WO2013051586A1

WO2013051586A1 - Display device, display method, program, and computer-readable recording medium

Info

Publication number: WO2013051586A1
Application number: PCT/JP2012/075571
Authority: WO
Inventors: 岸本　和之; 時彦四宮; 窪田　悟; 雅憲竹本; 健太今林; 陽一五十嵐; 武弘中枝; 秀一芳賀; 達彦松本
Original assignee: シャープ株式会社; パナソニック液晶ディスプレイ株式会社; ソニー株式会社
Priority date: 2011-10-05
Filing date: 2012-10-02
Publication date: 2013-04-11
Also published as: JP2013080172A

Abstract

A display device (100) is provided with a display (1), a screen brightness detector (5), an average luminance level computation unit (9), and a luminance controller (6), the luminance controller (6) being provided with: a maximum suitable display luminance determination unit (21) for determining the maximum suitable display luminance for each observer age group from the horizontal viewing angle, the screen brightness, the average luminance level, and the age group of each observer; and a weighted average luminance computation unit (22) for calculating the weighted average luminance obtained by taking the weighted average of the maximum suitable display luminance levels according to the proportion of number of people in each age group.

Description

Display device, display method, program, and computer-readable recording medium

The present invention relates to a display device including a brightness control unit that controls display brightness on a display screen, a display method for controlling display brightness on a display screen of the display device, a program, and a computer-readable recording medium. .

In a display device such as a liquid crystal television, appropriate display brightness control is important in terms of both reducing power consumption and preventing visual fatigue.

Conventionally, various controls are performed on the display brightness in the display device depending on, for example, ambient brightness, video content, and the like.

However, it cannot be said that the above-mentioned control is controlled taking into account the visual characteristics depending on the age of the observer, such as a change in visual function with respect to the age of the observer. The appropriate display brightness varies greatly depending on the age of the observer.

Generally, the display brightness of LCD TVs is often set high. Excessive display brightness causes a burden on vision and leads to waste of energy.

For this reason, as the super-aging society progresses, it will become increasingly important to perform display brightness control according to the age of the observer, particularly appropriate display brightness control for the elderly.

Note that there have been prior patents and products related to display devices that perform luminance control according to the age of the observer.

For example, in Patent Document 1, the observer starts to feel dazzling, calculated from the illuminance near the display screen, the age or visual acuity of the observer as observer information, and the viewing distance between the display screen and the observer. It is disclosed that an image is displayed with brightness according to the brightness of the environment and the age group of the observer by determining the maximum brightness (maximum display brightness) of the display screen based on the brightness of the display screen.

According to Patent Document 1, the luminance Lw of the display screen that the observer starts to feel dazzling is given by the following formula: Lw = k × Laα
Indicated by

Here, k is a luminance adjustment constant related to the viewing angle obtained from the viewing distance between the display screen and the viewer, La is an average background luminance calculated from the screen illuminance, and α is , A constant related to age and viewing angle.

Patent Document 1 discloses that the value of the visual constant α is divided into a young person and an elderly person to set a suitable range, and generally uses an intermediate value of each. It is disclosed that the visual constant calculator can be simplified or deleted by setting the visual constant α to a fixed value.

Japanese Patent Publication “Japanese Unexamined Patent Application Publication No. 2007-279405 (published on Oct. 25, 2007)” Japanese Patent Publication “JP-A-6-168317 (published on June 14, 1994)” Japanese Patent Publication “JP 2000-152109 A (published May 30, 2000)”

However, as shown in Patent Document 1, the conventional control of display luminance with respect to the age of the observer, which has been known so far, is “young” and “elderly”, or “young” and “elderly”. In addition to the “person”, the control was based on the division of “standard”.

In addition, the prior patents and products related to display devices that perform brightness control according to the age of the observer, which have been known so far, are brightness control assuming one observer, and a plurality of greatly different ages. Appropriate brightness control for one observer was not considered.

Elderly people need higher brightness than younger people. For this reason, for example, when a young person and an elderly person are watching (observing) TV at the same time, if the young person looks at the display when performing brightness control for the elderly, it is easy to feel dazzling, That power consumption is wasted. Conversely, when performing brightness control for young people, elderly people tend to feel that the screen is dark.

Moreover, since the technique described in Patent Document 1 performs luminance control based on luminance measurement data that an observer starts to feel dazzling, the display luminance is higher than the optimum display luminance, and the power consumption is correspondingly increased. Become more.

Therefore, for example, when a plurality of viewers of different age groups watch TV, it is set to “standard”, and it is uniform and intermediate for any viewer (observer) age and viewing conditions. A method of performing control with luminance is conceivable.

However, the degree of change in visual characteristics that change with aging varies depending on the viewing environment and conditions. That is, under a certain viewing environment (such as ambient brightness), there is no significant difference in appropriate luminance between young and elderly people, but a large difference may occur under another viewing environment.

Therefore, fine-tuned brightness control taking these conditions into account leads to lower power consumption.

The present invention has been made in view of the above-described problems, and its purpose is to be the most appropriate in a comprehensive manner according to the age and viewing conditions of the observer even when there are a plurality of observers of different age groups. An object of the present invention is to provide a display device, a brightness control method, a program, and a computer-readable recording medium capable of controlling display brightness.

In order to solve the above problems, a display device according to the present invention provides:
A display unit;
A screen illuminance detection unit for detecting the screen illuminance of the display screen of the display unit;
An average luminance level calculator that calculates an average luminance level from a video signal that is a video source of the video displayed on the display screen;
A brightness control unit for controlling the display brightness of the display screen,
The brightness control unit
The preferred maximum display brightness for each age group of the viewer on the display screen is determined using the horizontal viewing angle, the screen illuminance, the average brightness level, and the age group for each viewer on the display screen as parameters. A suitable maximum display brightness determination unit;
The preferred maximum display brightness determined by the preferred maximum display brightness determining unit for each age group of the observer on the display screen is associated with the ratio of the number of persons per age group of the observer on the display screen. A weighted average luminance calculation unit for calculating a weighted average luminance obtained by weighted averaging using
The maximum display brightness of the display screen is controlled so as to be the weighted average brightness.

In addition, the display method according to the present invention solves the above-described problems.
An average luminance level calculating step for calculating an average luminance level from a video signal which is a video source of video displayed on the display screen of the display device;
The preferred maximum display for each age group of the observer on the display screen, using the horizontal viewing angle, the screen illuminance on the display screen, the average luminance level, and the age group for each observer on the display screen as parameters. A preferred maximum display brightness determination step for determining brightness;
The weighting coefficient corresponding to the ratio of the number of persons for each age group of the observer on the display screen, the suitable maximum display brightness for each age group of the observer on the display screen, determined in the step of determining the preferable maximum display brightness A weighted average luminance calculation step for calculating a weighted average luminance obtained by weighted averaging using
And a luminance control step for controlling the maximum display luminance of the display screen so as to be the weighted average luminance calculated in the weighted average luminance calculation step.

According to the present invention, when observing the display screen of the display device with a plurality of persons having different ages as described above, the age group of the observer is accurately grasped, and the number of observers in each age group is considered. By averaging the luminance, it is possible to control the luminance so that the dissatisfaction with the luminance as a whole is minimized.

In addition, according to the present invention, since the luminance is averaged in consideration of the number of observers of each age group as described above, any age group is used as is currently done on many liquid crystal televisions. Compared to the case where the brightness is adjusted so as to correspond only to, it is often possible to display at a lower brightness.

In the present invention, as described above, the preferred maximum display luminance for each age group is determined using three main parameters (screen illuminance, average luminance level, horizontal viewing angle of view) that affect the display luminance. is doing. According to the present invention, since the brightness control is performed in consideration of the average brightness level that has a great influence on the preferred display brightness, more accurate brightness control is possible.

According to the present invention, as described above, even when a plurality of persons observe the display screen at the same time, luminance control that is considered to be most appropriate overall is performed, so that dissatisfaction with display glare and darkness can be reduced. it can.

Note that each step of the above display method may be realized by a computer. In this case, since each step of the display method can be executed by the computer according to the program, the program for realizing the display method on the computer also falls within the scope of the present invention. A computer-readable recording medium that records the program also falls within the scope of the present invention.

According to the present invention, when observing the display screen of a display device with a plurality of persons with different ages, the age group of the observer is accurately grasped, and the luminance is averaged in consideration of the number of observers of each age group. By doing so, it is possible to control the luminance so that the dissatisfaction with the luminance as a whole is minimized.

For this reason, according to the present invention, even when there are a plurality of observers of different age groups, it is possible to control the display luminance that is considered to be the most appropriate in accordance with the age of the observer and viewing conditions. Display device, brightness control method, program, and computer-readable recording medium can be provided.

1 is a block diagram illustrating a configuration of a main part of a display device according to a first embodiment. It is a table | surface which shows an example of (alpha), (beta), (gamma), and C for every age calculated | required by the subjective evaluation experiment. It is a figure which shows an example of the two-dimensional LUT which uses a fixed value as a horizontal viewing angle of view, and provides suitable display brightness | luminance (PL) from a screen illumination intensity (E) and an average luminance level (AL) for every age. It is a figure explaining a horizontal viewing angle of view. It is a graph which shows the example of the change of the suitable brightness with respect to age. FIG. 6 is a block diagram illustrating a configuration of a main part of a display device according to a second embodiment. It is a figure which shows an example of the three-dimensional LUT which gives suitable display brightness | luminance (PL) from a horizontal viewing angle of view (SA), screen illumination intensity (E), and an average luminance level (AL) for every age. FIG. 6 is a block diagram illustrating a configuration of a main part of a display device according to a third embodiment.

Hereinafter, an embodiment of the present invention will be described in detail.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to FIGS.

In the following description, the display screen side in the display device according to the present embodiment is described as the upper surface side, and the back surface side, which is the opposite surface side, is described as the lower surface side.

In this embodiment, the display device receives a broadcast signal such as terrestrial digital broadcast or terrestrial analog broadcast, or an input signal such as DVD (Digital Versatile Disc) from an input data supply source (not shown) as a video source. Description will be made on the assumption that the television receiver is a television receiver that receives and displays a video corresponding to the received video source on the display screen of the display unit.

However, the present embodiment is not limited to this, and any other type of display can be used as long as the viewer can visually grasp the video displayed on the display screen of the display unit. It may be a device.

<Configuration of display device>
First, the configuration of the display device according to this embodiment will be described.

FIG. 1 is a block diagram showing a configuration of a main part of the display device according to the present embodiment.

In this embodiment, as described above, a television receiver (hereinafter, referred to as a television) is assumed as the display device according to this embodiment, and the viewer of the display device is described as a viewer.

As shown in FIG. 1, the display device 100 according to the present embodiment includes a display unit 1, a display control circuit 2, a light source 3, a light source drive circuit 4, a screen illuminance detection unit 5, a luminance control unit 6, and observer information extraction. A unit 7, an imaging unit 8, an average luminance level calculation unit 9, and an LUT storage unit 10.

The display unit 1 includes a display panel such as a liquid crystal panel and includes a display screen 1a (see FIG. 4). As described above, the display unit 1 displays video corresponding to a video source received from an input data supply source (not shown) such as a broadcast signal such as terrestrial digital broadcast or terrestrial analog broadcast, or an input signal such as a DVD. Display on the screen.

As the display panel such as a liquid crystal panel used for the display unit 1, various known display panels can be used. Therefore, detailed description and illustration regarding each substrate configuration of the display panel are omitted here.

Further, the driving method of the display panel is not particularly limited. Examples of the driving method include a VA (Vertical Alignment) mode, but are not limited thereto.

An example of the display panel is an active matrix type liquid crystal panel in which a plurality of pixels are arranged in a matrix pattern. The liquid crystal panel has a configuration in which a liquid crystal layer is sandwiched between an active matrix substrate (not shown) and a counter substrate.

In the liquid crystal panel, a plurality of gate lines and a plurality of source lines are arranged so as to cross each other. A region surrounded by the gate line and the source line is one pixel, and each pixel is provided with a pixel electrode and a switching element such as a TFT.

The gate line and source line are connected to the gate driver and source driver, respectively. In addition, a gate line, a source line, and a pixel electrode are connected to the gate electrode, the source electrode, and the drain electrode of the switching element, respectively.

Thus, the source signal is selectively supplied to the pixel electrode by controlling the switching element ON / OFF. Specifically, when a gate signal is supplied from the gate driver to the switching element via the gate line, the switching element is turned on, and the source signal flows from the source electrode to the drain electrode of the switching element and is supplied to the pixel electrode. The The source signal is supplied from a source driver via a source line.

The display control circuit 2 displays a video corresponding to a video source received from an input data supply source (not shown) on the display screen 1a of the display unit 1.

In addition to the video source (for example, pixel data such as R (red), G (green), and B (blue) data), the input data input from the input data supply source to the display control circuit 2 includes a horizontal synchronization signal, vertical A control signal such as a synchronization signal is included.

The display control circuit 2 receives control signals such as a horizontal synchronization signal and a vertical synchronization signal from an input data supply source, generates a gate control signal and a source control signal based on the received control signal, and generates a gate driver and a source driver. To supply each.

The gate control signal and the source control signal are timing signals for controlling the driving timing of the gate driver and the source driver, respectively. The source driver supplies source signals to each source line in the scanning order based on the timing signal supplied from the display control circuit 2.

The light source 3 is an illumination device that irradiates light onto the display screen 1a of the display unit 1. In the present embodiment, it is assumed that a backlight that irradiates light from the back side of the display screen 1 a of the display unit 1 is used as the light source 3.

For the light source 3, various conventionally known illumination devices can be used. Specifically, for example, an LED illumination device such as an LED backlight using LEDs (Light Emitting Diodes) as light emitting elements, a cold cathode ray tube illumination device in which a plurality of cold cathode ray tubes are arranged in parallel, and the like. However, the present invention is not limited to this.

The lighting device may be an edge light type in which a light emitting element is provided on a side surface of a light guide plate provided on the back surface of the display unit 1, and is displayed by a light emitting element provided on the back surface of the display unit 1. A direct type that directly irradiates the screen 1a may be used. The driving method is not particularly limited.

The light source drive circuit 4 is a drive circuit that drives the light source 3 based on the output value of the luminance control unit 6.

The screen illuminance detection unit 5 is a sensor unit that detects the screen illuminance of the display screen 1 a of the display unit 1. The screen illuminance detection unit 5 includes a brightness sensor 11 and a screen illuminance calculation unit 12 that calculates the screen illuminance from the detection result of the brightness sensor 11.

Already, most LCD TVs are equipped with brightness sensors. The brightness sensor is arranged in the vicinity of the display screen 1a (on the same plane as the display screen 1a) so as to face the viewer, and measures the illuminance of light hitting the display screen 1a.

As the brightness sensor 11, these existing brightness sensors (illuminance sensors) can be used. An example of the brightness sensor 11 includes, for example, a light receiving element including a silicon photodiode subjected to visibility correction and an amplifier, but is not limited thereto.

既存 Existing brightness sensors are often installed in the frame area at the bottom of the display screen. However, the installation position of the brightness sensor 11 is not particularly limited as long as it is installed on the same plane as the display screen 1a and facing the viewer. By measuring the relationship between the output value of the brightness sensor 11 and the screen illuminance in advance, the screen illuminance can be obtained from the measured value of the brightness sensor 11 regardless of the installation position of the brightness sensor 11. .

The luminance control unit 6 controls the luminance (display luminance) of the display screen 1 a of the display unit 1 from the screen illuminance detected by the screen illuminance detection unit 5 and the average luminance level calculated by the average luminance level calculation unit 9. .

Specifically, the luminance control unit 6 controls the luminance of the light source 3 by changing the output of the light source 3 that irradiates the display unit 1 with light. In this way, the luminance control unit 6 controls the luminance of the display screen 1 a of the display unit 1 by controlling the luminance of the light source 3. Details of the luminance control process in the luminance control unit 6 will be described later.

The observer information extraction unit 7 obtains the age group (age) and the number of observers observing the display screen of the display unit 1 and outputs the information to the luminance control unit 6 as observer information. It is supposed to be. Details of the configuration of the observer information extraction unit 7 and the observer information extraction process will be described later.

The imaging unit 8 captures an observer who is observing an image displayed on the display screen of the display unit 1.

In the present embodiment, a single-lens camera is used as the imaging unit 8.

In addition, the imaging part 8 should just be provided in the position which can image the observer of a display screen. The imaging unit 8 is disposed, for example, in a frame portion around the display screen of the display unit 1.

Note that the image picked up by the image pickup unit 8 includes at least all the observers who are observing the display screen, and includes the face of each observer.

The imaging timing by the imaging unit 8 includes, for example, immediately after turning on the display device 100 or immediately after receiving a remote control operation signal, but is not limited thereto.

The imaging by the imaging unit 8 may be performed continuously after the power of the display device 100 is turned on, or may be repeated intermittently at regular intervals.

The image captured by the imaging unit 8 is sent to the observer information extraction unit 7 as image data.

The average luminance level calculation unit 9 calculates, for example, average luminance for each frame from a broadcast signal or an input signal (input video signal) such as a DVD received as a video signal that is a video source of a video displayed on the display screen of the display unit 1. The level is calculated and the calculated value is output to the luminance control unit 6.

For example, when the input video signal is a video signal of 30 frames per second, the average luminance level calculation unit 9 calculates the average luminance level 30 times per second.

The LUT storage unit 10 stores a luminance control LUT (Look Up Table) preset for each age group (age) of the observer, and these LUTs are stored in the luminance control unit. 6 is read out as necessary.

<Observer information extraction unit 7>
The observer information extraction unit 7 (image recognition unit) includes an object separation unit 31 and an observer information analysis unit 32. The observer information extracted from the image data sent from the imaging unit 8 is weighted at the subsequent stage. The data is output to the coefficient determination unit 13.

The object separation unit 31 analyzes the image content of the image data sent from the imaging unit 8, extracts the contour that is the object (observer) and separates it from the background, and the separated contour data as an observer. The information is output to the information analysis unit 32.

The observer information analysis unit 32 analyzes what the separated data is from the separated data. Specifically, the observer information analysis unit 32 extracts a certain pattern from image data that is a set of pixels, performs pattern recognition (analysis), and an object separated from the background is an observer (viewer). Recognize that

As a result, the observer information analysis unit 32 extracts the number of observers and the age for each observer as observer information from the analyzed (recognized) data.

Note that, for example, a face recognition technique can be used to extract the observer information. Techniques for recognizing viewer information from images are well known and have already been put into practical use in digital cameras, surveillance cameras, and the like. In addition, a technique for estimating age based on information such as facial contour, skeleton, wrinkle, sagging, etc. has already been put into practical use. For example, Patent Document 2 provides a detailed description of face recognition. Therefore, the description is omitted in the present embodiment.

In the following, for example, a case in which two people in their 20s are analyzed and one person in their 60s is analyzed and this analysis result is extracted as observer information will be described as an example.

The observer information extracted by the observer information analysis unit 32 is output to the subsequent weighting factor determination unit 13.

The weighting coefficient determination unit 13 determines the weighting coefficient to be assigned to the LUT corresponding to each age from the observer information sent from the observer information analysis unit 32.

The weighting factor is determined by the number of observers per age / total number of observers.

The weighting coefficient determination unit 13 may calculate each time observer information is input from the observer information analysis unit 32 using the number of observers for each age / the total number of observers as a weighting coefficient, as shown in FIG. As indicated by the alternate long and short dash line, the display device 100 stores a table (LUT) indicating a weighting factor associated with the observer information (number of observers and age for each observer) in advance as described above. Each time the observer information is input from the observer information analysis unit 32, the corresponding weighting coefficient may be read from the storage unit 14.

For example, when the observer information indicates two in the 20s and one in the 60s, as described above, the weighting coefficient determination unit 13 determines the LUT for the 20s and below corresponding to the 20s. Is assigned with a weighting coefficient of 0.67 (= 2/3), a 60-year-old LUT with a weighting coefficient of 0.33 (= 1/3), and other age LUTs with a weighting coefficient of 0 (zero).

Here, the LUT for each age to which the weighting coefficient determined by the weighting coefficient determination unit 13 is assigned is a luminance value suitable for each age by the subsequent luminance control unit 6 according to the input video signal. Is the determined LUT.

<Luminance control unit 6>
As shown in FIG. 1, the luminance control unit 6 includes a suitable maximum display luminance determination unit 21, a weighted average luminance calculation unit 22, and a light source output calculation unit 23. The weighting coefficient determined by the weighting coefficient determination unit 13 and A light source output value to be output to the light source driving circuit 4 is obtained from the screen illuminance detected by the screen illuminance detection unit 5 and the average luminance level calculated by the average luminance level calculation unit 9.

<Preferable Maximum Display Brightness Determination Unit 21>
The suitable maximum display luminance determining unit 21 is configured to store the LUT for each age in advance from the screen illuminance detected by the screen illuminance detecting unit 5 and the average luminance level calculated by the average luminance level calculating unit 9. The LUT for each age is read out, and the suitable display brightness for each age is obtained.

The inventors of the present application have predicted the preferred display brightness (PL) (unit: cd / m ² ) in the form of the following equation (1) through subjective evaluation experiments conducted to nearly 200 subjects so far. It was found that this can be done (for example, see Non-Patent Document 1).

log PL = α log E + β log SA + γ log AL + C (1)
In Equation (1), E is the screen illuminance (lux: lx), SA is the horizontal viewing angle (degree: deg), AL is ALL (average luminance level) (%), and α, β, γ, C Are different coefficients depending on the age.

Α, β, γ, and C are preferably set for each age.

FIG. 2 is a table showing an example of α, β, γ, and C for each age obtained by a subjective evaluation experiment.

However, the coefficients of each age shown in FIG. 2 are examples as described above, and α, β, γ, and C for each age are not limited to the values in the table shown in FIG.

Here, if the suitable range of each parameter is given, since the value of α tends to decrease as the age increases as shown in FIG. 2, for example, the values in the table shown in FIG. The range is ± 0.05, and β and γ do not show a clear tendency with respect to age, so β is set to −0.2 to −0.35, γ is set to −0.2 to −0.4, and C Contrary to α, there is a tendency to increase as the age increases, so the value is in the range of ± 0.2 in the table. Note that β and γ always take negative values.

As described above, it is possible to obtain a suitable display luminance (hereinafter referred to as “preferred display luminance”) in each age by using the coefficient corresponding to each age using the above formula (1).

Here, the preferred display brightness indicates the brightness of the white peak (gradation level 255), and is a value mainly determined by the brightness of the light source 3 (backlight).

In this embodiment, since there is no means for measuring the horizontal viewing angle, the horizontal viewing angle is set to a fixed value (for example, 20 deg, 33 deg, etc.) using a representative value. Each time, a two-dimensional LUT is used that provides suitable display brightness from the screen illuminance (E) and the average brightness level (ALL; indicated by AL in the LUT shown in FIG. 3).

FIG. 3 is a diagram illustrating an example of the above-described two-dimensional LUT.

Here, three parameters (screen illuminance, average luminance level, horizontal viewing angle of view) used for obtaining the preferred display brightness (PL) by the preferred maximum display brightness determination unit 21 will be described.

<Screen illuminance>
The screen illuminance indicates the illuminance of the vertical plane at the center of the display screen. In practice, the screen illuminance can be obtained from the measurement value of the brightness sensor already installed in most liquid crystal TVs as described above.

<Average luminance level>
The average brightness level is

And can be calculated from a received broadcast signal or a video signal such as a DVD input signal.

In the equation, H and W indicate the number of vertical and horizontal pixels of the image displayed on the display unit 1, and Y (i, j) is the luminance signal level (0 to 255) of the pixel at the coordinates (i, j). ).

<Horizontal view angle>
FIG. 4 is a diagram for explaining the horizontal viewing angle of view.

As shown in FIG. 4, the horizontal viewing angle of view is such that when the upper end of the display screen 1 a of the display unit 1 is looked down from directly above, the eye 40 of the observer viewing the display screen 1 a and the right end of the display screen 1 a And an angle SA formed between the line connecting the eyes 40 and the line connecting the eyes 40 and the left end of the display screen 1a.

<Weighted average luminance calculation unit>
The weighted average luminance calculation unit 22 calculates the weighted average luminance from the weighting coefficient determined for each age of the observer and the preferred display luminance obtained for each age of the observer.

Here, the weighting factors of 20 years old or younger, 30 years old, 40 years old, 50 years old, 60 years old, 70 years old or older are set as α ₂₀ , α 3 ₃₀ , α ₄₀ , α ₅₀ , α ₆₀ , α, respectively. ₇₀ , the preferred display brightness (PL) is PL ₂₀ , PL ₃₀ , PL ₄₀ , PL ₅₀ , PL ₆₀ , PL ₇₀ , and the weighted average brightness is PL _H , the weighted average brightness PL _H is ).

_{_{_{PL H = (α 20 · PL}}} 20 + α 30 · PL 30 + α 40 · PL 40 + α 50 · PL 50 + α 60 · PL 60 + α 70 · PL 70) / 6 ... (2)
For example, 20s observers 2 persons, 60 years old observer one person, when other age observer is 0 people, as described above, the twenties following weighting factor alpha ₂₀ 0 .67 (= 2/3), 60's weighting coefficient α ₃₀ is 0.33 (= 1/3), and other age weighting coefficients α ₃₀ · α ₄₀ · α ₅₀ · α ₇₀ are all 0, The weighted average luminance (PL _H ) is expressed by the following equation (3) from the above equation (2).

_{_{PL H = (0.67 × PL 20}} + 0 × PL 30 + 0 × PL 40 + 0 × PL 50 + 0.33 × PL 60 + 0 × α 70 · PL 70) / 6 ... (3)
The weighted average luminance (PL _H ) obtained as described above is sent to the light source output calculation unit 23 in the subsequent stage.

<Light source output calculation unit 23>
The light source output calculation unit 23 determines an output value to be given to the light source 3 so that the peak white luminance of the display unit 1 becomes the input weighted average luminance (PL _H ), and sends it to the light source driving circuit 4.

The light source driving circuit 4 controls the luminance of the display screen 1a by driving the light source 3 based on the output value determined by the light source output calculation unit 23.

<Effect>
Next, effects of the display device 100 configured as described above will be described.

FIG. 5 is a graph showing an example of a change in suitable display luminance (referred to as suitable luminance in FIG. 5) with respect to age. This graph shows the result of a subjective evaluation experiment in which images are displayed for 20 subjects for each age group and adjusted to the desired brightness.

As shown in FIG. 5, when the geometric average value of the preferred display brightness is plotted logarithmically with respect to the average age of each age, the preferred display brightness increases linearly.

Note that FIG. 5 shows the results when a video with a screen illuminance (E) of 100 lux (lx), a horizontal viewing angle (SA) of 33 deg, and an average luminance level (ALL) of 39% is viewed. .

Here, it can be read from the graph shown in FIG. 5 that the suitable display luminance difference between the 20s and 70s is about 70 cd / m ² . However, the listening environmental conditions such as the image of the genre or listen listen, the difference in the preferred display luminance from being spread and 100 cd / ^{m 2} about, or narrowed and 40 cd / ^{m 2} approximately.

The conditions when the difference in the preferred display luminance exceeds 100 cd / m ² are E = 30 lux (lx), SA = 17 deg, ALL = 6.6%, and a dark image from a relatively long distance in a dark room. It corresponds to the case of seeing.

The conditions when the difference in the preferred display brightness is less than 40 cd / m ² are E = 30 lux (lx), SA = 62 deg, ALL = 82%, and a very bright image from a relatively long distance in a dark room Is equivalent to seeing

As described above, the suitable display luminance greatly varies depending on the age, and the degree of the variation varies depending on viewing conditions.

However, the conventional brightness control methods only adjust to a suitable brightness for each age, and all viewers cannot be satisfied when watching TV with multiple people of different ages.

On the other hand, according to the display method using the brightness control method according to the present embodiment, when watching TV with a plurality of persons with different ages, the age group of the observer is accurately grasped, and each age group By averaging the luminance in consideration of the number of observers, it is possible to control the luminance so that dissatisfaction with the luminance as a whole is minimized.

In addition, in the display method using the brightness control method according to the present embodiment, as described above, the brightness is averaged in consideration of the number of observers in each age group. As shown, it is often possible to display with lower luminance than when the luminance is adjusted so as to correspond only to any age group.

Moreover, in the display method using the luminance control method according to the present embodiment, the value (average value) obtained by the subject (observer) as the suitable luminance obtained in the preferred luminance evaluation experiment (subjective evaluation experiment) is used. Therefore, it is possible to reduce excess luminance without causing dissatisfaction with the luminance. Therefore, it has an effect of reducing power consumption.

Further, according to the present embodiment, as described above, since the luminance is controlled based on the result of the preferred luminance evaluation experiment (subjective evaluation experiment), the luminance “becomes dazzling” as in Patent Document 1, for example. Compared with the case where luminance control is performed based on this, it is possible to achieve a low visual burden and low power consumption, and more appropriate luminance control can be performed.

According to the present embodiment, as described above, even when a plurality of people watch TV simultaneously, the luminance control that is considered to be most appropriate overall is performed, so that dissatisfaction with display glare and darkness is reduced. Can do.

Moreover, in this embodiment, the preferred maximum display brightness of each age group is determined using three main parameters (screen illuminance, average brightness level, and horizontal viewing angle of view) that affect the display brightness.

As described above, according to the present embodiment, the luminance control is performed in consideration of the average luminance level that has a great influence on the suitable display luminance, so that more accurate display luminance control is possible.

Further, in the present embodiment, the horizontal viewing angle is set to a variable value for the screen illuminance and the average luminance level by fixing the viewing angle to a preset value.

As described above, there are three parameters that affect the preferred display brightness: screen illuminance, average brightness level, and horizontal viewing angle. However, among these, in order to obtain the horizontal viewing angle of view, it is necessary to know the relative position of the observer with respect to the television. In addition, when a plurality of people watch TV at the same time, the horizontal viewing angle is often different for each observer.

The inventors of the present application fixed the average viewing distance of the TV to 2.5 m from the result of actually measuring the viewing distance in 83 households (see Non-Patent Document 1). Thus, a subjective evaluation experiment was performed to obtain a suitable viewing angle (SA).

As a result, the viewing angle of view (SA) was about 22 deg with a 30-40 type TV popular in the home. In addition, when an actual field survey was conducted for 32 households of liquid crystal TV users, the average viewing angle (SA) was 15.7 deg. Thus, the viewing angle of view (SA) actually obtained in these studies was a value around 20 deg.

Further, 33 deg corresponds to a relative viewing distance (ratio to the height of the television screen) 3H (H: height of the television screen), and is generally a distance that is said to be an optimum distance when watching high-definition broadcasting.

Therefore, according to the present embodiment, as described above, the horizontal viewing angle is a fixed value using a typical value such as 20 deg or 33 deg, for example, and the screen illuminance and the average luminance level for each age. By using a two-dimensional LUT that gives suitable display brightness, it is possible to omit devices necessary for measuring the horizontal viewing angle, calculation of the horizontal viewing angle, etc., and it is inexpensive and relatively simple. Effective brightness control can be implemented with the configuration.

[Embodiment 2]
Another embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, differences from the first embodiment will be mainly described. Components having the same functions as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. To do.

<Configuration of Display Device 100>
FIG. 6 is a block diagram illustrating a configuration of a main part of the display device 100 according to the present embodiment.

As shown in FIG. 6, the display device 100 according to the present embodiment is similar to the first embodiment in that the display unit 1, the display control circuit 2, the light source 3, the light source driving circuit 4, the screen illuminance detection unit 5, the luminance A control unit 6, an observer information extraction unit 7, an imaging unit 8, an average luminance level calculation unit 9, and an LUT storage unit 10 are provided.

In Embodiment 1, a preset value was used for the horizontal viewing angle of the observer. On the other hand, in the present embodiment, in the display device 100, the horizontal viewing angle of view of each observer used as one of the parameters for obtaining the preferred display brightness by the preferred maximum display brightness determining unit 21 is acquired. In order to do so, a horizontal viewing angle calculation unit 41 is further provided.

That is, in this embodiment, the horizontal viewing angle of the observer who is actually auditioning is calculated.

In order to calculate the horizontal viewing angle of view, a binocular camera is used for the imaging unit 8 in the present embodiment. Details of the horizontal viewing angle calculation will be described later.

In the present embodiment, in the observer information extraction unit 7, in addition to the processing (calculation of the number of observers and age) performed in the first embodiment, the horizontal view is obtained from the image data sent from the imaging unit 8. The position information of the observer necessary for obtaining the viewing angle is obtained.

<Observer Information Analysis Unit 32>
The observer information extraction unit 7 (image recognition unit) according to the present embodiment includes an object separation unit 31, an observer information analysis unit 32, and a distance measurement unit 33, and an imaging unit 8 (two-lens camera). The observer information extracted from the image data sent from is output to the weighting coefficient determination unit 13 at the subsequent stage.

The object separation unit 31 analyzes the image content of the image data sent from the imaging unit 8, extracts the contour data to be the object (observer) and separates it from the background, and the separated object data Is output to the observer information analysis unit 32.

The observer information analysis unit 32 analyzes what the separated data is from the data of the object separated by the object separation unit 31. Specifically, the observer information analysis unit 32 extracts a certain pattern from image data that is a set of pixels, performs pattern recognition (analysis), and recognizes that the object separated from the background is the observer. To do.

As described above, the observer information analysis unit 32 extracts the number of observers and the age of each observer as observer information from the analyzed (recognized) data. For example, as shown in the first embodiment, two people in their 20s and one in their 60s are analyzed and this analysis result is extracted as observer information.

The observer information extracted by the observer information analysis unit 32 is output to the subsequent weighting coefficient determination unit 13.

Furthermore, in the present embodiment, since the binocular camera is used for the imaging unit 8 as described above, parallax information can be obtained by photographing the same object (observer). That is, the parallax information is also included in the image data sent from the imaging unit 8 to the observer information extraction unit 7.

The distance measuring unit 33 measures the distance from each of the two images obtained by the imaging unit 8 (two-lens camera) to each point in the imaging space.

The distance measuring unit 33 measures the distance to the measurement target point using the triangulation principle from the parallax information of the same object (observer) imaged by the imaging unit 8 (two-lens camera). The position information of the observer viewed from (information indicating the approximate distance from the television to the observer) is acquired. The above method is known by a name such as stereo vision.

The acquisition of position information using the principle of triangulation is described in detail, for example, in FIG. For this reason, in this Embodiment, the description is abbreviate | omitted.

The distance measuring unit 33 outputs the position information obtained from the parallax information to the observer information analyzing unit 32 at the subsequent stage.

In the observer information analysis unit 32, the relative position between the television and each observer is determined from the position information sent from the distance measurement unit 33 and the observer information extracted from the data sent from the object separation unit 31. The observer position information indicating the relationship is extracted. The extracted observer position information is output to the horizontal viewing angle calculation unit 41.

The horizontal viewing angle calculation unit 41 determines the horizontal viewing angle (SA) of the viewer who is watching the television from that position based on the obtained viewer position information (relative positional relationship between the television and the viewer). ) Is calculated.

That is, with reference to FIG. 4 of the first embodiment, the horizontal viewing angle calculation unit 41 looks at the display screen 1a when looking down at the upper end of the display screen 1a of the display unit 1 from directly above. The angle SA (horizontal viewing angle of view) formed between the line connecting the eye 40 of the viewer and the right end of the display screen 1a and the line connecting the eye 40 and the left end of the display screen 1a Ask every time.

Then, the horizontal viewing angle (SA) obtained for each observer by the horizontal viewing angle calculation unit 41 is supplied to the preferred maximum display luminance determination unit 21 and the weighting coefficient determination unit 13 of the luminance control unit 6 at the subsequent stage. Sent.

The weighting coefficient determination unit 13 corresponds to each age based on the observer information from the observer information analysis unit 32 and the horizontal viewing angle (SA) obtained for each observer by the horizontal viewing angle calculation unit 41. The weighting coefficient assigned to the LUT is determined.

For example, as described above, when the observer information indicates 2 in the 20s and 1 in the 60s, it corresponds to the 20s when the horizontal viewing angle (SA) is not considered LUT for 20's and below as a weighting coefficient 0.67 (= 2/3), LUT for 60's as a weighting coefficient 0.33 (= 1/3), LUT for other ages 0 (zero) is assigned.

However, when the horizontal viewing angle (SA) is taken into consideration, the horizontal viewing angles (SA) of the two 20s are not the same, and the horizontal viewing angle (SA) of the 60s is not the same. ) Is not the same as the horizontal viewing angle (SA) of the 20's, so in order to obtain each suitable display luminance, SA = SA1 of the first 20's and the second 20's When SA = SA2 and SA = SA3 in the 60s, the weighting coefficients are 0.33 (1/3) in the 20s (SA1), 20s (SA21 is 0.33 (1/3), The 62s (SA3) becomes 0.33 (1/3).

In this embodiment, when there are a plurality of persons of the same age as described above, the weighting coefficient is determined based on the value of the horizontal viewing angle of view (SA) taken by each observer.

<Preferable Maximum Display Brightness Determination Unit 21>
In the present embodiment, the preferred maximum display luminance determining unit 21 performs substantially the same control as in the first embodiment.

The difference between the present embodiment and the first embodiment is that the first embodiment does not have a means for measuring (calculating) the horizontal viewing angle, and therefore uses a preset horizontal viewing angle. On the other hand, in the present embodiment, as described above, the display device 100 according to the present embodiment includes the horizontal viewing angle calculation unit 41, so that the horizontal viewing for each observer is performed. This is the point of using the horizontal viewing angle obtained by measuring the angle of view in real time.

In other words, in the present embodiment, the suitable maximum display luminance determining unit 21 determines the screen illuminance (E) detected by the screen illuminance detecting unit 5, the average luminance level (ALL) calculated by the average luminance level calculating unit 9, and the horizontal The LUT for each age is read from the LUT storage unit 10 that stores the LUT for each age in advance from the horizontal viewing angle (SA) of each observer obtained by the viewing angle calculation unit 41. The suitable display brightness in each age is obtained.

Here, the formula (1) shown in the first embodiment is used for calculating the preferred display luminance (PL) (cd / m ² ).

In the present embodiment, since the horizontal viewing angle calculation unit 41 is provided as means for measuring the horizontal viewing angle, the horizontal viewing angle of each observer who actually listens to the television is determined. Use. Accordingly, for each age, a three-dimensional image that provides a suitable display luminance (PL) from the horizontal viewing angle (SA), the screen illuminance (E), and the average luminance level (ALL; indicated by AL in the LUT shown in FIG. 7). LUT is used.

FIG. 7 is a diagram illustrating an example of the three-dimensional LUT.

<Weighted average luminance calculation unit 22>
The weighted average luminance calculation unit 22 obtains the weighted average luminance from the weighting coefficient determined for each age of the observer and the preferred display luminance obtained for each age of the observer. Here, the weighted average luminance is obtained by the same method as in the first embodiment. The obtained weighted average luminance is sent to the light source output calculation unit 23 in the subsequent stage.

<Light source output calculation unit 23>
In the light source output computing unit 23, so that the weighted average brightness PL _H of the brightness of the display unit 1 is input, determine the output value to be provided to the light source 3, and sends the light source drive circuit 4.

The light source drive circuit 4 drives the light source 3 based on the output value determined by the light source output calculation unit 23.

<Effect>
Since the horizontal viewing angle varies depending on the position at which the television is viewed, the preferred display brightness also depends on the position at which the television is viewed.

In the first embodiment, since the effect of the horizontal viewing angle is not taken into account and the preferred display brightness is calculated on the assumption that the image is viewed at a certain representative horizontal viewing angle, this embodiment is performed. As compared with the display device 100 according to the embodiment, the luminance control is relatively coarse control.

On the other hand, in this embodiment, since the influence of the position of the observer (relative positional relationship between the television and the observer) is taken into consideration, it is possible to control the preferred display brightness with higher accuracy.

For this reason, according to the display device 100 according to the present embodiment, compared to the effect obtained by the display device 100 according to the first embodiment, when the television is listened to by a plurality of persons having different ages, for each observer. Using the calculated horizontal viewing angle of view, it is possible to accurately grasp the age group of the observer and average the luminance in consideration of the number of observers in each age group, so that the entire observer is dissatisfied with the luminance. Further, the luminance can be controlled to be reduced.

<Modification>
In the present embodiment, the case where a binocular camera is used as the imaging unit 8 has been described as an example for obtaining the parallax information. However, the present embodiment is not limited to this, and 2 Instead of the eye camera, a plurality of imaging devices (for example, two cameras) installed in parallel at a known interval may be used, and an observer can use a television (more specifically, a display screen of the display unit 1). The parallax information may be acquired using a sensor for knowing what distance and position it is with respect to 1a).

[Embodiment 3]
The following will describe still another embodiment of the present invention with reference to FIG. In the present embodiment, differences from the first and second embodiments will be mainly described, and the same numbers are given to components having the same functions as the first and second embodiments. The description is omitted.

<Configuration of Display Device 100>
FIG. 8 is a block diagram showing a configuration of a main part of the display device 100 according to the present embodiment.

As shown in FIG. 8, the display device 100 according to the present embodiment is similar to the first embodiment in that the display unit 1, the display control circuit 2, the light source 3, the light source driving circuit 4, the screen illuminance detection unit 5, and the luminance. A control unit 6, an observer information extraction unit 7, an imaging unit 8, an average luminance level calculation unit 9, and an LUT storage unit 10 are provided.

In the present embodiment, unlike the first and second embodiments, instead of having the imaging unit 8 and the observer information extraction unit 7 (the object separation unit 31 and the observer information analysis unit 32), an input unit 51.

In other words, in the present embodiment, the image data is not used to obtain the observer information, but the number of observers and the age are directly input from the input unit 51 and the weighting coefficient determining unit 13 obtains the weighting coefficient. When the luminance control by one route or the number of viewers and the age are not input, the population ratio data of each age (for each age group) in a certain region (that is, the country or region where the display device 100 is used) is weighted. Any luminance control of the luminance control by the second path used instead of the coefficient is executed.

<First route: Using the menu screen>
First, luminance control by the first route will be described.

In the first route, first, the number of viewers and the age of the viewer are input from the input unit 51 as the viewer information. The observer information can be input from, for example, a menu screen. The input observer information is output to the weighting coefficient determination unit 13.

Next, the weighting coefficient determination unit 13 determines the weighting coefficient to be assigned to the LUT corresponding to each age from the input observer information. This determination method is the same as the determination method by the weighting coefficient determination unit 13 of the first embodiment. The determined weighting coefficient is output to the weighted average luminance calculation unit 22.

<Second route: Using population ratio data>
Next, luminance control by the second route will be described.

In the second route, when the observer information is not input from the input unit 51 within a predetermined time after the TV is started (that is, after the power is turned on), each age group stored in the population ratio data storage unit 52 in advance is stored. Population ratio data is output to the weighted average luminance calculator 22 as a weighting coefficient.

In the present embodiment, as in the first embodiment, since there is no means for measuring the observer's horizontal viewing angle of view, the preferred maximum display brightness determining unit 21 sets the preferred display brightness. The LUT used for obtaining is a two-dimensional LUT that outputs a suitable display luminance from the screen illuminance and the average luminance level.

Therefore, the display brightness control by the brightness control unit 6 is the same as that in the first embodiment for both the first route and the second route, and therefore the description thereof is omitted here.

In this case, by performing weighted average luminance control using the population ratio as a weighting coefficient as described above, even when there is no information about the age and number of TV viewers, the most appropriate (the most dissatisfaction with luminance is the most comprehensive). Luminance control can be performed.

According to the present embodiment, luminance control can be performed with the simplest configuration, so that the cost can be reduced.

<Modification common to Embodiments 1 to 3>
Next, modifications common to the first to third embodiments will be described below.

First, an example of calculating the preferred display brightness by the average brightness level calculator 9 will be described.

<Calculation Example for Obtaining Preferred Display Luminance 1: When Obtaining Average Luminance Level for Each Frame>
In general, for example, many broadcast videos in Japan have 30 frames per second. For this reason, when obtaining the average luminance level for each frame, the average luminance level is obtained 30 times per second. For this reason, the calculation for obtaining the preferred display luminance is also performed 30 times per second. The calculation for obtaining the preferred display brightness by the preferred maximum display brightness determining unit 21 in the first to third embodiments is also performed for each frame.

In the above description, the case where the broadcast video is 30 frames per second has been described as an example. However, the number of calculations for obtaining the preferred display luminance may be appropriately set according to, for example, the broadcasting country, the broadcasting region, etc. It goes without saying that if the numbers are different, the number of operations per second for obtaining the preferred display luminance is also changed accordingly.

<Calculation Example 2 for Determining Preferred Display Luminance: When Obtaining an Average Value at Fixed Times>
Here, when the broadcast video has almost no change in luminance as in the case of a still image, or when there is almost no change in luminance even in the case of a moving image, the average luminance level hardly changes.

On the other hand, the screen illuminance and the horizontal viewing angle do not change depending on the type of broadcast video, unlike the average luminance level. The screen illuminance depends on the environment in which the display device 100 is installed, and the horizontal viewing angle is related to the number of observers and the relative position of the observer with respect to the television.

As described above, in the first to third embodiments, even when there are periods in which the three parameters (screen illuminance, horizontal viewing angle of view, and average luminance level) for obtaining the preferred display luminance hardly change, Since the preferred display brightness is being calculated, a wasteful calculation is being performed.

Therefore, in order to eliminate wasteful computation for obtaining the preferred display brightness, the following

modifications

1 and 2 are conceivable.

<Modification Example 1 of Calculation for Finding Preferred Display Luminance>
The preferred maximum display brightness determination unit 21 does not perform calculation for obtaining the preferred display brightness during a period in which the three input parameters (screen illuminance, horizontal viewing angle of view, and average brightness level) do not change. When any of them changes, a calculation for obtaining a suitable display luminance is performed.

That is, the preferred display luminance is calculated in at least one of the three parameters when the screen illuminance changes, the horizontal viewing angle changes, or the average luminance level changes.

Usually, since the change in screen illuminance and horizontal viewing angle is small, the preferred display brightness is calculated by the change in average brightness level.

However, in order to calculate the preferred display brightness at the timing of the change of the three parameters as described above, it is necessary to always monitor the three parameters, but the preferred display brightness is calculated at regular intervals as follows. In this way, it is not necessary to monitor the three parameters.

<Modification Example 2 of Calculation for Finding Preferred Display Luminance>
Next, as a second modification example of the calculation for obtaining the preferred display brightness, a case where the preferred display brightness is computed at regular intervals will be described.

Here, the average luminance level calculation unit 9 obtains an average value of the average luminance level for every fixed time, and each time (that is, every time the average value of the average luminance level for every fixed time is obtained), a suitable maximum display luminance determining unit. 21. By outputting the average value of the average luminance level to 21, the suitable display luminance is calculated for every predetermined period.

For example, when the input image is an image of 30 frames per second, when calculating a suitable display luminance per second, an average value of average luminance levels for the previous 30 frames is obtained. From the average value of the average luminance level per second, the preferred display luminance per second is calculated (first method).

Further, when the average luminance level is a moving average value, in order to obtain a moving average for one second, an average luminance level for the last 30 frames is obtained every 1/30 second (second method).

Specific description of the first method and the second method is as follows.

First, when the average luminance level (ALL) of each frame is set to ALL1, ALL2, ALL3,... Sequentially from the first frame, in the first method, the average of ALL1 to ALL30, the average of ALL311 to ALL60,.・ Calculate every second. On the other hand, in the second method, next to the average of ALL1 to ALL30, the average of ALL2 to ALL31 is obtained after 1/30 seconds, and further the average of ALL3 to ALL32 is obtained after 1/30 seconds. The average value of the average luminance level (ALL) shifted by 1 frame is obtained every 1/30 seconds.

<Variation 3 of how to obtain suitable display brightness>
In the first to third embodiments, the preferred maximum display brightness determination unit 21 reads the LUTs of all ages, obtains the preferred display brightnesses of all ages, and outputs them to the weighted average brightness calculation unit 22. Yes. For this reason, since the weighted average luminance calculation unit 22 obtains the weighted average luminance in consideration of the preferable display luminance of all ages, the amount of calculation increases.

In view of this, the preferred maximum display brightness determination unit 21 reads the LUT of only the age of the viewer who is actually listening to the television to obtain the preferred display brightness of each age. The calculation amount can be reduced by calculating only the preferred display luminance of the age of the viewer who is actually listening to the television to obtain the weighted average luminance.

For example, in the display device 100 shown in FIG. 1 of Embodiment 1, the observer information from the observer information analysis unit 32 of the observer information extraction unit 7 is output to the suitable maximum display luminance determination unit 21 of the luminance control unit 6. The preferred maximum display luminance determination unit 21 may read only the LUT corresponding to the age of the observer obtained from the observer information from the LUT storage unit 10.

The preferred maximum display brightness determination unit 21 obtains the preferred display brightness of each age from the input LUT of the age and outputs it to the weighted average brightness calculation unit 22.

The weighted average luminance calculation unit 22 calculates the weighted average luminance from the suitable display luminance and the weighting coefficient for each age.

In this way, if only the LUT corresponding to the age of the viewer who is actually listening to the television is selected, and the preferred display brightness is determined by the preferred maximum display brightness determining unit 21, the weighted average brightness calculating unit 22 The amount of calculation is reduced, and it is possible to display the image with a suitable luminance more quickly.

<Variation 4 of How to Obtain Preferred Display Luminance>
In the first to third embodiments, the suitable display luminance is determined using the LUT stored in the LUT storage unit 10 as described above. As described above, by using the LUT for determining the suitable display luminance, an inexpensive configuration can be obtained, and processing in a short time is possible.

However, the embodiment of the present invention is not limited to this, and the suitable display luminance for each age can be determined by calculation from the above-described equation (1) (that is, the calculation equation). In this case, the LUT storage unit 10 can be removed from the configuration, or the capacity can be reduced.

When the LUT is used as described above, the average between the screen illuminance (E) between the screen illuminance (E) shown in the LUT and the average luminance level (ALL; indicated by AL in FIGS. 3 and 7). The preferred display brightness (PL) corresponding to the brightness level (ALL) is determined by interpolation calculation from the preferred display brightness (PL) obtained by the LUT from the values of the front and back screen illuminance (E) and the average brightness level (ALL). The

That is, the preferred display brightness (PL) value for each age that is not included in the LUT is determined by interpolation calculation from the value obtained from the LUT. As a result, the size of the LUT can be reduced.

<Program, computer-readable recording medium>
In addition, each means (block) of the brightness | luminance control part 6 in each said embodiment may be comprised with a hardware logic, and CPU (Central Processing Unit) and MPU (Micro Processing Unit) are as follows. And may be realized by software. That is, each unit of the brightness control unit 6 may be executed by software by causing a computer to function as each unit described above using a program.

In addition, each step of the luminance control (that is, the luminance control method according to the present invention) by the luminance control unit 6 in each of the above embodiments is performed by causing a computer to execute each of the above steps using a program. It may be executed by.

That is, the luminance control unit 6 is a CPU or MPU that executes instructions of a program that implements each function (step), a ROM (Read Only Memory) that stores this program, and a RAM (RAM that expands the program into an executable format). Random (Access Memory) and a storage device (recording medium) such as a memory for storing the program and various data.

An object of the present invention is to provide program codes (execution format program, intermediate code program, source program) of a control program of each unit (each unit) of the luminance control unit 6 which is software for realizing the above-described functions (steps) on a computer. This can also be achieved by supplying a recording medium recorded so as to be readable to each unit of the luminance control unit 6, and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

Note that the recording medium for supplying the program code to the luminance control unit 6 is not limited to a specific structure or type. That is, the recording medium includes, for example, 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. A disk system, a card system such as an IC card (including a memory card) / optical card, or a semiconductor memory system such as a mask ROM / EPROM / EEPROM (registered trademark) / flash ROM can be used.

Further, even if the luminance control unit 6 is configured to be connectable to a communication network, the object of the present invention can be achieved. In this case, the program code is supplied to the luminance control unit 6 via the communication network. The communication network is not limited to a specific type or form as long as it can supply the program code to the luminance control unit 6. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network (Virtual Private Network), telephone line network, mobile communication network, satellite communication network, etc. may be used.

The transmission medium constituting the communication network may be any medium that can transmit the program code, and is not limited to a specific configuration or type. For example, even with wired lines such as IEEE 1394, USB (Universal Serial Bus), power line carrier, cable TV line, telephone line, ADSL (Asymmetric Digital Subscriber Line), etc., infrared rays such as IrDA and remote control, Bluetooth (registered trademark), 802.11 It can also be used by radio such as radio, HDR, mobile phone network, satellite line, terrestrial digital network. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

<Summary>
As described above, the display device according to each of the above-described embodiments includes the display unit, the screen illuminance detection unit that detects the screen illuminance of the display screen of the display unit, and the video source of the video displayed on the display screen. An average luminance level calculation unit that calculates an average luminance level from the video signal and a luminance control unit that controls the display luminance of the display screen. Then, the luminance control unit uses (I) the horizontal viewing angle of view, the screen illuminance, the average luminance level, and the age group for each observer of the display screen as parameters. A preferred maximum display brightness determination unit for determining a preferred maximum display brightness for each age group, and (II) a preferred maximum display brightness for each age group of an observer on the display screen, determined by the preferred maximum display brightness determination unit A weighted average luminance calculation unit that calculates a weighted average luminance using a weighting coefficient associated with the ratio of the number of viewers in each age group of the observer on the display screen, and obtains the weighted average luminance. Thus, the maximum display brightness of the display screen is controlled.

In addition, as described above, the display method according to each embodiment described above includes an average luminance level calculation step for calculating an average luminance level from a video signal that is a video source of a video displayed on the display screen of the display device, The preferred maximum display for each age group of the observer on the display screen, using the horizontal viewing angle, the screen illuminance on the display screen, the average luminance level, and the age group for each observer on the display screen as parameters. The preferred maximum display brightness determination step for determining the brightness, and the preferred maximum display brightness for each age group of the viewer on the display screen, determined in the preferred maximum display brightness determination step, is the age group of the viewer on the display screen. A weighted average luminance calculation step for calculating a weighted average luminance obtained by weighted averaging using a weighting coefficient associated with the ratio of each person, and the weight calculated in the weighted average luminance calculation step. So that the average luminance and a luminance control step of controlling the maximum display luminance of the display screen.

According to the display device and the display method, when observing the display screen of the display device with a plurality of persons with different ages, the age group of the observer is accurately grasped, and the number of observers in each age group is taken into consideration. By averaging the brightness, it is possible to control the brightness so as to minimize the dissatisfaction with the brightness as a whole observer, and compared to adjusting the brightness to correspond only to any age group, It can often be displayed with low brightness.

Further, in the display device and the display method described above, since the brightness control is performed in consideration of the average brightness level that greatly affects the preferred display brightness, more accurate brightness control is possible.

For this reason, even when there are a plurality of observers with different age groups, it is possible to control the display luminance that is considered to be the most appropriate in accordance with the age of the observer and viewing conditions.

Further, the display device stores a look-up table that stores a look-up table indicating the relationship between the screen illuminance and the average luminance level provided for each age group of the viewer of the display screen according to the horizontal viewing angle. The preferred maximum display luminance determination unit further includes a lookup table stored in the lookup table storage unit from the horizontal viewing angle, the screen illuminance, and the average luminance level. It is preferable to determine a suitable maximum display luminance for each age group of the observer on the display screen.

As described above, by determining a suitable maximum display luminance for each age group of the observer on the display screen using a look-up table, an inexpensive configuration can be achieved and processing in a short time is possible. .

Further, the horizontal viewing angle is a fixed parameter, and is preferably fixed to a preset value.

The three parameters that affect the preferred display brightness are screen illuminance, average brightness level, and horizontal viewing angle. However, among these, in order to obtain the horizontal viewing angle of view, it is necessary to know the relative position of the observer with respect to the display device. When a plurality of persons observe the display screen at the same time, the horizontal viewing angle is often different for each observer.

Therefore, the horizontal viewing angle is set to a fixed value using a representative value based on, for example, a result obtained in a subjective evaluation experiment or the like. Calculation of the horizontal viewing angle of view and the like can be omitted, and effective luminance control can be performed with an inexpensive and relatively simple configuration.

In addition, the display device includes an imaging unit that images an observer on the display screen, and an observation that extracts, as observer information, the number of observers on the display screen for each age group from the captured image captured by the imaging unit. It is preferable to further include an observer information extraction unit and a weighting coefficient determination unit that determines the weighting coefficient from the observer information extracted by the observer information extraction unit.

In addition, the display method includes an imaging step of imaging the observer on the display screen, and an observation in which the number of observers on the display screen for each age group is extracted as observer information from the captured image captured in the imaging step. It is preferable to further include an observer information extraction step and a weighting coefficient determination step for determining the weighting coefficient from the observer information extracted in the observer information extraction step.

In this way, by imaging the observer on the display screen in the imaging unit or imaging step and extracting the number of observers on the display screen for each age group as observer information, a plurality of persons with different ages are displayed. When observing the screen, it is possible to accurately grasp the number of observers of each age group on the display screen as observer information. From this observer information, the luminance is averaged in consideration of the number of observers. The preferred maximum display brightness can be determined.

In the display device, the horizontal viewing angle is a variable parameter, and the display device calculates a horizontal viewing angle for each observer of the display screen with respect to the display screen. The display unit further includes a calculation unit, and the preferable maximum display brightness determination unit uses the horizontal viewing angle calculated by the horizontal viewing angle calculation unit to display a preferable maximum display for each age group of the observer on the display screen. It is preferable to determine the brightness.

Since the horizontal viewing angle varies depending on the position where the display screen is observed, the preferred display brightness also depends on the position where the display screen is observed.

Therefore, by determining the preferred maximum display brightness using the horizontal viewing angle as a variable parameter and determining the preferred maximum display brightness for each observer, it is possible to perform a more accurate preferred display brightness control.

For this reason, when observing the display screen with a plurality of people with different ages, it is possible to accurately grasp the age group of the observer using the horizontal viewing angle calculated for each observer as described above. By averaging the luminance in consideration of the number of observers, it is possible to control the luminance so that dissatisfaction with the luminance as a whole is further reduced.

Further, the display device includes an imaging unit that images an observer of the display screen;
An observer information extraction unit that extracts the number of observers for each age group of the display screen and the relative position information for each observer with respect to the display screen from the captured image captured by the imaging unit;
And further comprising a weighting factor determination unit that determines the weighting factor from the number of viewers for each age group extracted by the observer information extraction unit,
The horizontal viewing angle of view calculating unit extracts the observer's horizontal viewing angle of the display screen relative to the display screen from the position information of the observer relative to the display screen extracted by the observer information extracting unit. Is preferably calculated.

According to the above configuration, a plurality of persons with different ages are displayed by imaging the observer on the display screen with the imaging unit and extracting the number of observers on the display screen for each age group as observer information. When observing the screen, the number of viewers of each age group on the display screen can be accurately grasped as observer information.

Then, the horizontal viewing angle calculation unit extracts the observer's horizontal viewing of the display screen relative to the display screen from the positional information of the observer relative to the display screen extracted by the observer information extraction unit. By calculating the angle of view, the preferred maximum display luminance can be determined using the horizontal viewing angle of view for each observer. Therefore, it is possible to control the preferred display brightness with higher accuracy.

The preferred maximum display brightness is based on a value derived from a subjective evaluation experiment for obtaining a preferred maximum display brightness for each age group of the viewer on the display screen from the horizontal viewing angle, the screen illuminance, and the average brightness level. Preferably it is.

In this way, by performing luminance control based on the value (average value) that the observer thinks is suitable luminance obtained in the subjective evaluation experiment, it is possible to reduce excess luminance without causing dissatisfaction with the luminance. . Therefore, according to said structure, the reduction effect of power consumption can be acquired, without bringing dissatisfaction with respect to a brightness | luminance.

Further, according to the above configuration, in order to control the luminance based on the result of the subjective evaluation experiment as described above, for example, when performing luminance control based on the luminance “beginning to feel glare” as in Patent Document 1. As compared with the above, it is possible to achieve a low visual burden and low power consumption, and more appropriate luminance control can be performed.

The display device further includes an observer information input unit that inputs an age group and the number of observers on the display screen as observer information, and the weighted average luminance calculation unit is input by the observer information input unit. , The ratio of the number of persons for each age group of the observers included in the received observer information, the preferred maximum display brightness for each age group of the observer of the display screen determined by the suitable maximum display brightness determination unit It is preferable to calculate a weighted average luminance obtained by performing weighted averaging using a weighting coefficient associated with.

In this case, an imaging unit that images the observer on the display screen, and an observer information extraction unit that extracts the number of observers on the display screen for each age group from the captured image captured by the imaging unit as observer information are provided. Without observing the display screen with a plurality of people with different ages, the number of viewers of each age group on the display screen can be accurately grasped as observer information. In consideration of the number of persons, the luminance can be averaged to determine the preferred maximum display luminance.

Further, in the display device, the weighted average luminance calculation unit receives input from the observer information input unit when there is no input from the observer information input unit within a certain time after the display device is turned on. The preferred maximum display brightness determined by the preferred maximum display brightness determination unit for each age group of the viewer of the display screen, the population ratio for each age group in a certain region is the age group of the viewer of the display screen It is preferable to calculate a weighted average luminance obtained by weighted averaging using a weighting coefficient used as a ratio of the number of people for each.

In this case, by performing weighted average luminance control using the population ratio as a weighting factor as described above, even when there is no information about the age and number of observers on the display screen, the most appropriate (the total dissatisfaction with luminance is Brightness control (which is minimized).

Further, in this case, since the brightness control can be performed with the simplest configuration, the cost can be reduced.

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.

The present invention can be suitably used for a display device such as a liquid crystal TV.

DESCRIPTION OF SYMBOLS 1 Display part 1a Display screen 2 Display control circuit 3 Light source 4 Light source drive circuit 5 Screen illumination intensity detection part 6 Brightness control part 7 Observer information extraction part 8 Imaging part 9 Average brightness level calculation part 10 LUT memory | storage part 11 Brightness sensor 12 Screen Illuminance calculation unit 13 Weighting coefficient determination unit 14 Storage unit 21 Suitable maximum display luminance determination unit 22 Weighted average luminance calculation unit 23 Light source output calculation unit 31 Object separation unit 32 Observer information analysis unit 33 Distance measurement unit 41 Horizontal viewing angle of view Calculation unit 51 Input unit 52 Population ratio data storage unit 100 Display device

Claims

A display unit;
A screen illuminance detection unit for detecting the screen illuminance of the display screen of the display unit;
An average luminance level calculator that calculates an average luminance level from a video signal that is a video source of the video displayed on the display screen;
A brightness control unit for controlling the display brightness of the display screen,
The brightness control unit
Using the horizontal viewing angle of view, the screen illuminance, the average brightness level, and the age group for each observer on the display screen as parameters, the preferred maximum display brightness for each age group of the viewer on the display screen is determined. A suitable maximum display brightness determination unit;
The preferred maximum display brightness determined for each age group of the viewer on the display screen, determined by the preferred maximum display brightness determination unit, is associated with the ratio of the number of persons for each age group of the viewer on the display screen. A weighted average luminance calculation unit for calculating a weighted average luminance obtained by weighted averaging using
A display device that controls a maximum display luminance of the display screen so as to be the weighted average luminance.
A lookup table storage unit that stores a lookup table indicating the relationship between the screen illuminance and the average luminance level provided for each age group of the viewer on the display screen according to the horizontal viewing angle. ,
The preferred maximum display luminance determination unit refers to a lookup table stored in the lookup table storage unit from a horizontal viewing angle of view, the screen illuminance, and the average luminance level. The display device according to claim 1, wherein a suitable maximum display luminance for each age group of the observer is determined.
The display device according to claim 1 or 2, wherein the horizontal viewing angle is a fixed parameter and is fixed to a preset value.
An imaging unit for imaging an observer on the display screen;
An observer information extracting unit that extracts, as observer information, the number of observers in each age group of the display screen from the captured image captured by the imaging unit;
4. The display device according to claim 1, further comprising a weighting coefficient determination unit that determines the weighting coefficient from the observer information extracted by the observer information extraction unit. .
The horizontal viewing angle is a variable parameter,
A horizontal viewing angle calculator that calculates a horizontal viewing angle for each observer of the display screen with respect to the display screen;
The preferred maximum display brightness determining unit determines a preferred maximum display brightness for each age group of the viewer on the display screen, using the horizontal viewing angle calculated by the horizontal viewing angle calculating unit. The display device according to claim 1, wherein the display device is a display device.
An imaging unit for imaging an observer on the display screen;
An observer information extraction unit that extracts the number of observers for each age group of the display screen and the relative position information for each observer with respect to the display screen from the captured image captured by the imaging unit;
And further comprising a weighting factor determination unit that determines the weighting factor from the number of viewers for each age group extracted by the observer information extraction unit,
The horizontal viewing angle of view calculating unit extracts the observer's horizontal viewing angle of the display screen relative to the display screen from the position information of the observer relative to the display screen extracted by the observer information extracting unit. The display device according to claim 5, wherein the display device is calculated.
The preferred maximum display brightness is based on a value derived from a subjective evaluation experiment for obtaining a preferred maximum display brightness for each age group of the viewer on the display screen from the horizontal viewing angle, the screen illuminance, and the average brightness level. The display device according to any one of claims 1 to 6, wherein:
An observer information input unit for inputting the age group and number of observers on the display screen as observer information;
When the weighted average luminance calculation unit receives an input from the observer information input unit, the weighted average luminance calculation unit has received the preferable maximum display luminance for each age group of the viewer of the display screen determined by the preferable maximum display luminance determination unit. 4. The weighted average luminance obtained by weighted averaging using a weighting coefficient associated with the ratio of the number of viewers in each age group included in the observer information is calculated. The display device described in 1.
The weighted average luminance calculation unit is configured to display the preferred maximum display until the input by the observer information input unit is received when there is no input by the observer information input unit within a certain time after the display device is turned on. The suitable maximum display brightness for each age group of the viewer on the display screen determined by the brightness determining unit is used as the ratio of the number of people for each age group of the viewer on the display screen in the fixed area. 9. The display device according to claim 8, wherein a weighted average luminance obtained by weighted averaging using a weighted coefficient is calculated.
An average luminance level calculating step for calculating an average luminance level from a video signal which is a video source of video displayed on the display screen of the display device;
The preferred maximum display for each age group of the observer on the display screen, using the horizontal viewing angle, the screen illuminance on the display screen, the average luminance level, and the age group for each observer on the display screen as parameters. A preferred maximum display brightness determination step for determining brightness;
The weighting coefficient corresponding to the ratio of the number of persons for each age group of the observer on the display screen, the suitable maximum display brightness for each age group of the observer on the display screen, determined in the step of determining the preferable maximum display brightness A weighted average luminance calculation step for calculating a weighted average luminance obtained by weighted averaging using
And a luminance control step for controlling the maximum display luminance of the display screen so as to be the weighted average luminance calculated in the weighted average luminance calculation step.
An imaging step of imaging the observer on the display screen;
An observer information extraction step for extracting, as observer information, the number of persons for each age group of the observer on the display screen from the captured image captured in the imaging step;
The display method according to claim 10, further comprising a weighting coefficient determination step for determining the weighting coefficient from the observer information extracted in the observer information extraction step.
A program for causing a computer to execute each step of the display method according to claim 10 or 11.
A computer-readable recording medium in which the program according to claim 12 is stored.