902 and 903. The image processing unit 111 acquires the values ​​input into the text boxes 902 and 903 and sets them as the minimum and maximum luminance values ​​of the display luminance information.

[0052] 9, allowing the user to input a brightness value allows the user to manipulate the contrast of dark areas of a printout output from recording device 110. In other words, even if there are individual differences in the appearance of an image displayed on a desired display and the appearance on a printout output from recording device 110, appropriate control can be performed to reduce the difference in appearance.

[0053] 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.

[0054] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0055] 101 Image processing unit: 102 CPU: 103 RAM: 104 HDD: 108 HDR display: 110 Recording device

Claims

1. a first acquisition means for acquiring input image data; a second acquiring means for acquiring display luminance information including a maximum luminance value and a minimum luminance value in a display on the display device, and print luminance information including a maximum luminance value and a minimum luminance value reproduced in a printed matter output by the printing device; a conversion means for converting a first luminance range of the input image data for display by the display device into a second luminance range that is smaller than the first luminance range and is for printing by the printing device, thereby generating output image data having the second luminance range; Equipped with the minimum luminance value of the display luminance information is greater than the minimum luminance value of the print luminance information, the conversion means converts the luminance values ​​of the input image data into the luminance values ​​of the output image data using a conversion curve that is generated by associating the luminance values ​​of the input image data with the luminance values ​​of the output image data and that has an inflection point that is darker than a reference point where the input luminance and the output luminance match.

1. An information processing device comprising:

2. 2. The information processing device according to claim 1, wherein in the conversion curve, the correspondence relationship of luminance values ​​between a dark area darker than the reference point in the first luminance range and a dark area darker than the reference point in the second luminance range is convex toward the second luminance range.

3. 3. The information processing apparatus according to claim 2, wherein the conversion curve is set based on a luminance value darker than the reference point in the first luminance range.

4. An information processing device as described in Claim 3, characterized in that the inflection point of the conversion curve is set based on a brightness value darker than the reference point, the minimum brightness value of the display brightness information, and the minimum brightness value of the printing brightness information.

5. 5. The information processing device according to claim 4, wherein the conversion curve is set so that the inflection point is the intersection of a luminance value darker than the reference point and a luminance value obtained by adding the difference between the minimum luminance value of the display luminance information and the minimum luminance value of the print luminance information to the luminance value darker than the reference point.

6. 6. The information processing apparatus according to claim 1, wherein the reference point is set based on a predetermined reflectance.

7. 7. The information processing apparatus according to claim 1, wherein the conversion means is stored in the information processing apparatus as a lookup table.

8. 8. The information processing apparatus according to claim 1, wherein the second acquisition means acquires the display luminance information via a user interface screen.

9. 9. The information processing apparatus according to claim 1, wherein the second acquisition means acquires the print luminance information based on a reference lighting condition.

10. 10. The information processing apparatus according to claim 1, further comprising a control unit that causes the printing device to output the output image data generated by the conversion unit.

11. 11. The information processing apparatus according to claim 1, wherein the input image data is HDR (High Dynamic Range) image data.

12. An information processing method executed in an information processing device, a first acquisition step of acquiring input image data; a second acquisition step of acquiring display luminance information including a maximum luminance value and a minimum luminance value in a display on the display device and printing luminance information including a maximum luminance value and a minimum luminance value reproduced in a printed matter output by the printing device; a conversion step of converting a first luminance range of the input image data for display by the display device into a second luminance range for printing by the printing device, the second luminance range being smaller than the first luminance range, thereby generating output image data having the second luminance range; and the minimum luminance value of the display luminance information is greater than the minimum luminance value of the print luminance information, In the conversion step, the luminance values ​​of the input image data are associated with the luminance values ​​of the output image data, and the luminance values ​​of the input image data are converted into the luminance values ​​of the output image data using a conversion curve generated with an inflection point being a point darker than a reference point where the input luminance and the output luminance match.

1. An information processing method comprising:

13. A program for causing a computer to function as each of the means of the information processing apparatus according to any one of claims 1 to 11.

Images