Image processing apparatus, image processing method and program

Abstract

To enable correcting a difference of perception contrast and to enable reducing work of a user.SOLUTION: An image processing apparatus acquires a first observation condition and a second observation condition which is different from the first observation condition in observing an image. And, the image processing apparatus corrects contrast of the image on the basis of visual frequency characteristics in the first observation condition and visual frequency characteristics in the second observation condition.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a technique for correcting an image. [Background technology]

[0002] It is known that when the viewing angle when a person views an object of observation is different, even if the colorimetric contrast is the same, the contrast perceived by the person will differ. For example, when an object of observation, which is an image created on a display screen and printed in a size different from the display size on the screen, is observed at the same distance as when it was created on the screen, the viewing angle of the user to the object of observation will be larger than the viewing angle to the displayed image when it was created on the screen. In this way, when the viewing angle is different when creating on the screen and when observing the object of observation, even if the colorimetric contrast is the same, a difference will occur in the contrast perceived by the person. For this reason, if there is a difference in the perceived contrast between when creating on the screen and when observing the object of observation, the user must create on the screen taking into consideration the perceived contrast at the time of observation. In other words, the user must perform an operation of reproducing and evaluating the contrast perceived in the actual object of observation when creating on the screen.

[0003] To address such problems, Patent Document 1 discloses a technique for correcting the difference in contrast perceived at different viewing angles by applying a correction table corresponding to the viewing angle to the contrast of an image of an object to be observed. Patent Document 1 also discloses a technique for simulating the appearance when printed, etc., by applying a correction technique for the difference in perceived contrast. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-109628 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, even when the technique described in Patent Document 1 is used, the difference in perceived contrast may not be completely corrected, so the user still needs to reproduce and evaluate the perceived contrast at the time of observation.

[0006] Therefore, an object of the present invention is to make it possible to correct the difference in perceived contrast and reduce the work required by the user. [Means for solving the problem]

[0007] The image processing device of the present invention has a first acquisition means for acquiring first viewing conditions when observing an image, a second acquisition means for acquiring second viewing conditions different from the first viewing conditions, and a correction means for correcting the contrast of the image, wherein the correction means corrects the contrast of the image based on the visual frequency characteristics under the first viewing conditions and the visual frequency characteristics under the second viewing conditions. Effect of the Invention

[0008] According to the present invention, the difference in perceived contrast can be corrected, and the work of the user can be reduced. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an example of the configuration of an image processing system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating a relationship between a user and a viewing angle. [Diagram 3] FIG. 1 is a diagram illustrating frequency characteristics of vision. [Figure 4] 1 is a functional block diagram of an image processing device according to a first embodiment. [Diagram 5] FIG. 2 is a diagram illustrating an example of a UI according to the first embodiment. [Figure 6] 4 is a flowchart of a process in the image processing apparatus according to the first embodiment. [Figure 7]13A and 13B are diagrams illustrating another example of an assumed viewing distance input in the UI. [Figure 8] FIG. 11 is a functional block diagram of an image processing device according to a second embodiment. [Figure 9] 10 is a flowchart of a process in an image processing apparatus according to a second embodiment. [Figure 10] FIG. 1 is a diagram illustrating a frequency characteristic of vision that changes depending on luminance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following embodiment does not limit the present invention, and not all of the combinations of features described in the present embodiment are necessarily essential to the solution of the present invention. The configuration of the embodiment may be appropriately modified or changed depending on the specifications of the device to which the present invention is applied and various conditions (such as the conditions of use and the environment in which the device is used). In the following embodiments, the same configurations and functions are given the same reference symbols, and duplicated descriptions will be omitted.

[0011] First Embodiment Fig. 1 is a diagram showing an example of the configuration of an image processing system including an image processing device 10 according to this embodiment. As shown in Fig. 1, the image processing system of this embodiment includes the image processing device 10, a server 11, a distance measuring device 12, a display device 13, an output device 14, and an operation device 15. The server 11 holds multiple pieces of image data and is connected to the image processing device 10 via a communication network or the like. In the following description, for the sake of simplicity, the image data handled in the image processing system of this embodiment will be referred to simply as an image.

[0012] The display device 13 is connected to the image processing device 10 and has a display capable of displaying images, etc. A user interface (hereinafter, referred to as a UI) screen, which will be described later, and the like are also displayed on the display device 13. Details of the UI screen displayed on the display of the display device 13 will be described later.

[0013] The output device 14 is an inkjet printer, a projector, or the like. In this embodiment, the output device 14 is an inkjet printer that prints images created on the screen of the display device 13 and processed by the image processing device 10. In this embodiment, the printed matter on which the image is printed by the output device 14 is the object to be observed by the user. If the output device 14 is, for example, a projector, the object to be observed is the projected image. Alternatively, the output device 14 may be a display device having, for example, a screen size different from that of the display device 13, and in this case, the object to be observed is the image displayed on the display of that display device.

[0014] The operation device 15 is an input device such as a keyboard or mouse connected to the image processing device 10, or a touch panel arranged on the screen of the display device 13, which acquires operation instructions from a user and outputs them to the image processing device 10. Through operations on the operation device 15, the user selects an image to be used for creating an observation target from among multiple images held by the server 11, and operates a UI screen to be described later.

[0015] The distance measuring device 12 obtains a visual distance, which is a distance from the screen to the user, as one of the observation conditions when the user is viewing the screen of the display device 13, and outputs information on the visual distance to the image processing device 10. Note that the positional relationship between the distance measuring device 12 and the display device 13 is known. The distance measuring device 12 has, for example, a stereo camera or a depth camera, and obtains the visual distance by a known distance measurement calculation using the stereo camera or the depth camera. As an example of the stereo camera, a passive stereo camera using parallax obtained by combining two cameras can be given. As an example of the depth camera, an infrared active camera can be given. Also, for example, the distance measuring device 12 may obtain the visual distance based on an image captured by a digital camera. In this case, the distance measuring device 12 detects a person (i.e., a user) from an image captured by the digital camera, and obtains the visual distance from the user to the display device 13 by a known calculation based on the distance between the eyes of the detected person. Note that the distance measuring device 12 may be any device capable of obtaining distance information between the user and the display device 13, and is not limited to the above-mentioned example.

[0016] The image processing device 10 acquires user operation information from the operation device 15, and acquires an image from the server 11 in response to the user operation. The image processing device 10 also acquires viewing distance information from the distance measuring device 12, that is, information on the user's viewing distance from the display device 13 when the user is viewing the screen of the display device 13. The image processing device 10 also transmits control instructions and data required for display, etc. to the display device 13, and transmits control instructions and data required for printing, etc. to the output device 14. The image processing device 10 of this embodiment also performs a process of correcting contrast differences in human perception, and a process of displaying the contrast-corrected image as a simulated image. The process of correcting contrast differences in perception and the simulated image will be described in detail later.

[0017] The image processing device 10 includes a control unit 101, a storage unit 102, a UI processing unit 103, a working memory 104, and the like. The storage unit 102 stores and manages an operating system (OS), processing programs according to this embodiment, various application programs, and parameter data required for various processes. This storage unit 102 is configured with a storage medium such as a hard disk or a flash ROM. The control unit 101 is configured with a CPU (Central Processing Unit) and the like, and executes and generally controls the processing in the image processing device 10 of this embodiment by expanding the programs stored in the storage unit 102 into the working memory 104 and executing them. The UI processing unit 103 is a functional unit that performs processing related to a UI screen, which will be described later.

[0018] The operation of the image processing system according to this embodiment will be described below, assuming that an image or the like created by a user while viewing the display on the display screen of the display device 13 is printed by the output device 14 and the user observes the printed object as an observation object. In this embodiment, the viewing angle of the user when creating an image or the like on the screen of the display device 13 is different from the viewing angle when the user observes the observation object printed by the output device 14 from the image or the like created on the screen.

[0019] Here, as an example of a case where the viewing angle at the time of creation on the screen is different from the viewing angle at the time of observation of the observation object, a case where an observation object in which an image or the like is printed at a size different from the display size at the time of creation on the screen is observed at the same viewing distance as when it was created on the screen is assumed. In this case, the viewing angle of the user with respect to the observation object is different from the viewing angle of the user with respect to the display image at the time of creation on the screen. For example, when an observation object printed larger than the display size (size) at the time of creation on the screen is observed at the same viewing distance as when it was created on the screen, the viewing angle with respect to the observation object is larger than the viewing angle with respect to the screen. Conversely, when an observation object printed smaller than the display size at the time of creation on the screen is observed at the same viewing distance as when it was created on the screen, the viewing angle with respect to the observation object is smaller than when it was created on the screen. In this way, when the viewing angle at the time of creation on the screen is different from the viewing angle with respect to the observation object, even if the colorimetric contrast is the same, a difference may occur in the contrast perceived by a person.

[0020] FIG. 2 is a diagram used to explain the viewing angle of a user. The viewing angle 201 is an angle determined based on the size 204 and visual distance 205 of an object 203 when a user 202 is viewing the object 203. When the user 202 is creating an image or the like on a screen, the object 203 in FIG. 2 is the image or the like displayed on the screen. On the other hand, when the user 202 is viewing a printed object to be observed, the object 203 in FIG. 2 is the object to be observed. Then, assuming that the viewing angle 201 of the user 202 with respect to the object 203 is θ, the size 204 of the object 203 is s, and the visual distance 205 of the user 202 to the object 203 is d, the viewing angle θ can be calculated by the following formula (1).

[0021] θ=2arctan(s / 2d) Equation (1)

[0022] For example, when an object to be observed is printed larger than when it was created on a screen, and observed at the same viewing distance as when it was created on the screen, the user's viewing angle for the object to be observed becomes larger than the viewing angle for the displayed image when it was created on the screen, resulting in a difference in perceived contrast. According to the technology described in Patent Document 1 mentioned above, it is possible to correct the difference in contrast perceived at different viewing angles, and by applying the technology described in Patent Document 1 to an image processing device, it is possible to correct the difference in perceived contrast due to the difference in viewing angle. However, the difference in contrast perceived by humans is also caused by the difference in the frequency characteristics of human vision. In the technology of Patent Document 1 described above, a correction process is performed according to the colorimetric contrast, but a correction process according to the frequency of the target area is not performed.

[0023] FIG. 3 is a diagram used to explain that differences in perceived contrast occur depending on the frequency characteristics of human vision. FIG. 3 is a diagram showing the frequency characteristics of human vision, with the horizontal axis representing frequency and the vertical axis representing contrast sensitivity. The frequency characteristics of human vision are sensitivity characteristics that indicate contrast that humans can visually recognize at a certain frequency, and it is known that the peak frequency of contrast sensitivity changes when the viewing distance differs. In FIG. 3, a solid line 301 indicates the visual characteristics at a viewing distance d1, and a dashed line 302 indicates the visual characteristics at a viewing distance d2 that is different from the viewing distance d1. Comparing the perceived contrast at these two viewing distances d1 and d2, in the low frequency region 303, (sensitivity of solid line 301)>(sensitivity of dashed line 302). Therefore, the contrast observed at the viewing distance d1 is perceived stronger than the contrast observed at the viewing distance d2. On the other hand, in the high frequency region 304, (sensitivity of solid line 301)<(sensitivity of dashed line 302), so the contrast when observed at a viewing distance d2 is perceived as stronger than the contrast when observed at a viewing distance d1. Furthermore, for example, when an image is enlarged or reduced (hereinafter referred to as enlargement or reduction), the frequency components of the image change before and after the enlargement or reduction. For example, when an image is enlarged, the frequency components of the image change to the lower frequency side, and conversely, when an image is reduced, the frequency components of the image change to the higher frequency side, so that the perceived contrast also changes. For these reasons, even if the correction process described in Patent Document 1 is applied without considering the frequency components of the target region, there is a problem that the difference in perceived contrast based on the difference in the frequency characteristics of vision cannot be completely corrected.

[0024] Therefore, in this embodiment, when the viewing angle at the time of creation on the screen is different from the viewing angle at the time of observing the printed observation object, etc., it is also possible to correct the difference in perceived contrast caused by the difference in the frequency characteristics of vision. In the following embodiment, an example will be described in which the difference in perceived contrast caused by the difference in the frequency characteristics of vision when the observation object is observed at a viewing angle different from that at the time of creation on the screen is simulated and displayed at the time of creation on the screen.

[0025] The image processing device of this embodiment acquires, as a first observation condition when observing an image, a first image size, which is the size of an image to be printed on an object to be observed, and a first viewing distance, which is the viewing distance when the object to be observed is observed. Furthermore, the image processing device calculates a first frequency characteristic, which is the frequency characteristic of vision at the time of observation, based on the first viewing distance at the time of observation. Furthermore, the image processing device acquires, as a second observation condition different from the first observation condition, a second image size, which is the size of an image displayed at the time of creation on a screen, and a second viewing distance, which is the viewing distance at the time of creation on the screen. Furthermore, the image processing device calculates a second frequency characteristic, which is the frequency characteristic of vision at the time of creation on the screen, based on the second viewing distance at the time of creation on the screen.

[0026] The image processing device of this embodiment performs a correction process of the perceived contrast according to the frequency components of the image based on the first image size and the second image size and the first frequency characteristic and the second frequency characteristic. That is, the image processing device generates a contrast-corrected image in which the difference in the perceived contrast occurring when the observation object is observed at a viewing angle different from that at which it is created on the screen is corrected. Furthermore, the image processing device displays the contrast-corrected image on the screen as a simulated image that simulates the contrast perceived when the observation object is observed at a viewing angle different from that at which it is created on the screen. As a result, according to this embodiment, when the image is created on the screen at a viewing angle different from that at which the observation object is observed, the user can create an image or the like on the screen while recognizing the difference in perceived contrast that is approximately the same as that at which the observation object is observed. That is, according to this embodiment, the user can evaluate the perceived contrast at the time of observation at the time of creation on the screen without reproducing the perceived contrast at the time of observation of the observation object.

[0027] FIG. 4 is a diagram showing an example of the functional configuration of an image processing device according to this embodiment, which corrects the difference in contrast perceived by a person when observing an object to be observed at a viewing angle different from that at which the object is created on a screen, and enables simulation at the time of creating the object on a screen. The image acquisition unit 401 acquires from the server 11 an image that is used by the user to create an observation target.

[0028] The first size acquisition unit 402 acquires a first image size indicating the size of an image to be printed as an observation target based on information acquired via a UI screen described later. The details of the first image size acquired by the first size acquisition unit 402 will be described later. The first distance acquisition unit 403 acquires a first visual distance, which is a visual distance when the user observes the observation object. The first visual distance acquired by the first distance acquisition unit 403 will be described in detail later. The first characteristic calculation unit 404 calculates a first frequency characteristic, which is a frequency characteristic of vision at a first visual distance. The first frequency characteristic calculated by the first characteristic calculation unit 404 will be described in detail later.

[0029] The second size acquisition unit 405 acquires a second image size indicating the size of the image to be displayed on the screen when it is created. The second image size acquired by the second size acquisition unit 405 will be described in detail later. The second distance acquisition unit 406 acquires a distance measured by the distance measuring device 12 when the image was created on the screen, that is, a second visual distance which is the visual distance of the user from the screen when the image was created. The second visual distance acquired by the second distance acquisition unit 406 will be described in detail later. The second characteristic calculation unit 407 calculates a second frequency characteristic which is a frequency characteristic of vision at a second viewing distance. The second frequency characteristic calculated by the second characteristic calculation unit 407 will be described in detail later.

[0030] The image correction unit 408 corrects the contrast of the image acquired by the image acquisition unit 401. In this embodiment, the image correction unit 408 performs contrast correction processing according to the frequency components of the image based on the first image size, the second image size, and the first frequency characteristic, and the second frequency characteristic to generate a contrast-corrected image. The contrast correction processing by the image correction unit 408 will be described in detail later. Then, the image correction unit 408 outputs the contrast-corrected image to the display control unit 409.

[0031] The display control unit 409 performs display control to display the image acquired from the server 11, the contrast-corrected image after the correction process by the image correction unit 408, etc. on the screen of the display device 13. That is, the display device 13 displays not only the image acquired from the server 11 for creating the observation object, but also the contrast-corrected image in which the difference in perceived contrast caused by the difference in the visual frequency characteristics when creating the observation object on the screen and when observing the observation object is corrected. By looking at the contrast-corrected image displayed on the screen of the display device 13, the user can evaluate the difference in perceived contrast without checking the actual printed observation object.

[0032] Each functional unit shown in Fig. 4 may be formed by executing a processing program according to this embodiment by the CPU of the control unit 101 in Fig. 1, or some or all of the functions of each functional unit may be realized by a dedicated circuit, etc. Also, some of the functions of each functional unit may be realized by using a cloud computer, etc.

[0033] 5 is a diagram showing an example of a UI screen 500 displayed on the display device 13 during on-screen creation. The UI screen 500 is an example of a UI screen assuming a case where an image created on the screen is printed and observed as described above. The UI screen 500 is generated by the UI processing unit 103 of the image processing device 10 shown in FIG. 1, and is displayed on the display screen of the display device 13. Note that the UI screen 500 shown in FIG. 5 is an example, and the UI screen according to this embodiment is not limited to the example of FIG. 5.

[0034] In the UI screen 500 shown in FIG. 5, the image input box 501 is a text box in which the file name of the image to be acquired from the server 11 is input. The reference button 502 is a button operated when referring to an image stored in the server 11 and inputting the file name of the image in the image input box 501. As an example, when the user presses the reference button 502 through the operation of the operation device 15, thumbnail images of each image stored in the server 11 are displayed on a pop-up screen (not shown) or the like. Then, when the user selects a desired thumbnail image from among them, the file name of the image corresponding to the selected thumbnail image is input in the image input box 501. The image acquisition unit 401 in FIG. 4 acquires an image corresponding to the image file name in the image input box 501 from the server 11.

[0035] Print paper size box 505 is a box in which print paper sizes are displayed as a drop-down list, and is provided with drop-down list button 515. When drop-down list button 515 is operated by the user, a drop-down list is displayed in print paper size box 505. The user can select the paper size to be used for printing from this drop-down list. When the user selects a paper size from the drop-down list by operating operation device 15, first size acquisition unit 402 in FIG. 4 acquires the size of the image when printed on print paper of the selected paper size as the above-mentioned first image size.

[0036] The assumed viewing distance box 506 is a text box into which a viewing distance assumed when the user observes an observation object is input. When the user inputs a viewing distance into the assumed viewing distance box 506 through the operation of the operation device 15, the first distance acquisition unit 403 in Fig. 4 acquires the input viewing distance as the above-mentioned first viewing distance. The paper size (first image size) selected through the print paper size box 505 and the expected viewing distance (first viewing distance) for the object to be observed input through the expected viewing distance box 506 are obtained as the first viewing conditions when the user observes the object to be observed.

[0037] The input image display area 503 is an area in which an image acquired from the server 11 according to the image file name input in the image input box 501 is displayed as an input image 509. The input image 509 displayed in the input image display area 503 is an image to be created on the display screen. Note that two subjects, a first subject 511 and a second subject 512, are shown in the input image 509 illustrated in Fig. 5, but this is just one example.

[0038] The simulated image display area 504 is an area for displaying a simulated image 510 which shows how the input image 509 in the input image display area 503 looks to the user when the user observes an observation object printed by the output device 14. A first subject 511 and a second subject 512 in the simulated image display area 504 are the same subjects as the corresponding first subject 511 and second subject 512 in the input image display area 503, respectively.

[0039] The simulate button 507 is a button with which the user instructs starting the contrast correction process in this embodiment and displaying the contrast-corrected image after the contrast correction process in the simulated image display area 504. When the user presses the simulate button 507 through the operation of the operation device 15, the image correction unit 408 executes the contrast correction process on the input image 509 and generates a contrast-corrected image. Then, the display control unit 409 in FIG. 4 displays the contrast-corrected image in the simulated image display area 504 as a simulated image.

[0040] Here, the first subject 511 and the second subject 512 are subjects having different frequency components, and have frequency characteristics that cause a difference in the perceived contrast between when the subject is created on the screen and when the printed object is observed. For example, the first subject 511 has frequency characteristics that cause the contrast to be perceived as attenuated on the object, while the second subject 512 has frequency characteristics that cause the contrast to be perceived as enhanced on the object. Therefore, the first subject 511 and the second subject 512 in the simulated image displayed in the simulated image display area 504 are displayed with a different contrast from the first subject 511 and the second subject 512 in the input image display area 503, as shown in FIG. 5. This allows the user to evaluate the perceived contrast of the first subject 511 and the second subject 512 when observing the object on the screen at the time of creation.

[0041] The end button 508 is an operation button used by the user to instruct the end of the simulation by the contrast correction process. When the user presses the end button 508 by operating the operation device 15, the control unit 101 ends the simulation of the contrast correction process. The user's operations on the simulate button 507, the end button 508, and the reference button 502 described above differ depending on the type of the operation device 15, and are performed by, for example, clicking the mouse in the case of a mouse, or tapping in the case of a touch panel.

[0042] 5, a simulated image 510 that visualizes a change in perceived contrast between a first object 511 and a second object 512 when observing an object to be observed is displayed in a simulated image display area 504 of a UI screen 500. Therefore, a user can create an object to be observed while evaluating the perceived contrast when observing the object to be observed through the display in the simulated image display area 504.

[0043] FIG. 6 is a flowchart showing the flow of processing in the image processing device 10 according to this embodiment. First, in step S601, the image acquisition unit 401 acquires from the server 11 an image having the image file name input in the image input box 501. Then, the image acquisition unit 401 outputs the acquired image to the image correction unit 408.

[0044] Next, in the process of step 602, the first size acquisition unit 402 acquires a first image size, which is the size of the image when the input image is printed by the output device 14, and outputs information on the first image size to the image correction unit 408. The first size acquisition unit 402 may acquire, as the first image size, a paper size selected by the user from a drop-down list displayed by operating the drop-down list button 515 of the print paper size box 505 of the UI screen 500 shown in FIG. 5. For example, an observation image size input text box (not shown) may be provided in the UI screen 500 of FIG. 5, and the first size acquisition unit 402 may acquire, as the first image size, the image size input by the user in the observation image size input text box. For example, when the observation target is composed of multiple printed matter obtained by dividing an image into multiple prints and printing them, the first size acquisition unit 402 may acquire, as the first image size, the size of the entire observation target composed of the multiple prints, rather than the size of each printed matter divided and printed.

[0045] Next, in the process of step S603, the first distance acquisition unit 403 acquires the viewing distance when the user observes the observation object as the first viewing distance, and outputs information on the first viewing distance to the first characteristic calculation unit 404. In the case of this embodiment, the first distance acquisition unit 403 acquires, as the first viewing distance, information input by the user to the assumed viewing distance box 506 on the UI screen 500 in Fig. 5 described above.

[0046] In addition, the UI screen 500 in FIG. 5 is an example in which an assumed viewing distance box 506, which is a text box, is provided for inputting the first viewing distance, but an observation condition selection box 701 displaying a drop-down list as shown in FIG. 7 may be provided. That is, the UI screen 500 shown in FIG. 7 is generally similar to the UI screen 500 in FIG. 5, but instead of the assumed viewing distance box 506, an observation condition selection box 701 is provided. The observation condition selection box 701 is a box that displays a plurality of observation conditions when an observation object is observed as a drop-down list, and a drop-down list button 702 is provided. When the drop-down list button 702 is operated by the user, a drop-down list showing a plurality of observation conditions when an observation object is observed is displayed in the observation condition selection box 701. Examples of the observation conditions displayed as a drop-down list include a case in which an observation object is observed as a flyer, a case in which an observation object exhibited indoors is observed, and a case in which an observation object exhibited outdoors is observed.

[0047] 7, the storage unit 102 holds a table showing the correspondence between each of a plurality of viewing conditions, such as leaflets, indoor displays, and outdoor displays, and a plurality of viewing distances. When the user selects any of the viewing conditions from the drop-down list of the viewing condition selection box 701, the first distance acquisition unit 403 refers to the table in the storage unit 102 and acquires the viewing distance corresponding to the selected viewing condition as the first viewing distance. In the example of FIG. 7, the user only needs to select the desired viewing condition from the drop-down list of the viewing condition selection box 701, and there is no need to input a numerical viewing distance as in the example of the assumed viewing distance box 506 in FIG.

[0048] Next, in the process of step S604, first characteristic calculation unit 404 calculates a first frequency characteristic, which is a visual frequency characteristic corresponding to the first viewing distance acquired by first distance acquisition unit 403 in step S603, and outputs the first frequency characteristic to image correction unit 408. First characteristic calculation unit 404 calculates the visual frequency characteristic (VTF) using, for example, the Dooley approximation formula shown in the following formula (2). In formula (2), d is the viewing distance [mm], and f is the frequency [cycle / mm].

[0049] VTF=5.05×exp(-0.138×πdf / 180)×(1-exp(-0.1×πdf / 180)) Equation (2)

[0050] In the present embodiment, the Dooley approximation formula (2) is used to calculate the frequency characteristic of vision, but the present invention is not limited to this. The frequency characteristic of vision may be calculated in any manner as long as it is a sensitivity characteristic that indicates contrast that can be visually recognized by humans according to frequency.

[0051] Next, in the process of step S605, the second size acquisition unit 405 acquires the second image size, which is the size of the image displayed on the display device 13 at the time of creation on the screen, and outputs it to the image correction unit 408. In the case of the UI screen 500 of FIG. 5 described above, the second size acquisition unit 405 acquires the size of the input image 509 displayed in the input image display area 503 as the second image size. For example, in the case where the input image is displayed on the entire screen of the display device 13, apart from the example of the UI screen 500 of FIG. 5, the second size acquisition unit 405 may acquire the size of the screen of the display device 13 as the second image size. For example, in the case where the input image is displayed in a size different from the entire screen of the display device 13, the second size acquisition unit 405 acquires the size of the displayed image as the second image size. For example, in the case where the image is enlarged beyond the size that can be displayed on the display device 13, the second size acquisition unit 405 acquires the size of the entire image, not the size displayed on the display device 13, as the second image size.

[0052] Next, in the process of step S606, the second distance acquisition unit 406 acquires the distance measured by the distance measuring device 12, that is, the second visual distance which is the visual distance of the user with respect to the display device 13, and outputs it to the second characteristic calculation unit 407. In the configuration example of the image processing system shown in FIG. 1, the distance measuring device 12 acquires the second visual distance, but the second visual distance may be acquired without using the distance measuring device 12. For example, the UI processing unit 103 may provide a visual distance input text box (not shown) on the above-mentioned UI screen 500, and the second distance acquisition unit 406 may acquire the visual distance input by the user into the visual distance input text box as the second visual distance. Also, for example, an assumed visual distance according to the screen size of the display device 13 may be stored in the storage unit 102 in advance, and the second distance acquisition unit 406 may acquire the assumed visual distance according to the second image size acquired in step S605 from the storage unit 102, and set it as the second visual distance.

[0053] Next, in the process of step S607, second characteristic calculation unit 407 calculates second frequency characteristics which are frequency characteristics of vision at the second viewing distance acquired in step S606, and outputs the second frequency characteristics to image correction unit 408. Note that second characteristic calculation unit 407 can calculate the second frequency characteristics at the second viewing distance by the same process as that of first characteristic calculation unit 404 in step S604.

[0054] Next, in the process of step S608, the image correction unit 408 converts the input image acquired by the image acquisition unit 401 in step S601 into a luminance image. For example, when the input image is RGB data, the image correction unit 408 can convert it into YCbCr data using the following formulas (3) to (5). Note that the conversion formula from RGB to YCbCr is just an example, and other conversion formulas may be used.

[0055] Y=0.299·R+0.587·G+0.114·B Equation (3) Cb=-0.169·R-0.331·G+0.5·B Formula (4) Cr=0.5·R-0.419·G-0.081·B Formula (5)

[0056] Next, in the process of step S609, image correction unit 408 corrects the contrast of the luminance image acquired in step S608 based on the difference between the first image size, the second image size, and the first frequency characteristic and the second frequency characteristic. A method for generating a contrast-corrected image, in which the difference in perceived contrast has been corrected based on the frequency characteristics of vision, as a simulated image will be described below.

[0057] The image correction unit 408 first converts the luminance image to be corrected into a frequency image. A known technique such as two-dimensional Fourier transform (FFT: Fast Fourier Transform) can be used for the conversion into a frequency image. The frequency contained in the image can be calculated based on the image size and the number of pixels of the image. For example, the maximum frequency f [cycle / mm] contained in an image with an image size s [mm] and the number of pixels of the image is n [pix] can be calculated by the following formula (6).

[0058] f=n / 2s Equation (6)

[0059] In this way, each frequency component in the image calculated based on the image size and the number of pixels is multiplied by the visual frequency characteristic, and the obtained frequency image is inversely converted into a luminance image, thereby calculating a perceived contrast image that simulates the contrast perceived by humans. Note that in this embodiment, since it is assumed that the image is rectangular, the image size is the width of the rectangle, but the image is not necessarily rectangular. In that case, the frequency components in the image may be calculated using, for example, the width or height of the shape of the image as the image size. Also, for example, the average value of the height and width of the shape of the image may be used as the image size to calculate the frequency in the image.

[0060] The image correction unit 408 according to this embodiment generates a contrast-corrected image that can simulate the contrast perceived when observing an object when creating an image on a screen. The image correction unit 408 according to this embodiment corrects the contrast of the image by dividing the frequency components of the image by the frequency characteristics of vision under the second observation condition and further multiplying the frequency components by the frequency characteristics of vision under the first observation condition.

[0061] More specifically, image correction unit 408 first divides each frequency component in the luminance image calculated using formula (3) at the second image size by the second frequency characteristic. This makes it possible to calculate an image (here, referred to as a first corrected image) that cancels out the change in contrast that is perceived as being emphasized or attenuated by the frequency characteristic of vision when the image is observed at the second image size and the second viewing distance.

[0062] Next, the image correction unit 408 multiplies each frequency component in the image at the first image size by the first frequency characteristic for the first corrected image. This makes it possible to calculate a contrast-corrected luminance image in which a change in contrast perceived as being emphasized or attenuated by the frequency characteristic of vision when an image is observed at the first image size and the first viewing distance is superimposed. In other words, by observing the calculated contrast-corrected luminance image at the second image size and the second viewing distance, it is possible to simulate the contrast perceived when an image is observed at the first image size and the first viewing distance.

[0063] Next, in the process of step S610, the image correction unit 408 generates a contrast-corrected image by replacing the luminance image of the input image with the luminance image whose contrast has been corrected in step S609 as described above, and outputs the contrast-corrected image to the display control unit 409. At this time, the image correction unit 408 performs conversion from YCbCr to RGB using the following equations (7) to (9).

[0064] R = Y + 1.402 Cr Equation (7) G=Y-0.344·Cb-0.714·Cr Formula (8) B=Y+1.772·Cb Equation (9)

[0065] Next, in step S611, the display control unit 409 controls the display of the contrast-corrected image generated in step S610 on the display device 13. As an example of the display, a screen may be divided horizontally or vertically as in the UI screen 500 illustrated in FIG. 5, and an input image selected by the user when creating the image on the screen and a contrast-corrected image (simulated image) may be displayed side by side. Alternatively, instead of displaying two images side by side, the input image and the contrast-corrected image may be arranged in the same position so that the user can freely switch between them. Alternatively, for example, only the contrast-corrected image may be displayed, and an image for an observation object may be created on the contrast-corrected image.

[0066] Next, in the process of step S612, second size acquisition unit 405 determines whether or not the image size has changed when this step is executed, based on the second image size acquired in step S605. Whether or not the second image size has changed can be determined, for example, by whether or not the window size of input image display area 503 has changed. If the image size has not changed, second size acquisition unit 405 proceeds to the process of step S613, whereas if the image size has changed, second size acquisition unit 405 returns to the process of step S605.

[0067] When the process proceeds to step S613, second distance acquisition unit 406 determines whether the visual distance at the time of executing this step has been changed from the second visual distance acquired in step S606. For example, second distance acquisition unit 406 determines whether there has been a change in the distance information acquired by distance measuring device 12. Then, if there has been no change in the visual distance, second distance acquisition unit 406 proceeds to step S614, whereas if there has been a change in the visual distance, second distance acquisition unit 406 returns to step S606.

[0068] When the process proceeds to step S614, the control unit 101 determines whether or not to end the process of the flowchart in Fig. 6. For example, the control unit 101 ends the process when the end button 508 in the UI screen 500 described above is pressed, and returns the process to step S611 when the end button 508 is not pressed. When the process returns to step S611, the display of the contrast-corrected image generated in step S610 continues as described above.

[0069] As described above, the image processing device of this embodiment acquires the image size and viewing distance when creating on the screen and the image size and viewing distance when observing the observation object, and generates an image in which the difference in perceived contrast caused by the difference in the frequency characteristics of vision is corrected. Then, when creating on the screen, the contrast-corrected image is displayed. This allows the user to evaluate the contrast perceived in the observation object when creating on the screen, without actually printing the observation object and reproducing the viewing angle when observing it. That is, according to this embodiment, when the viewing angle is different between when creating on the screen and when observing the observation object, the difference in perceived contrast caused by the difference in the frequency characteristics of vision can be corrected, so that the user can always perform evaluation with the same perceived contrast. Therefore, according to this embodiment, the evaluation work when the user creates the observation object can be reduced, and the work efficiency can be improved.

[0070] <Variation 1> In the first embodiment described above, an example was given in which the contrast perceived on an actually printed object to be observed is simulated and displayed on a display screen, so that the object to be observed can be created while estimating the contrast perceived during observation. In addition, the contrast correction process may be a correction process in which the contrast perceived on the display screen during creation is reproduced on the printed object to be observed. In this case, the processes in steps S611 to S614 in FIG. 6 can be omitted. That is, in this case, it is possible to reproduce the contrast perceived during creation on the screen in the printed matter (object to be observed). This allows the user to create the object to be observed without being aware of the difference in perceived contrast due to the difference in the frequency characteristics of vision.

[0071] <Variation 2> In the above-described first embodiment, an example of observing an observation object printed using an inkjet printer as the output device 14 has been given, and a system for correcting the difference in perceived contrast in the observation object has been described. The observation object is not limited to an object printed by an inkjet printer, and may be, for example, an image displayed by a projector or a display. Similarly to the above, when the observation object is an image displayed on a projector or a display, a difference in perceived contrast may occur between when the image is created on the screen and when it is observed due to a difference in visual frequency characteristics. In other words, in this example as well, by applying the processing of the above-described first embodiment, it is possible to evaluate the perceived contrast of the observation object when it is created on the screen, without reproducing the observation conditions related to the viewing angle at the time of actual observation.

[0072] Second Embodiment In the first embodiment, an example is given assuming that the viewing distance when observing an object to be observed is constant, regardless of changes in image size and viewing distance when the object is created on a screen. In the second embodiment described below, an example is described in which the viewing distance assumed when observing an object to be observed is updated in response to changes in image size and viewing distance when the object is created on a screen, thereby making it possible to reproduce changes in perceived contrast when the object is observed due to changes in viewing distance when the object is created on a screen.

[0073] Fig. 8 is a functional block diagram showing a configuration example of the image processing device 10 according to the second embodiment. Note that since the configuration example of the image processing system including the image processing device 10 according to the second embodiment is similar to that shown in Fig. 1, its illustration and description will be omitted. In the image processing device of the second embodiment shown in Fig. 8, each functional unit from the image acquisition unit 401 to the display control unit 409 is the same as the corresponding functional unit of the image processing device of the first embodiment shown in Fig. 4, so the description of those functional units will be omitted. Below, the functional units different from those of the image processing device of the first embodiment will be described.

[0074] In the image processing device 10 of the second embodiment, the second size acquisition unit 405 outputs information on the second image size to the image correction unit 408 and also to the first distance update unit 803. In addition, the second distance acquisition unit 406 outputs information on the second visual distance to the second characteristic calculation unit 407 and also to the first distance update unit 803.

[0075] The third size acquisition unit 801 acquires a third image size that is a reference for the image size displayed on the screen of the display device 13, and outputs it to the first distance update unit 803. For example, the third size acquisition unit 801 acquires the size of the image displayed on the screen of the display device 13 as the third image size. Alternatively, for example, a reference image size acquisition button (not shown) may be provided in the UI screen 500 shown in FIG. 5, and the third size acquisition unit 801 may acquire the image size displayed on the display device 13 at the time when the user presses the reference image size acquisition button as the third image size. Alternatively, for example, a reference image size input box (not shown) may be provided in the UI screen 500 shown in FIG. 5, and the third size acquisition unit 801 may acquire the image size input by the user into the reference image size input box as the third image size.

[0076] The third distance acquisition unit 802 acquires a third viewing distance that is a reference for the viewing distance to the display device 13, and outputs the third viewing distance to the first distance update unit 803. For example, the third distance acquisition unit 802 acquires the viewing distance measured by the distance measuring device 12 as the third viewing distance. Alternatively, for example, a reference viewing distance acquisition button (not shown) may be provided in the UI screen 500 shown in FIG. 5, and the third distance acquisition unit 802 may acquire the viewing distance measured by the distance measuring device 12 at the time when the user presses the reference viewing distance acquisition button as the third viewing distance. Alternatively, for example, a reference viewing distance input box (not shown) may be provided in the UI screen 500, and the third distance acquisition unit 802 may acquire the viewing distance input by the user into the reference viewing distance input box as the third viewing distance.

[0077] First distance update unit 803 updates the first viewing distance based on the difference between the viewing angle at the third image size and the third viewing distance and the viewing angle at the second image size and the second viewing distance, and outputs the updated first viewing distance to first characteristic calculation unit 404. Details of the update process of the first viewing distance by first distance update unit 803 will be described later. The first characteristic calculation unit 404 in the second embodiment acquires the first frequency characteristic at the first visual distance updated by the first distance update unit 803 .

[0078] Fig. 9 is a flowchart showing the flow of processing in the image processing device 10 of the second embodiment. Steps S601 to S603, steps S606 to S608, and steps S611 to S617 in Fig. 9 are similar to the corresponding steps in Fig. 6, and detailed explanations thereof will be omitted. Below, processing steps that differ from the flowchart in Fig. 6 will be explained.

[0079] The image processing apparatus 10 of the second embodiment proceeds to processing in step S904 after acquiring an image in step S601, acquiring a first image size in step S602, and acquiring a first visual distance in step S603. In step S 904 , the third size obtaining unit 801 obtains a third image size that is a reference for the size of the image displayed on the screen at the time of creation, and outputs the third image size to the first distance updating unit 803 .

[0080] Next, in the process of step S905, third distance acquisition unit 802 acquires a third visual distance that is a reference in the visual distance for display device 13, and outputs the third visual distance to first distance update unit 803. After the process of step S905, the image processing device acquires a second image size in step S605, acquires a second visual distance in step S606, and calculates second frequency characteristics in step S607, and proceeds to the process of step S909.

[0081] In step S909, first distance update unit 803 calculates the difference between the second image size obtained in step S605 and the third image size obtained in step S904, and the difference between the second visual distance obtained in step S606 and the third visual distance obtained in step S905. Then, first distance update unit 803 updates the first visual distance obtained in step S603 based on the difference between the second image size and the third image size and the difference between the second visual distance and the third visual distance, and outputs the updated first visual distance to first characteristic calculation unit 404.

[0082] Hereinafter, the update process of the first viewing distance in the first distance update unit 803 will be described. As described above, the viewing angle can be calculated by the formula (1) using the image size and the viewing distance. In step S909, the first distance update unit 803 first calculates the viewing angle θ1 at the time of creation on the screen based on the second image size and the second viewing distance. Next, the first distance update unit 803 calculates the reference viewing angle θ2 based on the third image size and the third viewing distance. Furthermore, the first distance update unit 803 calculates the viewing angle difference Δθ (=θ2-θ1) by subtracting the viewing angle at the time of creation on the screen from the reference viewing angle. Then, the first distance update unit 803 calculates the updated first viewing distance d' by adding a value obtained by multiplying the viewing angle difference Δθ by a predetermined coefficient α to the first viewing distance d, as shown in formula (10).

[0083] d´=d+αΔθ···Eq.(10)

[0084] The method of updating the first viewing distance is not limited to the example described above, and any method may be used as long as it updates the first viewing distance according to the difference between the second image size and the third image size and the difference between the second viewing distance and the third viewing distance.

[0085] Next, in the process of step S910, first characteristic calculation unit 404 calculates a first frequency characteristic which is the visual frequency characteristic at the first visual distance updated by first distance update unit 803, and outputs the first frequency characteristic to image correction unit 408. The visual frequency characteristic can be calculated by the same process as in step S604.

[0086] As described above, the image processing device of the second embodiment acquires a reference image size and a viewing distance when the image is created on the screen. The image processing device then dynamically updates the assumed viewing distance (first viewing distance) for the observed object based on the difference between the reference image size and the image size when the image is created on the screen, and the difference between the reference viewing distance and the viewing distance when the image is created on the screen. According to the image processing device of the second embodiment, it is possible to evaluate the difference in perceived contrast caused by a change in the assumed viewing distance for the observed object when the image is created on the screen, without actually evaluating the observed object.

[0087] <Third embodiment> Next, as a third embodiment, an image processing device 10 that acquires maximum luminance information at the time of creation on a screen and performs contrast correction processing using the visual frequency characteristics calculated based on the maximum luminance information and the visual distance will be described. Note that, since an example of the configuration of an image processing system including the image processing device 10 of the third embodiment is the same as that shown in Fig. 1 described above, and the functional configuration of the image processing device 10 is the same as that shown in Fig. 4 and Fig. 8 described above, illustration and description thereof will be omitted.

[0088] It is known that the visual frequency characteristics change depending on the luminance, as shown in Fig. 10. In Fig. 10, the horizontal axis represents frequency, and the vertical axis represents contrast sensitivity. A solid line 1001 and a dashed line 1002 represent the visual frequency characteristics in different luminance situations, with the solid line 1001 representing the visual frequency characteristics when the luminance is high, and the dashed line 1002 representing the visual frequency characteristics when the luminance is low. As can be seen from the solid line 1001 and the dashed line 1002, as the luminance decreases, the perceived contrast sensitivity decreases overall, and the peak frequency of the contrast sensitivity shifts toward lower frequencies.

[0089] In the third embodiment, it is assumed that an image is created on the screen of an HDR (High Dynamic Range) display and printed by the output device 14. The HDR display is capable of image expression using a wide luminance range with a maximum luminance of 1000 nit (1000 cd / m2) or more. On the other hand, the luminance of the print surface of the observation object is determined by conditions such as the luminance of the illumination light in the observation environment, and is usually set to, for example, about 100 nit. For this reason, there is a large difference in the perceived luminance when creating an image on an HDR display and when observing the observation object. In other words, there is a large difference in the frequency characteristics of vision, and therefore the difference in perceived contrast is also large. Note that even if the output device 14 is not a printer but a projector or a display, there is a similar difference in the perceived luminance when creating and when observing.

[0090] Therefore, the image processing device 10 of the third embodiment acquires maximum luminance information corresponding to when the image is displayed on the display device 13 at the time of creation on the screen and when the output device 14 outputs the image. Note that, if the maximum luminance of either the display device 13 or the output device 14 is known in advance, the maximum luminance information of the other device, which is not known, may be acquired. For example, a drop-down list button for selecting a display / output device (not shown) may be provided in the UI screen 500 of FIG. 5, and multiple display / output devices and maximum luminance information for each device may be associated in the drop-down list button. In this example, when a user selects a display / output device from the drop-down list button for selecting a display / output device, the first characteristic calculation unit 404 acquires maximum luminance information corresponding to the selected output device. Also, the second characteristic calculation unit 407 acquires maximum luminance information corresponding to the display device selected from the drop-down list button for selecting a display / output device. For example, the image processing device 10 may have a function for acquiring maximum luminance information of the display device 13 and the output device 14 connected thereto. In the case of the image processing device 10 of the third embodiment, the first characteristic calculation unit 404 and the second characteristic calculation unit 407 calculate the visual frequency characteristics based on the maximum luminance information in addition to the above-mentioned visual distance.

[0091] The frequency characteristic of the viewing angle according to the luminance can be calculated using, for example, an approximation formula of VTF expressed by formula (11) disclosed in the following Reference 1. In formula (11), u is the frequency [cycle / deg], X0 is the viewing angle [deg], and L is the luminance [cd / m2].

[0092]

number

[0093] Reference 1: Barten, Peter GJ. “Formula for the contrast sensitivity of the human eye.” Image Quality and System Performance. Vol. 5294. International Society for Optics and Photonics, 2003.

[0094] According to the image processing device of the third embodiment, information on the maximum luminance in at least one of the display device 13 and the output device 14 is acquired, and the visual frequency characteristic corresponding to the maximum luminance is calculated. This makes it possible to improve the accuracy of correction of the difference in perceived contrast when there is a large difference in luminance between when an image is created on a screen and when an object to be observed is observed, for example, when there is a large difference in luminance between an image displayed on an HDR display and when a printed object to be observed is observed.

[0095] In the above embodiment, the observation conditions when observing a printed observation object are set as the first observation conditions, and the observation conditions when viewing an image displayed on a screen during creation are set as the second observation conditions, but the present invention is not limited to these. The image correction unit may correct the contrast of the image by dividing the frequency components of the image by the visual frequency characteristics under the first observation conditions, and further multiplying the frequency components by the visual frequency characteristics under the second observation conditions.

[0096] The present invention can also be realized by supplying a program that realizes one or more functions of the above-mentioned 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. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions. The above-mentioned embodiments are merely examples of concrete implementations of the present invention, and the technical scope of the present invention should not be interpreted as being limited by them. In other words, the present invention can be implemented in various forms without departing from its technical concept or main features.

[0097] The disclosure of each embodiment includes the following configurations, methods, and programs. (Configuration 1) A first acquisition means for acquiring a first observation condition when observing an image; a second acquisition means for acquiring a second observation condition different from the first observation condition; a correction means for correcting the contrast of the image; having The image processing device according to claim 1, wherein the correction means corrects contrast of the image based on a visual frequency characteristic under the first viewing condition and a visual frequency characteristic under the second viewing condition. (Configuration 2) The image processing device according to configuration 1, wherein the correction means corrects contrast of the image by dividing a frequency component of the image by a visual frequency characteristic under the second viewing condition and further multiplying the frequency component by a visual frequency characteristic under the first viewing condition. (Configuration 3) The image processing device according to configuration 1, wherein the correction means corrects contrast of the image by dividing a frequency component of the image by a visual frequency characteristic under the first viewing condition and further multiplying the frequency component by a visual frequency characteristic under the second viewing condition. (Configuration 4) 4. The image processing device according to any one of configurations 1 to 3, further comprising an update means for updating the first observation condition in response to a change in the second observation condition. (Configuration 5) The method further includes a third acquisition means for acquiring a third observation condition that is a reference when observing the image, 5. The image processing device according to configuration 4, wherein the update means updates the first viewing condition based on a difference between the second viewing condition and the third viewing condition. (Configuration 6) 6. The image processing device according to any one of configurations 1 to 5, wherein the viewing conditions include a size of the image and a viewing distance for the image. (Configuration 7) 7. The image processing device according to configuration 6, wherein the correction means acquires the visual frequency characteristic based on the visual distance. (Configuration 8) 8. The image processing device according to claim 7, wherein the correction means corrects the contrast of the image based on the size of the image and the frequency characteristics of vision. (Configuration 9) the first viewing condition includes a size and a viewing distance of the image on an observation object on which the image is printed or displayed; 9. The image processing device according to any one of configurations 6 to 8, wherein the second viewing conditions include a size and a viewing distance of the image when the image is displayed on a screen of a display device. (Configuration 10) 10. The image processing device according to any one of configurations 6 to 9, wherein the viewing conditions further include luminance information. (Configuration 11) 11. The image processing device according to configuration 10, wherein the correction means acquires the visual frequency characteristics based on maximum luminance information under the viewing conditions and the visual distance. (Configuration 12) 12. The image processing device according to any one of configurations 1 to 11, wherein the correction means converts the image into a luminance image, corrects the contrast of the luminance image, and replaces the luminance of the image with the luminance image with the contrast corrected to generate a contrast-corrected image. (Configuration 13) 13. The image processing device according to any one of configurations 1 to 12, further comprising a display unit that displays the image whose contrast has been corrected by the correction unit as a simulated image observed under the first observation condition. (Configuration 14) 14. The image processing apparatus according to claim 13, wherein the display means displays the image, the contrast of which has been corrected by the correction means, as the simulated image under the second observation condition. (Method 1) a first acquisition step of acquiring a first observation condition when observing an image; a second acquisition step of acquiring a second observation condition different from the first observation condition; a correction step of correcting the contrast of the image; having An image processing method, characterized in that in the correction step, contrast of the image is corrected based on the visual frequency characteristics under the first viewing conditions and the visual frequency characteristics under the second viewing conditions. (Program 1) A program that causes a computer to function as the image processing device according to any one of configurations 1 to 14. [Explanation of symbols]

[0098] 10: image processing device, 11: server, 12: distance measuring device, 13: display device, 14: output device, 15: operation device

Claims

1. A first acquisition means for acquiring a first observation condition when observing an image; a second acquisition means for acquiring a second observation condition different from the first observation condition; a correction means for correcting the contrast of the image; having The image processing device according to claim 1, wherein the correction means corrects contrast of the image based on a visual frequency characteristic under the first viewing condition and a visual frequency characteristic under the second viewing condition.

2. 2. The image processing device according to claim 1, wherein the correction means corrects the contrast of the image by dividing the frequency components of the image by the visual frequency characteristics under the second viewing conditions and further multiplying the divided frequency components by the visual frequency characteristics under the first viewing conditions.

3. 2. The image processing device according to claim 1, wherein the correction means corrects the contrast of the image by dividing the frequency components of the image by the visual frequency characteristics under the first viewing conditions and further multiplying the divided frequency components by the visual frequency characteristics under the second viewing conditions.

4. 2. The image processing apparatus according to claim 1, further comprising an update unit for updating the first observation condition in response to a change in the second observation condition.

5. The method further includes a third acquisition means for acquiring a third observation condition that is a reference when observing the image, 5. The image processing apparatus according to claim 4, wherein said updating means updates said first viewing condition based on a difference between said second viewing condition and said third viewing condition.

6. 6. The image processing apparatus according to claim 1, wherein the viewing conditions include a size of the image and a viewing distance for the image.

7. 7. The image processing apparatus according to claim 6, wherein the correction means acquires the frequency characteristic of the visual sense based on the visual distance.

8. 8. The image processing apparatus according to claim 7, wherein the correction means corrects the contrast of the image based on the size of the image and the frequency characteristics of the human eye.

9. the first viewing condition includes a size and a viewing distance of the image on an observation object on which the image is printed or displayed; 7. The image processing apparatus according to claim 6, wherein the second viewing conditions include a size and a viewing distance of the image when the image is displayed on a screen of a display device.

10. 7. The image processing apparatus according to claim 6, wherein the viewing conditions further include luminance information.

11. 11. The image processing apparatus according to claim 10, wherein the correction means acquires the visual frequency characteristics based on maximum luminance information under the viewing conditions and the visual distance.

12. 2. The image processing device according to claim 1, wherein the correction means converts the image into a luminance image, corrects the contrast of the luminance image, and replaces the luminance of the image with the luminance image with the contrast corrected to generate a contrast-corrected image.

13. 2. The image processing apparatus according to claim 1, further comprising display means for displaying the image, the contrast of which has been corrected by said correction means, as a simulated image observed under said first observation conditions.

14. 14. The image processing apparatus according to claim 13, wherein the display means displays the image, the contrast of which has been corrected by the correction means, as the simulated image under the second observation condition.

15. a first acquisition step of acquiring a first observation condition when observing an image; a second acquisition step of acquiring a second observation condition different from the first observation condition; a correction step of correcting the contrast of the image; having An image processing method, characterized in that in the correction step, contrast of the image is corrected based on the visual frequency characteristics under the first viewing conditions and the visual frequency characteristics under the second viewing conditions.

16. Computer, A first acquisition means for acquiring a first observation condition when observing an image; a second acquisition means for acquiring a second observation condition different from the first observation condition; a correction means for correcting the contrast of the image; having The correction means is a program that causes the image processing device to function as an image processing device that corrects the contrast of the image based on the visual frequency characteristics under the first viewing conditions and the visual frequency characteristics under the second viewing conditions.

Images