JP4787654B2 - Image illumination device, image display device, and imaging device - Google Patents

Description

  The present invention relates to an image illumination device, an image display device, and an imaging device, and more particularly to a technique for illuminating an image displayed on a display surface.

Conventionally, a backlight having a plurality of light sources for illuminating the liquid crystal display from the back is provided, and an average luminance of video signals in a plurality of video areas on the liquid crystal display corresponding to the arrangement of the light sources is detected, and based on the average luminance A liquid crystal display device that adjusts the brightness of a light source is disclosed (Patent Document 1). In Patent Document 2, the brightness of the light source corresponding to the image display area is adjusted based on the difference between the average luminance level of the video signal in the image display area obtained by virtually dividing the liquid crystal panel and a predetermined reference luminance level. A liquid crystal display device that is controlled in a controlled manner is disclosed. Further, in Patent Document 3, when the illumination light is divided into a plurality of areas and emitted to the liquid crystal display panel, the brightness distribution of the image signal corresponding to the plurality of areas is calculated, and the brightness of the illumination light for each area is calculated. An illuminating device that determines the above is disclosed.
JP 2000-321571 A JP 2005-70690 A JP 2005-258403 A

  In Patent Documents 1 to 3, the brightness of the illumination light is controlled based on the average brightness and brightness distribution of the area obtained by dividing the display surface of the liquid crystal. When a dark portion is included, it is difficult to perform dimming control in accordance with an extremely bright portion.

  The present invention has been made in view of such circumstances, and an image illuminating device and an image display device capable of ensuring a dynamic range and illuminating an image displayed on a display surface so as to have natural brightness. And an imaging apparatus.

In order to achieve the above object, an image illuminating device according to a first aspect of the present invention includes an illuminating unit that illuminates an image displayed on a predetermined display surface, and displays in a plurality of display areas obtained by dividing the display surface. A luminance value detecting means for acquiring a luminance value of the image to be detected and detecting a peak luminance value of each display area, and the brightness of the illumination light emitted from the illuminating means according to the peak luminance value And an illumination control means for controlling each of them.

According to the image lighting device according to the first aspect , the dynamic range can be secured by controlling the brightness of the illumination light for each display area according to the peak luminance value of each display area, For example, even when an extremely bright part and an extremely dark part are included in one display area, the light part is naturally controlled by dimming control according to the bright part (peak luminance value). Can be bright.

The image illumination device according to a second aspect of the present invention is the image illumination apparatus according to the first aspect , wherein the illumination control unit is configured to illuminate the display area when a peak luminance value of a certain display area is a black value. It is characterized in that the brightness of light is minimized or zero.

According to the image illuminating device according to the second aspect , for example, when the display area is black, it is not necessary to irradiate the illumination light. Therefore, the illumination light is limited due to the limitation of the light shielding rate on the display surface such as a liquid crystal panel. Can be prevented from leaking and the black floating phenomenon occurs, and the display surface can be illuminated with natural brightness. In addition, power for irradiation with illumination light can be reduced.

Image lighting apparatus according to a third aspect of the present invention, in the first or second aspect, the lighting control means in the display area, a high luminance image of the peak luminance value or its near luminance value When located in the vicinity of the boundary of the display area, depending on the peak luminance value of the adjacent area adjacent to the display area at the boundary and the larger one of the peak luminance values of the display area, the adjacent area The brightness of illumination light irradiated to the area is controlled.

According to the image illuminating device according to the third aspect , when a high-luminance image is located in the vicinity of the display area, it is possible to perform dimming control according to the image having a high luminance value.

The image illumination device according to a fourth aspect of the present invention is the image illumination apparatus according to the third aspect , wherein the illumination control unit is configured to display a high-luminance image having a peak luminance value or a luminance value close thereto in the display area. When the pixel is located in a region within 10% of the size of the display area, the peak luminance value of the adjacent area adjacent to the display area at the boundary and the peak luminance of the display area The brightness of the illumination light applied to the adjacent area is controlled according to the larger one of the values. In the fourth aspect , the range in the vicinity of the boundary of the third aspect is limited.

An image illuminating device according to a fifth aspect of the present invention includes an illuminating unit that illuminates an image displayed on a predetermined display surface, and a plurality of displays obtained by dividing the display surface into substantially the same number of pixels as the display surface. Illumination control means for controlling the brightness of illumination light emitted from the illumination means for each of the plurality of display areas in accordance with an image signal of an image displayed in the area.

According to the image illumination device of the fifth aspect , the brightness of the illumination light irradiated on the display surface can be controlled in units of one to several pixels on the display surface, so that a dynamic range can be ensured. The display surface can be illuminated with natural brightness.

Image lighting apparatus according to a sixth aspect of the present invention, in any of the embodiments of the fifth from the first, the illumination unit may fluorescent tubes, light emitting diodes, an organic EL or inorganic EL . In the sixth aspect , the types of light sources of the illumination means are limited.

According to a seventh aspect of the present invention, there is provided an image display device that displays an image on a predetermined display surface in response to an input of an image signal, illuminates the display surface, and displays the image on the display surface . To an image lighting device according to any one of the sixth to sixth aspects . The image display device according to an eighth aspect of the present invention is characterized in that, in the seventh aspect , the image display means is a liquid crystal panel. According to the image display device of the seventh aspect , by providing the image illumination device of the present invention, the image displayed on the image display means that does not emit light such as a liquid crystal panel is displayed with natural brightness. Can do.

Imaging device according to a ninth aspect of the present invention is characterized by comprising an image display device in accordance with aspects of the seventh or eighth.

According to the imaging device according to the ninth aspect , by providing the image display device, it is possible to display the captured image with natural brightness.

  According to the present invention, the dynamic range can be secured by controlling the brightness of the illumination light for each display area according to the peak luminance value of each display area. For example, in one display area Even when an extremely bright part and an extremely dark part are included, it is possible to control the brightness of the area illumination unit in accordance with the bright part (peak luminance value).

  Preferred embodiments of an image illumination device, an image display device, and an imaging device according to the present invention will be described below with reference to the accompanying drawings.

[Configuration of imaging device]
FIG. 1 is a block diagram showing the main configuration of an imaging apparatus according to an embodiment of the present invention. As shown in FIG. 1, the CPU 12 is connected to each unit in the imaging device 10 via a bus 14 and is a general control unit that controls the operation of the imaging device 10 based on an operation input from the operation unit 16 or the like. is there. The operation unit 16 includes a release button, a power switch, an operation mode switch, a cross key, and the like, and is an operation member that receives an operation input from a user. The release button is composed of two stages, and AF and AE are activated by automatic focusing (AF) and automatic exposure control (AE) in the state of “half-press (S1 = ON)” to stop by pressing the release button lightly. Is locked, and imaging is executed in a state of “full press (S2 = ON)” in which the press is further pushed from “half press”.

  The memory 18 is controlled by the memory control unit 20 and serves as a ROM that stores a program processed by the CPU 12 and various data necessary for the control, and a work area and an image processing area in which the CPU 12 performs various arithmetic processes. It has SDRAM etc.

  An external communication interface (external communication I / F) 22 is a device for connecting to a network or an external output device (for example, a personal computer, a television, a display, a printer, an external recording device), and the like. Send and receive data. As a data transmission / reception method, for example, USB, IEEE 1394, wired LAN, infrared communication (IrDA), or the like can be used.

  The imaging element 26 is an element that receives light that has entered through the optical system (lens) 24 and converts it into an electrical signal, and is, for example, a CCD. This electrical signal is amplified by a preamplifier (not shown), converted into a digital signal by the A / D converter 28, and input to the image processing unit 30.

  The imaging device 10 includes two operation modes, an imaging mode for capturing an image and a playback mode for displaying and reproducing the captured image. The operation mode is set by an operation from the operation unit 16 by the user. This is done by input.

  In the imaging mode, the electrical signal output from the imaging device 26 is processed by the image processing unit 30 to create image data for checking the angle of view (through image). The image data (through image) is output to the display unit (liquid crystal monitor) 100 as an image signal (Sn10 in FIG. 2). As a result, a through image is displayed on the liquid crystal monitor 100. When the release button is operated to capture an image, the electrical signal output from the image sensor 26 is processed by the image processing unit 30 to create an image file for storage. This image file for storage is stored in the memory card 32 in a predetermined file format. Here, the memory card 32 is, for example, a semiconductor memory or the like, and input / output to / from the memory card 32 is controlled by the external memory control unit 34. On the other hand, in the playback mode, image data stored in the memory card 32 is read out by the image processing unit 30 and image data for display is created. This display image data is output to the liquid crystal monitor 100 as an image signal (Sn10 in FIG. 2). As a result, the image in the memory card 32 is displayed on the liquid crystal monitor 100.

[First Embodiment]
FIG. 2 is a block diagram showing the main configuration of the liquid crystal monitor 100 according to the first embodiment of the present invention. As shown in FIG. 2, the liquid crystal monitor 100 includes a liquid crystal panel 102, a backlight 104, and a backlight control circuit 106. The liquid crystal panel 102 is obtained by enclosing a liquid crystal substance between two glass plates, and applying a voltage to the liquid crystal molecules in accordance with an image signal Sn10 input from the image processing unit 30 to align the liquid crystal molecules. , And display the image by increasing or decreasing the light transmittance. The backlight 104 is disposed on the back side of the liquid crystal panel 102 and illuminates the liquid crystal panel 102. The backlight 104 is turned on (turned on) / off (turned off) by a backlight ON / OFF control signal Sn12 input from the CPU 12. Is controlled. As shown in FIG. 3A, the backlight 104 is composed of a plurality of area illumination units A11 to A55. The area illumination units A11 to A55 are displayed on the liquid crystal panel 102 shown in FIG. 3B, respectively. Areas D11 to D55 are illuminated. The backlight control circuit 106 controls the brightness of the illumination light L applied to each display area of the liquid crystal panel 102 from each area illumination unit. In addition, although area illumination part A11 to A55 shown in FIG. 3 is a rectangle, you may make it polygons, such as a triangle and a hexagon.

  FIG. 4 is a diagram for explaining the backlight control circuit 106. As shown in FIG. 4, current control circuits C11 to C55 are connected to the area illumination units A11 to A55, respectively. In the area illumination units A11 to A55, a light emitting diode LED is disposed as a light source. The amount of current flowing through the light emitting diodes LED disposed in the area illumination units A11 to A55 is controlled by current control circuits C11 to C55, respectively.

  In the present embodiment, the image signal Sn10 from the image processing unit 30 is also input to the CPU 12. The CPU 12 divides the liquid crystal panel 102 into display areas D11 to D55 corresponding to the area illumination units A11 to A55, and the luminance values of the pixels in each display area based on the image signal Sn10 input from the image processing unit 30. The maximum value (peak luminance value) is detected. Then, the CPU 12 outputs an area-specific peak detection signal Sn14 indicating the peak luminance value of each display area of the liquid crystal panel 102 to the backlight control circuit 106.

  The backlight control circuit 106 acquires the peak luminance value of each display area by the area-specific peak detection signal Sn14 input from the CPU 12. The correspondence between the peak luminance value of the display area and the brightness of the illumination light from the area illumination unit is stored in the illumination light control table in the memory 18, and the backlight control circuit 106 refers to this illumination light control table. Then, the backlight control signal Sn16 is output to the current control circuits C11 to C55, the amount of current flowing through the light emitting diodes LED of each area illumination unit A11 to A55 is controlled, and the illumination irradiated by each area illumination unit A11 to A55 The brightness of the light L is controlled. For example, when a very bright image exists in the display area, that is, when the peak luminance value is high, the corresponding area illumination unit is brightened. On the contrary, when the display area is a black image, that is, when the peak luminance value is a black value, the corresponding area illumination unit is darkened or the amount of current flowing through the light emitting diode LED is made zero.

  Note that only the display area including the high-luminance portion having the peak luminance value equal to or higher than the predetermined value may be brighter than the normal level.

[Flow of processing for controlling brightness of backlight 104]
Next, the flow of processing for controlling the backlight 104 will be described with reference to FIG. First, the CPU 12 divides the liquid crystal panel 102 into display areas D11 to D55 corresponding to the area illumination units A11 to A55 of the backlight 104 (step S10). Based on the image signal Sn10 input from the image processing unit 30, the peak luminance value is detected for each display area (step S12) and stored in the memory 18 (step S14).

  Next, when the steps S12 to S14 are repeated and the detection of the peak luminance values of all the display areas D11 to D55 is completed (Yes in step S16), the CPU 12 causes the area-specific peak detection signal Sn14 to be subjected to backlight control. It is output to the circuit 106. Then, the backlight control signal Sn16 is output from the backlight control circuit 106 to the current control circuits C11 to C55 according to the area-specific peak detection signal Sn14, and the amount of current flowing through the light emitting diodes LED of each area illumination unit A11 to A55 is determined. Thus, the brightness of the illumination light L emitted from each area illumination unit A11 to A55 is controlled (step S18). Then, when the brightness control of all area illumination units A11 to A55 is completed (Yes in step S20), the process returns to step S10 and shifts to the next screen (frame) control.

  According to the present embodiment, by independently controlling the brightness of the illumination light L emitted from the area illumination units A11 to A55 of the backlight 104, a portion including an image with high luminance is brightened and an image with high luminance is obtained. A portion not included can be darkened, and a dynamic range can be secured. Further, by controlling the brightness of the illumination light L emitted from the corresponding area illumination units A11 to A55 according to the peak luminance values of the display areas D11 to D55, for example, it is extremely bright in one display area. Even when a portion and an extremely dark portion are included, it is possible to control the brightness of the area illumination unit in accordance with the bright portion (peak luminance value).

  As the light source of the backlight 104, a fluorescent tube (for example, a cold cathode fluorescent tube), an organic EL, an inorganic EL, or the like can be used in addition to the above-described light emitting diode LED.

[Second Embodiment]
In addition, when a high luminance image having a peak luminance value or a luminance value close to the peak luminance value is located in the vicinity of the boundary of the display area, an adjacent display area (adjacent area) is selected according to the peak luminance value of the high luminance image. ) Brightness may be controlled.

  FIG. 6 is a plan view showing the liquid crystal panel 102. In FIG. 6, the brightest display area is white (D23, etc.), the medium brightness display area is grid (D11, etc.), and the darkest display area is black (D22, etc.).

  As shown in FIG. 6, the high luminance image T10 having a peak luminance value or a luminance value close to the peak luminance value is in the vicinity of the lower right boundary of the display area D23 and adjacent to the right and lower sides of the display area D23. When the distance from the boundary with D33 and D34 is located in a region having a predetermined value or less (about 10% or less of the dimension of the display area D23), the area illumination unit A24, according to the brightness value of the high brightness image T10, The brightness of A33 and A34 is controlled, and the brightness of adjacent areas D24, D33, and D34 is increased.

  Further, as shown in FIG. 6, the high luminance image T12 having a peak luminance value or a luminance value close to the peak luminance value is in the vicinity of the left boundary of the display area D45 and the boundary with the adjacent area D44 adjacent to the left side of the display area D45. If the display area D44 is located in an area where the distance from the display area is less than or equal to a predetermined value (about 10% or less of the dimension of the display area D23) and the display area D44 does not include a high-intensity image, The brightness control of the area illumination unit A44 is performed using the peak luminance value as the peak luminance value of the adjacent area D44. In other words, when the high-brightness image T12 is included in a rectangular area (high-brightness image detection range) D44 ′ in which the adjacent area D44 is expanded by 10% of the size in the vertical and horizontal directions, The brightness of the adjacent area D44 is increased according to the brightness value.

  That is, in the present embodiment, when the high brightness image is in the vicinity of the boundary of the display area, the border is adjacent to the display area at the boundary and does not include the high brightness image in accordance with the peak brightness value of the high brightness image. Perform dimming control of the area.

[Flow of processing for controlling brightness of backlight 104]
Next, the flow of processing for controlling the backlight 104 will be described with reference to FIG. First, the CPU 12 divides the liquid crystal panel 102 into display areas D11 to D55 corresponding to the area illumination units A11 to A55 of the backlight 104 (step S30). Based on the image signal Sn10 input from the image processing unit 30, the peak luminance value a is detected for each display area (step S32).

  Next, the position (peak position) of the pixel having the peak luminance value a or the luminance close to the peak luminance value a in the display area (peak position) is detected, and the distance d between the boundary (four sides) of the display area and the peak position is calculated. (Step S34), an adjacent area adjacent to the boundary where the distance d is equal to or less than a predetermined value (10% or less of the size of the display area) is detected (Step S36). If the value b is already stored as the peak luminance value of the adjacent area detected in step S36 (Yes in step S38), the larger one of the value a and the value b is the peak luminance value of the adjacent area. Is stored in the memory 18 (step S40). On the other hand, when the peak luminance value of the adjacent area is not stored (No in step S38), the value a is stored in the memory 18 as the peak luminance value of the adjacent area (step S42).

  Next, when the steps S32 to S42 are repeated and the detection of the peak luminance values of all the display areas D11 to D55 is completed (Yes in step S44), the CPU 12 causes the area-specific peak detection signal Sn14 to be backlight controlled. It is output to the circuit 106. Then, the backlight control signal Sn16 is output from the backlight control circuit 106 to the current control circuits C11 to C55 according to the area-specific peak detection signal Sn14, and the amount of current flowing through the light emitting diodes LED of each area illumination unit A11 to A55 is determined. The brightness of each area illumination unit A11 to A55 is controlled (step S46). Then, when the brightness control of all area illumination units A11 to A55 is completed (Yes in step S48), the process returns to step S30, and shifts to the next screen (frame) control.

  According to the present embodiment, when an image having a high luminance value is displayed near the boundary between adjacent display areas, it is possible to perform dimming control according to the image having the high luminance value.

[Third Embodiment]
Next, a third embodiment of the liquid crystal monitor 100 will be described. FIG. 8 is a diagram schematically showing a liquid crystal monitor 100 according to the third embodiment of the present invention. As shown in FIG. 8, the backlight 104 of the present embodiment is, for example, an organic EL or inorganic EL having the same number and arrangement of pixels as the liquid crystal panel 102, and each pixel of the backlight 104 is a pixel of the liquid crystal panel 102. Area illumination parts A11,..., Amn corresponding to D11,.

  FIG. 9 is a diagram for explaining the backlight control circuit 106. As shown in FIG. 9, in this embodiment, the image signal Sn <b> 10 from the image processing unit 30 is input to the liquid crystal panel 102 and the backlight control circuit 106.

  The backlight control circuit 106 acquires the luminance values of the pixels D11,..., Dmn of the liquid crystal panel 102 from the image signal Sn10 input from the image processing unit 30. The correspondence relationship between the luminance value of the pixel of the liquid crystal panel 102 and the brightness of the area illumination unit is stored in the correspondence table of luminance value and backlight shown in FIG. 10, and the backlight control circuit 106 is based on this table. The amount of current supplied from the area illumination unit A11 to Amn is controlled, and the brightness of each area illumination unit A11 to Amn is controlled. In the correspondence table between the luminance value and the backlight shown in FIG. 10, the brightness of the illumination light is divided only in four stages, but it may be controlled with finer detail.

[Flow of processing for controlling brightness of backlight 104]
Next, the flow of processing for controlling the backlight 104 will be described with reference to FIG. First, the backlight control circuit 106 acquires the luminance of each pixel D11,..., Dmn of the liquid crystal panel 102 from the image signal Sn10 input from the image processing unit 30. Then, the brightness of the area illumination units A11,..., Amn corresponding to each pixel is determined according to the luminance value of each pixel D11,..., Dmn (step S50). Next, the amount of current supplied from each area illumination unit A11 to Amn is controlled by the backlight control circuit 106, and the brightness of each area illumination unit A11 to Amn is controlled (step S52). When the brightness control of all area illumination units A11 to A55 is completed (Yes in step S54), the process proceeds to the next screen (frame) control.

  According to this embodiment, the dynamic range can be ensured by controlling the brightness of the illumination light L applied to each pixel of the liquid crystal panel 102.

  In this embodiment, an organic EL or an inorganic EL is used as the backlight 104. However, a light emitting diode or a fluorescent tube having substantially the same size as the pixel of the liquid crystal panel 102 may be used. In this embodiment, one area illumination unit is provided for one pixel of the liquid crystal panel 102. For example, one area illumination unit is provided for two to several tens of pixels of the liquid crystal panel 102. Also good.

  In each of the above-described embodiments, the imaging apparatus 10 including the backlight 104 and the liquid crystal monitor 100 of the present invention has been described. However, the present invention may be applied to, for example, a liquid crystal display, a liquid crystal television, a mobile phone, etc. The present invention can be applied to a device having display means such as an information terminal (PDA).

1 is a block diagram illustrating a main configuration of an imaging apparatus according to an embodiment of the present invention. 1 is a block diagram showing the main configuration of a liquid crystal monitor 100 according to a first embodiment of the present invention. FIG. 3A: a plan view showing the backlight 104, FIG. 3B: a plan view showing the liquid crystal panel 102 The figure for demonstrating the backlight control circuit 106 which concerns on 1st Embodiment. The flowchart which shows the flow of the process which controls the backlight 104 which concerns on 1st Embodiment. The top view which shows the liquid crystal panel 102 which concerns on 2nd Embodiment The flowchart which shows the flow of the process which controls the backlight 104 which concerns on 2nd Embodiment. The figure which shows typically the liquid crystal monitor 100 which concerns on 3rd Embodiment. The figure for demonstrating the backlight control circuit 106 which concerns on 3rd Embodiment. Luminance value and backlight correspondence table The flowchart which shows the flow of the process which controls the backlight 104 which concerns on 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Imaging device, 12 ... CPU, 14 ... Bus, 16 ... Operation part, 18 ... Memory, 20 ... Memory control part, 22 ... External communication I / F, 24 ... Optical system, 26 ... Imaging element, 28 ... A / D converter, 30 ... Image processing unit, 32 ... Memory card, 34 ... External memory control unit, 100 ... Display unit (liquid crystal monitor), 102 ... Liquid crystal panel, 104 ... Backlight, 106 ... Backlight control circuit

Claims (8)

Illumination means for illuminating an image displayed on a predetermined display surface;
Luminance value detection means for acquiring luminance values of images displayed in a plurality of display areas obtained by dividing the display surface, and detecting peak luminance values of each display area;
Illumination control means for controlling the brightness of the illumination light emitted from the illumination means for each display area according to the peak luminance value, and the peak luminance value or a luminance value close to the peak luminance value in the display area When the high-intensity image is located in the vicinity of the boundary of the display area, the peak luminance value of the adjacent area adjacent to the display area at the boundary and the larger one of the peak luminance values of the display area In response, illumination control means for controlling the brightness of illumination light applied to the adjacent area ;
An image illumination apparatus comprising:   The illumination control means minimizes or reduces the brightness of illumination light applied to the display area when the peak luminance value of a certain display area is a black value. The image illumination device described. The illumination control means, when the high-intensity image is located in a region where a distance from a boundary between a display area including the high-intensity image and an adjacent area adjacent to the display area is a predetermined value or less, Controlling the brightness of illumination light irradiated to the adjacent area according to a peak luminance value of an adjacent area adjacent to the display area at a boundary and a larger value of the peak luminance values of the display area The image illuminating device according to claim 1 or 2. In the display area, the illumination control means is a region in which a high-luminance image having a peak luminance value or a luminance value close thereto is along the boundary of the display area, and is within 10% of the size of the display area when located, the peak brightness value of the neighboring area adjacent to the display area in the boundary, depending on the larger one of the peak brightness value of the display area, the illumination light irradiated to the adjacent areas The image illumination device according to claim 3, wherein the brightness of the image is controlled. The illumination means, fluorescent tubes, light emitting diodes, image lighting apparatus according to any one of claims 1, wherein 4 is an organic EL or inorganic EL. An image display means for displaying an image on a predetermined display surface in response to an input of an image signal, and not emitting light by itself;
The image illuminating device according to any one of claims 1 to 5 , which illuminates the display surface;
An image display device comprising: 7. The image display device according to claim 6 , wherein the image display means is a liquid crystal panel. Imaging device characterized by comprising an image display apparatus according to claim 6 or 7, wherein.

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