WO2018147196A1 - Display device, television receiver, video processing method, backlight control method, reception device, video signal generation device, transmission device, video signal transmission system, reception method, program, control program, and recording medium - Google Patents

Abstract

A display device (1) is provided with a switching unit (4) that switches a conversion means in accordance with the brightness level of a video signal. The switching unit switches the conversion means by referring to the brightness level of a corrected image that is obtained by excluding an area including an artificial display object from an image to be displayed.

Description

Display device, television receiver, video processing method, backlight control method, receiving device, video signal generating device, transmitting device, video signal transmission system, receiving method, program, control program, and recording medium

The present invention relates to a video processing device and a receiving device that switch a conversion function between a gradation value and a luminance value.

In recent years, as one of the high image quality technologies, HDR (High Dynamic Range) has more gradations (number of possible gradation values) and higher brightness information than SDR (Standard Dynamic Range) signals. ) The signal is getting attention. In addition, UHDBD discs capable of storing HDR signals have been commercialized. By using the HDR technology, it is possible to obtain a powerful image with higher brightness and higher contrast than before. The HDR signal includes luminance information of a maximum of about 10,000 nits as a standard. When the video indicated by the HDR signal includes a caption, the caption is also displayed with high luminance.

As a technique for processing subtitles included in video, Patent Document 1 discloses that an original image is divided into video from which subtitles are extracted and information of subtitles that are extracted, and the divided information is interpolated and expanded. A circuit for synthesizing after performing reduction processing is disclosed.

In recent years, HDR (High Dynamic Range) signals such as the PQ method and the HLG method have attracted attention as one of the image quality enhancement techniques. In addition, when a video signal such as an HDR signal including content is received by a receiving device such as a television set or STB (Set Top Box), a technique for converting a gradation value indicated by the video signal into a luminance value is generalized. According to such a technique, it is possible to display a high-contrast image by displaying an image with appropriate luminance based on an HDR signal having a large number of gradations.

In a receiving apparatus that converts such gradation into luminance, for example, when a user displays subtitles on a video, the gradation value may not be accurately converted into a luminance value. As a result, the receiving device may not be able to display an appropriate video desired by the user.

Here, in Patent Document 1, when there is subtitle information in the video, the subtitle is extracted from the original image, divided into a video and subtitle extracted from the subtitle, and image processing is performed on each of the video and the subtitle. A technique for later synthesis is described.
The technology is described.

Japanese Patent Publication “Japanese Patent Laid-Open No. 2001-169199 (published on June 22, 2001)”

In the HDR technology, there is a demand for a technology for displaying video with a more appropriate luminance according to the video signal.

However, the size relationship between the luminance value of the video obtained by extracting the caption from the original image and the caption, the color of the caption, etc. are not constant. For this reason, even if the image and the caption are subjected to image processing using the technique as described in Patent Document 1, the image is displayed with appropriate luminance according to the image signal depending on the scene or the like. There is a problem that can not be.

One aspect of the present invention has been made in view of the above-described problems, and an object thereof is to display an image with a more appropriate luminance according to a video signal in a technology for adjusting the luminance.

In order to solve the above problem, a display device according to one embodiment of the present invention includes a plurality of conversion units that set luminance values from gradation values indicated by a video signal of a display target image, and the luminance of the video signal. A switching unit that switches the conversion means according to a level, and the switching unit refers to a luminance level of a corrected image obtained by excluding a region including an artificial display object from the display target image. Switch the conversion means.

In order to solve the above-described problem, a video processing method according to an aspect of the present invention is a video processing method by a display device having a plurality of conversion units for setting a luminance value from a gradation value indicated by a video signal of a display target image. A switching step of switching the conversion means according to the luminance level of the video signal, wherein the switching step is a correction obtained by excluding a region including an artificial display object from the display target image. The conversion means is switched with reference to the luminance level of the image.

A display device according to one embodiment of the present invention includes a backlight that includes a plurality of areas and can individually control the brightness of the plurality of areas, and a backlight control unit that controls the backlight. The backlight control unit makes the brightness of the corresponding area corresponding to the area including the artificial display object in the display target image different from the brightness of the other areas.

In order to solve the above problems, a video processing method according to an aspect of the present invention includes a backlight that includes a plurality of areas and that can individually control the brightness of the plurality of areas, and controls the backlight. A backlight control method by a display device comprising a backlight control unit, wherein in the backlight control step, the brightness of a corresponding area corresponding to a region including an artificial display object in a display target image, Different from the brightness of other areas.

A receiving device according to one aspect of the present invention is a receiving device that receives a video signal including video data and metadata, and transmits information on the maximum luminance of the content indicated by the video data to one content. A plurality of acquisition units, and a conversion unit that converts the luminance of the video indicated by the video data with reference to at least one of the plurality of pieces of information about the maximum luminance acquired by the acquisition unit.

A video signal generation device according to an aspect of the present invention is a video signal generation device that generates a video signal including video data and metadata, and includes information on the maximum luminance of content indicated by the video data. A metadata generation unit that generates a plurality of metadata for the content.

A video signal transmission system according to an aspect of the present invention is a video signal transmission system including a transmission device and a reception device, and the transmission device transmits a video signal including video data and metadata. A metadata generation unit that generates metadata including a plurality of pieces of information regarding the maximum luminance of the content indicated by the video data for one content, and the receiving device receives the video signal. The acquisition unit that acquires a plurality of pieces of information regarding the maximum luminance of the content indicated by the video data with respect to one content, and at least one of the plurality of pieces of information about the maximum luminance acquired by the acquisition unit is referred to A conversion unit that performs luminance conversion of the video indicated by the video data.

A reception method according to an aspect of the present invention is a reception method for receiving a video signal including video data and metadata, and information on the maximum luminance of the content indicated by the video data is received for one content. A plurality of acquisition steps, and a conversion step for converting the luminance of the video indicated by the video data with reference to at least one of the plurality of pieces of information regarding the maximum luminance acquired in the acquisition step.

According to one aspect of the present invention, a video can be displayed with a more appropriate luminance according to a video signal in the technology for adjusting the luminance.

It is a block diagram which shows the structure of the display apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the external appearance of the television receiver provided with the display apparatus which concerns on Embodiment 1 of this invention. It is a flowchart explaining the video processing method which concerns on Embodiment 1 of this invention. (A) is a front view which shows the external appearance of the display apparatus which is displaying the display target image containing a caption. (B) is a graph which shows the PQ curve of the display target image which the display apparatus shown to (a) of FIG. 4 displays. It is a block diagram which shows the structure of the display apparatus which concerns on Embodiment 2 of this invention. It is a flowchart explaining the video processing method which concerns on Embodiment 2 of this invention. It is a flowchart explaining the video processing method which concerns on Embodiment 3 of this invention. It is a block diagram which shows the structure of the video signal transmission system provided with the receiver concerning Embodiment 4 of this invention. It is a figure which shows the external appearance of the receiver which concerns on Embodiment 4 of this invention. It is a flowchart explaining the reception method which concerns on Embodiment 4 of this invention. It is a figure for demonstrating the reception method which concerns on Embodiment 4 of this invention. It is a block diagram which shows the structure of the video signal transmission system provided with the receiver concerning Embodiment 5 of this invention. It is a figure for demonstrating the reception method which concerns on Embodiment 5 of this invention. It is a flowchart for demonstrating the reception method which concerns on Embodiment 5 of this invention. It is a block diagram which shows the structure of the video signal transmission system provided with the receiver concerning Embodiment 6 of this invention. It is a figure for demonstrating the reception method which concerns on Embodiment 6 of this invention. It is a flowchart for demonstrating the reception method which concerns on Embodiment 6 of this invention.

Hereinafter, embodiments of the present invention will be described in detail. However, unless otherwise specified, the configuration described in the present embodiment is merely an illustrative example, and is not intended to limit the scope of the present invention. In the present specification, “switching tone mapping” means switching a method for converting a gradation value indicated by a video signal into a luminance value used when displaying a video.

Embodiment 1
(Display device 1)
A display device 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram illustrating a configuration of a display device 1 according to the present embodiment. FIG. 2 is a front view showing an appearance of a television receiver including the display device 1. As shown in FIG. 1, the display device 1 includes a video processing unit 2, a backlight 7, and a display unit 8. The video processing unit 2 is a member that performs conversion (tone mapping) between a gradation value and a luminance value indicated by the video signal using a conversion function (conversion means in the claims), and includes a caption detection unit 3 and a switching unit 4. A conversion unit 5 and a backlight control unit 6 are provided.

The caption detection unit 3 detects an artificial display object (caption in this embodiment) in the display target image indicated by the video signal acquired from the outside, and artificially detects the luminance data (gradation value) of the display target image. Luminance data of a corrected image obtained by excluding luminance data of a region including a display object is generated.

The switching unit 4 switches the conversion function used in the conversion unit 5 according to the luminance level of the corrected image generated by the caption detection unit 3.

The conversion unit 5 converts the gradation value of the corrected image into a luminance value using the conversion function switched by the switching unit 4 (specifically, used when displaying video from the gradation value indicated by the video signal). Conversion to luminance value (tone mapping)).

The backlight control unit 6 controls the luminance of each area of the backlight 7 corresponding to the corrected image displayed on the display unit 8 to the luminance value converted by the conversion unit 5. In addition, the backlight control unit 6 sets the luminance of each area of the backlight 7 corresponding to the region including the artificial display object displayed by the display unit 8 (the region detected by the caption detection unit 3) of other areas. The brightness value is controlled to be different from the brightness (local dimming).

The backlight 7 is composed of a plurality of areas, the brightness of the plurality of areas can be individually controlled, and the display unit 8 is irradiated with light based on the control by the backlight control unit 6.

The display unit 8 is a non-luminous display and displays a display target image indicated by a video signal (RGB data excluding luminance data). A liquid crystal display etc. are mentioned as an example of a non-light-emitting display.

In the present embodiment, a configuration using the non-light emitting display unit 8 and the backlight 7 is shown. However, each area of the backlight 7 corresponding to the region including the artificial display object displayed on the display unit 8 is displayed. When the configuration (local dimming) for controlling the brightness to be different from the brightness of other areas is not adopted, only the self-luminous display is used as the display unit 8 without using the backlight 7. May be. Examples of the self-luminous display include an organic EL display, a plasma display, and an LED display.

(Video processing method)
A flow of a video processing method executed by the display device 1 according to the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing the flow of the backlight control method of the display device 1. Hereinafter, for simplification, description of the control of the display unit 8 is omitted.

First, the caption detection unit 3 detects captions in a display target image indicated by an externally acquired video signal, and brightness data of an area including an artificial display object from brightness data (gradation value) of the display target image. The brightness data of the corrected image obtained by excluding is generated (step S0).

Note that the caption detection unit 3 performs image processing such as edge detection using a filter on a display target image indicated by a video signal acquired from the outside, and excludes luminance data of a region including an artificial display object. be able to. However, the specific process of excluding the luminance data of the area including the artificial display object is not limited to the present embodiment.

An example of the video signal processed by the caption detection unit 3 is an HDR signal. The HDR signal may be an HDMI signal based on the HDMI (registered trademark) (High-Definition Multimedia Interface) standard, a Tuner signal (a signal received by a tuner), or the like.

Further, the artificial display object detected by the caption detection unit 3 refers to a display object artificially created by CG (Computer Graphics) or the like, and is an object synthesized or added to the content video of the display target image. It can be. Examples of such objects include subtitles, logos (channel display), and control panels (OSDs that are superimposed on the transmission side such as STB and BD).

As the next step after step S0, the switching unit 4 switches the conversion function used in the conversion unit 5 according to the luminance level of the luminance data of the corrected image generated by the caption detection unit 3 (step S1). As an example of the luminance level that the switching unit 4 refers to in order to switch the conversion function, the maximum gradation value or the average value of the gradation values in the luminance data of the corrected image can be cited.

Next, the conversion unit 5 converts the gradation value of the corrected image into a luminance value using the conversion function switched by the switching unit 4 (step S2).

Next, the backlight control unit 6 controls the luminance value of each area of the backlight 7 corresponding to the corrected image displayed on the display unit 8 to the luminance value converted by the conversion unit 5 (step S3).

In step S3, the backlight control unit 6 determines the luminance of each area of the backlight 7 corresponding to the region including the artificial display object displayed by the display unit 8 (the region detected by the caption detection unit 3). The brightness value is controlled to be different from the brightness of other areas. Note that the backlight control unit adjusts the brightness (brightness) of the area corresponding to the region including the artificial display object displayed on the display unit 8 according to the gradation of the artificial display object. It is preferable that the brightness is different.

In the present embodiment, the video processing unit 2 includes the conversion unit 5, and the conversion unit 5 converts the gradation value of the corrected image into a luminance value using the conversion function switched by the switching unit 4. Explained. However, one embodiment of the present invention is not limited to this. In one aspect of the present invention, the video processing unit 2 only needs to have a plurality of conversion means for setting the luminance value from the gradation value of the corrected image instead of using the conversion function (in this embodiment, a plurality of The switching unit 4 has only to switch the conversion unit according to the luminance level of the corrected image. For example, the video processing unit 2 has a table indicating correspondence between gradation values and luminance values in order to set luminance values from the gradation values of the corrected image, and the switching unit 4 displays the luminance level of the corrected image. The table to be referenced may be switched depending on

In one aspect of the present invention, steps S0 to S2 may be omitted in the above processing. Even with such a configuration, the effect of displaying a video with a more appropriate luminance in accordance with the video signal, more specifically, even if the display target image includes an artificial display object, There is an effect that an image can be displayed with luminance.

(Concrete example)
A specific example of the video processing method according to the present embodiment will be described below with reference to FIG. FIG. 4A is a front view showing an appearance of the display device 1 displaying a display target image including subtitles. FIG. 4B is a graph showing a PQ curve of the display target image displayed by the display device 1 shown in FIG. In FIG. 4B, the horizontal axis represents the gradation value before conversion, and the vertical axis represents the luminance value after conversion (luminance when displaying an image).

4A, the display unit 8 displays the corrected image A and the caption B obtained by excluding the luminance data of the area including the caption. In step S0 described above, the caption detection unit 3 detects the caption B in the display target image indicated by the video signal acquired from the outside, and the region including the caption B from the luminance data (gradation value) of the display target image. The brightness data of the corrected image A obtained by excluding the brightness data is generated.

Next, in step S1, the switching unit 4 uses the PQ curve (EOTF according to SMPTE-ST2084) in which the graph of the gradation value before conversion and the luminance value after conversion corresponds to the maximum luminance level of the corrected image A. Switch to a conversion function that converts to the curve shown by. More specifically, the switching unit 4 converts the gradation value into a luminance value so that the luminance value corresponding to the maximum gradation value indicated by the video signal becomes a value of a predetermined maximum luminance level C. Switch to conversion function. Here, the predetermined maximum luminance level C may be an arbitrary value set in advance, but is set according to the luminance range that the video signal can take and the luminance range of the light that the backlight 7 can irradiate. Is preferred. An example of a specific value of the predetermined maximum luminance level C is 1000 nit.

Next, in step S2, the conversion unit 5 converts the gradation value of the corrected image A into a luminance value using the conversion function switched by the switching unit 4. Next, in step S <b> 3, the backlight control unit 6 controls the luminance of each area of the backlight 7 corresponding to the corrected image A displayed on the display unit 8 to the luminance value converted by the conversion unit 5. Further, the backlight control unit 6 controls the luminance value of each area of the backlight 7 corresponding to the caption B displayed on the display unit 8 to a luminance value different from the luminance of the corrected image A.

In the above specific example, for example, the gradation value corresponding to the caption B is larger than the gradation value corresponding to the corrected image A, and the switching unit 4 sets the maximum gradation value in the caption B in step S1 described above. When the conversion function is switched with reference, the PQ curve formed by the gradation value before conversion and the luminance value after conversion becomes like the dotted line in FIG. 4B, and the image becomes dark. .

Therefore, in the present embodiment, in step S1, the switching unit 4 switches the conversion function with reference to the maximum gradation value of the corrected image A excluding the caption B from the display target image. As a result, the PQ curve formed by the gradation value before conversion and the luminance value after conversion becomes as shown by the solid line in FIG. 4B, and an image can be displayed with more appropriate luminance according to the video signal. it can.

However, when only the brightness in the corrected image A is adjusted in this way, the brightness of the caption B may be relatively high. Therefore, the backlight control unit 6 controls the luminance of each area of the backlight 7 corresponding to the caption B displayed on the display unit 8 to be lower than the luminance of the corrected image A.

Also, the video processing method according to the present embodiment is effective when the gradation value corresponding to the caption B is smaller than the gradation value corresponding to the corrected image A. In that case, the brightness of the corrected image A displayed by the display unit 8 is compared with the case where the subtitle B is not removed by switching the conversion function with reference to the maximum gradation value of the corrected image A excluding the subtitle B. As a result, the image becomes dark, and the image can be displayed with a more appropriate luminance according to the image signal. Further, the backlight control unit 6 may control the luminance of each area of the backlight 7 corresponding to the caption B displayed on the display unit 8 to be higher than the luminance of the corrected image A.

In this specific example, an example of an absolute luminance method (including a PQ method) is shown as a luminance method when converting from a gradation value to a luminance value, but a relative luminance method (an HLG method or the like) is used as the luminance method. May be adopted. Even in that case, it is possible to achieve the same effect as the display device 1 according to the present embodiment.

(Summary of Embodiment 1)
When the display device displays the caption of the video indicated by the HDR signal, the conversion function applied to the luminance data of the image indicated by the HDR signal is switched with reference to the peak luminance and the average luminance in the luminance data included in the HDR signal. In that case, there is a problem that the conversion function is switched with reference to the peak luminance and the average luminance including the luminance data of the caption that may greatly change the peak luminance or the average luminance (APL).

When a user displays subtitles with a controller or the like, if the video is originally low in peak luminance and low in average luminance, the PQ curve is set to MAX CLL (for example, 10,000 nits) as the maximum luminance value. By changing the PQ curve to a PQ curve suitable for a display device, the optimum image quality can be supplied. However, due to the above problem, when the white character of the subtitle (current UHD-BD is set to 128/255 which is half of normal data) is displayed, this subtitle portion is detected as the peak luminance and PQ Create a curve. Further, even when a PQ curve is created with reference to the average luminance, the luminance of the subtitle portion is added, and the average luminance data cannot be obtained accurately. For this reason, it is not possible to display an image with the optimum brightness desired by the user.

Therefore, the display device 1 according to the present embodiment switches the conversion means with reference to the luminance level of the corrected image obtained by excluding the region including the artificial display object from the display target image. Accordingly, the luminance value can be set from the gradation value by the conversion unit according to the luminance level of the corrected image excluding an artificial display object that may greatly change the maximum luminance level or the average luminance level. . As a result, when the tone mapping method is switched with reference to the maximum luminance level or the average luminance level, the influence of the luminance of the artificial display object on the maximum luminance level or the average luminance level can be suppressed. Therefore, it is possible to display an image with a more appropriate luminance according to the image signal.

[Embodiment 2]
Embodiment 2 of the present invention will be described below with reference to FIGS. 5 and 6. For convenience of explanation, members having the same functions as those described in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

(Display device 10)
The display device 10 according to the present embodiment will be described with reference to FIG. FIG. 5 is a block diagram illustrating a configuration of the display device 10 according to the present embodiment. As illustrated in FIG. 5, the display device 10 further includes a reception unit 12 of the video processing unit 11 in addition to the configuration of the display device 1 according to the first embodiment.

The accepting unit 12 accepts selection by the user as to whether or not to execute the function of switching the conversion means with reference to the brightness level of the corrected image. In addition, the reception unit 12 determines whether or not to execute a function of making the brightness of the area (corresponding area) corresponding to the area including the artificial display object in the display target image different from the brightness of the other areas. Accepts selection by.

(Video processing method by display device 10)
A flow of a video processing method executed by the display device 10 according to the present embodiment will be described with reference to FIG. FIG. 6 is a flowchart showing the flow of the video processing method executed by the display device 10. Note that description of steps similar to those described in Embodiment 1 is omitted.

First, the accepting unit 12 accepts a selection by the user as to whether or not to execute the function of switching the conversion means with reference to the brightness level of the corrected image (step S10). Further, in step S10, the reception unit 12 performs a function of making the brightness of the area (corresponding area) corresponding to the area including the artificial display object in the display target image different from the brightness of the other areas. The selection by the user is accepted.

Hereinafter, an example of step S10 will be described. For example, when the artificial display object is a caption, a logo, or a control panel, the user sets whether or not to display these in the user menu, and the reception unit 12 receives the setting. And when the reception part 12 receives the setting which displays a subtitle, a logo, or a control panel, it progresses to the next process. In addition, when the reception unit 12 receives a setting for displaying a caption, a logo, or a control panel, the backlight control unit 6 displays an area (corresponding area) corresponding to an area including an artificial display object in the display target image. The backlight control unit 6 is instructed to execute a function of making the brightness different from the brightness of other areas.

As the next step of step S10, the caption detection unit 3 detects the caption in the display target image indicated by the video signal acquired from the outside based on the user's selection received by the reception unit 12, and the luminance of the display target image. From the data (gradation value), the luminance data of the corrected image obtained by excluding the luminance data of the area including the artificial display object is generated (step S11).

Next, the switching unit 4 switches the conversion function used in the conversion unit 5 in accordance with the luminance level of the luminance data of the corrected image generated by the caption detection unit 3 (step S12).

Next, the conversion unit 5 converts the gradation value of the corrected image into a luminance value using the conversion function switched by the switching unit 4 (step S13).

Next, the backlight control unit 6 controls the luminance value of each area of the backlight 7 corresponding to the corrected image displayed on the display unit 8 to the luminance value converted by the conversion unit 5 (step S14).

In step S <b> 14, the backlight control unit 6 includes an artificial display object displayed on the display unit 8 based on the user selection received by the reception unit 12 (region detected by the caption detection unit 3). The brightness of each area of the backlight 7 corresponding to is controlled to a brightness value different from the brightness of other areas.

Note that in one aspect of the present invention, steps S11 to S13 may be omitted in the above processing.

Even with such a configuration, the effect of displaying a video with a more appropriate luminance in accordance with the video signal, more specifically, even if the display target image includes an artificial display object, There is an effect that an image can be displayed with luminance.

(Summary of Embodiment 2)
As described above, the display device 10 according to the present embodiment accepts the selection by the user as to whether or not to execute the function of switching the conversion means with reference to the luminance level of the corrected image. Thereby, the user can select whether to switch the conversion means with reference to the luminance level of the corrected image.

Further, the display device 10 according to the present embodiment determines whether or not to execute the function of making the brightness of the corresponding area corresponding to the area including the artificial display object in the display target image different from the brightness of the other areas. , Accepts selection by the user. This adjusts the brightness of the backlight corresponding to each area so that there is no unnatural boundary between the area containing the artificial display object and the area other than the area containing the artificial display object. Can do. Therefore, it is possible to display an image with a more appropriate luminance according to the image signal.

[Embodiment 3]
Embodiment 3 of the present invention will be described below with reference to FIG. Note that the video processing method according to the present embodiment can be executed by using the display device 1 according to the first embodiment. Therefore, for convenience of explanation, members having the same functions as those described in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

(Video processing method according to Embodiment 3)
A flow of a video processing method executed by the display device 1 according to the present embodiment will be described with reference to FIG. FIG. 7 is a flowchart showing the flow of the video processing method executed by the display device 1. Note that description of steps similar to those described in Embodiment 1 is omitted.

First, the caption detection unit 3 determines the category, genre, or scene type of the display target image indicated by the video signal from the metadata included in the video signal acquired from the outside, and converts it with reference to the luminance level of the corrected image. It is determined whether or not to execute a function for switching means (step S20). When the caption detection unit 3 determines to execute the function of switching the conversion means with reference to the luminance level of the corrected image, the process proceeds to step S21. When the caption detection unit 3 determines not to execute the function of switching the conversion unit with reference to the luminance level of the corrected image, the process ends.

As an example of a method for determining whether or not to execute the function of switching the conversion means with reference to the luminance level of the corrected image, the caption detection unit 3 uses a display object whose category, genre, or scene is an artificial display object. In the case of a category, genre, or scene that has a high possibility of being included, there is a method of determining to execute a function of switching conversion means with reference to the luminance level of the corrected image. In that case, when the category of the display target image is a movie, the display target image is likely to include subtitles, so the subtitle detection unit 3 executes a function of switching the conversion means with reference to the luminance level of the corrected image. Judge that. When the category of the display target image is sports, the caption detection unit 3 further determines whether the scene of the display target image is indoor or outdoor, and based on the determination, the switching unit 4 The conversion function may be switched (for example, in conjunction with the average luminance of the display target image).

In step S20, the caption detection unit 3 determines the category, genre, or scene type of the display target image indicated by the video signal from the metadata included in the video signal acquired from the outside, and artificially displays the image in the display target image. It is determined whether or not to execute a function of making the brightness of the corresponding area corresponding to the area including the display object different from the brightness of the other areas. The determination method is the same as the method for determining whether to execute the function of switching the conversion means with reference to the luminance level of the corrected image. For this reason, the caption detection unit 3 performs a function of switching the conversion means with reference to the brightness level of the corrected image to determine whether to execute the function of making the brightness of the corresponding area different from the brightness of the other areas. It may be determined depending on whether or not to do so.

In step S21, the caption detection unit 3 detects the caption in the display target image indicated by the video signal acquired from the outside, and includes an artificial display object from the luminance data (gradation value) of the display target image. The brightness data of the corrected image obtained by excluding the brightness data of the area is generated (step S21).

Next, the switching unit 4 switches the conversion function used in the conversion unit 5 in accordance with the luminance level of the luminance data of the corrected image generated by the caption detection unit 3 (step S22).

Next, the conversion unit 5 converts the gradation value of the corrected image into a luminance value using the conversion function switched by the switching unit 4 (step S23).

Next, the backlight control unit 6 controls the luminance value of each area of the backlight 7 corresponding to the corrected image displayed on the display unit 8 to the luminance value converted by the conversion unit 5 (step S24).

If it is determined in step S20 that the caption detection unit 3 performs the function of making the brightness of the corresponding area different from the brightness of the other areas, the backlight control unit 6 displays the display unit 8 in step S24. The luminance of each area of the backlight 7 corresponding to the area including the artificial display object (area detected by the caption detection unit 3) displayed by is controlled to a luminance value different from the luminance of the other areas.

In one aspect of the present invention, steps S21 to S23 may be omitted in the above processing. In that case, step S20 executes the following process instead of the process described above.

(Step S20a)
The caption detection unit 3 determines the category, genre, or scene type of the display target image indicated by the video signal from the metadata included in the video signal acquired from the outside.

(Step S20b)
Subsequently, the brightness of each area of the backlight 7 corresponding to the area including the artificial display object displayed on the display unit 8 (the area detected by the caption detection unit 3) is different from the brightness of the other areas. Whether to control the brightness value is determined according to the determination result in step S20a. When it determines with controlling the backlight 7 as mentioned above, it progresses to step S24.

Even with such a configuration, the effect of displaying a video with a more appropriate luminance in accordance with the video signal, more specifically, even if the display target image includes an artificial display object, There is an effect that an image can be displayed with luminance. Moreover, suitable backlight control can be performed according to the category, genre, or scene of the display target image indicated by the video signal.

(Summary of Embodiment 3)
As described above, the display device 1 according to the present embodiment switches the conversion unit with reference to the luminance level of the corrected image according to the category, genre, or scene of the display target image. As a result, when there is a high possibility that the category, genre, or scene of the display target image includes an artificial display object, the conversion means is switched with reference to the luminance level of the corrected image as necessary. The conversion means can be switched.

Further, the display device 1 according to the present embodiment makes the brightness of the corresponding area different from the brightness of other areas according to the category, genre, or scene of the display target image. As a result, when there is a high possibility that the category, genre, or scene of the display target image contains an artificial display object, the brightness of the corresponding area is made different from the brightness of other areas as necessary. Local dimming can be performed.

[Example of software implementation]
The control blocks of the display devices 1 and 10 (in particular, the caption detection unit 3, the switching unit 4, the conversion unit 5, the backlight control unit 6, and the reception unit 12) are logic circuits formed in an integrated circuit (IC chip) or the like. (Hardware) or software using a CPU (Central Processing Unit).

In the latter case, the display devices 1 and 10 include a CPU that executes instructions of a program that is software that realizes each function, and a ROM (Read Only Memory) in which the program and various data are recorded so as to be readable by a computer (or CPU). ) Or a storage device (these are referred to as “recording media”), a RAM (Random Access Memory) that expands the program, and the like. The computer (or CPU) reads the program from the recording medium and executes the program, thereby achieving the object of one embodiment of the present invention. As the recording medium, a “non-temporary tangible medium” such as a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. The program may be supplied to the computer via an arbitrary transmission medium (such as a communication network or a broadcast wave) that can transmit the program. Note that one embodiment of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

<Embodiment 4>
[Video signal transmission system 100B]
A video signal transmission system 100B according to Embodiment 4 of the present invention will be described with reference to FIGS.

FIG. 8 is a block diagram showing a configuration of the video signal transmission system 100B according to the present embodiment. As shown in FIG. 8, the video signal transmission system 100B includes a transmission device 1B and a reception device 10B.

[Transmitter 1B]
The configuration of the transmission device 1B according to the present embodiment will be described with reference to FIG. As shown in FIG. 8, the transmission device 1B according to the present embodiment includes a video signal generation device 2B and a transmission unit 5B.

The transmission device 1B transmits a video signal including the video data and metadata generated by the video signal generation device 2B to the reception device 10B via the transmission unit 5B. The transmission unit 5B transmits a video signal to the reception device 10B by performing wireless communication with the reception device 10B.

Examples of the transmitting device 1B include a broadcasting station such as a television station.

[Video signal generator 2B]
The video signal generation device 2B generates a video signal including video data and metadata. As shown in FIG. 8, the video signal generation device 2B includes video data generation units 3B and 4B.

The video signal generation device 2B adds the metadata created by the metadata generation unit 4B to the video data generated by the video data generation unit 3B, and sends the video data to the transmission unit 5B.

Here, in this embodiment, an HDR signal is used as the video signal. Examples of HDR signals include HDMI (registered trademark) signals based on the HDMI (registered trademark) (High-Definition Multimedia Interface) standard, Tuner signals (signals received by a tuner), and the like. be able to. The HDR signal includes metadata such as MAX CLL indicating the maximum luminance level of content in addition to video data of character information including gradation values and captions taken by each image.

(Video data generator 3B)
The video data generation unit 3B generates video data such as gradation values and subtitle information taken by each image. The video data generation unit 3B generates video data to be transmitted as a video signal, for example, by converting video data acquired from the outside.

(Metadata generator 4B)
The metadata generation unit 4B generates metadata including a plurality of pieces of information regarding the maximum luminance of the content indicated by the video data for one content.

In the present embodiment, MAX CLL indicating the maximum luminance level of content including subtitles and MAX CLL (CHAROFF) indicating the maximum luminance level of content excluding subtitles are used as information regarding the maximum luminance.

As described above, the metadata generation unit 4B generates metadata including information regarding the maximum luminance according to the case where the caption information is included and information regarding the maximum luminance according to the case where the caption information is not included. can do. As a result, the receiving device 10B that has received the metadata generated by the metadata generation unit 4B can display a video with a more appropriate luminance corresponding to the video signal including the video data.

In the above example, the metadata generation unit 4B generates a plurality of pieces of information related to the maximum luminance of the content, depending on whether or not caption information is included in the video data. However, the present embodiment is not limited to this.

For example, the metadata generation unit 4B may generate a plurality of pieces of information related to the maximum brightness of the content, depending on the condition other than whether or not caption information is included in the video data. In this case, for example, two pieces of information regarding MAX CLL and another maximum luminance can be used as the information regarding the maximum luminance. Also in this case, similarly to the above-described example, an image can be displayed with a more appropriate luminance according to the image signal.

In the above example, only two of MAX CLL and MAX CLL (CHAROFF) are used as information about the maximum luminance, but the present embodiment is not limited to this. In the present embodiment, the metadata generation unit 4B may further generate information regarding another maximum luminance. As the information on the other maximum luminance, for example, the maximum value of the luminance level corresponding to the gradation value taken by each pixel constituting each frame or each scene in the video signal can be mentioned.

[Receiver 10B]
Next, the receiving device 10B according to the present embodiment will be described with reference to FIGS. As illustrated in FIG. 8, the receiving device 10B includes an acquisition unit 11, a conversion unit 12B, a control unit 13B, and a display panel 14B. FIG. 2 is a front view illustrating an appearance of the receiving device 10B. Examples of the receiving device 10B include a television receiver equipped with a tuner, an STB (Set Top Box), and the like.

(Acquisition unit 11B)
The acquisition unit 11B receives the video signal transmitted from the transmission unit 5B of the transmission device 1B. Accordingly, the acquisition unit 11B receives a video signal including video data and metadata. In addition, the acquisition unit 11B acquires a plurality of pieces of information related to the maximum luminance of content indicated by video data included in the video signal. That is, the acquisition unit 11B acquires MAX CLL and MAX CLL (CHAROFF).

(Conversion unit 12B)
The conversion unit 12B performs luminance conversion of the video indicated by the video data with reference to one of the plurality of pieces of information regarding the maximum luminance acquired by the acquisition unit 11B.

That is, the conversion unit 12B switches the conversion function by referring to MAX CLL or referring to information on MAX CLL (CHAROFF). Then, the conversion unit 12B performs conversion between the gradation value and the luminance value indicated by the video signal using the switched conversion function. For example, the conversion unit 12B performs conversion (tone mapping) from a gradation value indicated by the video signal to a luminance value used when displaying the video.

Here, in the present embodiment, the conversion unit 12B refers to MAX CLL (CHAROFF) when the subtitle information is included in the video data in the video signal. Also, the conversion unit 12B refers to the MAX CLL when the caption data is not included in the video data in the video signal.

In this way, the conversion unit 12B refers to information regarding the maximum luminance of the appropriate content according to each of the case where the subtitle information is included in the video data and the case where the subtitle information is not included in the video data. be able to. As a result, the receiving device 10B can display a video with a more appropriate luminance according to the video signal including the video data.

(Control unit 13B and display panel 14B)
The control unit 13B controls the luminance of each pixel of the display panel 14B to the luminance value converted by the conversion unit 12B. The display panel 14B may be realized by any device as long as it can display video. Examples of the display panel 14B include a liquid crystal display, an organic EL (Electro Luminescence) display, a plasma display, and a projector.

[Reception method]
A flow of a reception method executed by the reception device 10B according to the present embodiment will be described with reference to FIG. Transmission of the video signal to the receiving device 10B by the transmitting device 1B is performed in accordance with the description of each member described above, and the description thereof is omitted.

FIG. 10 is a flowchart showing the flow of the receiving method.

The receiving device 10B according to the present embodiment performs a reception process by executing steps S101B to S105B described below.

Step S101B (acquisition step): As shown in FIG. 10, first, the reception device 10B receives a video signal from the transmission device 1B via the acquisition unit 11B. Further, the acquisition unit 11B acquires MAX CLL and MAX CLL (CHAROFF) included in the video signal. In this way, the acquisition unit 11B acquires a plurality of pieces of information regarding the maximum luminance. The acquisition unit 11B supplies information about the acquired maximum luminance to the conversion unit 12B.

Step S102B: The conversion unit 12B confirms whether or not caption information is included in the video data in the video signal. If the conversion unit 12B determines that caption information is included (YES in step S102B), the process proceeds to step S103B. When the conversion unit 12B determines that no caption information is included (NO in step S102B), the process proceeds to step S104B. In step S103B and step S104B, examples of conversion functions used by the conversion unit 12B will be described later.

Step S103B (conversion step): The conversion unit 12B performs conversion (tone mapping) between a gradation value and a luminance value indicated by the video signal with reference to information on MAX CLL (CHAROFF). Specifically, the conversion unit 12B performs conversion between a gradation value and a luminance value using a conversion function according to the format of the video signal (for example, a PQ curve indicated by EOTF according to SMPTE-ST 2084). Thereafter, the conversion unit 12B supplies the converted luminance value to the control unit 13B.

Step S104B (conversion step): The conversion unit 12B performs conversion (tone mapping) between the gradation value and the luminance value indicated by the video signal with reference to information on the MAX CLL (conversion step). Specifically, the conversion unit 12B performs conversion between the gradation value and the luminance value using a conversion function according to the format of the video signal (for example, a conversion function according to SAMPLE-ST 2084). Thereafter, the conversion unit 12B supplies the converted luminance value to the control unit 13B.

Step S105B: The control unit 13B controls the luminance value of each pixel constituting the display panel 14B to the luminance value after conversion by the conversion unit 12B.

[Example of conversion function]
Next, an example of a conversion function used by the conversion unit 12B will be described with reference to FIG. FIG. 11 is a graph showing the conversion (tone mapping) between the gradation value and the luminance value by the conversion function.

In (a) and (b) of FIG. 11, the horizontal axis represents the gradation value before conversion indicated by the video signal, and the vertical axis represents the luminance value after conversion (luminance when displaying the video). Represents.

(Conversion function when referring to MAX CLL (CHAROFF))
The solid curve shown in FIG. 11A is a conversion function that the conversion unit 12B generates with reference to MAX CLL (CHAROFF). As described above, when the caption data is included in the video data in the video signal, the conversion unit 12B refers to the conversion function generated with reference to MAX CLL (CHAROFF).

Hereinafter, for comparison, a case will be described in which a conversion unit (not shown) that refers only to the MAX CLL corresponding to the maximum luminance level of content including subtitles performs tone mapping without using a plurality of conversion functions.

The above conversion unit refers to the MAX CLL corresponding to the maximum luminance level of the content including the caption even when the caption is displayed on the video. Therefore, for example, when a white caption is displayed on the video, this conversion unit may create a PQ curve with the brightness value of the white caption as the maximum brightness value MAX CLL.

That is, this conversion unit refers to the maximum luminance value MAX CLL having a high value that matches the luminance value of the white caption. Then, the conversion unit switches the conversion function from the PQ curve indicated by the EOFT according to SAMPTE-ST2084, which is normally used, to another conversion function. Thereby, it switches to the PQ curve shown with the broken line of (a) of FIG.

In this case, as in the PQ curve indicated by the broken line in FIG. 11A, the maximum luminance value (MAX CLL) of the content including subtitles is the maximum luminance value of the original content (of FIG. 11A). Compared with MAX CLL (CHAROFF)), there is a possibility of becoming higher. At this time, the value of the MAX CLL can take 1000 nit (cd / m ² ), for example.

Further, as shown in FIG. 11A, the luminance value in the dashed PQ curve is, for example, the original PQ curve at the gradation value X ₁ (for example, 128) which is the same intermediate gradation value. there is a possibility that the results in a luminance value Y ₁ is lower than the luminance value Y _2.

On the other hand, in the present embodiment, even when captions or the like are displayed on the video, the conversion unit 12B, as shown in FIG. 11A, the maximum brightness value of the content excluding the captions as the maximum brightness value. Reference is made to MAX CLL (CHAROFF). Thereby, it can switch to the PQ curve shown with the continuous line of (a) of FIG. Thus, the conversion unit 12, by switching to the optimal PQ curve in accordance with a video signal, the receiving device 10B displays an image of the appropriate quality for the intermediate gradation value or the like, including X ₁ be able to. Note that the value of MAX CLL (CHAROFF) in FIG. 11A can be, for example, 800 nit (cd / m ² ).

(Conversion function when referring to MAX CLL)
A curve shown in FIG. 11B is a conversion function (PQ curve indicated by EOFT according to SAMPTE-ST2084) when the conversion unit 12B refers to MAX CLL. As described above, when the caption data is not included in the video data in the video signal, the conversion unit 12B refers to the MAX CLL. Also in this case, the receiving device 10B can display an image with optimum image quality.

Note that MAX CLL in (b) of FIG. 11 indicates the same value as the value of MAX CLL (CHAROFF), which is the maximum luminance value of content excluding subtitles, and is, for example, a value of 800 nit (cd / m ² ). obtain.

<Embodiment 5>
In the fifth embodiment, the conversion unit 12B of the receiving apparatus 10 performs tone mapping by referring to MAX CLL or referring to information on MAX CLL (CHAROFF). However, as in the fifth embodiment, the receiving device 20B performs tone mapping by referring to information on MAX CLL or MAX CLL and MAX CLL (CHAROFF) by the converting unit 22B instead of the converting unit 12B. Also good.

Embodiment 5 will be described with reference to FIGS. For convenience of explanation, members having the same functions as those described in the fourth embodiment are denoted by the same reference numerals and description thereof is omitted.

[Video signal transmission system 200B]
FIG. 12 is a block diagram showing a main configuration of the video signal transmission system 200B according to the present embodiment. As shown in FIG. 5, the video signal transmission system 200B according to the present embodiment includes a transmission device 1B and a reception device 20B.

The receiving device 20B includes a conversion unit 22B instead of the conversion unit 12B. Except for this point, the receiving device 20B has the same configuration as the receiving device 10B.

[Receiver 20B]
The conversion unit 22B of the reception device 20B refers to two pieces of information about the maximum luminance acquired by the acquisition unit 11B and performs luminance conversion of the video indicated by the video data. That is, the conversion unit 12B in the fourth embodiment refers to information about one maximum luminance, whereas the conversion unit 22B in the present embodiment refers to information about another maximum luminance.

More specifically, the conversion unit 22B refers to both MAX CLL and MAX CLL (CHAROFF) when the subtitle information is included in the video data in the video signal. Further, when the subtitle information is not included in the video data in the video signal, the conversion unit 22B refers to the MAX CLL as in the fourth embodiment.

[Example of conversion function]
An example of the conversion function used by the conversion unit 22B will be described with reference to FIG. FIG. 13 is a graph showing conversion (tone mapping) between a gradation value and a luminance value by a conversion function.

(Conversion function when referring to MAX CLL and MAX CLL (CHAROFF))
A solid PQ curve shown in FIG. 13A is a conversion function generated by the conversion unit 22B with reference to MAX CLL and MAX CLL (CHAROFF) when caption information is included in the video data. .

More specifically, as shown in FIG. 13A, the conversion unit 22B creates a conversion function with reference to information on MAX CLL (CHAROFF) for luminance values up to MAX CLL (CHAROFF). For luminance values exceeding MAX CLL (CHAROFF), a conversion function is created by further referring to MAX CLL. As a result, as shown in FIG. 13A, the luminance value of the PQ curve gradually increases to the MAX CLL as the gradation value increases with the luminance value of MAX CLL (CHAROFF) as the boundary. To do.

Thus, the solid line PQ curve (a) in FIG. 13, in the same tone value X _1, the broken lines refer only MAX CLL corresponding to the maximum luminance level of the contents, including the subtitle, etc. PQ curve The luminance value Y ₂ is higher than the luminance value Y ₁ . The dashed PQ curve is the same PQ curve as the PQ curve in FIG.

In the present embodiment, the conversion unit 22B refers to the MAX CLL for a luminance value exceeding MAX CLL (CHAROFF).

Here, in Embodiment 1 of the third invention, when subtitle information is included in video data, the conversion unit 12B refers only to information related to MAX CLL (CHAROFF).

Therefore, as shown in FIG. 11A, the PQ curve created by the conversion unit 12B does not display a luminance value corresponding to a gradation value higher than MAX CLL (CHAROFF) _TONE. As a result, in the fourth embodiment, even if an image can be displayed with an appropriate luminance at the intermediate gradation value, the gradation value higher than MAX CLL (CHAROFF) _TONE depends on the gradation value. High brightness values cannot be displayed.

On the other hand, in this embodiment, when subtitle information is included in the video data, the conversion unit 22B refers to information on both MAX CLL and MAX CLL (CHAROFF). For this reason, as shown in FIG. 13A, a gradation value higher than MAX CLL (CHAROFF) _TONE and a luminance value that increases accordingly are also expressed as a PQ curve. As a result, the receiving device 20B including the conversion unit 22B can display a video with a high luminance value appropriately corresponding to a gradation value higher than MAX CLL (CHAROFF) _TONE.

Therefore, according to the receiving device 20B according to the present embodiment, it is possible to display a video with a luminance more appropriately according to a video signal including video data including subtitles and the like.

(Conversion function when referring to MAX CLL)
FIG. 13B shows a conversion function (PQ curve indicated by EOFT according to SAMPTE-ST2084) when the conversion unit 22B refers to MAX CLL. The PQ curve in FIG. 13B is the same as the PQ curve in FIG.

[Reception method]
Next, the flow of the reception method executed by the reception device 20B according to this embodiment will be described with reference to FIG. FIG. 14 is a flowchart showing the flow of the receiving method.

14 are the same as steps S101B, S102B, S104B, and S105B shown in FIG. 10, and thus the description thereof is omitted here.

Step S203B (conversion process): When the process proceeds to YES in step S202B and proceeds to step S203B, in step S203B, the conversion unit 22B refers to information on MAX CLL and MAX CLL (CHAROFF). Then, the conversion unit 22B performs conversion (tone mapping) between the gradation value and the luminance value indicated by the video signal.

Specifically, the conversion unit 12B performs conversion between a gradation value and a luminance value by using a conversion function according to the format of the video signal (for example, a PQ curve indicated by EOTF according to SAMPTE-ST 2084). Thereafter, the conversion unit 22B supplies the converted luminance value to the control unit 13B.

In the above-described example, the conversion unit 22B of the reception device 20B performs the luminance conversion of the video indicated by the video data with reference to two of the plurality of pieces of information regarding the maximum luminance. However, it is not limited to this. In the present embodiment, the conversion unit 22B can refer to two or more pieces of information among a plurality of pieces of information regarding the maximum luminance.

For example, in addition to the above two, the conversion unit 22B can further refer to information on the maximum value of the luminance level corresponding to the gradation value taken by each pixel constituting each frame or each scene.

<Embodiment 6>
In the fourth and fifth embodiments, the conversion units 12B and 22B automatically select and refer to at least one piece of information about the maximum luminance separately when there is subtitle information and when there is no subtitle information. is doing. However, as in the sixth embodiment, instead of the conversion units 12B and 22B, a conversion unit 32B that selects which of a plurality of pieces of information regarding the maximum luminance is to be referred to is provided according to an instruction from the user. Also good.

Embodiment 6 will be described with reference to FIGS. For convenience of explanation, members having the same functions as those described in the fourth and fifth embodiments are denoted by the same reference numerals and description thereof is omitted.

[Video signal transmission system 300B]
FIG. 15 is a block diagram showing a main configuration of a video signal transmission system 300B according to the present embodiment. As shown in FIG. 15, the video signal transmission system 300B according to the present embodiment includes a transmission device 1B and a reception device 30B.

As illustrated in FIG. 15, the receiving device 30B according to the present embodiment includes a converting unit 32B instead of the converting unit 12B of the receiving device 10B. Except for this point, the video signal transmission system 300B according to the present embodiment has the same configuration as the video signal transmission system 100B according to the fourth embodiment.

[Receiver 30B]
As illustrated in FIG. 15, the conversion unit 32B of the reception device 30B includes a selection unit 33B. The selection unit 33B selects which of a plurality of pieces of information regarding the maximum luminance is to be referred to according to an instruction from the user.

More specifically, the selection unit 33B of the conversion unit 32B selects which one of MAX CLL, MAX CLL (CHAROFF), or a combination thereof is to be referred to according to an instruction from the user.

[Example of conversion function]
An example of the conversion function used by the conversion unit 32B will be described with reference to FIG. FIG. 16 is a graph showing conversion (tone mapping) between a gradation value and a luminance value by a conversion function.

(Conversion function when referring to MAX CLL and MAX CLL (CHAROFF))
The solid PQ curve shown in FIG. 16A is a conversion function when the selection unit 33B refers to MAX CLL and MAX CLL (CHAROFF). The PQ curve shown in (a) of FIG. 16 is the same as the solid PQ curve shown in (a) of FIG.

(Conversion function when referring to MAX CLL (CHAROFF))
A solid PQ curve shown in (b) of FIG. 16 is a conversion function when the selection unit 33B refers to MAX CLL (CHAROFF). The PQ curve shown in (b) of FIG. 16 is the same as the solid PQ curve shown in (a) of FIG.

(Conversion function when referring to MAX CLL)
A solid PQ curve shown in FIG. 16C is a conversion function when the selection unit 33B refers to MAX CLL. The PQ curve shown in (c) of FIG. 16 is the same as the PQ curve shown in (b) of FIG. 11 and (b) of FIG.

[Selection Example by Selection Unit 33B]
In the present embodiment, the user can cause the selection unit 33B to select which of MAX CLL, MAX CLL (CHAROFF), and a combination thereof is to be referred to. The criteria for this selection are not particularly limited. The user can arbitrarily cause the selection unit 33B to select which of MAX CLL, MAX CLL (CHAROFF), and a combination thereof is referred to. Below, an example of how the selection unit 33B is selected when the user is selected is shown.

For example, when the caption data is not included in the video data in the video signal, the user instructs the selection unit 33B to select MAX CLL.

Suppose that caption data is included in the video data in the video signal. In this case, the user instructs the selection unit 33B to select whether to refer to only MAX CLL (CHAROFF) or to refer to both MAX CLL and MAX CLL (CHAROFF).

Here, when the user thinks that it is sufficient that the intermediate gradation value can be converted into an appropriate luminance value and displayed on the video, the user should refer only to MAX CLL (CHAROFF) to the selection unit 33B. May be selected. In addition, when the user wants to display not only the intermediate gradation value but also the high gradation value into a high luminance value corresponding to the high gradation value and display it on the video, the selection unit 33B displays MAX CLL and MAX CLL (CHAROFF). You may choose to refer to both.

In this way, the user can cause the selection unit 33B to select which of a plurality of pieces of information regarding the maximum luminance is to be referred to. As a result, the receiving device 30B can display a video with a luminance in accordance with a video signal including video data including subtitles and the like and according to the user's intention.

[Reception method]
Next, the flow of the reception method executed by the reception device 30B according to this embodiment will be described with reference to FIG. FIG. 17 is a flowchart showing the flow of the reception method.

Since steps S301B, S302B, S305B, S306B, and S307B in FIG. 17 are the same as steps S101B to S105B shown in FIG. 10, description thereof is omitted here. In addition, step S304B in FIG. 17 is the same as step S203B in FIG. 14, and thus the description thereof is omitted here.

Step S303B: The user causes the selection unit 33B to select whether to refer to information related to both MAX CLL and MAX CLL (CHAROFF) or only information related to MAX CLL (CHAROFF).

When the selection unit 33B selects to refer to information on both MAX CLL and MAX CLL (CHAROFF) (YES in step S303B), the process proceeds to step S304B. When the selection unit 33B selects to refer to information related to only MAX CLL (CHAROFF) (NO in step S303B), the process proceeds to step S305B.

In the above-described example, the selection unit 33B selects whether to refer to information related to both MAX CLL and MAX CLL (CHAROFF) or only to information related to MAX CLL (CHAROFF). In the present embodiment, the selection unit 33B is not limited to this, and the selection unit 33B may select another option for a plurality of pieces of information related to maximum luminance in addition to MAX CLL and MAX CLL (CHAR OFF). Good.

As another option, for example, the maximum value of the luminance level corresponding to the gradation value taken by each pixel constituting each frame or each scene in the video signal can be mentioned. As described above, by further increasing the choices for the selection unit 33B to select, the user can display a video with a luminance more appropriately corresponding to the video signal including the video data on the receiving device 30B.

[Modification Example of Selection Unit 33B]
In the above-described example, the selection unit 33B selects which of a plurality of pieces of information related to maximum luminance is to be referred to according to an instruction from the user. However, the present embodiment is not limited to this. Instead of selecting according to the user's instruction, the selection unit 33B may select which of a plurality of pieces of information regarding the maximum luminance is to be referred to according to the content genre. In this case, the selection unit 33B includes identification means (not shown) for identifying what the content genre is.

For example, it is assumed that the selection unit 33B has identified that the genre of the content is a predetermined genre (for example, a Japanese movie or a sports program). In this case, the selection unit 33B determines that caption information is not included in the video data, and selects to refer to information on the MAX CLL.

Further, it is assumed that the selection unit 33B determines that the genre of the content is a genre other than the predetermined genre (for example, a Western movie). In this case, the selection unit 33B determines that the subtitle information is included in the video data, and MAX CLL (CHAROFF) or MAX CLL and MAX.
Select to refer to information on CLL (CHAROFF).

Thus, the selection unit 33B selects to refer to any one of a plurality of pieces of information regarding the maximum luminance according to the content genre. As a result, the receiving device 30B can display a video with a luminance appropriate for each genre of content with respect to a video signal including video data.

In the above-described example, the selection unit 33B selects which of a plurality of pieces of information related to the maximum luminance is referred to by connecting the content genre and the presence / absence of captions. That is, the selection unit 33B estimates whether there is subtitle information in the video data in the video signal from the genre of the content, and selects which of a plurality of pieces of information regarding the maximum luminance is to be referred to based on this. However, the present embodiment is not limited to this.

[Example of software implementation]
The control blocks (particularly the conversion units 12B, 22B, and 32B) of the receiving devices 10B, 20B, and 30B may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or a CPU (Central It may be realized by software using a Processing Unit.

In the latter case, the receiving devices 10B, 20B, and 30B include a CPU that executes instructions of a program that is software that realizes each function, and a ROM (Read that records the above-described program and various data so that the computer (or CPU) can read them Only Memory) or a storage device (these are referred to as “recording media”), RAM (Random Access Memory) for expanding the program, and the like. And the objective of this invention is achieved when a computer (or CPU) reads the said program from the said recording medium and runs it. As the recording medium, a “non-temporary tangible medium” such as a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. The program may be supplied to the computer via an arbitrary transmission medium (such as a communication network or a broadcast wave) that can transmit the program. Note that one embodiment of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[Summary]
The display devices (1, 10) according to the first aspect of the present invention have a plurality of conversion means for setting a luminance value from the gradation value indicated by the video signal of the display target image, according to the luminance level of the video signal. A switching unit (4) for switching the conversion means, and the switching unit refers to the luminance level of a corrected image obtained by excluding a region including an artificial display object from the display target image. Switch means.

According to the above configuration, the luminance value is set from the gradation value by the conversion unit according to the luminance level of the corrected image excluding an artificial display object that may greatly change the maximum luminance level or the average luminance level. can do. As a result, when the tone mapping method is switched with reference to the maximum luminance level or the average luminance level, the influence of the luminance of the artificial display object on the maximum luminance level or the average luminance level can be suppressed. Therefore, it is possible to display an image with a more appropriate luminance according to the image signal.

A display device (1, 10) according to aspect 2 of the present invention is the above-described aspect 1, wherein the display device (1, 10) is composed of a plurality of areas, and the backlight (7) capable of individually controlling the brightness of the areas, and the backlight A backlight control unit (6) for controlling the light, wherein the backlight control unit makes the brightness of the area corresponding to the area including the artificial display object different from the brightness of the other areas. May be.

According to the above configuration, the brightness of the backlight corresponding to each region so that there is no unnatural boundary between the region including the artificial display object and the region other than the region including the artificial display object. Can be adjusted.

In the display device (1, 10) according to aspect 3 of the present invention, in the aspect 2, the backlight control unit determines the brightness of the area corresponding to the area including the artificial display object. Depending on the gradation of the display object, the brightness of other areas may be different.

According to the above configuration, in the display device according to aspect 2, each region is set so that there is no unnatural boundary between the region including the artificial display object and the region other than the region including the artificial display object. The backlight brightness corresponding to can be adjusted more appropriately.

In the display device (1, 10) according to aspect 4 of the present invention, in the above aspects 1 to 3, the artificial display object may be an object synthesized or added to the content video of the display target image. .

According to the above configuration, according to the above configuration, when the tone mapping method is switched with reference to the maximum luminance level or the average luminance level, the maximum luminance level based on the luminance of the object synthesized or added to the content video. Alternatively, the influence on the average luminance level can be suppressed.

In the display device (1, 10) according to aspect 5 of the present invention, in the aspect 4, the object may be a caption, a logo, or a control panel.

According to the above configuration, when the tone mapping method is switched with reference to the maximum luminance level or the average luminance level, the influence on the maximum luminance level or the average luminance level due to the luminance of the caption, logo, or control panel is suppressed. be able to.

In the display device (1, 10) according to the sixth aspect of the present invention, in the first to fifth aspects, the conversion means is a conversion function between a gradation value and a luminance value by a conversion function, and the switching unit The conversion function may be switched to a conversion function that converts the graph of the gradation value before conversion and the luminance value after conversion into a PQ curve corresponding to the maximum luminance level of the corrected image.

According to the above configuration, an image can be displayed with a more appropriate luminance corresponding to the HDR signal.

The display device (10) according to aspect 7 of the present invention provides a display device (10) according to any one of aspects 1 to 6, wherein the switching unit performs a function of switching the conversion unit with reference to a luminance level of the corrected image. You may further provide the reception part which receives selection.

According to the above configuration, the user can select whether to switch the conversion means with reference to the luminance level of the corrected image.

In the display device (1, 10) according to aspect 8 of the present invention, in the above-described aspects 1 to 7, the switching unit refers to the luminance level of the corrected image according to the category, genre, or scene of the display target image. Then, the conversion means may be switched.

According to the above configuration, when there is a high possibility that the category, genre, or scene of the display target image includes an artificial display object, the conversion unit is switched by referring to the luminance level of the corrected image. The switching of the conversion means can be executed as necessary.

The television receiver (100) according to the ninth aspect of the present invention includes any one of the display devices according to the first to eighth aspects.

According to the above configuration, the television receiver can obtain the effects that the display device exhibits in each of the above aspects.

A video processing method according to aspect 10 of the present invention is a video processing method by a display device (1, 10) having a plurality of conversion means for setting a luminance value from a gradation value indicated by a video signal of a display target image, A switching step of switching the conversion means according to the luminance level of the video signal, wherein the switching step includes a luminance level of a corrected image obtained by excluding a region including an artificial display object from the display target image. The conversion means is switched with reference to FIG.

According to said structure, there exists an effect similar to the said aspect 1.

The video processing apparatus according to each aspect of the present invention may be realized by a computer. In this case, the video processing apparatus is operated on each computer by causing the computer to operate as each unit (software element) included in the video processing apparatus. Also included in the scope of the present invention are a control program for the video processing apparatus to be realized and a computer-readable recording medium on which the control program is recorded.

A display device (1, 10) according to an aspect 11 of the present invention includes a backlight (7) that includes a plurality of areas and can individually control the brightness of the plurality of areas, and a backlight that controls the backlight. A light control unit (6), and the backlight control unit makes the brightness of the corresponding area corresponding to the region including the artificial display object in the display target image different from the brightness of the other areas.

According to the above configuration, an image can be displayed with a more appropriate luminance according to the image signal. More specifically, even when the display target image includes an artificial display object, an image can be displayed with appropriate luminance.

In the display device (1, 10) according to aspect 12 of the present invention, in the aspect 11, the backlight control unit determines the brightness of an area corresponding to the area including the artificial display object. Depending on the gradation of the display object, the brightness of other areas may be different.

According to the above configuration, the brightness of the backlight corresponding to each region can be adjusted more appropriately according to the gradation of the artificial display object.

In the display device (1, 10) according to aspect 13 of the present invention, in the aspect 11 or 12, the artificial display object may be an object synthesized or added to the content video of the display target image. .

According to the above configuration, it is possible to appropriately adjust the brightness of the backlight when displaying a display target image including an object combined or added to the content video.

In the display device (1, 10) according to aspect 14 of the present invention, in the aspect 13, the object may be a caption, a logo, or a control panel.

According to the above configuration, the brightness of the backlight can be appropriately adjusted when a display target image including a subtitle, a logo, or a control panel is displayed.

In the display device (10) according to the aspect 15 of the present invention, in the above aspects 11 to 14, whether or not the backlight control unit performs a function of making the brightness of the corresponding area different from the brightness of the other areas. An accepting unit (12) for accepting selection by the user may be further provided.

According to the above configuration, the user can select whether to make the brightness of the corresponding area different from the brightness of other areas.

In the display device (1, 10) according to the aspect 16 of the present invention, in the above aspects 11 to 15, the backlight control unit is configured such that the brightness of the corresponding area depends on a category, a genre, or a scene of the display target image. May be different from the brightness of other areas.

According to the above configuration, when the category, genre, or scene of the display target image is likely to include an artificial display object, the brightness of the corresponding area is made different from the brightness of the other areas. The local dimming can be preferably performed.

The television receiver (100) according to aspect 17 of the present invention may include any one of the display devices according to aspects 11 to 16.

According to the above configuration, the television receiver can obtain the effects that the display device exhibits in each of the above aspects.

The backlight control method according to aspect 18 of the present invention is based on a display device (1, 10) that includes a plurality of areas and includes a backlight (7) that can individually control the brightness of the plurality of areas. The backlight control method includes a backlight control step of making the brightness of the corresponding area corresponding to the area including the artificial display object in the display target image different from the brightness of the other areas.

According to said structure, there exists an effect similar to the said aspect 1.

The video processing apparatus according to each aspect of the present invention may be realized by a computer. In this case, the video processing apparatus is operated on each computer by causing the computer to operate as each unit (software element) included in the video processing apparatus. Also included in the scope of the present invention are a control program for the video processing apparatus to be realized and a computer-readable recording medium on which the control program is recorded.

The receiving device (10B, 20B, 30B) according to aspect 19 of the present invention is a receiving device (10B, 20B, 30B) that receives a video signal including video data and metadata, and the content indicated by the video data. The acquisition unit (11B) that acquires a plurality of pieces of information related to the maximum brightness of one content, and at least one of the plurality of pieces of information related to the maximum brightness acquired by the acquisition unit (11B), And a conversion unit (12B, 22B, 32B) that performs luminance conversion of the video indicated by the video data.

According to the above configuration, the conversion unit (12B, 22B, 32B) can refer to one or more pieces of information related to the maximum luminance of the appropriate content according to the video data. Therefore, the receiving devices (10B, 20B, 30B) can display a video with appropriate luminance according to the video signal including the video data.

In the reception device (20B, 30B) according to aspect 20 of the present invention, in the aspect 19, the conversion unit (22B, 32B) includes at least one of a plurality of pieces of information regarding the maximum luminance acquired by the acquisition unit (11B). The luminance conversion of the video indicated by the video data may be performed with reference to the two pieces of information.

According to the above configuration, in the receiving device (20B, 30B), the conversion unit (22B, 32B) can refer to two or more pieces of information related to the maximum luminance of the appropriate content according to the video data. Therefore, the receiving device (20B, 30B) can display a video with a more appropriate luminance according to the video signal including the video data.

In the reception device (30B) according to aspect 21 of the present invention, in the aspect 19 or 20, the selection unit (33B) that selects which of the plurality of pieces of information related to the maximum luminance the conversion unit (32B) refers to. ), And the selection unit (33B) may select which of a plurality of pieces of information regarding the maximum luminance is to be referred to in accordance with an instruction from the user.

According to the above configuration, the user can cause the selection unit (33B) to select which of a plurality of pieces of information regarding the maximum luminance is to be referred to. As a result, the receiving device (30B) can display a video with brightness according to the video signal including video data including captions and the like according to the user's intention.

In the receiving device (30B) according to the aspect 22 of the present invention, in the aspect 1 or 2, the selection unit (33B) that selects which of the plurality of pieces of information related to the maximum luminance the conversion unit (32B) refers to. ), And the selection unit (33B) may select which of a plurality of pieces of information regarding the maximum luminance is to be referred to according to the genre of the content.

According to the above configuration, the selection unit (33B) selects to refer to any one of a plurality of pieces of information regarding the maximum luminance according to the content genre. As a result, the receiving device (30B) can display a video with a luminance appropriate for each genre of content with respect to a video signal including video data.

A television receiver according to aspect 23 of the present invention includes the receiving device (10B, 20B, 30B) described in aspects 19-22.

According to said structure, the effect which the said receiver (10B, 20B, 30B) show | plays in each said aspect can be acquired in the said television receiver.

The video signal generation device (2B) according to the aspect 24 of the present invention is a video signal generation device (2B) that generates a video signal including video data and metadata, and relates to the maximum luminance of the content indicated by the video data. A metadata generation unit (4B) that generates metadata including a plurality of pieces of information for one content is provided.

According to the above configuration, the metadata generation unit (4B) can generate metadata including a plurality of pieces of information related to the maximum luminance of the content according to the video data. As a result, the receiving devices (10B, 20B, 30B) that have received the metadata generated by the metadata generation unit (4B) can display the video with a more appropriate luminance according to the video signal including the video data. .

The transmission device (1B) according to aspect 25 of the present invention includes the video signal generation device (2B) according to aspect 24 above.

According to said structure, the effect which said video signal generation apparatus (2B) has in each said aspect can be acquired in said transmission apparatus (1B).

The video signal transmission system (100B, 200B, 300B) according to the aspect 26 of the present invention is a video signal transmission system (100B, 200B, 300B) including a transmission device (1) and a reception device (10B, 20B, 30B). The transmission device (1B) transmits video signals including video data and metadata, and includes a plurality of pieces of information regarding the maximum luminance of the content indicated by the video data for one content. The metadata generation unit (4B) for generating the video signal is received, and the reception devices (10B, 20B, 30B) receive the video signal. Of the plurality of pieces of information regarding the maximum luminance acquired by the acquisition unit (11B) that acquires a plurality of contents and the acquisition unit (11B) Referring to Kutomo one information comprises converting unit for performing luminance conversion image indicated by a picture data (12B, 22B, 32B) and a.

According to said structure, there can exist an effect similar to the receiver (10B, 20B, 30B) of the said aspect 19. FIG.

A receiving method according to an aspect 27 of the present invention is a receiving method for receiving a video signal including video data and metadata, and a plurality of pieces of information regarding the maximum luminance of the content indicated by the video data for a single content. An acquisition step of acquiring, and a conversion step of converting the luminance of the video indicated by the video data with reference to at least one of a plurality of pieces of information regarding the maximum luminance acquired in the acquisition step.

According to said structure, there can exist an effect similar to the receiver (10B, 20B, 30B) of the said aspect 19. FIG.

The receiving device (10B, 20B, 30B) according to each aspect of the present invention may be realized by a computer. In this case, each unit (software element) included in the receiving device (10B, 20B, 30B). A program of a receiving device that realizes the receiving device (10B, 20B, 30B) by a computer by operating as a computer and a computer-readable recording medium on which the program is recorded also fall within the scope of the present invention.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

(Cross-reference of related applications)
This application claims the benefit of priority to the Japanese patent applications filed on Feb. 9, 2017: Japanese Patent Application Nos. 2017-022034, 2017-022038, 2017-022039, and this is referred to. The entire contents of which are included in this document.

DESCRIPTION OF SYMBOLS 1,10 Display apparatus 2,11 Video processing part 3 Subtitle detection part 4 Switching part 5 Conversion part 6 Backlight control part 7 Backlight 8 Display part 12 Acceptance part 1B Transmission apparatus 2B Video signal generation apparatus 3B Video data generation part 4B Meta Data generation unit 5B Transmission unit 10B, 20B, 30B Reception device 11B Acquisition unit 12B, 22B, 32B Conversion unit 13B Control unit 14B Display panel 33B Selection unit 100B, 200B, 300B Video signal transmission system

Claims (33)

A plurality of conversion means for setting a luminance value from a gradation value indicated by a video signal of a display target image;
According to the luminance level of the video signal, comprising a switching unit for switching the conversion means,
The display device, wherein the switching unit switches the conversion means with reference to a luminance level of a corrected image obtained by excluding a region including an artificial display object from the display target image. A backlight composed of a plurality of areas and capable of individually controlling the brightness of the plurality of areas,
A backlight control unit for controlling the backlight;
The display device according to claim 1, wherein the backlight control unit makes the brightness of an area corresponding to the area including the artificial display object different from the brightness of another area. The backlight control unit makes the brightness of an area corresponding to the area including the artificial display object different from the brightness of other areas according to the gradation of the artificial display object. The display device according to claim 2. 4. The display device according to claim 1, wherein the artificial display object is an object synthesized or added to a content video of the display target image. The display device according to claim 4, wherein the object is a caption, a logo, or a control panel. The conversion means is a conversion function between a gradation value and a luminance value by a conversion function,
The switching unit switches the conversion function to a conversion function that converts the graph of the gradation value before conversion and the luminance value after conversion to form a PQ curve corresponding to the maximum luminance level of the corrected image. 6. The display device according to claim 1, wherein the display device is characterized. 7. The apparatus according to claim 1, further comprising a reception unit that receives a selection by a user as to whether or not the switching unit executes a function of switching the conversion unit with reference to a luminance level of the corrected image. The display device according to any one of the above. The switching unit according to any one of claims 1 to 7, wherein the switching unit switches the conversion unit with reference to a luminance level of the corrected image according to a category, a genre, or a scene of the display target image. The display device described. A television receiver comprising the display device according to any one of claims 1 to 8. A video processing method by a display device having a plurality of conversion means for setting a luminance value from a gradation value indicated by a video signal of a display target image,
A switching step of switching the conversion means according to the luminance level of the video signal,
In the switching step, the conversion means is switched with reference to a luminance level of a corrected image obtained by excluding a region including an artificial display object from the display target image. A control program for causing a computer to function as the display device according to claim 1, wherein the control program causes the computer to function as the switching unit. A computer-readable recording medium on which the control program according to claim 11 is recorded. A backlight composed of a plurality of areas and capable of individually controlling the brightness of the plurality of areas,
A backlight control unit for controlling the backlight,
The display apparatus according to claim 1, wherein the backlight control unit changes the brightness of a corresponding area corresponding to a region including an artificial display object in a display target image, from the brightness of another area. The backlight control unit makes the brightness of an area corresponding to the area including the artificial display object different from the brightness of other areas according to the gradation of the artificial display object. The display device according to claim 13. 15. The display device according to claim 13, wherein the artificial display object is an object synthesized or added to a content video of the display target image. The display device according to claim 15, wherein the object is a caption, a logo, or a control panel. The said backlight control part is further provided with the reception part which receives the selection by a user whether the function which makes the brightness of the said corresponding area different from the brightness of another area is performed. The display device according to any one of 13 to 16. 18. The backlight control unit according to claim 13, wherein the brightness of the corresponding area differs from the brightness of other areas according to the category, genre, or scene of the display target image. Item 1. A display device according to item 1. A television receiver comprising the display device according to any one of claims 13 to 18. A backlight control method by a display device comprising a plurality of areas and having a backlight capable of individually controlling the brightness of the plurality of areas,
A backlight control method, comprising: a backlight control step of causing the brightness of a corresponding area corresponding to a region including an artificial display object in a display target image to be different from the brightness of another area. 14. A control program for causing a computer to function as the display device according to claim 13, wherein the control program causes the computer to function as the backlight control unit. A computer-readable recording medium on which the control program according to claim 21 is recorded. A receiving device for receiving a video signal including video data and metadata,
An acquisition unit that acquires a plurality of pieces of information regarding the maximum luminance of the content indicated by the video data for one content;
A receiving apparatus, comprising: a conversion unit that performs luminance conversion of a video indicated by the video data with reference to at least one of a plurality of pieces of information regarding the maximum luminance acquired by the acquisition unit. The said conversion part performs the brightness | luminance conversion of the image | video which the said video data shows with reference to at least 2 information among the several information regarding the said maximum brightness | luminance which the said acquisition part acquired. Receiver. The conversion unit includes a selection unit that selects which of a plurality of pieces of information related to the maximum luminance is to be referred to,
The receiving device according to claim 23 or 24, wherein the selection unit selects which of a plurality of pieces of information related to the maximum luminance is to be referred to according to an instruction from a user. The conversion unit includes a selection unit that selects which of a plurality of pieces of information related to the maximum luminance is to be referred to,
25. The receiving apparatus according to claim 23, wherein the selection unit selects which of a plurality of pieces of information related to the maximum luminance is to be referred to according to a content genre. A television receiver comprising the receiving device according to any one of claims 23 to 26. A video signal generation device that generates a video signal including video data and metadata,
A video signal generation apparatus comprising: a metadata generation unit that generates metadata including a plurality of pieces of information related to the maximum luminance of content indicated by the video data for one content. A transmission apparatus comprising the video signal generation apparatus according to claim 28. A video signal transmission system including a transmission device and a reception device,
The transmitter is
Transmits a video signal including video data and metadata,
A metadata generation unit that generates metadata including a plurality of pieces of information regarding the maximum luminance of the content indicated by the video data for one content;
The receiving device is
Receiving the video signal,
An acquisition unit that acquires a plurality of pieces of information regarding the maximum luminance of the content indicated by the video data for one content;
A video signal transmission system comprising: a conversion unit that performs luminance conversion of a video indicated by the video data with reference to at least one of a plurality of pieces of information about the maximum luminance acquired by the acquisition unit . A receiving method for receiving a video signal including video data and metadata,
An acquisition step of acquiring a plurality of pieces of information regarding the maximum luminance of the content indicated by the video data for one content;
A reception method comprising: a conversion step of performing luminance conversion of a video indicated by the video data with reference to at least one of a plurality of pieces of information regarding the maximum luminance acquired in the acquisition step. 24. A program for causing a computer to function as the receiving device according to claim 23, wherein the program causes the computer to function as the conversion unit. A computer-readable recording medium on which the program according to claim 32 is recorded.

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