JP2013228627A - Display control device, method of controlling display control device, reproducer, television receiver, program, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve display quality of a video including subtitles.SOLUTION: A display control device includes: a subtitles determination unit 123 that determines whether a difference in light emission luminance between mutually adjacent division regions, out of division regions constituting a subtitles region that is a region on a display surface 2011 where subtitles are displayed by a liquid crystal display device 201, exceeds a predetermined value; and an LED control unit 122 that controls the light emission luminance of the division regions constituting the subtitles region so as not to exceed the light emission luminance of the division regions circumscribing the subtitles region.

Description

  The present invention relates to a display control device that can control the luminance of subtitles displayed on a display surface.

  2. Description of the Related Art Conventionally, a playback device that performs video playback and playback control performs control to dynamically change the light emission luminance of a backlight provided in a display device that displays the video according to the video to be played back. As a result, the playback apparatus can produce a sharp image according to the video content.

  In particular, by dividing the backlight into a plurality of divided regions and controlling the output of a light emitting diode (hereinafter referred to simply as “LED”) for each divided region, Reproducing devices that change the brightness of the backlight are in widespread use. That is, the LED emission is controlled for each divided area, such as suppressing the LED emission in a dark area on the screen and increasing the LED emission in a bright area on the screen (High Dynamic Range (HDR)). ) Can be synthesized). The above technique is generally called “local deming”.

  As a technique related to the local dimming, for example, in Patent Document 1 below, area active driving is performed in which correct gradation display can be performed while suppressing power consumption in consideration of light emitted from a surrounding light source. An image display device is disclosed.

  However, in the case of displaying a video in which subtitles are displayed by OSD (On Screen Display) display or a video in which subtitles are included in the video itself, the device displays the subtitles on the screen when the luminance of the backlight changes. The brightness of the subtitles also changes. Thereby, when the user reads the subtitle, the user feels uncomfortable due to the luminance of the subtitle changing.

  Therefore, as disclosed in, for example, Patent Document 2, even when the image luminance is improved and the power consumption is reduced by optimizing the screen luminance dynamically according to the input video signal, the OSD There has been devised an image display device that prevents a reduction in display quality due to a change in display brightness.

JP 2010-249996 A (published November 4, 2010) Japanese Patent Laying-Open No. 2005-321424 (published on November 17, 2005)

  However, in the image display device described in Patent Document 2 described above, since the brightness of the OSD display is kept constant regardless of the change in the brightness of the other video, the user can select between the OSD display and the other video. There is a problem that it is difficult to get a feel.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to optimize the display quality of video including subtitles by optimizing the brightness of the subtitles according to the video. It is to provide a display control device and the like.

In order to solve the above problems, a display control device of the present invention provides:
(1) A backlight using a light emitting diode as a light source for illuminating a display surface provided in the display device is divided into a plurality of divided regions, and the output of the light emitting diode is controlled for each of the divided regions. Is a display control device capable of controlling the brightness of the image displayed on the display surface,
(2) Determining whether or not the difference in light emission luminance between adjacent divided areas among the divided areas constituting the closed caption area, which is the area on the display surface where the caption is displayed by the display device, exceeds a predetermined value Brightness determination means for
(3) When the luminance determination means determines that the difference in light emission luminance exceeds a predetermined value, the light emission of the divided areas constituting the subtitle area does not exceed the light emission luminance of the divided area circumscribing the subtitle area Backlight control means for controlling luminance is provided.

In addition, in order to solve the above problems, a display control device control method of the present invention includes:
(1) A backlight using a light emitting diode as a light source for illuminating a display surface provided in the display device is divided into a plurality of divided regions, and the output of the light emitting diode is controlled for each of the divided regions. Is a control method of a display control device capable of controlling the brightness of an image displayed on the display surface,
(2) Determining whether or not the difference in light emission luminance between adjacent divided areas among the divided areas constituting the closed caption area, which is the area on the display surface where the caption is displayed by the display device, exceeds a predetermined value A luminance determination step,
(3) When it is determined in the luminance determination step that the difference in emission luminance exceeds a predetermined value, the emission of the divided areas that constitute the subtitle area so as not to exceed the emission luminance of the divided area that circumscribes the subtitle area And a backlight control step for controlling luminance.

  The conventional image display device described in Patent Document 2 performs control so that the brightness of OSD display does not become too high. However, the image display device merely controls to keep the brightness of the OSD display constant regardless of the change in the brightness of the video other than the OSD display. For this reason, the user may feel a large difference in luminance between the OSD display and other images, and it is difficult to obtain a sense of unity of the entire image.

  On the other hand, the display control device or the like according to the present invention first determines whether the difference in emission luminance between adjacent divided areas exceeds a predetermined value among the divided areas constituting the closed caption area that is an area on the display surface where the closed caption is displayed. Determine whether or not. When the display control device or the like according to the present invention determines that there is a divided area that is adjacent to each other and the difference in emission luminance exceeds a predetermined value, the emission luminance of the divided area that circumscribes the subtitle area is determined. The emission luminance of the divided areas constituting the caption area is controlled so as not to exceed. That is, control is performed so as to optimize the light emission luminance of the subtitle according to the light emission luminance of the divided area circumscribing the subtitle area.

  As a result, the subtitle emission luminance does not protrude and become larger than the emission luminance circumscribing the subtitle area, so that the user does not feel the subtitles dazzling when reading the subtitles, and obtains a sense of unity of the entire video. Can do.

  In addition, the image display device described in Patent Document 2 described above only controls so that the luminance of the caption does not become too high only when the caption is OSD-displayed.

  On the other hand, the display control device of the present invention determines whether or not a caption exists by extracting a difference in light emission luminance between adjacent divided areas. This determination can be performed regardless of whether subtitles are displayed in the OSD or directly on the video (video with subtitles).

  As a result, the display control device of the present invention can control not only the subtitles displayed in OSD but also the subtitles included in the video with subtitles so that the luminance of the subtitles does not become too high.

  Therefore, the display control device and the control method for the device of the present invention can improve the display quality of the video as compared with the conventional technology.

In the display control device of the present invention,
(1) The backlight control means controls the light emission luminance of the divided area constituting the caption area so as to be equal to the maximum value of the light emission luminance of the divided area circumscribing the caption area.

  According to the above configuration, the light emission luminance of the subtitle area, particularly the light emission luminance of the subtitle displayed in the subtitle area, becomes equal to the maximum value of the light emission luminance of the divided area circumscribing the subtitle area. That is, the light emission luminance of the subtitle is the same as the light emission luminance of the video displayed in the divided area outside at least one subtitle area. For this reason, the light emission luminance of the subtitle does not protrude and become larger than the light emission luminance outside the subtitle area.

  Therefore, the display control device of the present invention can improve the display quality of the video because the user rarely feels the glare of the caption when the user reads the caption.

The display control device of the present invention is
(1) A black band determining unit that determines whether or not the divided areas constituting the subtitle area are included in a black band that does not display an image when the luminance determining unit determines that the predetermined value is exceeded. Prepared,
(2) When the backlight control unit determines that the black band part is included in the black band part, the divided area that constitutes the subtitle area so as to be equal to the average luminance of the entire backlight. It is characterized by controlling the light emission luminance.

  According to the above configuration, when the display control device determines that the difference in the light emission luminance exceeds a predetermined value, whether or not the divided region constituting the subtitle region is included in the black belt portion where no image is displayed. Determine. When it is determined that the display control device is included in the black belt portion, the display control device controls the light emission luminance of the divided regions constituting the caption region so as to be equal to the average luminance of the entire backlight.

  That is, the display control device of the present invention can make the emission luminance of the subtitle equal to the average emission luminance level of the entire backlight when the subtitle existing in the subtitle area is displayed in the black belt portion. Therefore, the display control device can display the subtitles in an easy-to-view manner for the user without making the subtitles too dark even when the subtitles are present in the black belt portion.

Also, the playback device of the present invention is
(1) the display control device;
(2) A playback device that outputs an image to be displayed on the display device to the display device is provided.

  As in the above configuration, the playback apparatus including the display control device and the playback device has the same effects as described above.

Moreover, the television receiver of the present invention is
(1) A television receiver capable of receiving a broadcast television program,
(2) a display device for displaying the television program;
(3) The playback apparatus for outputting the television program as the image to the display device.

  As in the above configuration, the television receiver including the display device and the playback device has the same effects as described above.

  The display control device may be realized by a computer. In this case, a control program that causes the display control device to be realized by the computer by operating the computer as each unit of the display control device, and a computer-readable recording medium that records the control program also fall within the scope of the present invention. .

  As described above, the display control device of the present invention provides a difference in light emission luminance between divided areas adjacent to each other among divided areas constituting the closed caption area that is an area on the display surface on which the caption is displayed by the display device. Luminance determination means for determining whether or not the luminance exceeds a predetermined value, and when the luminance determination means determines that the difference in emission luminance exceeds a predetermined value, does not exceed the emission luminance of the divided area circumscribing the subtitle area As described above, the backlight control means for controlling the light emission luminance of the divided areas constituting the caption area is provided.

  Further, the display control device control method of the present invention provides a difference in light emission luminance between adjacent divided areas among the divided areas constituting the closed caption area that is an area on the display surface where the display device displays the closed caption. And a luminance determination step for determining whether or not a luminance exceeds a predetermined value, and if the luminance determination step determines that the difference in emission luminance exceeds a predetermined value, the emission luminance of the divided area circumscribing the caption area is not exceeded As described above, the backlight control step for controlling the light emission luminance of the divided areas constituting the caption area is included.

  Therefore, the display control device and the control method of the device of the present invention can optimize the brightness of captions according to the video, and can improve the display quality of the video including the captions.

It is a block diagram which shows the principal part structure of the reproducing | regenerating apparatus concerning the 1st Embodiment of this invention. It is a schematic diagram which shows an example of the image | video displayed on the display screen of a display apparatus. It is the schematic diagram which showed an example of the position on the display surface of a caption area. 6 is a flowchart illustrating an example of a caption display control process executed by a display control unit of the playback apparatus illustrated in FIG. 1. FIG. 3 is an enlarged view in which a partial region of the display screen shown in FIG. 2 is enlarged. It is a flowchart which shows the flow of the caption display determination process performed by a display control part. It is a graph which shows the specific example of the method of light emission luminance adjustment, Comprising: It is the graph which extracted the light emission luminance of the backlight area | region on the ROW1 line shown in FIG. 2, (a) is light emission luminance before a caption display control process. (B) is a graph which shows the light emission luminance after the process. It is the graph which extracted the light emission luminance of the backlight area | region on the ROW _OUT line shown in FIG. It is the graph which extracted the light emission luminance of the backlight area | region on the COL1 line shown in FIG. It is a block diagram which shows the principal part structure of the reproducing | regenerating apparatus based on the 2nd Embodiment of this invention. FIG. 11 is a flowchart showing a subtitle display control process executed by a display control unit of the playback apparatus shown in FIG. 10. FIG. It is the graph which extracted the light emission luminance of the backlight area | region on the ROW2 line shown in FIG. It is a block diagram which shows the principal part structure of the TV receiver which concerns on the 3rd Embodiment of this invention.

[Embodiment 1]
Based on FIGS. 1-9, the 1st Embodiment of this invention is described in detail.

[Outline of playback apparatus 1]
Based on FIG. 1, the structure of the reproducing | regenerating apparatus 1 is demonstrated. FIG. 1 is a block diagram showing a main configuration of the playback apparatus 1 according to the present embodiment. Note that, from the viewpoint of ensuring the simplicity of the description, portions not directly related to the present embodiment are omitted from the description of the configuration and the block diagram. However, the reproducing apparatus 1 may include the omitted configuration in accordance with the actual situation.

  The playback device 1 is a device that includes a display control unit 12 and a playback unit 11 that outputs an image to be displayed on the liquid crystal display device 201 (see FIG. 13) to the liquid crystal display device. That is, the playback device 1 plays back video from a video signal included in a stream signal acquired from a tuner or the like. Then, the video reproduced by the reproduction device 1 is displayed on the liquid crystal display device 201.

  In the present embodiment, it is assumed that the video reproduced by the playback device 1 is a video with subtitles including subtitles in the video itself. An example of a stream signal including a video signal is MPEG2 (Moving Picture Experts Group phase 2) -TS (Transport Stream).

  As described above, the playback device 1 includes the playback unit 11, the display control unit 12, and the frame memory unit 13 (hereinafter abbreviated as the memory unit 13).

  The reproduction unit (reproduction device) 11 outputs an image to be displayed on the liquid crystal display device 201 to the liquid crystal display device. Details of the reproducing unit 11 will be described later.

  The display control unit (display control device) 12 divides a backlight using a light emitting diode (LED) as a light source for illuminating a display surface 2011 (see FIG. 13) included in the liquid crystal display device 201 into a plurality of divided regions, It is a device that can control the luminance of an image displayed on the display surface by the liquid crystal display device 201 by controlling the output of the LED for each divided region.

  Each function of the display control unit 12 may be realized by a CPU (Central Processing Unit) executing a program stored in a storage element such as a RAM (Random Access Memory) or a flash memory. Details of the display control unit 12 will also be described later.

  The memory unit 13 is a recording medium that stores various data and programs. A ROM (Read Only Memory) that is a read-only semiconductor memory that stores fixed data such as a program necessary for operation of the display control unit 12 and communication control data, data used for calculation, and calculation results are temporarily stored. The memory unit 13 can be configured by a RAM as a so-called working memory that is stored in the memory, various setting data, a large capacity HDD (Hard Disk Drive) that stores the stream signal, and the like.

  Next, details of the configuration of the playback unit 11 and the display control unit 12 will be described.

[Details of playback unit 11]
As shown in FIG. 1, the playback unit 11 includes a decoder unit 111, an external input terminal unit 112, a main control unit 113, and a main frame memory unit 114 (hereinafter abbreviated as main memory unit 114). .

  The decoder unit 111 receives a television broadcast wave or the like via an antenna and a tuner (not shown), and decodes a video signal included in the stream signal of the broadcast wave. As a result, video in a format that can be displayed on the display device is reproduced. Then, the decoder unit 111 sends the decoded video signal to the display control unit 12.

  Various external devices such as a solid-state memory such as an HDD and an SD card, a disk device such as a BD (Blue-ray DISC), a DVD (Digital Versatile Disk), and a CD can be connected to the external input terminal unit 112. . The decoder unit 111 may receive and decode video signals from these external devices connected to the external input terminal unit 112 and reproduce the decoded video.

[Details of Display Control Unit 12]
As shown in FIG. 1, the display control unit 12 includes an area active control unit 121, an LED control unit 122, and a caption determination unit 123.

  A caption determination unit (luminance determination means) 123 is configured to detect a difference in light emission luminance between divided areas adjacent to each other among divided areas constituting a closed caption area that is an area on the display surface 2011 on which a caption is displayed by the liquid crystal display device 201. It is determined whether or not a predetermined value is exceeded.

  Specifically, the caption determination unit 123 acquires the video output from the decoder unit 111, and in a predetermined subtitle area of the video, for each divided area obtained by dividing the subtitle area, the video in the divided area is displayed. Extract the maximum gradation value. Then, it is determined whether or not there are adjacent divided areas where the difference between the maximum gradation values is equal to or greater than a predetermined value.

  The operation of the caption determination unit 123 is controlled by the main control unit 113 provided in the playback unit 11. In addition, the caption determination unit 123 extracts the maximum gradation value of the video for each divided area. However, in addition to the maximum gradation value, for example, other predetermined statistics such as the average gradation value of the video in each divided area. The structure which extracts a value may be sufficient. In this case, it is the extracted predetermined statistical value that is subject to the determination.

  The LED control unit (backlight control means) 122, when the subtitle determination unit 123 determines that the difference in light emission luminance exceeds a predetermined value, the subtitle so as not to exceed the light emission luminance of the divided area circumscribing the subtitle area The light emission luminance of the divided areas constituting the area is controlled.

  In other words, the LED control unit 122 acquires the result of the determination by the caption determination unit 123, and controls the backlight of the display device using the region corresponding to the divided region as a unit region based on the determination result. Here, the LED control unit 122 may control the light emission luminance of the divided areas constituting the caption area so as to be equal to the maximum value of the light emission luminance of the divided area circumscribing the caption area.

  The area active control unit 121 acquires a video signal from the caption determination unit 123 and controls the gradation of each pixel on the display surface 2011 provided in the liquid crystal display device 201.

  In addition, since the said divided area respond | corresponds to the unit area | region when controlling a backlight, the said divided area is hereafter called a "backlight area".

[Display video and subtitle area]
Based on FIG. 2, caption display positions on the display surface 2011 provided in the liquid crystal display device 201 will be described. FIG. 2 is a schematic diagram illustrating an example of an image displayed on the display surface 2011 of the liquid crystal display device 201.

  There are areas (areas B1 and B2) where no video is displayed at the upper and lower ends of the display surface 2011. And the image | video is displayed so that it may be pinched | interposed into both (area | region A). Hereinafter, the regions B1 and B2 are referred to as black belt portions, and the region A is referred to as a normal image region.

  In FIG. 2, subtitles (“Ai”) are displayed at a position below the normal image area and in the center in the left-right direction. As shown in FIG. 2, subtitles displayed with a normal image are generally displayed along either the top, bottom, left, or right end of the normal image area, or are displayed inside a black belt portion. Is.

As a feature of video with subtitles displayed,
1. There is a sharp change in brightness between adjacent pixels.
2. Almost uniform high-luminance pixels appear continuously.
Can be mentioned.

  1. The feature is that subtitles are generally displayed with a much higher luminance than normal images, and such a change in luminance appears at positions where normal images and subtitles are adjacent to each other.

  2. The feature is that since the pixel size of the display device is sufficiently smaller than the display size of the caption, a plurality of pixels are included in the area where the caption is displayed.

  Note that the above-described backlight region is set to a size larger than the pixel and sufficiently smaller than the subtitle display size (for example, a size equal to or smaller than ½ of the subtitle display size). Thereby, a plurality of backlight areas are included in the area where the caption is displayed.

  As shown in FIG. 2, when the subtitle is displayed below or above the normal image area, it is generally displayed in horizontal writing. On the other hand, when subtitles are displayed along the left or right edge of the normal image area, they are generally displayed vertically.

  In addition, when a subtitle is displayed in a black belt portion, the subtitle is generally displayed in horizontal writing if the black belt portion is displayed above and / or below the normal image area. On the other hand, if the black belt portion is displayed on the left and / or left of the normal image area, the subtitle is generally displayed in vertical writing.

  Based on FIG. 3, the display position of the caption area, which is the area on the display surface where the caption is displayed, will be described. FIG. 3 is a schematic diagram showing an example of the position of the caption area on the display surface. A horizontally long rectangular portion (region X) indicated by diagonal lines on the lower side of the display screen (outer frame) shown in FIG. 3 is a caption region.

  As shown in FIG. 3, the display control unit 12 sets the caption area on the display screen so as to include the above-described area where the caption is generally displayed. The caption area is a range defined by the width w0 in the horizontal direction, and is a range that covers both the above-described black belt portion (region B1) and the normal image portion (region A) in the vertical direction.

  In the present embodiment, description will be made assuming that the caption area shown in FIG. 3 is set.

[Subtitle display control processing]
Based on FIG. 4, when displaying video with captions reproduced by the playback device 1 on the liquid crystal display device 201, caption display in which the display controller 12 controls the light emission luminance of the backlight included in the liquid crystal display device 201. The control process will be described.

  First, an outline of subtitle display control processing will be described. The display control unit 12 divides the caption area into a matrix and performs control for each divided unit area (backlight area). The display control unit 12 determines whether or not there is a backlight area including subtitles in the subtitle area of the video to be played back by the playback device 1, and when such a backlight area exists, Controls the brightness of the corresponding backlight.

  The display control unit 12 performs caption display control processing for each ROW1 line and ROW2 line (see FIGS. 2 and 3). On each line, the backlight areas are arranged in a line. The display control unit 12 determines whether or not there is a backlight area including subtitles among all the backlight areas existing on a certain line. Then, when there is no backlight area including subtitles on the line, the display control unit 12 executes the subtitle control process in the procedure of moving to a line adjacent to the line and performing the same determination. When the backlight area including the caption is not found on any line, the display control unit 12 executes the caption display control processing for all the backlight areas included in the caption area.

  Next, the details of the caption display control process will be described with reference to the flowchart shown in FIG. In the following description, “˜step” in parentheses represents each step of the control method.

  The display control unit 12 (caption determination unit 123) performs a caption display determination process for determining whether or not there is a backlight region including a caption for each backlight region on the line (S100, luminance determination step). Details of this processing will be described later.

  In subsequent steps, the display control unit 12 uses the flag FLAG to indicate whether or not a backlight area including subtitles has been found. If it is determined in step S100 that no caption exists in the backlight area on the line, the display control unit 12 sets FLAG to 0 (FLAG = 0). On the other hand, if it is determined that there is a caption in the backlight area on the line, the display control unit 12 sets FLAG to 1 (FLAG = 1).

  Next, the display control unit 12 determines whether or not FLAG = 1 (S200). If FLAG = 1 is not satisfied (NO in S200), that is, if FLAG = 0, the display control unit 12 moves to a line adjacent to the current line (S300). Thereafter, the display control unit 12 determines whether or not the destination line is outside the caption area (S400), and if the line is within the caption area (NO in S400), the backlight area on the line. The subtitle display determination process is performed (S100). On the other hand, if the destination line is outside the caption area (YES in S400), the display control unit 12 ends the caption display control process.

  When the process proceeds from step S100 to step S200 and FLAG = 1 (YES in S200), the display control unit 12 (LED control unit 122) circumscribes the light emission luminance of the subtitle area (in the normal image area). ) Match the maximum value of the light emission luminance of the backlight region (S300, backlight control step). Then, the display control unit 12 ends the caption display control process.

  As described above, when the caption determination unit 123 determines that a caption exists in a certain backlight area within a predetermined caption area of the video, the display control unit 12 emits light from the backlight area that forms the caption area. The brightness is adjusted to the light emission brightness of the normal image area that circumscribes the caption area. Thereby, since the subtitle is displayed with the same light emission luminance as that of the normal image, it is unlikely that the user who reads the subtitle feels dazzling the subtitle.

[Subtitle display determination processing]
Based on the flowchart shown in FIG. 6, the caption display determination process executed as step S100 of the caption display control process described above will be described. The caption display determination process will be described with reference to FIG. 5 which is an enlarged view of a partial area included in the caption area in the entire area of the display surface 2011 illustrated in FIG.

  As described above, in the caption display determination process, the caption determination unit 123 determines whether or not there is a backlight area including a caption for each backlight area on one line.

  Hereinafter, a case where the caption display determination process is performed on the line indicated as ROW1 in FIG. 2 will be described as an example.

  First, the caption determination unit 123 sets FLAG = 0. Then, the light emission luminance of the leftmost backlight area (PB (1) in FIG. 5) of the caption area is acquired (S101).

  Next, the caption determination unit 123 moves the reference position of the area to the backlight area right next to the leftmost backlight area (PB (2) in FIG. 5) (S102). Then, the caption determination unit 123 determines whether or not the destination backlight area exceeds the right end of the preset caption area (PB (n) in FIG. 5) (S103). When the destination backlight area exceeds the right end of the caption area (YES in S103), the caption determination unit 123 moves the reference position of the area to an adjacent line (subtitle display control processing step S200), and the line The subtitle display determination process is repeated from step S101 for the upper backlight region.

  On the other hand, when the current backlight area does not exceed the right end of the caption area (NO in S103), the caption determination unit 123 acquires the light emission luminance of the destination backlight area (S104), and the backlight on the left side thereof. It is determined whether or not the difference between the light emission luminances of the region is equal to or greater than a predetermined value (S105). More specifically, in step S105, the caption determination unit 123 determines whether or not the light emission luminance of the right backlight region is higher than a predetermined value as compared with the light emission luminance of the left backlight region.

  Step S105 is the first step for determining whether or not a caption exists in the caption area. Features of the above-mentioned captions According to the above, in a video in which subtitles exist, the light emission luminance of the backlight changes sharply at the boundary between the region where subtitles exist and the region where subtitles do not exist. In step S105, it is determined whether or not this feature appears.

  If the difference between the light emission luminances is not equal to or greater than the predetermined value (NO in step S105), the caption determination unit 123 moves the reference position of the region to the right next backlight region (S102), and repeats the above-described processing.

  On the other hand, when the light emission luminance difference is equal to or greater than the predetermined value (YES in step S105), the caption determining unit 123 moves the reference position of the area to the right backlight area (S106), and the destination backlight. It is determined whether the area is the rightmost backlight area of the caption area (S107).

  When the current backlight area is the rightmost backlight area of the subtitle area (YES in step S107), the subtitle determining unit 123 moves the reference position of the area to an adjacent line (step S200 of the subtitle display control process), Subtitle display determination processing for the line is performed.

  On the other hand, when the current backlight area is not the rightmost backlight area of the subtitle area (NO in step S107), the subtitle determination unit 123 moves the reference position of the area to the right adjacent backlight area (S107). The light emission luminance of the backlight area is acquired (S108).

  Next, the caption determination unit 123 determines whether or not the light emission luminance extracted from the current backlight region is substantially the same value as the light emission luminance of the left adjacent backlight region (S109).

  If the light emission luminances of the two backlight areas are not substantially the same value (NO in S109), the caption determination unit 123 moves the reference position of the area to the right adjacent backlight area (S102), and repeats the above-described processing.

  On the other hand, when the light emission luminances of the two backlight areas are approximately the same value (YES in S109), the caption determination unit 123 determines that the light emission luminances are approximately the same value including the two backlight areas. It is determined whether a predetermined number or more of backlight areas are continuous (S110).

  Step S109 and step S110 are the second step for determining whether or not a caption exists in the caption area. Features of the captions described above 2. According to the above, in a video in which subtitles exist, an area showing high luminance emission luminance with substantially uniform backlight emission luminance appears corresponding to the region in which subtitles exist. It is the step S109 and the step S110 that determine whether or not this feature appears.

  When a predetermined number or more of backlight areas having substantially the same emission luminance are not continuous (NO in S110), the caption determination unit 123 moves the reference position of the area to the right adjacent backlight area (S106), and Repeat the process.

  When a predetermined number or more of backlight areas having substantially the same emission luminance are present (YES in S110), the caption determination unit 123 determines that captions exist in a series of backlight areas having substantially the same emission luminance. Determination is made (S111), and FLAG = 1. Thus, the caption display determination process (S100) (in the ROW1 line) is completed.

  In this way, in the caption display determination process, the caption determination unit 123 determines whether or not there is a backlight area where captions exist for each line in the caption area.

  In the present embodiment, the caption determination unit 123 first extracts a backlight area in which the difference in emission luminance from the left adjacent backlight area is equal to or greater than a predetermined value (YES in step S105), and the backlight area Are determined to be present in the series of backlight areas (YES in steps S109 and S110). However, the present invention is not limited to this.

  Specifically, the caption determination unit 123 extracts captions in the backlight area having the higher emission luminance when the adjacent backlight areas having the emission luminance difference equal to or larger than the predetermined value are extracted (YES in step S105). May be determined to exist. As a result, the above-described subtitle feature 2. Since the accuracy of determining the presence of subtitles is reduced, there is an advantage that the processing is simplified.

(Adjusting the brightness)
In the above-described caption display control process, it has been described that “when it is determined that a caption exists in a predetermined caption area of a video, the light emission luminance of the subtitle area is matched with the light emission luminance of the normal image area”. Here, a specific example of the light emission luminance adjustment method executed by the LED control unit 122 based on the graph obtained by extracting the issue luminance of the backlight region on the ROW1 line shown in FIGS. 7A and 7B. An example will be described.

  In FIG. 7A, the LED control unit 122 extracts the light emission luminance of the backlight area existing on the ROW1 line (see FIG. 5) before adjusting the light emission luminance of the backlight area in the caption area. It is a bar graph which shows a result. Each bar of the graph corresponds to each backlight area, and the height of the bar represents the light emission luminance. As indicated by the three arrows in the figure, there are three areas in the caption area that are lined up with three backlight areas that protrude and have a high emission luminance and a substantially uniform emission luminance. These indicate that subtitles exist in this area (caption display area). In this way, subtitles exist at positions where substantially uniform high-brightness backlight regions continue.

  FIG. 7B shows an example in which the LED control unit 122 matches the light emission brightness of the backlight area in the caption area with the light emission brightness of the backlight area in the normal image area adjacent to the caption area. It is a graph which shows the result of having extracted the light emission brightness | luminance of the backlight area | region. As can be seen from the figure, the light emission brightness of the backlight area in the caption area is matched with the light emission brightness of the backlight area (indicated by R in the figure) in the normal image area adjacent to the caption area. By doing so, the light emission luminance of the subtitles displayed in the subtitle area is not prominently higher than the light emission luminance of the normal image. Thereby, the LED control part 122 can suppress that the user who reads subtitles feels the subtitles dazzling.

Other examples of the method for adjusting the light emission luminance include the following examples.
1. The light emission luminance of the backlight area determined to have subtitles is set to the light emission luminance that is the maximum value among the light emission luminances of the backlight areas adjacent to the backlight area.
2. When the adjacent backlight area is a backlight area that is determined to have a caption, the emission luminance of the backlight area (within the caption area) determined immediately before is set.

[Supplement of caption display determination processing]
In general video, subtitles are displayed with higher brightness than normal images. Therefore, before performing the caption display control process, the backlight area (FIG. 5) includes the caption adjacent to the backlight area as compared to the light emission luminance of the backlight area (PB (k) in FIG. 5) that does not include the caption. 5, the light emission luminance of PB (k + 1)) is high.

  Further, in a general video, the difference between the light emission luminance of the backlight area including subtitles and the light emission luminance of the backlight area not including subtitles is larger than the difference between the light emission luminances of the two backlight areas not including subtitles. .

  On the premise of the above, a predetermined value of the difference in luminance of adjacent backlights is set as a reference for the determination performed in step S105.

In particular,
1. It is lower than the difference between the light emission luminance that can be extracted from the backlight region including only the normal image and the light emission luminance of the backlight region including the caption.
2. It is higher than the difference in light emission luminance between the two backlight areas including only the normal image.
The predetermined value is set so as to be a value.

FIG. 8 shows a result of extracting the light emission luminance of the backlight region along the ROW _OUT line when the image of FIG. 2 is displayed. The ROW _OUT line exists in the normal image area, that is, outside the caption area. Therefore, the backlight area on the ROW _OUT line does not include subtitles. Therefore, as can be understood from FIG. 8, the backlight region existing on the ROW _OUT line does not include a region having a characteristic high luminance indicating the presence of a caption.

  As can be understood from a comparison between the graph of FIG. 8 and the graph of FIG. 7A (a graph in which a backlight area including subtitles exists), the normal image and the subtitles have a characteristic emission luminance. It can be determined by the presence or absence of a write area.

[Modification]
In the present embodiment, the processing in the case where the subtitle area is located below the display surface 2011 and is a horizontally long rectangular area has been described (see FIG. 3). However, the present invention is not limited to this. In addition, the caption area may be a vertically long rectangular area located on the left side of the display surface 2011, for example. Accordingly, it is possible to cope with a case where subtitles are displayed in vertical writing on the left side of the display surface 2011. In general, the caption area may be an area in which captions are generally displayed in the entire area of the display surface 2011. Moreover, the caption area may be composed of a plurality of areas as well as one area.

  When the caption area is a vertically long rectangular area, the caption determination unit 123 performs the caption display determination process for each vertical line instead of the horizontal lines (ROW1, ROW2) as in the present embodiment. Do it.

  FIG. 9 shows the result of extracting the light emission luminance of the backlight region on the COL1 line which is an example of the vertical line when the image of FIG. 2 is displayed. The direction from the left to the right of the graph in FIG. 9 corresponds to the direction from the top to the bottom of the display surface 2011 in FIG.

  The characteristic light emission luminance indicated by two arrows in FIG. 9 indicates that subtitles exist in the backlight area. Thus, the caption determination unit 123 can also perform caption display determination processing for each line in the vertical direction.

[Embodiment 2]
Based on FIGS. 10-12, the 2nd Embodiment of this invention is described in detail. In the present embodiment, when subtitles are included in the black belt portion of the video, the method for controlling the light emission luminance of the backlight in the subtitle display control processing is different from that of the first embodiment. Other configurations are the same as those of the first embodiment. Therefore, in the following, the caption display control process having the characteristics of the present embodiment will be mainly described. Further, the same configurations and steps as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Based on FIG. 10, the structure of the reproducing | regenerating apparatus 2 of this Embodiment is demonstrated. FIG. 10 is a block diagram showing a main configuration of the playback device 2. As shown in FIG. In addition to the configuration of the playback apparatus 1 according to the first embodiment, the playback device 2 further includes a black band determination unit (black band determination unit) 124.

  The black belt portion determination unit 124, when the subtitle determination unit 123 determines that there is a backlight region in which the difference in light emission luminance between adjacent backlight regions exceeds a predetermined value among the backlight regions constituting the subtitle region Then, it is determined whether or not the backlight area constituting the caption area is included in a black belt portion where no image is displayed.

  The LED control unit 122 acquires the determination result by the black belt determination unit 124, and changes the backlight control method according to the determination result.

[Subtitle display control processing]
Based on the flowchart shown in FIG. 11, the feature of the caption display control processing in the present embodiment will be described. In the present embodiment, it is assumed that subtitles exist in the black belt portion of the video.

  In the caption display control process of the present embodiment, when the caption determining unit 123 determines that a caption exists in the backlight area on a certain line in step S100, that is, when FLAG is set to 1, the determination in step S200 is YES and the process proceeds to step S3000. The black belt portion determination unit 124 determines whether or not the subtitle is located within the black belt portion (S3000).

  When the black belt portion determination unit 124 determines that no subtitles exist in the black belt portion, that is, exists in the normal image area (NO in S3000), the LED control unit 122 is the same as in the first embodiment. In addition, the light emission brightness of the caption area is matched with the light emission brightness (maximum value) of the backlight area circumscribing the caption area (S3001b). Then, the caption display control process ends.

  On the other hand, when the subtitle is present in the black belt portion (YES in S3000), the LED control unit 122 matches the emission luminance of the subtitle area with the average luminance (Average Picture Level; APL) (S3001a), and the subtitle display control process Exit. For example, based on the aspect ratio (screen size) of the display surface 2011 and the pixel size of the video, the black belt portion determination unit 124 calculates a region that is a black belt portion of the entire display surface 2011.

  FIG. 12 shows an example of the result of extracting the light emission luminance of the backlight region on the ROW2 line (see FIG. 2) when the subtitle is present in the black belt portion. A characteristic high luminance indicating the presence of captions appears at the position indicated by three arrows in the figure.

  In the first embodiment, not only when the subtitle exists in the normal image area, but also when the subtitle area exists in the black belt portion, the luminance of the subtitle area is increased in the backlight area that circumscribes the subtitle area. Adapted. Therefore, when the subtitle exists in the black belt portion, the light emission luminance of the subtitle region is matched with the light emission luminance of the black belt portion. In that case, since the subtitle is displayed darkly, it is difficult for the user to see the subtitle.

  On the other hand, in the caption display control processing of the present embodiment, when the caption is present in the black belt portion, the light emission luminance of the caption area is adjusted to APL. APL is the average level of the emission luminance of the entire video (entire backlight) displayed on the display screen 2011. Therefore, elements for calculating APL include not only the light emission luminance of the black belt portion but also the light emission luminance of the normal image area. Therefore, the light emission luminance of the caption area is higher than at least the light emission luminance in the black belt portion, so that the subtitle visibility is improved as compared with the first embodiment.

[Embodiment 3]
Based on FIG. 13, an example in which the playback apparatus 1 according to the first embodiment is applied to a television receiver 200 (hereinafter abbreviated as a TV receiver 200) will be described. Note that a description of the playback apparatus 1 described in the first embodiment is omitted.

  FIG. 13 is a block diagram showing a main configuration of the TV receiver 200. As shown in the figure, the TV receiver 200 includes a liquid crystal display device 201 having a display surface 2011 and a backlight 2012. The TV receiver 200 includes a tuner unit 204, an antenna unit 240, an LED driver unit 205, and a timing controller unit 206.

  The liquid crystal display device 201 can display a television program by adjusting the output of the backlight 2012 according to signals input from the timing controller unit 206 and the LED driver unit 205 and displaying image data on the display screen 2011. Device.

  In the present embodiment, a liquid crystal display (LCD) using a liquid crystal display panel on the display surface 2011 is assumed as the liquid crystal display device 201, but a device having a display function capable of local deming control ( In particular, the type of hardware is not limited as long as it is a flat panel display.

  For example, a display element such as a plasma display panel (PDP) or an EL (Electroluminescence) display, and a driver circuit that drives the display element based on signals input from the timing controller unit 206 and the LED driver unit 205 The liquid crystal display device 201 can be configured by an apparatus provided.

  The backlight 2012 is an illumination device that uses an LED as a light source for illuminating the display surface 2011. The brightness of the LED of the backlight 2012 is controlled according to control information by PWM (Pulse Width Modulation) control, current control, or a combination thereof.

  The TV receiver 200 further includes a playback device 1. The operation of the TV receiver 200 is controlled by the main control unit 113 provided in the playback apparatus 1 and various control programs stored in the main memory unit 114. That is, the TV receiver 200 is controlled by a computer system including the main control unit 113, and a program for operating the TV receiver 200 by the computer system is stored in the main memory unit 114.

  The TV receiver 200 includes a tuner unit 204 and can receive a digital broadcast (television program). In addition, the TV receiver 200 may include an IP broadcast tuner unit and be capable of receiving IP broadcasts.

  The tuner unit 204 selects a digital television broadcast signal received via the digital broadcast receiving antenna unit 240. The received signal from the tuner unit 204 is demodulated and then sent to the decoder unit 111.

  The LED driver unit 205 controls light emission of the LEDs that constitute the backlight 2012. The LED driver unit 205 acquires an instruction to control the light emission luminance of the backlight 2012 from the LED control unit 122. The LED driver unit 205 controls the light emission luminance of the LEDs that constitute the backlight 2012.

  The timing controller unit 206 acquires data (image data) indicating the gradation of each pixel on the display surface 2011 from the area active control unit 121. Then, the timing controller unit 206 outputs the acquired image data so that an image synchronized with the light emission of the backlight 2012 is displayed on the display surface 2011.

  As in the first embodiment, when a subtitle exists in a predetermined subtitle area of the image to be displayed, the display control unit 12 matches the light emission luminance of the subtitle area with the light emission luminance of the backlight area circumscribing the subtitle area. . Then, the video is displayed on the display surface 2011 as described above. Therefore, when a caption is included in the image displayed on the display surface 2011, the light emission luminance of the caption is suppressed.

  Therefore, the TV receiver 200 can provide an image with high display quality that does not feel dazzling for the user when the subtitle is included in the subtitle area.

  In the above description, a TV receiver is taken as an example. However, other than the above, television broadcasting can be performed by a portable device capable of viewing television broadcasting, such as a mobile phone, a car navigation system, and a portable game terminal. It is obvious that the playback apparatus according to the present invention can be applied to the case of receiving the signal.

  Further, the present invention can be applied to a local deming technique.

  In conventional local dimming, a region with high emission luminance causes the backlight to emit light more strongly, while a region with low emission luminance causes the backlight to emit light more weakly. Therefore, when the conventional local dimming is applied, the backlight of the area including the caption with high emission luminance emits light more strongly. Therefore, the user feels the subtitles dazzling.

  However, combining the present invention that suppresses the light emission luminance of the caption area with local deming control can prevent the luminance of the caption from becoming excessively strong. That is, according to the present invention, when it is determined that there is a caption in the caption area, the emission luminance of the caption area is matched with the emission luminance of the backlight area circumscribing the caption area. Therefore, according to the present invention, it is possible to prevent the luminance of subtitles included in the subtitle area from increasing.

[Supplement]
Finally, each block of the playback device 1 and the TV receiver 200, particularly the display control unit 12, may be configured by hardware logic, or may be realized by software using a CPU as follows.

  That is, the playback device 1 is a storage device (recording device) such as a CPU that executes instructions of a control program that realizes each function, a ROM that stores the program, a RAM that expands the program, a memory that stores the program and various data, and the like. Medium). The object of the present invention is to record the program code (execution format program, intermediate code program, source program) of the control program of the playback apparatus 1 / TV receiver 200, which is software that implements the functions described above, so that it can be read by a computer. This can also be achieved by supplying the recorded medium to the playback apparatus 1 / TV receiver 200 and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

  Examples of the recording medium include a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, and an optical disk such as a CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  Further, the playback apparatus 1 / TV receiver 200 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Further, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used.

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

  Since the present invention is applied to a display device having a backlight as described above, it can be used for any reproducing device that reproduces video displayed on at least a liquid crystal display device.

1. Playback device (playback device)
12 Display control unit (display control device)
122 LED control unit (backlight control means)
123 Subtitle determination unit (luminance determination means)
124 Black belt portion determination unit (black belt portion determination means)
200 Television receiver (television receiver)
201 Liquid crystal display device (display device)
2011 Display surface (display surface)
2012 Backlight (Backlight)

Claims (8)

By dividing a backlight using a light emitting diode as a light source for illuminating a display surface included in the display device into a plurality of divided regions and controlling the output of the light emitting diode for each of the divided regions, the display device performs the display. A display control device capable of controlling the brightness of an image displayed on a screen,
Luminance determination that determines whether or not the difference in emission luminance between adjacent divided areas exceeds a predetermined value among divided areas that constitute a closed caption area that is an area on the display surface where closed captions are displayed by the display device Means,
When the luminance determination means determines that the difference in emission luminance exceeds a predetermined value, the emission luminance of the divided areas constituting the caption area is controlled so as not to exceed the emission luminance of the divided area circumscribing the caption area. A display control device comprising a backlight control means for performing the above operation.   The backlight control means controls the light emission luminance of the divided areas constituting the caption area so as to be equal to the maximum value of the light emission luminance of the divided area circumscribing the caption area. The display control device described. When it is determined by the luminance determination means that it exceeds a predetermined value, the black area determination means for determining whether or not the divided area constituting the subtitle area is included in a black band portion where no image is displayed,
When the backlight control means determines that the black belt part is included in the black belt part, the backlight control means emits luminance of divided areas constituting the caption area so as to be equal to the average luminance of the entire backlight. The display control device according to claim 1, wherein the display control device is controlled. A display control device according to any one of claims 1 to 3,
A playback device, comprising: a playback device that outputs an image to be displayed on the display device to the display device. A television receiver capable of receiving a broadcast television program,
A display device for displaying the television program;
A television receiver comprising: the reproduction device according to claim 4, wherein the reproduction program outputs the television program as the image to the display device. By dividing a backlight using a light emitting diode as a light source for illuminating a display surface included in the display device into a plurality of divided regions and controlling the output of the light emitting diode for each of the divided regions, the display device performs the display. A control method of a display control device capable of controlling the brightness of an image displayed on a surface,
Luminance determination that determines whether or not the difference in emission luminance between adjacent divided areas exceeds a predetermined value among divided areas that constitute a closed caption area that is an area on the display surface where closed captions are displayed by the display device Steps,
When it is determined in the luminance determination step that the difference in emission luminance exceeds a predetermined value, the emission luminance of the divided areas constituting the caption area is controlled so as not to exceed the emission luminance of the divided area circumscribing the caption area. And a backlight control step for controlling the display control device.   A control program for operating the display control device according to any one of claims 1 to 3, wherein the control program causes a computer to function as each means.   A computer-readable recording medium on which the control program according to claim 7 is recorded.

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