Image display system, image display method, and recording medium

Abstract

An object is to provide an image display system, an image display apparatus, an image display method, and a computer program that can improve the use feeling when changing a luminance setting value. The image processing section is configured to, if the image display system receives a request to change the luminance setting value of the image display section from a first luminance setting value to a second luminance setting value, switch the luminance setting value from the first luminance setting value to the second luminance setting value while making the gradation characteristic of the image data displayed on the image display section the first gradation characteristic, and then switch the gradation characteristic of the image data displayed on the image display section to the second gradation characteristic.

Description

TECHNICAL FIELD

[0001] The present application relates to an image display system, an image display apparatus, an image display method, and a recording medium. BACKGROUND

[0002] An image displayed on an image display section is sometimes preferably displayed with a desired gradation characteristic. For example, from the viewpoint of image interpretation, a mammography image, which is one of medical images, is preferably displayed with a gradation characteristic called GSDF (Grayscale Standard Display Function) of the DICOM (Digital Imaging and Communication in Medicine) standard. Thus, an image display system configured to change a gradation characteristic of an image displayed on an image display section depending on a kind of image displayed on the image display section has been proposed (see, for example, Patent Literature 1).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2016-42954 SUMMARY

[0006] (PROBLEMS TO BE SOLVED BY THE INVENTION)

[0007] Generally, an image display section can change luminance, for example, in order to improve visibility of a displayed image. Here, when a luminance setting value is changed, the image display system displays an image on the image display section with the changed luminance setting value, but at this time, the image display system needs to obtain a target luminance of each gradation value corresponding to the above-described desired gradation characteristic. The control device of the image display system needs to obtain the target luminance corresponding to the desired gradation characteristic based on a display luminance of the changed luminance setting value and a predetermined calculation when the target luminance is obtained. Furthermore, in order to realize a higher-precision gradation characteristic, the display luminance is preferably a measured value. In the past, in the change of the luminance setting value, if a request to change the luminance setting value is accepted, the following (1) to (4) need to be performed.

[0008] (1) Change the luminance setting value.

[0009] (2) After the luminance setting value is changed, measure the display luminance.

[0010] (3) Obtain the target luminance of each gradation value based on the measured display luminance.

[0011] (4) Switch the gradation value.

[0012] Therefore, a time lag occurs between when the user changes the brightness of the image display section and when the image display section displays an image corresponding to the desired gradation characteristic. During this time lag, the image based on the gradation characteristic before the brightness is changed is displayed at the display brightness after the brightness is changed, so the gradation characteristic of the displayed image deviates from the desired gradation characteristic, and it is possible that the use of the image display system will be impaired.

[0013] The present application has been achieved in view of such circumstances, and has an object to provide an image display system, an image display device, an image display method, and a computer program that improve the use when changing a brightness setting value.

[0014] (TECHNICAL SOLUTION FOR SOLVING THE PROBLEM)

[0015] According to the present application, there is provided an image display system that displays image data, the image display system including an image display section configured to display the image data, a brightness acquisition section configured to be able to acquire a display brightness of the image display section, and an image processing section configured to, if the image display system accepts a request to change a brightness setting value of the image display section from a first brightness setting value to a second brightness setting value, cause a gradation characteristic of the image data displayed in the image display section to be a first gradation characteristic while switching the brightness setting value from the first brightness setting value to the second brightness setting value, and then switch the gradation characteristic of the image data displayed in the image display section to a second gradation characteristic, the first gradation characteristic associating a gradation value with a first target brightness, the first target brightness being acquired based on the display brightness of the image display system in a state in which the first brightness setting value is accepted before the request, and the first target brightness being a target brightness estimated by the image display section in a manner in which the image data is displayed at the display brightness with the brightness setting value being the second brightness setting value, the second gradation characteristic associating the gradation value with a second target brightness, the second target brightness being acquired based on the display brightness in a state in which the image data of the first gradation characteristic is displayed at the second brightness setting value.

[0016] In the present application, if a request to change a brightness setting value from a first brightness setting value to a second brightness setting value is accepted, a gradation characteristic of image data displayed in an image display section is caused to be a first gradation characteristic while the brightness setting value is switched from the first brightness setting value to the second brightness setting value, and then the gradation characteristic of the image data displayed in the image display section is switched to a second gradation characteristic.

[0017] The first gradation characteristic is associated with a target luminance (i.e., a first target luminance) estimated using a second luminance setting value and a gradation value. On the other hand, the second gradation characteristic is associated with a target luminance (i.e., a second target luminance) obtained based on a display luminance obtained from the second luminance setting value actually obtained by the luminance acquisition section and a gradation value. Therefore, the first gradation characteristic is similar to the second gradation characteristic. Thus, from after the request is accepted until the image data corresponding to the second gradation characteristic is displayed in the image display section, the user can visually confirm the image data corresponding to the first gradation characteristic, which is more similar to the second gradation characteristic than the gradation characteristic before the request is accepted.

[0018] The following illustrates various embodiments of the present application. The embodiments shown below can be combined with each other.

[0019] Preferably, there is provided an image display system, wherein the first target luminance is based on the first luminance setting value before the image display system accepts the request and an operating current value of the image display section corresponding to the luminance setting value.

[0020] Preferably, there is provided an image display system, wherein the first gradation characteristic and the second gradation characteristic are constituted by a function or a table.

[0021] Preferably, there is provided an image display system, wherein the second luminance setting value is greater than the first luminance setting value.

[0022] Preferably, there is provided an image display system, wherein the second luminance setting value is a maximum value settable for the image display section.

[0023] Preferably, there is provided an image display system, wherein if a predetermined time elapses after the image display system accepts the request, the image processing section returns the luminance setting value of the image display section from the second luminance setting value to the first luminance setting value.

[0024] Preferably, there is provided an image display system, wherein the image processing section is configured to emphasize a frame of the image data displayed in the image display section if the image display system accepts the request.

[0025] According to another aspect of embodiments of the present application, there is provided an image display device that displays image data, the image display device including an image display section configured to display the image data, a luminance acquisition section configured to acquire a display luminance of the image display section, and an image processing section configured to, if the image display device receives a request to change a luminance setting value of the image display section from a first luminance setting value to a second luminance setting value, switch the luminance setting value from the first luminance setting value to the second luminance setting value while making a gradation characteristic of the image data displayed on the image display section a first gradation characteristic, and then switch the gradation characteristic of the image data displayed on the image display section to a second gradation characteristic, the first gradation characteristic associating a gradation value with a first target luminance that is acquired based on the display luminance in a state in which the image display device displays with the first luminance setting value before receiving the request, and the first target luminance being a target luminance estimated by the image display section in a manner in which the image display section displays the image data with the display luminance at a time when the luminance setting value is the second luminance setting value, the second gradation characteristic associating the gradation value with a second target luminance that is acquired based on the display luminance in a state in which the image data of the first gradation characteristic is displayed with the second luminance setting value.

[0026] According to another aspect of embodiments of the present application, there is provided an image display method that displays image data on an image display section, the image display method including a luminance acquisition step of acquiring a display luminance of the image display section, and an image processing step of, if a request to change a luminance setting value of the image display section from a first luminance setting value to a second luminance setting value is received, switching the luminance setting value from the first luminance setting value to the second luminance setting value while making a gradation characteristic of the image data displayed on the image display section a first gradation characteristic, and then switching the gradation characteristic of the image data displayed on the image display section to a second gradation characteristic, the first gradation characteristic associating a gradation value with a first target luminance that is acquired based on the display luminance in a state in which the image display device displays with the first luminance setting value before receiving the request, and the first target luminance being a target luminance estimated by the image display section in a manner in which the image display section displays the image data with the display luminance at a time when the luminance setting value is the second luminance setting value, the second gradation characteristic associating the gradation value with a second target luminance that is acquired based on the display luminance in a state in which the image data of the first gradation characteristic is displayed with the second luminance setting value.

[0027] According to another aspect of the embodiment of the present application, there is provided a computer program that executes the above-described image display method. That is, a computer program that executes the image display method of displaying image data on an image display section, the image display method including a luminance acquisition step of acquiring a display luminance of the image display section, and an image processing step of, if a request to change a luminance setting value of the image display section from a first luminance setting value to a second luminance setting value is accepted, switching a gradation characteristic of the image data displayed on the image display section to a first gradation characteristic while switching the luminance setting value from the first luminance setting value to the second luminance setting value, and then switching the gradation characteristic of the image data displayed on the image display section to a second gradation characteristic, the first gradation characteristic associating a gradation value with a first target luminance that is acquired based on the display luminance in a state in which the image display section displays the image data with the first luminance setting value before the request is accepted, and the first target luminance being a target luminance that the image display section estimates in such a manner that the image display section displays the image data with the display luminance when the luminance setting value is the second luminance setting value, the second gradation characteristic associating the gradation value with a second target luminance that is acquired based on the display luminance in a state in which the image display section displays the image data with the second luminance setting value and the first gradation characteristic. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a functional block diagram of an image display system 100 including the image display apparatus 1 of the embodiment.

[0029] Figure 2 is an explanatory diagram of a flow of acquisition of a first target luminance of a first gradation characteristic.

[0030] Figure 3 is an explanatory diagram of a flow of acquisition of a second target luminance of a second gradation characteristic.

[0031] Figure 4 is a control flowchart of the image display system 100 including the image display apparatus 1 of the embodiment.

[0032] Figure 5 is a graph for explaining the first and second gradation characteristics in the GSDF of the DICOM standard.

[0033] Figure 6 In the above-described embodiment, the first target luminance is calculated from the following equation (1) based on the display luminance in a state in which the image display section displays the image data with the first luminance setting value before the request is accepted. Figure 6 A denotes a contrast sensitivity function derived from the Barten-Model, Figure 6 B denotes an equation for calculating a luminance corresponding to a difference of one JND from an arbitrary luminance derived from the Barten-Model, Figure 6C represents a formula used when calculating the target JND value.

[0034] Figure 7 The image when the luminance increase mode is OFF, the image when the luminance increase mode is ON and based on the 1st gradation characteristic, and the image when the luminance increase mode is ON and based on the 2nd gradation characteristic are schematically represented.

[0035] Figure 8 In this case, Figure 8 A schematically represents the image displayed on the image display section when the luminance increase mode is OFF, Figure 8 B schematically represents the image displayed on the image display section when the luminance increase mode is ON.

[0036] Figure 9 is a functional block diagram of a variation of the image display system 100. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present application will be described with reference to the drawings. The various characteristic matters shown in the embodiments shown below can be combined with each other. Also, each characteristic matter independently makes the present application stand.

[0038] 1st gradation characteristic

[0039] The image display system 100 is configured to be able to display an image with a predetermined gradation characteristic. The embodiments will be described taking a mammography image as a medical image. Also, the predetermined gradation characteristic includes the 1st and 2nd gradation characteristics described later. The 1st and 2nd gradation characteristics of the embodiments both utilize a gradation characteristic referred to as GSDF (Grayscale Standard Display Function) of the DICOM standard. Specifically, Figure 5 The GSDF curve shown is a graph in which a target luminance is associated with a JND index, and the gradation characteristic of the GSDF is represented as a curve, and when the 1st and 2nd gradation characteristics are represented as curves, the curves overlap on the GSDF curve.

[0040] Note that the DICOM standard is an international standard for medical digital images, and is intended to ensure image display for correct interpretation of images or diagnosis by doctors. The visual characteristics of humans are nonlinear with respect to luminance, but the GSDF is specified in a manner in which visual linearity is established. Specifically, the GSDF is derived from the Barten-Model based on the visual characteristics of humans for image display.

[0041] In DICOM, an index called JND (Just-Noticeable Difference) index is used. In the JND index, the minimum luminance difference of a given target that an observer of an image can recognize is defined as 1 JND, and the JND index is a value of a 1 step in the JND index that is reduced to a luminance difference of a discrimination range. Note that in the embodiments, a case where the JND index based on the Barten-Model is used is described, but the embodiments are not limited thereto, and an index corresponding to the minimum luminance difference that an observer of an image can recognize, which is derived by a method other than the Barten-Model, can also be used.

[0042] 2 Overall Configuration

[0043] An overall configuration of an image display system 100 including the image display apparatus 1 of the embodiments will be described. As shown in FIG. 1, the image display system 100 of the present embodiment is provided with the image display apparatus 1 and an information processing apparatus 2. The image display apparatus 1 is provided with an image processing section 1A, a luminance processing section 1B, an operation section 1C, a request judging section 1D, a LUT (Look Up Table) 1E, a storage section 1F, an image display section 1G, a light sensor 1H, and a sensor control section 1I. The image processing section 1A, the luminance processing section 1B, and the request judging section 1D read programs stored in the storage section 1F and perform various arithmetic processing, for example, constituted by a CPU or the like. Figure 1

[0044] Each of the above-described components can be realized by software or by hardware. When realized by software, various functions can be realized by a CPU executing a computer program. The program can be stored in a built-in storage section or in a non-transitory recording medium that is readable by a computer. Furthermore, the program stored in an external storage section can be read and realized by so-called cloud computing. When realized by hardware, various circuits such as ASIC, FPGA, or DRP can be used. In the present embodiment, various information or concepts including the information are represented by a set of bits of a binary number constituted by 0 or 1 by a high or low of a signal value, and communication and arithmetic are performed by the above-described software or hardware.

[0045] The image display apparatus 1 acquires image data from the information processing apparatus 2 and outputs the image data subjected to image processing to the image display section 1G. The information processing apparatus 2 performs control of the image display apparatus 1. Also, the information processing apparatus 2 outputs image data of an image displayed on the image display section 1G to the image display apparatus 1. The light sensor 1H is configured to be able to measure the luminance of the image display section 1G. Although a case where the light sensor 1H is mounted on the image display apparatus 1 is described, the present embodiment is not limited thereto.

[0046] 3 Specific Configuration of the Image Display Apparatus 1​

[0047] When a doctor performs image interpretation on a medical image displayed on the image display section 1G, there are cases where the brightness of the image display section is increased. Therefore, the image display apparatus 1 of the embodiment is configured to be able to execute a brightness increase mode that increases the brightness of the image display section 1G. The brightness increase mode of the embodiment is a mode that sets the brightness setting value to the maximum value, and for example, functions to find a lesion or the like.

[0048] Here, in order to display an image corresponding to the GSDF that is a predetermined gradation characteristic on the image display section 1G, it is necessary to acquire the brightness of the image display section 1G. As a method of acquiring this brightness, a method of using a calculated value based on the operating current value (backlight current value or PWM value) of the image display section 1G can be considered, but due to aging or the like of the image display section 1G, it is possible that this calculated value deviates from the actual brightness (display brightness) of the image display section 1G. Specifically, the backlight that constitutes the image display section 1G ages, so that the brightness when a prescribed amount of current is applied to the aged backlight is smaller than the brightness when the same current is applied to the backlight before aging. In other words, the backlight that constitutes the image display section 1G ages, so that the luminous efficiency of the backlight decreases. Therefore, from the viewpoint of displaying an image on the image display section 1G in a GSDF characteristic that more closely matches the actual display light, it is preferable to use the display brightness acquired by measuring the display light of the image display section 1G, rather than using the above-described operating current value (backlight current value or PWM value). On the other hand, after the brightness setting value is changed, it takes time for the display brightness of the image display section 1G to stabilize, so the image display apparatus 1 needs time to acquire the stable display brightness.

[0049] Therefore, the image display apparatus 1 of the embodiment has a function of, if an execution request of the brightness increase mode is accepted (if the brightness setting value is changed), displaying an image of the first gradation characteristic, and then switching the image of the first gradation characteristic to an image of the second gradation characteristic. In other words, the brightness increase mode is a mode that displays an image in the first gradation characteristic and then displays an image in the second gradation characteristic.

[0050] Here, the first gradation characteristic can be acquired more quickly than the second gradation characteristic. The first gradation characteristic is a gradation characteristic that associates a gradation value with a first target brightness described later, and the first target brightness is acquired by using the above-described calculated value.

[0051] On the other hand, the second gradation characteristic is a gradation characteristic that more accurately reflects the actual brightness (display brightness). The second gradation characteristic is a gradation characteristic that associates a gradation value with a second target brightness described later, and the second target brightness is acquired by using the display brightness acquired by measuring the display light.

[0052] 3-1 Image processing section 1A

[0053] The image processing section 1A is configured to perform image processing based on the data stored in the LUT 1E, and display the image-processed data on the image display section 1G. As shown in Figure 1 The image processing section 1A includes a display switching section 1A1 and an emphasis processing section 1A2.

[0054] (Display switching section 1A1)

[0055] The display switching section 1A1 is configured to switch the gray scale characteristics of the image data displayed on the image display section 1G from the first gray scale characteristics to the second gray scale characteristics. In other words, if the image display apparatus 1 (the request judging section 1D) accepts the request to change the brightness setting value, the display switching section 1A1 switches the image displayed on the image display section 1G from the image of the first gray scale characteristics to the image of the second gray scale characteristics. The display switching section 1A1 performs the above-mentioned switching when the request judging section 1D judges that there is a brightness increase mode execution request.

[0056] (Emphasis processing section 1A2)

[0057] The emphasis processing section 1A2 is configured to emphasize the frame Fr (refer to Figure 8 A and Figure 8 B) of the image data displayed on the image display section 1G. The doctor sometimes forgets whether the operation section 1C has been operated, and cannot judge whether the brightness increase mode has been turned on or turned off. The image display apparatus 1 includes the emphasis processing section 1A2, so that the frame Fr of the image D is not emphasized when the brightness increase mode is turned off, but on the other hand, the frame Fr of the image D is emphasized when the brightness increase mode is turned on. Thus, the doctor visually confirms the frame Fr of the image D, so that it is possible to judge whether the brightness increase mode is turned on or turned off. In addition, the frame Fr (the outside) of the image D is emphasized instead of the inside of the image D, so that it is possible to avoid the emphasized display of the emphasis processing section 1A2 from hindering the image interpretation of the doctor, and it is possible to prevent misdiagnosis.

[0058] 3-2 Brightness processing section 1B

[0059] The brightness processing section 1B has a function of calculating the target brightness stored in the table of the LUT 1E. As shown in Figure 2 The brightness processing section 1B includes a brightness acquisition section 1B1, a brightness estimation section 1B2, a conversion section 1B3, a target JND value calculation section 1B4, and a target brightness calculation section 1B5.

[0060] (Brightness acquisition section 1B1)

[0061] As shown in Figure 2As shown, when acquiring the first grayscale characteristic, the brightness acquisition unit 1B1 acquires the temporary maximum brightness Lmax_t, which is the maximum brightness calculation value, and the temporary minimum brightness Lmin_t, which is the minimum brightness calculation value, calculated by the brightness estimation unit 1B2 described later.

[0062] like Figure 3 As shown, when acquiring the second grayscale characteristic, the brightness acquisition unit 1B1 acquires the display brightness (maximum brightness Lmax) acquired by the light sensor 1H, and the temporary minimum brightness Lmin_t calculated by the brightness estimation unit 1B2.

[0063] (Brightness estimation section 1B2)

[0064] like Figure 2 As shown, when acquiring the first grayscale characteristic, the brightness estimation unit 1B2 calculates the temporary maximum brightness Lmax_t as the maximum brightness calculation value based on the brightness setting value sv (an example of the first brightness setting value) before receiving the request from the image display device 1, and the operating current value cv of the image display unit 1G in the brightness setting value. For example, when the dimming mode of the image display unit 1G is DC current dimming mode, the operating current value cv can be the backlight current value of the image display unit 1G, and when the dimming mode of the image display unit 1G is PWM dimming, the PWM value can be used. It should be noted that the PWM value is a value corresponding to the pulse width of the PWM signal output to the backlight drive circuit. It should be noted that the brightness calculation value can be calculated using methods known, such as those disclosed in Japanese Patent Application Publication No. 2007-11246. The brightness estimation unit 1B2 calculates the temporary minimum brightness Lmin_t based on the calculated temporary maximum brightness Lmax_t and the contrast ratio ct. It should be noted that the contrast ratio is the ratio of the maximum brightness to the minimum brightness.

[0065] The contrast ratio ct can use the factory default contrast ratio stored in the storage unit 1E. Furthermore, the brightness estimation unit 1B2 can periodically acquire the maximum and minimum brightness of the image display unit 1G via the light sensor 1H, and periodically calculate the contrast ratio using the acquired maximum and minimum brightness. Additionally, the brightness estimation unit 1B2 can store the calculated contrast ratio in the storage unit 1E and update it appropriately; the brightness acquisition unit 1B1 uses this updated contrast ratio.

[0066] like Figure 3 As shown, when acquiring the second grayscale characteristic, the brightness estimation unit 1B2 calculates the minimum brightness Lmin based on the maximum brightness Lmax and contrast ct obtained by measuring the display light of the image display unit 1G. Alternatively, the minimum brightness Lmin can be obtained by directly measuring the minimum brightness of the image display unit 1G without calculating it. Furthermore, the brightness estimation unit 1B2 outputs the minimum brightness Lmin to the brightness acquisition unit 1B1.

[0067] (Conversion section 1B3)

[0068] The conversion section 1B3 has a function of converting the luminance to the JND value based on the formula 1 of DICOM as shown in A. Figure 6 A shown in A, the conversion section 1B3 acquires the temporary minimum luminance Lmin_t and the temporary maximum luminance Lmax_t from the luminance acquisition section 1B1 when acquiring the first gray scale characteristic. In addition, the conversion section 1B3 converts the temporary minimum luminance Lmin_t to the temporary minimum JND value Jmin_t and converts the temporary maximum luminance Lmax_t to the temporary maximum JND value Jmax_t.

[0069] As shown in A, the conversion section 1B3 acquires the temporary minimum luminance Lmin_t and the temporary maximum luminance Lmax_t from the luminance acquisition section 1B1 when acquiring the first gray scale characteristic. In addition, the conversion section 1B3 converts the temporary minimum luminance Lmin_t to the temporary minimum JND value Jmin_t and converts the temporary maximum luminance Lmax_t to the temporary maximum JND value Jmax_t. Figure 2

[0070] In addition, as shown in B, the conversion section 1B3 acquires the minimum luminance Lmin and the maximum luminance Lmax from the luminance acquisition section 1B1 when acquiring the second gray scale characteristic. In addition, the conversion section 1B3 converts the minimum luminance Lmin to the minimum JND value Jmin and converts the maximum luminance Lmax to the maximum JND value Jmax. Figure 3

[0071] (Target JND value calculation section 1B4)

[0072] The target JND value calculation section 1B4 has a function of calculating the target JND value of each gray scale based on the formula 3 as shown in C. In other words, the target JND value calculation section 1B4 calculates the target JND value of each gray scale based on the maximum JND value, the minimum JND value, and the predetermined number of gray scales. Note that, in the present embodiment, the gray scales of 0 to 255 are described, but the present embodiment is not limited thereto. Figure 6 The target JND value calculation section 1B4 calculates the temporary target JND value Jm_t of each gray scale based on the temporary minimum luminance Lmin_t, the temporary maximum luminance Lmax_t, and the number of gray scales (255) when acquiring the first gray scale characteristic.

[0073] The target JND value calculation section 1B4 calculates the target JND value Jm of each gray scale based on the minimum luminance Lmin, the maximum luminance Lmax, and the number of gray scales (255) when acquiring the second gray scale characteristic.

[0074] (Target luminance calculation section 1B5)

[0075] The target luminance calculation section 1B5 has a function of converting the JND value to the luminance based on the formula 2 of DICOM as shown in B.

[0076] Figure 6

[0077] ​​​​When the first gray scale characteristics are acquired, the target luminance calculating section 1B5 converts the provisional target JND value Jm_t of each gray scale into the first target luminance Lm_t as the provisional target luminance of each gray scale.

[0078] When the second gray scale characteristics are acquired, the target luminance calculating section 1B5 converts the target JND value Jm of each gray scale into the second target luminance Lm as the target luminance of each gray scale.

[0079] The first target luminance Lm_t of each gray scale calculated by the target luminance calculating section 1B5 is stored in the table of the LUT 1E. The same applies to the second target luminance Lm of each gray scale.

[0080] 3-3 Operation Section 1C

[0081] The operation section 1C is an operation section of the image display apparatus 1, and is constituted by, for example, a button, a touch panel, a voice input device, and the like. The operation section 1C is configured to be able to accept execution of the luminance increase mode. That is, the image display apparatus 1 accepts a request for execution of the luminance increase mode through the operation section 1C. Note that the image display apparatus 1 can also accept the request for execution of the luminance increase mode from the information processing apparatus 2, instead of the operation section 1C.

[0082] 3-4 Request Judging Section 1D

[0083] The request judging section 1D judges whether or not the doctor has operated the operation section 1C to start the function of the luminance increase mode, that is, has a function of judging whether or not there is a request for execution of the luminance increase mode. The luminance increase mode in the embodiment is a mode in which the luminance setting value before the request for the luminance increase mode is accepted is changed to the maximum luminance setting value. Therefore, the request judging section 1D has a function of judging whether or not there is a request for changing the luminance setting value before the request for the luminance increase mode is accepted to the maximum luminance setting value.

[0084] 3-5 LUT 1E

[0085] The LUT 1E has LUT data. The LUT data is constituted as a table (conversion table) of output data corresponding to input data. The input data corresponds to the image data acquired by the information processing apparatus 2, and the image data converted by the LUT 1E is subjected to image processing by the image processing section 1A and displayed on the image display section 1G. The first target luminance calculated each time is stored in the LUT 1E. That is, when the image display apparatus 1 accepts the request for execution of the luminance increase mode through the operation section 1C, the first target luminance is calculated by the luminance processing section 1B and stored in the LUT 1E. Thus, the first target luminance more suitable for the current state of the image display section 1G is stored in the LUT 1E.

[0086] It should be noted that the first target luminance is calculated by the luminance processing section IB when a predetermined condition is satisfied, and the calculated first target luminance can also be stored in advance in the storage section IE and updated. For example, the predetermined condition can be a condition for counting the number of times a request is accepted and confirming whether the count reaches a threshold value, or a condition for whether a prescribed time has elapsed after the first target luminance is calculated. Thus, the first target luminance does not need to be calculated for each request, and the table can be used as is. That is, when there is a request for the luminance increase mode, an image reflecting the characteristics of the GSDF can be quickly displayed on the image display section IG, and the decrease in the physician's sense of use can be effectively suppressed.

[0087] 3-5 Storage Section IF

[0088] The storage section IF stores various data or programs. For example, the storage section IF stores various data such as the formulas 1 to 3 shown in FIGS. 1 to 3, or the contrast of the image display section IG, or programs. Figure 6 A ~ Figure 6 C, or the contrast of the image display section IG.

[0089] 3-6 Image Display Section IG

[0090] The image display section IG displays an image of image data (including still images and moving images). The image display section IG can be constituted by, for example, a liquid crystal display or an organic EL display.

[0091] 3-7 Light Sensor IH and Sensor Control Section II

[0092] The light sensor IH and the sensor control section II are built into the image display apparatus 1. The light sensor IH can be disposed, for example, on the back side of the backlight of the image display section IG. The light sensor IH is configured to be able to directly measure the luminance of the backlight and operates under the control of the sensor control section II.

[0093] 4 Flowchart

[0094] Based on Figure 4 An example of a control flowchart of the image display system 100 will be described. If the request judging section ID judges that the operation to turn on the luminance increase mode has been performed, in other words, if the request judging section ID judges that a request to change the luminance setting value has been accepted, the control flowchart shown in FIG. 6 is started. Figure 4

[0095] (Step S1: Setting Value Acquisition Step)

[0096] The luminance estimation section IB2 acquires the luminance setting value sv, the operating current value cv, and the contrast ct.

[0097] (Step S2: First Target Luminance Calculation Step)

[0098] ​The luminance estimation section 1B2 calculates a temporary maximum luminance Lmax_t based on the luminance setting value sv and the operating current value cv. Also, the luminance estimation section 1B2 calculates a temporary minimum luminance Lmin_t based on the temporary maximum luminance Lmax_t and the contrast ct. The conversion section 1B3 converts the temporary minimum luminance Lmin_t into a temporary minimum JND value Jmin_t while converting the temporary maximum luminance Lmax_t into a temporary maximum JND value Jmax_t. The target JND value calculation section 1B4 calculates a temporary target JND value Jm_t for each gray scale based on the temporary minimum luminance Lmin_t and the temporary maximum luminance Lmax_t. The target luminance calculation section 1B5 converts the temporary target JND value Jm_t for each gray scale into a first target luminance Lm_t which is a temporary target luminance for each gray scale.

[0099] (Step S3: First Target Luminance Storing Step)

[0100] The luminance processing section 1B stores the acquired first target luminance Lm_t for each gray scale in the table of the LUT 1E.

[0101] (Step S4: First Image Display Step)

[0102] The image processing section 1A displays the image data input from the information processing apparatus 2 in the image display section 1G using the table of the LUT 1E in which the first target luminance Lm_t is stored. Thus, the image display section 1G switches from a state in which the image Dl having a relatively low luminance as shown in Figure 7 to a state in which the image D2 having a relatively high luminance as shown in Figure 7 is displayed. Also, as shown in Figure 8 B, the emphasis processing section 1A2 emphasizes the frame Fr of the image data displayed in the image display section 1G.

[0103] (Step S5: Stabilizing Step)

[0104] The luminance estimation section 1B2 judges whether or not the display luminance of the image display section 1G output from the light sensor 1H has stabilized. Since the display luminance needs time to stabilize after the luminance setting value is made maximum, the image display apparatus 1 judges whether or not the display luminance has stabilized to acquire a more accurate display luminance. This judgment can be made using, for example, a condition such as whether or not the luminance value output from the light sensor 1H is lower than or equal to a predetermined threshold value or whether or not it is within a predetermined range. Also, in this judgment, instead of using the luminance value of the light sensor 1H, a condition can be used whether or not a predetermined time has passed after the request judgment section 1D accepts a request to change the luminance setting value.

[0105] (Step S6: Luminance Acquiring Step)

[0106] The luminance estimation section 1B2 acquires the display luminance of the image display section 1G output by the light sensor 1H. In the embodiment, since the luminance setting value of the image display section 1G is changed to the maximum value, the luminance estimation section 1B2 acquires the maximum luminance Lmax.

[0107] (Step S7: 2nd target luminance calculation step)

[0108] The luminance estimation section 1B2 calculates the minimum luminance Lmin based on the maximum luminance Lmax and the contrast ct. The conversion section 1B3 converts the minimum luminance Lmin to the minimum JND value Jmin while converting the maximum luminance Lmax to the maximum JND value Jmax. The target JND value calculation section 1B4 calculates the target JND value Jm of each gray scale based on the minimum luminance Lmin and the maximum luminance Lmax. The target luminance calculation section 1B5 converts the target JND value Jm of each gray scale to the 2nd target luminance Lm of each gray scale.

[0109] (Step S8: 2nd target luminance storage step)

[0110] The luminance processing section 1B stores the acquired 2nd target luminance Lm of each gray scale to the table of the LUT 1E.

[0111] (Step S9: 2nd image display step)

[0112] The display switching section 1A1 of the image processing section 1A displays the image data input from the information processing apparatus 2 in the image display section 1G using the table of the LUT 1E in which the 2nd target luminance Lm is stored. In other words, the display switching section 1A1 of the image processing section 1A switches the gray scale characteristics of the image displayed in the image display section 1G from the 1st gray scale characteristics to the 2nd gray scale characteristics. Thus, the image display section 1G switches from the state of displaying the image D2 shown in Figure 7 to the state of displaying the image D3 shown in Figure 7 which more conforms to the GSDF characteristics of the actual display light. In addition, the emphasis processing section 1A2 emphasizes the frame Fr of the image data displayed in the image display section 1G. The 2nd image display step is one example of the image processing step.

[0113] (Step S10: timing step)

[0114] The image processing section 1A determines whether or not a predetermined time (for example, 1 minute) has passed since the request determination section 1D accepted the request to change the luminance setting value. Since the luminance increase mode in the embodiment makes the luminance setting value the maximum value, a large load is applied to the image display section 1G. Therefore, the image processing section 1A performs the timing step, and after the predetermined time has passed, the luminance setting value is decreased. Thus, the image display apparatus 1 can suppress the deterioration of the image display section 1G.

[0115] (Step S11: Luminance Reduction Step)

[0116] The display switching section 1A1 reduces the luminance setting value of the image display section 1G. Specifically, the display switching section 1A1 displays an image on the image display section 1G using the table of the LUT 1E in which the target luminance of each gray scale is lower than the second target luminance. In the embodiment, the display switching section 1A1 displays an image on the image display section 1G using the table of the first luminance setting value immediately before the request for the luminance increase mode is accepted. In other words, the display switching section 1A1 returns the luminance setting value of the image display section 1G from the maximum value of the luminance setting value (one example of the second set luminance value) to the luminance setting value immediately before the request for the luminance increase mode is accepted (one example of the first luminance setting value).

[0117] 5Effects of the Embodiment

[0118] The image display system 100 of the embodiment switches the gray scale characteristics of the image data displayed on the image display section 1G to the first gray scale characteristics while switching the luminance setting value from the luminance setting value immediately before the request for the luminance increase mode is accepted (one example of the first luminance setting value) to the maximum value of the luminance setting value (one example of the second set luminance value) if the change request for the luminance setting value is accepted. Then, the image display system 100 of the embodiment is configured to switch the gray scale characteristics from the first gray scale characteristics to the second gray scale characteristics.

[0119] Here, the first gray scale characteristics can be acquired even without the measurement result of the light sensor 1H. That is, the acquisition of the first gray scale characteristics does not require the increase of the display luminance of the image display section 1G, and thus the acquisition of the first gray scale characteristics can be performed simultaneously with the operation of increasing the display luminance of the image display section 1G or the operation of measuring the display luminance of the image display section 1G. Also, the first gray scale characteristics are not images reflecting the measurement result (display luminance) of the actually displayed light, but are characteristics suitable for image interpretation because they correspond to the GSDF.

[0120] The image display system of the related art does not display an image like the first gray scale characteristics of the embodiment, and thus there is a large time lag from the acceptance of the change request for the luminance setting value to the display of the image conforming to the GSDF, which can impair the sense of use.

[0121] In other words, in the conventional image display system, if a change request of the brightness setting value is accepted, the following operations are required: (1) changing the brightness setting value; (2) measuring the display brightness after the change of the brightness setting value; (3) acquiring the target brightness of each gray scale value based on the measured display brightness; and (4) switching the action of the gray scale value. Therefore, a time lag occurs between the change of the brightness of the image display unit by the user and the display of the image corresponding to the desired gray scale characteristic in the image display unit. During the time lag, the image based on the gray scale characteristic before the change of the brightness is displayed at the display brightness after the change of the brightness, and thus the gray scale characteristic of the displayed image can deviate from the desired gray scale characteristic, and the use of the image display system can be impaired.

[0122] To this end, the image display system 100 of the embodiment is configured to quickly display an image (an image of the first gray scale characteristic) close to the second gray scale characteristic after accepting a change request of the brightness setting value.

[0123] Here, the first gray scale characteristic is associated with the gray scale value using the target brightness (i.e., the first target brightness) estimated using the second brightness setting value. On the other hand, the second gray scale characteristic is associated with the gray scale value using the target brightness (i.e., the second target brightness) acquired based on the display brightness acquired by the brightness acquisition unit 1B1 using the second brightness setting value. Therefore, the first gray scale characteristic is close to the second gray scale characteristic. Thus, from the acceptance of the request to the display of the image data corresponding to the second gray scale characteristic in the image display unit 1G, the user can visually confirm the image data corresponding to the first gray scale characteristic, which is closer to the second gray scale characteristic than the gray scale characteristic before the acceptance of the request.

[0124] Thus, the image display system 100 of the embodiment is configured to quickly display the image data corresponding to the first gray scale characteristic close to the second gray scale characteristic, and thus the response is good, and the use is improved.

[0125] In most cases, the difference between the first gray scale characteristic and the second gray scale characteristic is not large. In addition, when displayed at the maximum brightness, the difference in brightness is difficult for a human to recognize because the set brightness is high. Therefore, it is difficult for the doctor to recognize the change from the image of the first gray scale characteristic to the image of the second gray scale characteristic. That is, the image display system 100 of the embodiment has the configuration described above, and thus the response is good, and it is difficult to recognize the change of the gray scale characteristic from the first gray scale characteristic to the second gray scale characteristic, and thus the doctor can easily concentrate on the image interpretation work, and the use is improved.

[0126] As described below, the configuration of the embodiment is effective, for example, when interpreting a medical image such as a mammogram image.

[0127] A doctor who interprets a medical image such as a mammogram image sometimes increases the luminance of the image display section so as to easily find a lesion. However, if the luminance of the image display section is always increased, the image display section deteriorates, and it is difficult to secure the luminance of the image display section. In this regard, a configuration can be considered in which the luminance is temporarily increased when the image display apparatus 1 receives a request, so that the doctor easily interprets the image while it is easier to secure the luminance.

[0128] On the other hand, a medical image such as a mammogram image is generally preferably reflected by the GSDF characteristic. Here, when a medical image is displayed with the GSDF characteristic, a measured value of the display luminance of the image display section needs to be acquired, and a target luminance value conforming to the GSDF needs to be calculated after the measured value is acquired. However, if the luminance of the image display section 1G is increased, an accurate measured value of the display luminance of the image display section cannot be acquired until the luminance of the image display section is stabilized. Furthermore, the calculation of the target luminance value conforming to the GSDF takes a certain degree of time.

[0129] Therefore, in the configuration in which the image display apparatus temporarily increases the luminance, since the acquisition of the measured value or the calculation of the target luminance value takes time, a time lag (for example, a degree of 1 second) occurs between the increase of the luminance of the image display section and the display of the image conforming to the GSDF. Thus, if the doctor increases the luminance of the image display section, an image in which the luminance is increased but which does not completely conform to the GSDF is displayed on the image display section (display in the first stage), and the image in which the luminance is increased and which conforms to the GSDF is displayed after the above-described time lag (display in the second stage). Thus, in the conventional configuration, when the image in the first stage display is switched to the image in the second stage display, the image greatly changes, and it is likely to cause inconvenience to the doctor and impair the sense of use of the doctor.

[0130] Thus, if the image display system 100 of the embodiment receives a request to change the luminance setting value, the gray scale characteristic is switched from the first gray scale characteristic conforming to the GSDF to the second gray scale characteristic conforming to the GSDF. That is, the images displayed before and after the change of the image gray scale characteristic both conform to the GSDF, and thus the doctor hardly recognizes the change of the image. Thus, the image display system 100 of the embodiment can suppress the inconvenience to the doctor who interprets a medical image such as a mammogram image and improve the sense of use of the doctor.

[0131] 6 Modification

[0132] 6-1 Functional Blocks of the Luminance Processing Section 1B

[0133] As Figure 9As shown in FIG. 1, in the image display system 100, the luminance processing section 1B can also be included in the information processing apparatus 2. Also, although not shown, the functional blocks of the luminance processing section 1B can also be provided separately in the image display apparatus 1 and the information processing apparatus 2. For example, the information processing apparatus 2 can also be provided with the luminance estimation section 1B2, and the image display apparatus 1 can be provided with the luminance acquisition section 1B1, the conversion section 1B3, the target JND value calculation section 1B4, and the target luminance calculation section 1B5.

[0134] 6-2 Color image display

[0135] The image display apparatus 1 of the embodiment can also be an image display apparatus that can display a color image. For example, the image display apparatus 1 can display an image in the first and second gradation characteristics when displaying a medical image in the GSDF.

[0136] 6-3 Luminance setting value in luminance increase mode

[0137] The embodiment describes a case where the luminance setting value of the image display apparatus 1 is the maximum value if the luminance increase mode is turned on as one example, but is not limited thereto. The luminance setting value of the image display apparatus 1 can also be a value other than the maximum value.

[0138] Also, the embodiment describes a case where the luminance is increased if the image display apparatus 1 accepts a request, but is not limited thereto. The structure can also be such that the luminance is decreased.

[0139] 6-4 Function for use

[0140] The embodiment describes a case where the image is displayed in the image display section 1G using the table of the LUT 1E, but is not limited thereto. A function corresponding to the table can also be used.

[0141] 6-5 Method of calculating temporary maximum luminance Lmax_t

[0142] The embodiment describes a case where the luminance estimation section 1B2 calculates the temporary maximum luminance Lmax_t as the maximum luminance calculation value based on the luminance setting value sv (one example of the first luminance setting value) immediately before the image display apparatus 1 accepts a request and the operating current value cv of the image display section 1G at the luminance setting value when acquiring the first gradation characteristic, but is not limited thereto. The luminance estimation section 1B2 can also use, for example, the maximum luminance setting value at the time of shipment instead of the luminance setting value sv immediately before the image display apparatus 1 accepts a request. In this case, the maximum luminance setting value at the time of shipment can be stored in the storage section 1E.

[0143] 6-6 Form of light sensor

[0144] The case where the light sensor 1H is built in the image display apparatus 1 is described in the embodiments, but is not limited thereto. The light sensor 1H can also be configured to be disposed on the front surface side of the image display section 1G of the image display apparatus 1, and to perform measurement of light from the image display surface of the image display section 1G. At this time, the luminance acquisition section 1B1 can also be configured in the following manner when calculating the 2nd target luminance.

[0145] The luminance acquisition section 1B1 can calculate the maximum luminance Lmax as shown in Figure 3

[0146] (Symbol Explanation)

[0147] 1: image display apparatus, 1A: image processing section, 1A1: display switching section, 1A2: emphasis processing section, 1B: luminance processing section, 1B1: luminance acquisition section, 1B2: luminance estimation section, 1B3: conversion section, 1B4: target JND value calculation section, 1B5: target luminance calculation section, 1C: operation section, 1D: request judgment section, 1E: LUT, 1F: storage section, 1G: image display section, 1H: light sensor, 2: information processing apparatus, 100: image display system, D: image, D1: image, D2: image, D3: image, Fr: frame, Jm: target JND value, Jm_t: temporary target JND value, Jmax: maximum JND value, Jmax_t: temporary maximum JND value, Jmin: minimum JND value, Jmin_t: temporary minimum JND value, Lm: 2nd target luminance, Lm_t: 1st target luminance, Lmax: maximum luminance, Lmax_t: temporary maximum luminance, Lmin: minimum luminance, Lmin_t: temporary minimum luminance, ct: contrast, cv: working current value, sv: luminance setting value.​

Claims

1. An image display system that displays image data, the image display system includes an image display unit, a luminance acquisition unit, and an image processing unit, the image display unit is configured to display the image data, the luminance acquisition unit is configured to be able to acquire a display luminance of the image display unit, the image processing unit is configured to, if the image display system accepts a request to change a luminance setting value of the image display unit from a first luminance setting value to a second luminance setting value, switch a gradation characteristic of the image data displayed in the image display unit from a gradation characteristic before acceptance of the request to a first gradation characteristic that approximates a second gradation characteristic while switching the luminance setting value from the first luminance setting value to the second luminance setting value, and then switch the gradation characteristic of the image data displayed in the image display unit from the first gradation characteristic to the second gradation characteristic, the first gradation characteristic is one in which a gradation value is associated with a first target luminance, the first target luminance is a target luminance that is estimated in such a manner that the image display unit displays the image data at the display luminance when the luminance setting value is the second luminance setting value, and the first target luminance is acquired on the basis of the display luminance of the image display system in a state in which the first luminance setting value is displayed before acceptance of the request, the second gradation characteristic is one in which the gradation value is associated with a second target luminance, the second target luminance is acquired on the basis of the display luminance of the image display unit in a state in which the image data of the first gradation characteristic is displayed at the second luminance setting value.

2. The image display system according to claim 1, wherein the first target luminance is based on the first luminance setting value before the image display system accepts the request, and a working current value of the image display unit corresponding to the luminance setting value.

3. The image display system according to claim 1 or 2, wherein the first gradation characteristic and the second gradation characteristic are constituted by a function or a table.

4. The image display system according to claim 1 or 2, wherein the second luminance setting value is greater than the first luminance setting value.

5. The image display system according to claim 4, wherein the second luminance setting value is a maximum value that can be set for the image display unit.

6. The image display system according to claim 1 or 2, wherein if a predetermined time elapses after the image display system accepts the request, the image processing unit returns the luminance setting value of the image display unit from the second luminance setting value to the first luminance setting value.

7. The image display system according to claim 1 or 2, wherein the image processing unit is configured to, if the image display system accepts the request, emphasize a frame of the image data displayed in the image display unit.

8. An image display method that displays image data in an image display unit, the image display method includes a luminance acquisition step, and an image processing step, In the luminance acquisition step, a display luminance of the image display section is acquired, In the image processing step, if a request to change a luminance setting value of the image display section from a first luminance setting value to a second luminance setting value is accepted, a gradation characteristic of the image data displayed on the image display section is switched from a gradation characteristic before acceptance of the request to a first gradation characteristic approximating a second gradation characteristic while the luminance setting value is switched from the first luminance setting value to the second luminance setting value, and then the gradation characteristic of the image data displayed on the image display section is switched from the first gradation characteristic to the second gradation characteristic, The first gradation characteristic is associated with a first target luminance, The first target luminance is acquired based on the display luminance in a state in which the image display section displays the image data with the first luminance setting value before acceptance of the request, and the first target luminance is a target luminance estimated in such a manner that the image display section displays the image data with the display luminance when the luminance setting value is the second luminance setting value, The second gradation characteristic is associated with a second target luminance, The second target luminance is acquired based on the display luminance in a state in which the image display section displays the image data with the second luminance setting value in the first gradation characteristic.

9. A recording medium, which is a computer-readable non-transitory recording medium storing a computer program, the computer program executing the image display method according to claim 8.

Images