JP2011118001A - Video display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure high visibility according to a change of viewing environment even when the viewing environment is changed because external light partially shines in. <P>SOLUTION: The video display apparatus is constituted such that an area-to-be-irradiated estimation part estimates an area to be irradiated which is partially irradiated with the external light from the detected results by a plurality of illuminance sensors, an RGB controller and a backlight controller cooperate and adjust the video in such an area to be irradiated, a display controller generates an output video signal on the basis of such adjustment of the video, and a correction part time-sequentially corrects the output video signal between areas. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a video display device capable of ensuring high visibility in accordance with a change in the viewing environment caused by partial external light injection or the like.

  2. Description of the Related Art Conventionally, a video display device that is provided in a car navigation system of an automobile and displays navigation information such as route information to a destination and traffic jam information, one-segment broadcasting, and the like on an in-vehicle display is known.

  Such a video display device has been required to ensure high visibility at all times in order to assist a driver who is exposed to various changes in visual environment such as changes in sunshine and weather due to time.

  For example, for open cars, devices such as transflective liquid crystal that can use external light as a light source are used for in-vehicle displays, such as in-vehicle displays, to ensure visibility even during daytime exposure to direct sunlight. .

  In recent years, video display devices using so-called dimmer technology have been introduced that detect changes in illuminance using an illuminance sensor placed in the vicinity of an in-vehicle display and control the brightness of the backlight of a liquid crystal display to ensure visibility. (For example, refer to Patent Document 1).

JP 2006-285064 A

  However, the above-mentioned transflective liquid crystal has a problem that display quality is inferior to that of a transmissive liquid crystal specialized for a backlight light source or a reflective liquid crystal specialized for an external light source, and is not excellent in night visibility. There is a point. Therefore, it is hardly used as a vehicle-mounted display in vehicles other than open cars.

  Moreover, it is normal that external light partially enters the interior of an automobile due to the influence of the shape and transmittance of the window, the arrangement of pillars (posts), and the like. Therefore, the incident of external light on the in-vehicle display is often partial. However, the technique of Patent Document 1 does not mention this point.

  For this reason, when the same technology is used, the backlight luminance of the entire in-vehicle display is uniformly controlled even when the illuminance change due to the partial external light is detected. As a result, there is a high possibility that unnecessary backlight control is performed even when there is no problem in the visibility from the driver's point of view. Further, the unnecessary control may increase power consumption.

  In the case of a display of a portable terminal device or the like, even if the visibility is lowered due to the partial external light, it can be dealt with by changing the direction of the device itself. However, in the case of an automobile, the traveling direction cannot be changed in response to such partial external light.

  For these reasons, even if changes in the viewing environment occur due to partial exposure of external light, etc., a major issue is how to realize a video display device that can ensure high visibility according to such changes. It has become.

  The present invention has been made in order to solve the above-described problems caused by the prior art, and even if a change in the viewing environment occurs due to partial external light injection, etc., high visibility is provided according to the change. An object of the present invention is to provide a video display device that can be secured.

  In order to solve the above-described problems and achieve the object, the present invention is an image display device that displays an image on a display, and a plurality of illuminance detection means for detecting illuminance in the vicinity of the display; An area specifying means for specifying a partial area that is a reduced visibility portion of the display based on a detection value by the illuminance detecting means, and an adjustment for adjusting an image displayed in the partial area specified by the area specifying means Means.

  According to the present invention, the illuminance in the vicinity of the display is detected by a plurality of illuminance sensors, the partial area that is a reduced visibility portion of the display is identified based on the detection values by the plurality of illuminance sensors, and the identified partial area Since the image displayed on the screen is adjusted, even if a change in the viewing environment due to a partial incident of external light occurs, there is an effect that high visibility can be secured according to the change.

FIG. 1 is a diagram showing an outline of a video display method according to the present invention. FIG. 2 is a schematic diagram of the video display device. FIG. 3 is a block diagram illustrating a configuration of the video display device. FIG. 4 is a diagram for explaining the relationship between the RGB control unit and the backlight control unit. FIG. 5 is a diagram for explaining correction processing in the correction unit. FIG. 6 is a diagram for explaining the processing in the case of estimating the irradiated region. FIG. 7 is a flowchart showing a processing procedure of processing executed by the video display device. FIG. 8 is a diagram illustrating a case where a self-luminous meter is a display control target.

  Hereinafter, preferred embodiments of a video display method according to the present invention will be described in detail with reference to the accompanying drawings. In the following, the outline of the video display method according to the present invention will be described with reference to FIG. 1, and then an embodiment of the video display device to which the video display method according to the present invention is applied will be described with reference to FIGS. I will explain.

  In the following, a display device (hereinafter referred to as “display”) having a so-called transmissive liquid crystal panel (hereinafter referred to as “liquid crystal panel”) that performs display by partially shielding or transmitting light emitted from the backlight. Will be described in the case where the video display device according to the present invention is the target of display control. In addition, such a display performs gradation expression by controlling an RGB pixel which is one of the components of the liquid crystal panel.

  First, an outline of a video display method according to the present invention will be described with reference to FIG. FIG. 1 is a diagram showing an outline of a video display method according to the present invention. Incidentally, (A) in the figure shows an example of arrangement of the illuminance sensor and an example of the partition of the liquid crystal panel 20, and (B) in the figure shows an outline of the processing procedure in the video display method according to the present invention. ing.

  As shown in FIG. 1A, in the video display method according to the present invention, a plurality of illuminance sensors are arranged in the vicinity of the liquid crystal panel 20. In addition, the liquid crystal panel 20 is divided into a plurality of regions in association with the plurality of sensors.

In FIG. 5A, four illuminance sensors AS _{a to} DS _d are arranged in the vicinity of the liquid crystal panel 20, and the liquid crystal panel 20 is arranged in four areas A20a to D20d corresponding to the sensors. An example of division is shown. Below, the outline | summary of the processing procedure on the assumption of this example is demonstrated using (B) of the figure.

  As shown in (B-1) of the figure, when direct sunlight is irradiated onto the liquid crystal panel 20, the area of the liquid crystal panel 20 that has received such irradiation is usually affected by direct sunlight reaching 140,000 lux. Visibility is extremely reduced.

  Further, such direct sunlight irradiation is very often partial due to the influence of the shape and arrangement of automobile windows and pillars (posts). Here, the partial region of the liquid crystal panel 20 that has received partial irradiation of the direct sunlight is hereinafter simply referred to as “irradiated region”. Note that (B-1) in the figure shows an example in which only the area A20a of the liquid crystal panel 20 receives direct sunlight and the visibility is extremely lowered.

  By the way, such a drop in visibility causes the liquid crystal panel 20 to reflect very strong external light such as direct sunlight, and a part of the maximum gradation expression width (hereinafter referred to as “dynamic range”) is reduced. Due to the loss.

  Since the gradation of the RGB pixels is assigned to the normal dynamic range, a part of the gradation is lost with the partial loss of the dynamic range. That is, the visibility is lowered due to the occurrence of gradation that cannot be expressed.

Therefore, as shown in (B-1) of the figure, in the video display method according to the present invention, if the illuminance sensor AS _a corresponding to the area A20a detects an increase in illuminance due to direct sunlight, the illuminance sensor The area A20a associated with the AS _a is estimated to be an “irradiated area” in which visibility is partially reduced.

  And as shown to (B-2) of the figure, in order to recover the visibility of area A20a which is an "irradiated area", it decided to perform the partial control which makes this area A20a object. Here, as the method of such partial control, the following two methods are taken.

  First, as a first method, gradation that can no longer be expressed by performing gradation control of RGB pixels is restored (see (B-2a) in the figure).

  Here, the video display apparatus generally performs gradation expression by adjusting the amount of light transmitted through the RGB pixels using a mechanism called an RGB shutter. By such control, the above-described gradation is assigned to the dynamic range.

  Therefore, in the first method, the gradation before being irradiated is projected and allocated within the range of the dynamic range still remaining after receiving direct sunlight, and the gradation that cannot be expressed is restored. Details of this point will be described later with reference to FIG.

  In the second method, the luminance of the backlight is controlled to extend the dynamic range (see (B-2b) in FIG. 1). Specifically, the dynamic range is expanded to an extent corresponding to the dynamic range before irradiation by increasing the amount of light of the backlight light source. Details of this point will also be described later with reference to FIG.

  Therefore, according to this second method, the second method expands the gradation before irradiation, which was assigned in a limited way by projecting into “the remaining dynamic range” in the first method. By assigning to the dynamic range, the gradation that can no longer be expressed can be restored more appropriately. That is, in the partial control shown in (B-2) of FIG. 1, proper visibility is restored by controlling the above two methods in cooperation.

  Subsequently, as shown in (B-3) of the same figure, the input video signal is corrected for the luminance of the output video signal generated through the partial control shown in (B-2) of the same figure. did. Here, in the video display method according to the present invention, the following two methods are used as such correction methods.

  First, in the first method, the luminance difference between areas is corrected. That is, by smoothing the difference in luminance generated between the area A20a, which is the “irradiated area”, and the adjacent area A20b using a predetermined parameter, the boundary between the areas is not conspicuous when an image is displayed. Like that. Details of this point will be described later with reference to FIG.

  In the second method, the luminance difference in time series is corrected. That is, by smoothing the difference in luminance that occurs in time series using a predetermined parameter, the flickering of the screen that occurs when an image is displayed is suppressed. Details of this point will also be described later with reference to FIG.

  As shown in (B-4) of FIG. 1, the video display device displays the output video signal subjected to the correction shown in (B-3) of FIG. That is, the visibility of the area A20a of the “irradiated area” is restored, and it is possible to provide information that supports the driver even in a visual environment that receives partial direct sunlight.

Heretofore, the case where the plurality of illuminance sensors AS _{a to} DS _d correspond to predetermined areas of the liquid crystal panel 20 has been described as shown in FIG. However, the “irradiated area” may be estimated based only on the detection result of each sensor without associating the predetermined area with each sensor. This will be described later with reference to FIG.

  As described above, according to the video display method according to the present invention, even when external light such as direct sunlight is partially incident on the liquid crystal panel 20, the "irradiated object" High visibility can be ensured by controlling only the “region”.

  In addition, by using a plurality of illuminance sensors, the “irradiated area” can be appropriately estimated according to partial direct sunlight, and power consumption is reduced by controlling only the “irradiated area”. be able to. Therefore, it is possible to ensure high visibility efficiently according to changes in the viewing environment.

  Below, the Example about the video display apparatus to which the video display method demonstrated using FIG. 1 is applied is described in detail.

  First, an outline of a video display apparatus according to the present invention will be described with reference to FIG. FIG. 2 is a schematic view of a video display device according to the present invention. In the figure, only a part of the mechanism necessary for explaining the characteristics of the video display device according to the present invention is shown, and the shape and components of the mechanism are not limited. Further, (A) in the figure shows a schematic diagram around the liquid crystal panel 20, and (B) in the figure shows a diagram showing an example of partial control of an arbitrary point P on the liquid crystal panel 20, respectively. .

As shown in FIG. 2A, the video display device according to the present invention includes a liquid crystal panel 20, a light guide plate 30, and a plurality of backlights BL _{1 to} BL _n as components of the display unit. Yes.

In addition, a plurality of illuminance sensors AS _{a to} DS _d are arranged in the vicinity of the liquid crystal panel 20 and correspond to areas A20 _{a to} D20 _d , which are divided areas of the liquid crystal panel 20, respectively. Such static association may not be performed, but this point will be described later with reference to FIG.

  The liquid crystal panel 20 has a structure in which the liquid crystal is sandwiched between a plurality of transparent substrates such as glass. When the image display device applies a voltage to the liquid crystal and changes the direction of the liquid crystal molecules, the light transmittance is increased or decreased. Can be made. That is, an image can be displayed on the liquid crystal panel 20 according to such a principle.

  The RGB shutter described above performs gradation expression by increasing or decreasing the amount of light transmitted through the RGB pixels according to such a principle.

The backlights BL _{1 to} BL _n are light sources that transmit light through the liquid crystal panel 20. The light emitted from the backlights BL _{1 to} BL _n is spread on the back surface of the liquid crystal panel 20 by the light guide plate 30. That is, the light guide plate 30 functions to convert n point light sources (LEDs and the like) shown in FIG. 5A into surface light sources and to arrange the surface light sources on the back surface of the liquid crystal panel 20.

  In addition, although (A) of the figure shows the case where the backlight is a point light source such as an LED, the type and number of light sources are not limited. For example, a line light source such as a cold cathode tube is used. There may be.

  In addition, the light guide plate 30 can freely reflect the light incident from the end face of the light guide plate 30 by performing processing for controlling the refractive index of light on the surface layer, the inside, or the like. Therefore, by controlling such reflection, it is possible to adjust only the amount of light that passes through an arbitrary region of the liquid crystal panel 20.

  Here, this point will be described with reference to FIG. FIG. 5B is a diagram illustrating an example of partial control of an arbitrary point P on the liquid crystal panel 20.

As shown in the figure (B), for example, an optical R ₂ emitted from the backlight BL _2, by superimposing the light R ₅ emanating from the backlight BL _5, the region D according two light intersect Brightness can be increased.

  That is, it is possible to increase the luminance of only the arbitrary point P on the liquid crystal panel 20 by combining such control of light intersection and reflection by the light guide plate 30 described above. It should be noted that the example shown in FIG. 5B is a simple model case and does not limit the actual control method.

  Next, the configuration of the video display apparatus according to the present invention will be described with reference to FIG. FIG. 3 is a block diagram showing the configuration of the video display device 10 according to the present invention. In the figure, only components necessary for explaining the characteristics of the video display device 10 are shown, and descriptions of general components are omitted.

  As shown in the figure, the video display device 10 includes an illuminance sensor unit 11, a display unit 12, a video input unit 13, a control unit 14, and a storage unit 15. The control unit 14 further includes an irradiated region estimation unit 14a, a partial control unit 14b, an RGB control unit 14c, a backlight control unit 14d, a display control unit 14e, and a correction unit 14f. The storage unit 15 stores irradiated area information 15a and correction information 15b.

  The illuminance sensor unit 11 is an input device that receives a signal from the illuminance sensor and notifies the irradiated region estimation unit 14a. Further, the illuminance sensor unit 11 exists individually for each sensor such as the illuminance sensors Asa to DSd illustrated in FIGS. 1 and 2. Therefore, in the video display device 10, the plurality of illuminance sensor units 11 operate in parallel.

  The display unit 12 is a device corresponding to the liquid crystal panel 20 shown in FIGS. 1 and 2, and displays an output video signal from the display control unit 14e. The configuration of the display unit 12 is not particularly limited, and for example, a PDP (Plasma Display Panel) may be used.

  The video input unit 13 is an input device that receives an input video signal and notifies the display control unit 14e, and the configuration is not particularly limited. Therefore, the type of signal to be received is not limited. For example, an RGB signal may be input, or a color difference signal may be input. In this embodiment, it is assumed that RGB signals are input as input video signals.

  The control unit 14 is a processing unit that performs processing of estimating an irradiated area based on a signal from the illuminance sensor unit 11, adjusting an image of the irradiated area, and displaying the image on the display unit 12.

  The irradiated region estimation unit 14a is a processing unit that performs processing for specifying or estimating an irradiated region that is irradiated with external light such as direct sunlight on the liquid crystal panel 20 based on the signal input from the illuminance sensor unit 11. It is.

  That is, when the irradiated region estimation unit 14a receives a signal indicating that the illuminance has increased from an illuminance sensor disposed in the vicinity of the liquid crystal panel 20, a predetermined region of the liquid crystal panel 20 associated with the illuminance sensor in advance is displayed. Then, it is specified that it is an irradiated region that requires partial image adjustment (see FIG. 1).

  The association between the illuminance sensor and the predetermined area is not particularly limited. Therefore, it may be based on hardware connection or may be controlled by software.

  Further, the irradiated area estimation unit 14a performs a process of estimating the irradiated area based on the detection result of each illuminance sensor when the illuminance sensor and the predetermined area are not associated with each other. But there is. In the estimation of the irradiated region, the irradiated region estimation unit 14 a refers to the irradiated region information 15 a in the storage unit 15. Details of this point will be described later with reference to FIG.

  Further, the irradiated region estimation unit 14a is also a processing unit that estimates a video adjustment value such as a gradation or luminance necessary for adjusting the image of the estimated irradiated region.

  For the estimation of the video adjustment value, for example, a threshold value of an illuminance level that is a guide for estimation is stored in the irradiation area information 15a of the storage unit 15 in advance, and the threshold value and the illuminance sensor unit 11 notify The estimation may be performed based on the illuminance.

  The irradiated region estimation unit 14a is also a processing unit that performs processing for notifying the partial control unit 14b of the estimated irradiated region and the image adjustment value.

  The partial control unit 14b performs processing for instructing the RGB control unit 14c and the backlight control unit 14d to perform image adjustment based on the irradiation region and the image adjustment value notified from the irradiation region estimation unit 14a. Part.

  The partial control unit 14b is also a processing unit that performs a process in which both processing units of the RGB control unit 14c and the backlight control unit 14d instruct to perform video adjustment appropriately in cooperation.

  In addition, the partial control unit 14b performs a process of instructing the RGB control unit 14c and the backlight control unit 14d to appropriately perform image adjustment of the plurality of regions when there are a plurality of irradiated regions. It is also a department.

  The RGB control unit 14c is a processing unit that performs a process of adjusting the gradation of the irradiated region by increasing / decreasing the amount of light transmitted through the RGB pixels using the above-described RGB shutter provided in the video display device 10. Details of this point will be described later with reference to FIG.

  The RGB control unit 14c is also a processing unit that performs a process of notifying the display control unit 14e of a video adjustment signal that is a result of the adjustment.

  The backlight control unit 14d is a processing unit that performs a process of adjusting the luminance of the irradiated region by adjusting the light amount of the backlight light source included in the video display device 10. Details of this point will be described later with reference to FIG.

  The backlight control unit 14d is also a processing unit that performs processing for notifying the display control unit 14e of a video adjustment signal that is a result of the adjustment.

  Here, details of the processing performed by the RGB control unit 14c and the backlight control unit 14d and the relationship between both processing units will be described with reference to FIG. FIG. 4 is a diagram for explaining the relationship between the RGB control unit 14c and the backlight control unit 14d.

  Note that (A) in the figure shows a case where only the RGB control unit 14c is used, and (B) in the same figure shows a case where the RGB control unit 14c and the backlight control unit 14d are used in cooperation. , Respectively.

  First, the case where only the RGB control unit 14c shown in FIG. As shown to (Aa) of the figure, when the liquid crystal panel 20 is not irradiated with external light such as direct sunlight, the video display device 10 has a dynamic range of width M. Therefore, in such a case, the gradation of the RGB pixels (for example, 256 levels) is assigned to the dynamic range of the width M.

  However, as shown in (Ab) of the figure, when the liquid crystal panel 20 is irradiated with external light, the video display device 10 loses the dynamic range of the irradiated region by, for example, a width l. . This indicates a state in which the liquid crystal panel 20 reflects external light such as very strong direct sunlight and is difficult to see (visibility is lowered).

  As a result, the RGB pixels in the irradiated region lose the gradation corresponding to the width l. That is, a gradation that cannot be expressed corresponding to the width l occurs.

  Therefore, the RGB control unit 14c performs a process of projecting and allocating the gradation expression performance before irradiation, which has been allocated to the dynamic range corresponding to the width M, to the dynamic range corresponding to the width r remaining after irradiation. (See (A-b) in the figure). Thereby, the RGB pixels in the irradiated region can perform gradation expression in the range of the width r.

  As for the calculated values of the width l and the width r, for example, a predetermined loss width unit is stored in the irradiated area information 15a in advance for every 1 level increase in illuminance, and the detected value of the illuminance sensor unit 11 and the loss thereof are stored. The width l may be calculated from the width unit, and the width r may be calculated by subtracting the width l from the width M.

  Specifically, when the width M is 256 and the unit of loss width for every increase in the illuminance level is 10, if the illuminance increases by 10 levels, the width l is 100 (= 10 (level) × 10 (loss). The width r) is calculated as 156 (= 256 (width M) −100 (width l)).

  Next, a case where the RGB control unit 14c and the backlight control unit 14d shown in FIG. Note that the loss of the dynamic range and gradation expression performance for the width l upon receiving external light irradiation is the same as that shown in FIG.

  As shown in FIG. 5B, when the RGB control unit 14c and the backlight control unit 14d perform processing in cooperation, the backlight control unit 14d increases the light amount of the backlight light source to increase the width e. Secure a new dynamic range of minutes. That is, the dynamic range corresponding to the width r is expanded by the width e, and reaches the width (r + e) (see (B−b) in the figure).

  Then, the RGB control unit 14c projects and assigns the gradation expression performance before irradiation, which has been assigned to the dynamic range corresponding to the width M, to the dynamic range corresponding to the width (r + e). (See (Ba) and (Bb) in the figure). As a result, the RGB pixels in the irradiated region can perform gradation expression in a range corresponding to the width (r + e).

  Here, the width M and the width (r + e) need not be equal. That is, it is not necessary to make the width l and the width e equal. This is because the loss l of the dynamic range of the irradiated region need only be small enough not to impair the driver's visibility. Therefore, if the dynamic range is expanded by an r width smaller than 1, the visibility is increased. This is because there are cases where it can be secured.

  Note that when the loss l of the dynamic range is so small that the driver's visibility is not affected, the backlight control itself may not be performed. In this case, only the processing of the RGB control unit 14c shown in FIG. 5A can be performed, and the power consumption of backlight dimming by the backlight control unit 14d can be suppressed.

  Returning to the description of FIG. 3, the display control unit 14e receives the input video signal from the video input unit 13, the video adjustment signal from the RGB control unit 14c and the backlight control unit 14d, and the video correction signal from the correction unit 14f. Is a processing unit that performs processing for generating an output video signal.

  The display control unit 14e is also a processing unit that performs processing for notifying the display unit 12 of the generated output video signal.

  The correction unit 14f is a processing unit that performs a process of correcting the output video signal generated by the display control unit 14e. Here, the content of the correction process performed by the correction unit 14f will be described in detail with reference to FIG. FIG. 5 is a diagram for explaining correction processing in the correction unit.

  Note that (A) in the figure shows a case where a luminance difference between partial areas in the liquid crystal panel 20 is corrected. Further, (A-0) in the figure shows an example of the division of the liquid crystal panel 20, and (A-1) in the figure shows a luminance difference between regions before correction, (A-2) in the figure. Shows the luminance difference between the corrected regions.

  Further, (B) in the figure shows a case where the luminance difference in the time series of the output video signal is corrected. Also, (B-1) in the figure shows the luminance difference on the time series before correction, and (B-2) in the figure shows the luminance difference on the time series after correction. .

First, the case where the luminance difference between the areas of the liquid crystal panel 20 is corrected will be described with reference to FIG. Assume that the liquid crystal panel 20 is divided into four areas A to D at predetermined horizontal positions B ₁ , B ₂ , and B ₃ as shown in FIG. That is, the horizontal positions B ₁ , B ₂ , and B ₃ are the boundary lines of each region.

Then, as shown in (A-1) of the figure, the method according to the present invention adjusts the image including the brightness for each irradiated region, so that the boundary lines B ₁ , B ₂ , and B ₃ Usually, a difference in luminance occurs. Such a luminance difference appears as a boundary line between the regions on the video.

Accordingly, the correction unit 14f smoothes the luminance difference at the boundary points B ₁ , B ₂ , and B ₃ . In other words, a process of blurring (so-called fading) the boundary lines between the regions that will appear on the image if they are not corrected is performed by smoothing the luminance difference.

Specifically, as shown in (A-2) of the figure, the correction unit 14f gradually changes the luminance in a predetermined section sandwiching the boundary point. For example, as shown in (A-2) of the figure, the boundary point B ₁ or the interval P _d sandwiching the boundary point B ₂ is gradually increased from a high luminance to a low luminance, that is, from a bright region to a dark region. It is a dark adaptation section that lowers.

Further, as shown in the figure (A-2), section P _l sandwiching the boundary point B ₃ is a Akirajun response interval is gradually increased brightness from a dark area to a bright area. Incidentally, such a period _{P d} and segment _{P l} are each dark adaptation period parameter _{P d,} a light adaptation interval parameter _{P l,} it assumed to be stored in the correction information 15b of the previously stored unit 15.

Next, a case where the luminance difference in the time series of the output video signal is corrected will be described with reference to FIG. As shown in (B-1) of the figure, it is assumed that there are points T _{1 to} T ₄ on the time axis where a significant difference in luminance is observed.

  In such a case, if the image is displayed without correction, the luminance fluctuates greatly in a very short time, resulting in flickering on the screen. For this reason, the correction unit 14f smoothes the luminance difference and suppresses the flickering of the screen.

Specifically, as shown in (B-2) of the figure, the correction unit 14f gradually changes luminance over a predetermined time from a point on the time axis where the luminance difference occurs. To. For example, the predetermined elapsed period T _d from the point T ₁ or the point T ₃ shown in (B-2) in the figure is a dark adaptation period in which the luminance is gradually lowered from high luminance to low luminance. .

In addition, a predetermined elapsed period T ₁ from the point T ₂ or the point T ₄ shown in (B-2) in the figure is a light adaptation period in which the luminance is gradually increased. Incidentally, such elapsed time T _d and the elapsed time T _l are each dark adaptation time parameter T _d, a light adaptation time parameter T _l, it assumed to be stored in the correction information 15b of the previously stored unit 15.

  Returning to the description of FIG. 3, the storage unit 15 is a storage unit configured by a storage device such as a hard disk drive, a nonvolatile memory, or a register, and stores irradiated area information 15 a and correction information 15 b.

  The irradiated area information 15a and the correction information 15b are stored in advance through a verification test before the operation of the video display device 10 and the like. Such setting values may be changed as appropriate according to the operation. Also, there is no particular limitation on the setting or changing method, and hardware or software may be used.

  The irradiated area information 15a is static definition information in which an irradiation pattern estimated from a combination of illuminances of a plurality of illuminance sensors is defined in advance. Such an irradiation pattern includes the shape of the irradiated region. In addition, such definition information is defined for each same vehicle type having the same shape and arrangement such as windows and pillars.

  The irradiated region information 15a is referred to by the irradiated region estimation unit 14a when the plurality of illuminance sensors and the predetermined region of the liquid crystal panel 20 are not associated with each other. This will be described later with reference to FIG.

The correction information 15b is a parameter group referred to when the correction unit 14f corrects the output video signal. Specifically, dark adaptation / photopic segment parameter for smoothing the brightness difference between areas of the liquid crystal panel 20 (see P _d and P _l of (A) in FIG. 5), the time series of the output video signal and a dark adaptation / photopic period parameter for smoothing the brightness difference of the upper (see T _d and T _l of (B) in FIG. 5).

  Until now, a case has been described in which a plurality of illuminance sensors arranged in the vicinity of the liquid crystal panel 20 are respectively associated with predetermined regions of the panel. The irradiated area may be estimated based on the detection result.

  Therefore, hereinafter, processing in a case where the illuminance sensor and the predetermined area are not associated will be described with reference to FIG. FIG. 6 is a diagram for explaining the processing in the case of estimating the irradiated region. In addition, (A) in the figure shows an arrangement of a plurality of illuminance sensors and irradiated areas, and (B) in the figure shows a setting example of irradiated area information 15a.

As shown in FIG. 6A, for example, six illuminance sensors 1S _{1 to} 6S ₆ are arranged in the vicinity of the liquid crystal panel 20. In such a case, external light such as direct sunlight enters the liquid crystal panel 20 as oblique light. In this case, the irradiated region is the irradiated region 20B shown in FIG.

Although not shown, the illuminance sensor detects the illuminance level with a decimal detection value, and the illuminance levels detected by the _six illuminance sensors 1S _{1 to} 6S ₆ are S ₁ = 7 and S ₂ =, respectively. Assume that 10, S ₃ = 3, S ₄ = 7, S ₅ = 10, and S ₆ = 3.

In such a case, the detection results of the illuminance sensors 1S _{1 to} 6S ₆ are different due to differences in various conditions such as the detection distance and the detection direction. Conversely, based on the difference in the results, the irradiation region 20B The shape can be estimated.

  Therefore, in the method according to the present invention, the shape pattern of the irradiated region 20B that can be estimated from the detection result of each illuminance sensor is stored in the irradiated region information 15a of the storage unit 15 in advance.

  However, as described above, the incident of external light such as direct sunlight is easily affected by the shape and arrangement of the window and pillar of the automobile. Suppose that it carries out for every same vehicle type which has the same shape and arrangement, the installation position of the display unit 12, and the like. Such patterning may be performed through a verification test of the video display device 20 or the like.

  Therefore, the irradiated region estimation unit 14a uses the detection signal from the illuminance sensor unit 11 and the irradiated region information 15a when each illuminance sensor and a predetermined region of the liquid crystal panel 20 are not associated with each other. Based on this, a process for estimating the irradiated region 20B is performed. Hereinafter, this point will be described.

  FIG. 6B shows an example of setting the irradiated area information 15a in the storage unit 15. As shown in FIG. 5B, the irradiated area information 15a is managed as information for each vehicle type. Therefore, it is necessary to associate the video display device 10 with the vehicle type on which the device is mounted, but the means is not particularly limited. Moreover, it is good also as having the information of only the vehicle model carrying the apparatus.

Here, the irradiated region estimating unit 14a receives the detection result of the illuminance sensor 1S ₁ ~6S ₆ from the illuminance sensor 11, the irradiated area information record having a combination of combination with matching illumination level of the detection result received Extract from 15a. That is, in the example shown in (A) of the same figure, the irradiated region estimation unit 14a has the combination No. shown in (B) of FIG. The record of 003 will be extracted.

  And the irradiation area estimation part 14a estimates the irradiation pattern linked | related with the combination of the extracted illumination intensity level as the irradiation area 20B. Further, the irradiated region estimation unit 14a estimates video adjustment values such as luminance and gradation according to each illuminance level of the extracted record.

  In the above description, when the detection result of each illuminance sensor matches the combination of the illuminance levels, the irradiation pattern corresponding to the combination is estimated as the irradiated region 20B. However, the present invention is not limited to this, and a combination of illuminance levels closest to the detection result of each illuminance sensor may be extracted, and an irradiation pattern corresponding to the extracted combination may be estimated as the irradiated region 20B.

  Next, a processing procedure executed by the video display device 10 will be described with reference to FIG. FIG. 7 is a flowchart showing a processing procedure executed by the video display device 10.

  As shown in FIG. 7, the video display apparatus 10 samples the detection signal output from each illuminance sensor (step S101). Then, it is determined whether or not each illuminance sensor is associated with a predetermined region of the liquid crystal panel 20 (step S102).

  If there is such correspondence (step S102, Yes), an area requiring partial control, that is, an irradiated area is identified from the sampling result in step S101 (step S103). If the determination condition in step S102 is not satisfied (No in step S102), the irradiated region is estimated from the sampling result in step S101 and the irradiated region information 15a (step S104).

  Then, the video display apparatus 10 determines whether there is an area that needs partial control, that is, an irradiated area (step S105). If there is an irradiated area (step S105, Yes), the control is shifted to the next step S106. If the determination condition in step S105 is not satisfied (No in step S105), the process in step S101 is repeated.

  Subsequently, the video display apparatus 10 estimates the dynamic range of the corresponding area, that is, the irradiated area (step S106). In addition, this estimation refers to estimating the dynamic range of a loss, and estimating the dynamic range after irradiation based on this loss (refer FIG. 4).

  Then, the video display device 10 determines whether or not the dynamic range is appropriate, that is, whether or not the visibility can be recovered with the gradation expression performance of the dynamic range after irradiation (step S107).

  If the dynamic range after irradiation is not appropriate (No in step S107), the video display apparatus 10 adjusts the dynamic range after irradiation by controlling the luminance of the backlight (step S108), and step S107. Repeat the process.

  If the dynamic range after irradiation is appropriate (Yes in step S107), the gradation is adjusted by controlling the RGB shutter (step S109). That is, the video display device 10 projects and assigns the gradation expression performance assigned to the dynamic range before irradiation to the dynamic range after irradiation (see FIG. 4).

  Subsequently, the video display device 10 corrects the luminance difference between the irradiated region and the other region (step S110), and corrects the luminance difference in time series (step S111) (see FIG. 5).

  Then, the video display device 10 displays the video on the display unit 12 (step S112), and ends the process.

  As described above, in this embodiment, the irradiated region estimation unit estimates the irradiated region that has received partial external light irradiation from the detection results of the plurality of illuminance sensors, and the RGB control unit and the backlight control. Adjust the video for the irradiated area in cooperation with each other, the display control unit generates an output video signal based on the adjustment of the video, and the correction unit corrects the output video signal between the areas and in time series. The video display device was configured to do so. Therefore, even if a change in the viewing environment due to a partial incident of external light or the like occurs, high visibility can be ensured according to the change.

  In the above-described embodiment, the case where the video display device according to the present invention uses a vehicle-mounted type liquid crystal display provided in a car navigation system or the like as a display control target has been described.

  By the way, in recent years, on the instrument panel of automobiles, instead of conventional analog display hands and dial instruments, digitally drawn instruments (hereinafter referred to as “drawable meters”) are integrated into a liquid crystal display, etc. The one using the so-called glass cockpit method is becoming popular.

  Among the instruments, in particular, the speedometer is easily confirmed by the driver while driving, as stipulated in the “Road Transport Vehicle Law” and “Safety Standards for Road Transport Vehicles”. It must be installed in a position where it can be made, and there should be no significant error from the actual speed when running on a flat paved road surface. Therefore, it is common for the instrument panel to take measures such as providing a long hook to prevent the speedometer from being exposed to external light.

  Thus, the speedometer is also required to ensure high visibility according to changes in the visual environment. Therefore, when the speedometer is a drawing meter, it may be a display control target of the video display method according to the present invention.

  That is, if a plurality of illuminance sensors are arranged near the speedometer (or the liquid crystal display displaying the speedometer) and the irradiated area is estimated, the gradation and brightness by the RGB control unit and the backlight control unit The visibility of the speedometer may be ensured by performing such control.

  In addition, when such a speedometer is a self-luminous meter that illuminates the hands and dial with backlight and makes the hands and characters themselves appear to emit light, the display of the video display method according to the present invention is also possible. It may be a control target.

  Therefore, the case where the speedometer is a self-luminous meter will be described below with reference to FIG. FIG. 8 is a diagram illustrating a case where a self-luminous meter is a display control target. In addition, (A) of the figure shows an example of arrangement of the illuminance sensor and an example of division of the speedometer, and (B) of the figure shows an example of setting the irradiated area information.

As shown in FIG. 5A, when four illuminance sensors AS _{a to} DS _d are arranged in the vicinity of the speedometer, for example, the speedometer is arranged in four areas in association with each sensor. It can be divided (see (Aa) to (Ad) in the figure).

Then, when the illuminance sensor AS _a detects an increase in illuminance, the video display device identifies the area A (see (A-a) in the figure) associated with the illuminance sensor AS _a as the irradiated region. Then, the visibility of the self-luminous meter can be ensured by controlling the gradation and brightness of the area.

  Further, even if the association between the sensor and the area is not performed, the irradiation pattern estimated from the combination of the illuminance levels of each sensor shown in FIG. You can do that. Thereby, the video display apparatus can estimate the irradiated area, and can control the gradation and brightness of the area to ensure the visibility of the speedometer.

  Further, a meter on which a part of such a self-luminous meter (only a needle, only a character, etc.) is drawn may be a display control target of the video display method according to the present invention.

  As described above, the video display device according to the present invention is useful when it is desired to ensure high visibility in accordance with such a change even if a change in the viewing environment occurs due to partial external light injection, etc. It is suitable for application to a video display device that is highly required to continuously provide information for supporting the driver.

DESCRIPTION OF SYMBOLS 10 Image | video display apparatus 11 Illuminance sensor part 12 Display part 13 Image | video input part 14 Control part 14a Irradiation area estimation part 14b Partial control part 14c RGB control part 14d Backlight control part 14e Display control part 14f Correction | amendment part 15 Memory | storage part 15a Irradiation Area information 15b Correction information 20 Liquid crystal panel 30 Light guide plate

Claims (7)

A video display device for displaying video on a display,
A plurality of illuminance detection means for detecting illuminance in the vicinity of the display;
Area specifying means for specifying a partial area that is a reduced visibility part of the display based on detection values by the plurality of illuminance detection means;
An image display device comprising: adjusting means for adjusting an image displayed in the partial area specified by the area specifying means. The region specifying means includes
The video display device according to claim 1, wherein an area associated with the illuminance detection unit whose detection value is equal to or greater than a predetermined threshold is specified as the partial area. Partial area information storage means for storing partial area information in which the partial areas corresponding to combinations of detection values by the plurality of illuminance detection means are defined in advance;
The region specifying means includes
The video display device according to claim 1, wherein the partial area is specified based on detection values by the plurality of illuminance detection means and the partial area information. An adjustment amount estimating means for estimating an adjustment amount for the video based on detection values by the plurality of illuminance detection means;
The adjusting means includes
4. The video display device according to claim 1, wherein the video displayed in the partial area is adjusted based on the adjustment amount estimated by the adjustment amount estimation unit. The adjusting means includes
A loss range of the dynamic range in the partial region is estimated based on detection values by the plurality of illuminance detection means, and the gradation of the entire range is calculated with respect to a remaining range obtained by subtracting the loss range from the entire range of the dynamic range. The video display apparatus according to claim 1, wherein the video is adjusted by projecting. The adjusting means includes
When the existence of the loss range is estimated, the remaining range is expanded by increasing the light amount of the light source in the display, and the gradation of the entire range is projected onto the remaining range after expansion. The video display device according to claim 5, wherein the video is adjusted. The adjusting means includes
Based on the luminance difference between the partial area that is the adjustment target of the video and the area adjacent to the partial area, and / or the time-series luminance difference in the partial area that is the adjustment target of the video, the luminance difference is calculated. The video display apparatus according to claim 1, wherein the video is adjusted by performing smoothing correction.

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