JP6541760B2 - Display device and control method of display device - Google Patents

Description

The present invention relates to a display device, and relates to control how the display device.

Conventionally, there is a technique of controlling (adjusting) the brightness of a display image (image displayed on the screen) by correcting the pixel value of the image data based on the shooting information of the image data (Japanese Patent Application Laid-Open No. 2008-101118).
Further, as a technique for controlling the light emission luminance of the backlight of the liquid crystal display device, based on the detection results of the backlight light sensor and the external light sensor, the change in display luminance due to the deterioration of the backlight and the influence of ambient light is suppressed. Thus, there is a technique for controlling the light emission luminance (Patent Document 2). The backlight light sensor is a sensor that detects backlight light (light from the backlight), and the outside light sensor is a sensor that detects outside light to the liquid crystal display device.

WO 2004/008755 JP 2008-9090A

  Here, in the case where image data to be displayed is image data generated by shooting, in order to realize an image display close to the impression of the subject at the time of shooting, the brightness of ambient light at the time of shooting is taken into consideration. It is preferable to control the display brightness.

  However, in the technology disclosed in Patent Document 1, since the influence of ambient light on the display device is not considered, the display brightness is changed by the ambient light. Therefore, an image display close to the impression of the subject at the time of shooting can not be realized with high accuracy.

  By combining the technology disclosed in Patent Document 1 and the technology disclosed in Patent Document 2, it is possible to suppress the change in display luminance due to the influence of the ambient light, and an image display closer to the impression of the subject at the time of shooting It can be realized.

  However, in the technique disclosed in Patent Document 1, the display luminance is controlled by correcting the pixel value of the image data. The pixel value has an upper limit value and a lower limit value. For this reason, the range of display luminance that can be controlled without causing blackout of a dark part or whiteout of a light part is limited to a narrow range. That is, if the pixel value is corrected so as not to cause blackening of a dark part or whiteout of a bright part, the dynamic range of display luminance is limited to a narrow range. Compared to that, the brightness of the ambient light for the subject at the time of shooting is various, and the dynamic range of the brightness of the subject is wide. Therefore, even if the technology disclosed in Patent Document 1 and the technology disclosed in Patent Document 2 are combined, it is not possible to accurately realize the image display close to the impression of the subject at the time of shooting.

  An object of the present invention is to provide a technology capable of realizing an image display close to the impression of a subject at the time of shooting with high accuracy.

The first aspect of the present invention is
A display device for displaying image data;
A first acquisition unit that acquires imaging information related to imaging conditions at the time of imaging of input image data;
A second acquisition unit configured to acquire environmental information on an installation environment of the display device;
Light emitting means,
Display means for displaying an image on a screen by modulating light from the light emitting means based on the input image data;
A determination unit that determines a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired by the first acquisition unit, and the environment information acquired by the second acquisition unit When,
Control means for controlling the light emission luminance of the light emission means to the target luminance determined by the determination means;
Have
The determination means adjusts the target brightness of the light emitting means so that when the brightness of the input image data is bright, the target brightness is lower than when the brightness is dark.
It is a display device characterized by the above.
The second aspect of the present invention is
A control method of a display device, comprising: light emitting means; and display means for displaying an image on a screen by modulating light from the light emitting means based on input image data,
A first acquisition step of acquiring imaging information on imaging conditions at the time of imaging of the input image data;
A second acquisition step of acquiring environment information on an installation environment of the control method of the display device;
A determination step of determining a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired in the first acquisition step, and the environment information acquired in the second acquisition step When,
A control system for controlling the light emission luminance of the light emitting means to the target luminance determined in the determination step
With step
Have
In the determining step, when the brightness of the input image data is bright, the target brightness of the light emitting means is adjusted so that the target brightness is lower than when the brightness is dark.
It is a control method of a display device characterized by things.

The third aspect of the present invention is
A display device for displaying image data;
A first acquisition unit that acquires imaging information related to imaging conditions at the time of imaging of input image data;
A second acquisition unit configured to acquire environmental information on an installation environment of the display device;
Light emitting means,
Display means for displaying an image on a screen by modulating light from the light emitting means based on the input image data;
A determination unit that determines a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired by the first acquisition unit, and the environment information acquired by the second acquisition unit When,
Control means for controlling the light emission luminance of the light emission means to the target luminance determined by the determination means;
Have
When the ratio of the area of the bright portion of the pixels of the input image data to the area of the image represented by the input image data is small, the determining unit determines that the ratio is small. Adjust the target brightness of the light emitting means so that the target brightness is higher than when it is large
It is a display device characterized by the above.
The fourth aspect of the present invention is
A control method of a display device, comprising: light emitting means; and display means for displaying an image on a screen by modulating light from the light emitting means based on input image data,
A first acquisition step of acquiring imaging information on imaging conditions at the time of imaging of the input image data;
A second acquisition step of acquiring environment information on an installation environment of the control method of the display device;
A determination step of determining a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired in the first acquisition step, and the environment information acquired in the second acquisition step When,
Controlling the light emission luminance of the light emitting means to the target luminance determined in the determination step;
Have
In the determining step, when the ratio of the area of a bright portion made up of pixels whose pixel values are equal to or larger than the threshold among the pixels of the input image data is smaller than the area of the image represented by the input image data. Adjust the target brightness of the light emitting means so that the target brightness is higher than when it is large
It is a control method of a display device characterized by things.

The fifth aspect of the present invention is
A display device for displaying image data;
A first acquisition unit that acquires imaging information related to imaging conditions at the time of imaging of input image data;
A second acquisition unit configured to acquire environmental information on an installation environment of the display device;
Display means for causing a light emitting means to emit light based on the input image data to display an image on a screen;
A determination unit that determines a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired by the first acquisition unit, and the environment information acquired by the second acquisition unit When,
Control means for controlling the light emission luminance of the light emission means to the target luminance determined by the determination means;
Have
The determination means adjusts the target brightness of the light emitting means so that when the brightness of the input image data is bright, the target brightness is lower than when the brightness is dark.
It is a display device characterized by the above.
The sixth aspect of the present invention is
A display device for displaying image data;
A first acquisition unit that acquires imaging information related to imaging conditions at the time of imaging of input image data;
A second acquisition unit configured to acquire environmental information on an installation environment of the display device;
Display means for causing a light emitting means to emit light based on the input image data to display an image on a screen;
A determination unit that determines a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired by the first acquisition unit, and the environment information acquired by the second acquisition unit When,
Control means for controlling the light emission luminance of the light emission means to the target luminance determined by the determination means;
Have
When the ratio of the area of the bright portion of the pixels of the input image data to the area of the image represented by the input image data is small, the determining unit determines that the ratio is small. Adjust the target brightness of the light emitting means so that the target brightness is higher than when it is large
It is a display device characterized by the above.
The seventh aspect of the present invention is
It is a control method of a display apparatus which has a display means which makes a light emission means emit light based on input image data, and displays an image on a screen,
A first acquisition step of acquiring imaging information on imaging conditions at the time of imaging of the input image data;
A second acquisition step of acquiring environment information on an installation environment of the control method of the display device;
A determination step of determining a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired in the first acquisition step, and the environment information acquired in the second acquisition step When,
Controlling the light emission luminance of the light emitting means to the target luminance determined in the determination step;
Have
In the determining step, when the brightness of the input image data is bright, the target brightness of the light emitting means is adjusted so that the target brightness is lower than when the brightness is dark.
It is a control method of a display device characterized by things.
The eighth aspect of the present invention is
It is a control method of a display apparatus which has a display means which makes a light emission means emit light based on input image data, and displays an image on a screen,
A first acquisition step of acquiring imaging information on imaging conditions at the time of imaging of the input image data;
A second acquisition step of acquiring environment information on an installation environment of the control method of the display device;
A determination step of determining a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired in the first acquisition step, and the environment information acquired in the second acquisition step When,
Controlling the light emission luminance of the light emitting means to the target luminance determined in the determination step;
Have
In the determining step, when the ratio of the area of a bright portion made up of pixels whose pixel values are equal to or larger than the threshold among the pixels of the input image data is smaller than the area of the image represented by the input image data. Adjust the target brightness of the light emitting means so that the target brightness is higher than when it is large
It is a control method of a display device characterized by things.

  According to the present invention, it is possible to realize an image display close to the impression of the subject at the time of shooting with high accuracy.

A figure showing an example of functional composition of a display device concerning Example 1 A diagram showing an example of a configuration etc. of an input image file according to the first embodiment FIG. 6 is a diagram showing an example of the format of image data according to the first embodiment A figure showing an example of functional composition of a separation part concerning Example 1 A figure showing an example of functional composition of a target luminosity deciding part concerning Example 1 FIG. 7 is a diagram showing an example of a method of correcting the reproduction target luminance according to the first embodiment. The figure which shows an example of the relationship between the PWM value which concerns on Example 1, and light-emitting luminance. FIG. 6 is a diagram showing an example of light emission luminance control according to the first embodiment. A figure showing an example of functional composition of a display concerning Example 2 The figure which shows an example of a function structure of the target brightness | luminance determination part which concerns on Example 2. The figure which shows an example of the determination method of the bright-part correction factor based on Example 2, and a dark-part correction factor. A figure showing an example of functional composition of a display concerning Example 3 A figure showing an example of functional composition of an image processing section concerning Example 3

Example 1
Hereinafter, the display device according to the first embodiment of the present invention and the control method thereof will be described with reference to the drawings.
Note that although an example in which the display device is a transmissive liquid crystal display device is described in this embodiment, the display device is not limited to the transmissive liquid crystal display device. The display device may be a display device having an independent light source. For example, the display device may be a reflective liquid crystal display device, a liquid crystal projector that projects an image on a screen, or the like. The display device may be a display device using another element capable of controlling the transmittance of light from the backlight instead of the liquid crystal element. For example, the display device may be a MEMS shutter type display that uses a micro electro mechanical system (MEMS) shutter instead of a liquid crystal element.

FIG. 1 is a block diagram showing an example of a functional configuration of a display device according to the present embodiment.
The display device according to the present embodiment includes a separation unit 101, an image processing unit 102, a display unit 111, a target brightness determination unit 108, a backlight module unit 109, a light emission brightness control unit 110, and the like. The display unit 111 includes a liquid crystal panel unit 103, a panel correction unit 104, a panel control unit 105, a scan signal supply unit 106, a data signal supply unit 107, and the like.

An image file such as a still image file or a moving image file, image data subjected to a decoding process, and the like are input to the separation unit 101 from an external apparatus. The external device is a personal computer, a digital camera, a smartphone or the like. In this embodiment, an example in which an image file is input from an external device will be described. Hereinafter, the image file input to the separation unit 101 will be referred to as an “input image file”.
The image file and the image data may be acquired from a storage medium provided inside the display device. The storage medium is a magnetic disk, an optical disk, a non-volatile memory, or the like.

  FIG. 2A is a view for explaining the data structure of the image file. Image files such as still image files and moving image files are composed of an image data portion and a header portion. The image data portion stores image data (for example, RGB values for each pixel). Hereinafter, the image data stored in the image data portion of the input image file is referred to as "input image data". Header data is stored in the header section. In this embodiment, it is assumed that the image data stored in the image data unit is the image data generated by photographing. In the header portion, header data including shooting information on shooting conditions at the time of shooting of the image data stored in the image data portion is stored. The shooting information includes, for example, information indicating at least one of an ambient light level at shooting, an ISO sensitivity, a shutter speed, an aperture value, and a shooting mode. As described above, it is general that photographing information on photographing conditions at the time of photographing is added to photographed image data. Examples of data formats of image files include OpenEXR, Tagged Image File Format (TIFF), Joint Photographic Experts Group (JPEG), Moving Picture Experts Group (MPEG), and Audio Video Interleave (AVI).

  FIG. 2B is a conceptual diagram for describing a procedure for adding ambient light level information (information indicating the ambient light level) as imaging information to an image file.

  The still image shooting or moving image shooting of the subject is performed by the camera 201, and the shot image data is recorded on the removable media 202 in the camera 201. Examples of the removable media 202 include a flash memory and an SD card.

Also, at the time of shooting a subject with the camera 201 (during shooting or after shooting), the photographer or the assistant measures the ambient light level with the measuring device 204. Specifically, the ambient light level is measured by placing a whiteboard that reflects light near the subject and measuring the reflected light of the whiteboard with the measuring instrument 204. Then, a measured value of the ambient light level is input to the camera 201 using a PC (personal computer) 203 connected to the camera 201, and the measured value is recorded on the removable medium 202. The camera 201 and the PC 203 are connected to each other using a USB cable or the like. The unit of the measurement value is, for example, cd (candela) / m ² .
The camera 201 and the PC 203 may be connected to each other by wire or may be connected to each other wirelessly.

  After the above processing, the captured image data is stored in the image data portion, and the image file in which the header data including the measured value of the ambient light level is stored in the header portion is recorded (generated) on the removable medium 202 .

The image file recorded on the removable media 202 is input to the display device 100 by removing the removable media 202 from the camera 201 and mounting the removable media 202 on the display device 100 according to the present embodiment.
Alternatively, the camera 201 and the display device 100 may be connected to each other using a USB cable or the like, and an image file may be input from the camera 201 to the display device 100. In that case, the camera 201 may be provided with a non-removable storage medium instead of the removable medium 202. The camera 201 and the display device 100 may be wired to each other or may be wirelessly connected to each other.
If the camera 201 does not have the recording function, the camera 201 and the recorder may be connected to each other, the recorder and the PC 203 may be connected to each other, and the image file may be recorded on the removable medium in the recorder. The recorder is a device having a function of recording received information (image data and ambient light level) in a storage medium.

The separation unit 101 acquires input image data and imaging information regarding imaging conditions at the time of imaging of the input image data, and outputs the acquired input image data and imaging information. Specifically, the separation unit 101 extracts input image data and imaging information from an input image file, and outputs the extracted input image data and imaging information. In this embodiment, input image data is converted to raster image data and output.
Note that acquisition of input image data and acquisition of imaging information (first acquisition) may be performed by different functional units.

  FIG. 3 is a diagram for explaining an example in which image data of n × m pixels is converted into image data of raster format. The raster format image data is a series of continuous pixel data strings obtained by sequentially scanning an image from the first line to the m-th line. The separation unit 101 adds a vertical synchronization signal indicating the start of each frame of image data and a horizontal synchronization signal indicating the start of each line to input image data, and outputs the image data to which the synchronization signal is added.

FIG. 4 is a block diagram showing an example of a functional configuration of the separation unit 101. As shown in FIG.
The separation unit 101 includes an image file memory unit 131, a system control unit 132, an image file decoder unit 133, a header data memory unit 134, an image data memory unit 135, a raster data conversion unit 136, and the like.

  The image file memory unit 131 stores an input image file. When storage of the input image file is completed, the image file memory unit 131 transmits an image file memory completion signal to the system control unit 132.

The image file decoder unit 133 acquires an input image file from the image file memory unit 131. Then, in response to the input of the decoding start signal from the system control unit 132, the image file decoder unit 133 decodes the acquired input image file. Specifically, the image file decoder unit 133 separates the acquired input image file into a header portion and an image data portion, extracts header data from the header portion, and extracts input image data from the image data portion. When the decoding is completed, the image file decoder unit 133 outputs the header data to the header data memory unit 134 and outputs the input image data to the image data memory unit 135. The system control unit 132 outputs a decoding start signal after receiving the image file memory completion signal.

  The header data memory unit 134 stores the header data received from the image file decoder unit 133. When the storage of the header data is completed, the header data memory unit 134 outputs the stored header data to the system control unit 132.

  The image data memory unit 135 stores input image data received from the image file decoder unit 133. When storage of the input image data is completed, the image data memory unit 135 outputs an image data memory completion signal to the system control unit 132.

  The system control unit 132 controls processing start timing of the other functional units included in the separation unit 101. The system control unit 132 also extracts imaging information from the header data received from the header data memory unit 134, and outputs the extracted imaging information.

A specific example of the method of extracting imaging information will be described. An example in which the data format of the image file is the OpenEXR format will be described below.
FIG. 2C is a diagram showing an example of data in the header portion of the OpenEXR format. The data of the header part consists of an attribute name (attribute name), an attribute type (attribute type), an attribute size (attribute size), and an attribute value (attribute value).
The attribute name (attribute name) indicates the type of imaging information. In the case of information indicating the brightness (ambient light level) of ambient light at the time of shooting, “white luminance” is described by an ASCII code. An attribute type (attribute type) indicates a data format of an attribute value (attribute value) described later. In the integer format, "int" is described. The attribute size (attribute size) represents the data size (Byte) of an attribute value (attribute value) described later. FIG. 2C shows an example of 4 bytes. The attribute value (attribute value) represents a value of shooting information (ambient light level, ISO sensitivity, shutter speed, aperture value, shooting mode).
When ambient light level information is extracted from the header as shooting information, a data group whose attribute name (attribute name) is "white luminance" is determined. Then, the value of the attribute value (attribute value) in the determined data group is extracted as ambient light level information.

  The raster data conversion unit 136 acquires input image data from the image data memory unit 135. Then, in response to the conversion start signal being input from the system control unit 132, the raster data conversion unit 136 adds the synchronization signal to the acquired input image data, thereby adding the input image data to the image data of raster format. Convert. When the conversion is completed, the raster data conversion unit 136 outputs the image data of the raster format (input image data to which the synchronization signal is added). The system control unit 132 outputs a conversion start signal after receiving the image data memory completion signal.

It returns to the explanation of FIG.
The image processing unit 102 performs predetermined image processing on input image data (input image data in raster format) received from the separation unit 101, and outputs the image data subjected to the predetermined image processing as display image data. Do. The predetermined image processing includes data format conversion processing, IP conversion processing, enlargement / reduction processing, edge enhancement processing, gain adjustment, offset adjustment, color adjustment, limit processing and the like. As the predetermined image processing, one type of image processing may be performed, or a plurality of types of image processing may be performed. The data format conversion process is a process of converting image data into image data of a data format suitable for the process in the display unit 111. For example, the data format conversion process is a process of converting image data into image data of the number of bits corresponding to the display unit 111. When the data format of the image data corresponding to the display unit 111 is an 8-bit unsigned integer type, the image data is converted into 8-bit unsigned integer type image data by data format conversion processing.
The image processing unit 102 may omit the predetermined image processing and output input image data as display image data.

  The backlight module unit 109 is a light emitting unit that emits light to the back surface of the liquid crystal panel unit 103. In the present embodiment, the backlight module unit 109 has a plurality of light sources capable of individually controlling the light emission luminance. The light source comprises one or more light emitting members. As a light emitting member, an LED, an organic EL element, a cold cathode tube, etc. can be used, for example.

The display unit 111 displays an image on the screen by modulating the light from the backlight module unit 109 based on the display image data.
As shown in FIG. 1, input image data is input to the display unit 111 via the image processing unit 102. Therefore, in the present embodiment, the light from the backlight module unit 109 is modulated based on the input image data that has been subjected to the processing by the image processing unit 102.

  The liquid crystal panel unit 103 has a plurality of liquid crystal elements arranged in a matrix, and in each liquid crystal element, data lines wired in a direction perpendicular to scanning lines wired in a horizontal direction are placed. The transmittance of each liquid crystal element of the selected line is controlled by selecting the line with the scanning line and giving the image data of the liquid crystal element from the data line to each liquid crystal element of the selected line. The transmittance of all liquid crystal elements is controlled by performing the above processing for all lines. Then, the light from the backlight module unit 109 is transmitted through each liquid crystal element to display an image on the screen.

The panel correction unit 104 performs distortion correction processing on the image data input to the panel correction unit 104, and outputs the image data (panel image data) after the distortion correction processing to the panel control unit 105. The distortion correction processing is processing for correcting distortion of the characteristic of the liquid crystal panel unit 103 based on the ideal characteristic of the transmittance of the liquid crystal element with respect to image data.
Further, the panel correction unit 104 outputs a synchronization signal of panel image data (that is, a synchronization signal of display image data) to the panel control unit 105.

  The panel control unit 105 generates a scan signal and a line data signal based on the panel image data and its synchronization signal (vertical synchronization signal and horizontal synchronization signal). Then, the panel control unit 105 outputs the generated scanning signal and line data signal. The scanning signal is a signal for selecting the lines of the liquid crystal panel unit 103 sequentially from the top in one line unit, and the line data signal is a signal for supplying image data to each liquid crystal element of the line selected by the scanning signal. is there.

  The scanning signal supply unit 106 sequentially selects the lines of the liquid crystal panel unit 103 based on the scanning signal from the panel control unit 105, and enables supply of image data to liquid crystal elements of the selected line.

  The data signal supply unit 107 supplies the image data of the liquid crystal element to each liquid crystal element of the line selected by the scanning signal supply unit 106 based on the line data signal from the panel control unit 105.

The target luminance determination unit 108 acquires environment information on the installation environment of the display device. In addition, the target brightness determination unit 108 receives the imaging information output from the separation unit 101. Then, the target brightness determination unit 108 determines the target brightness of the backlight module unit 109 based on the shooting information and the environment information, and outputs the determined target brightness.
Note that acquisition of environmental information (second acquisition) and determination of target brightness may be performed by different functional units.

FIG. 5 is a block diagram showing an example of a functional configuration of the target luminance determination unit 108. As shown in FIG.
The target luminance determination unit 108 includes a reproduction luminance determination unit 121, a visual range estimation unit 122, a correction factor determination unit 123, a correction unit 124, and the like.

The reproduction luminance determination unit 121 determines the target luminance of the backlight module unit 109 based on the imaging information received from the separation unit 101, and outputs the determined target luminance. Hereinafter, the target luminance determined by the reproduction luminance determination unit 121 will be referred to as “reproduction target luminance”. In this embodiment, the ambient light level at the time of shooting of the input image data is determined from the ambient light level information, and the reproduction target luminance is determined according to the determined ambient light level. Specifically, when the ambient light level at the time of shooting the input image data is high, the reproduction target brightness is adjusted so that the reproduction target brightness is higher than when the ambient light level is low. In the present embodiment, the ambient light level at the time of shooting of the input image data is set as the reproduction target luminance. Therefore, when the ambient light level at the time of shooting of the input image data is Lx [cd / m ² ], the reproduction target luminance is also Lx [cd / m ² ].
The method of determining the reproduction target luminance is not limited to the above method. For example, the reproduction target luminance may be determined according to other information such as ISO sensitivity, shutter speed, aperture value, shooting mode and the like. Further, the reproduction target luminance may be determined in accordance with a combination of a plurality of pieces of information. For example, the reproduction target luminance may be determined according to the combination of the ISO sensitivity, the shutter speed, and the aperture value. Further, the ambient light level may be estimated from information indicating at least one of the ISO sensitivity, the shutter speed, the aperture value, and the imaging mode, and the reproduction target luminance may be determined according to the estimated value of the ambient light level.

  In the present embodiment, the reproduction target luminance is corrected based on the following concept.

  It is known that the luminance range visible to humans with high visual sensitivity changes according to the adaptation luminance, and the relationship between light stimulus and visual sensitivity is modeled using an S-type function such as a Hill function, for example. There is. A light stimulus is a stimulus that a human receives when light with a certain luminance enters the human eye. Visual sensitivity is human sensitivity to the brightness of light incident on the human eye (visible brightness). The visual sensitivity is high for the range of visible brightness where the light stimulus changes significantly with respect to the change in visible brightness, and the visual sensitivity is high for the range of visible brightness where the light stimulus does not change much with respect to the change in visible brightness. The sensitivity is low.

FIG. 6A is a diagram showing an example of the relationship between the visible luminance, the light stimulation, and the visual environment. The viewing environment is the environment around humans when they look at an object. That is, when a human looks at a display image (image displayed on the screen of the display device), the viewing environment can also be referred to as the installation environment of the display device. Also, when a human looks at a display image, the visual recognition luminance can also be referred to as luminance on the screen (display luminance).
A curve indicated by a broken line in FIG. 6A indicates the visual characteristic when the adaptation luminance is low, and corresponds to the visual characteristic in a dark visual environment. The visual characteristic is a characteristic that indicates the relationship between the visible luminance and the light stimulus, and can also be referred to as a characteristic that indicates the relationship between the visible luminance and the visual sensitivity.
A curve indicated by an alternate long and short dash line in FIG. 6A indicates the visual characteristic when the adaptation luminance is high, and corresponds to the visual characteristic in a bright visual environment.
The curve shown by the solid line in FIG. 6A shows the visual characteristic when the adaptation luminance is a moderate value, and corresponds to the visual characteristic under a moderate brightness visual environment. Specifically, the curve shown by the solid line in FIG. 6A is the brightness of the viewing environment corresponding to the viewing characteristics shown by the broken line and the brightness of the viewing environment corresponding to the viewing characteristics shown by the one-dot chain line. Fig. 6 shows visual characteristics under a light visual environment between the brightness and the brightness.

As shown in FIG. 6A, when the brightness of the viewing environment is low, the visual sensitivity to high visible brightness is reduced compared to the case where the brightness of the viewing environment is appropriate brightness, and thus high brightness It turns out that the object becomes difficult to see. That is, it is understood that when the ambient light level in the installation environment of the display device is low, it is difficult to see a high-brightness display image.
Further, from FIG. 6A, when the brightness of the viewing environment is high, the visual sensitivity to low visible brightness is lowered compared to the case where the brightness of the viewing environment is appropriate brightness, and the low brightness is low. It becomes clear that it becomes difficult to see an object. That is, it can be seen that when the ambient light level in the installation environment of the display device is high, it is difficult to see a low brightness display image.
Therefore, when the ambient light level in the installation environment of the display device is low, it is desirable to reduce the display brightness to display an image of display brightness with high visual sensitivity. And when the ambient light level in the installation environment of a display apparatus is high, it is desirable to raise display brightness and to display the image of display brightness with high visual sensitivity.

  Therefore, when the ambient light level in the installation environment of the display device is high, the target brightness determination unit 108 sets the target brightness of the backlight module unit 109 so that the target brightness is higher than when the ambient light level is low. adjust. Specifically, when the ambient light level in the installation environment of the display device is high, the reproduction target brightness is corrected such that the target brightness after correction is higher than when the ambient light level is low.

The visual range estimation unit 122 acquires environment information related to the installation environment of the display device.
Specifically, the visual range estimation unit 122 acquires information indicating the ambient light level in the installation environment of the display device as the environmental information. The ambient light level in the installation environment of the display device is, for example, a value detected using a luminance sensor provided in the display device (such as the periphery of the screen).

  Then, based on the acquired environment information, the visual range estimation unit 122 estimates a visual range which is a range of display luminance in which good visual recognition is possible. Hereinafter, the visual range estimated by the visual range estimation unit 122 will be referred to as “estimated visual range”. In the present embodiment, as shown in FIG. 6B, information (table or function) representing the correspondence between the ambient light level and the maximum luminance value and the minimum luminance value of the visual range is prepared in advance. Then, the visual range estimation unit 122 determines the maximum luminance value and the minimum luminance value corresponding to the ambient light level indicated by the acquired environment information, using the information indicating the correspondence relationship. Thereafter, the visual range estimation unit 122 outputs the determined maximum luminance value and the minimum luminance value as the maximum luminance value and the minimum luminance value of the estimated visual range.

Although the example in which the maximum luminance value and the minimum luminance value of the visual range are estimated has been described in the present embodiment, the present invention is not limited thereto. For example, the central luminance of the visual range and the width of the visual range may be estimated. Any value may be estimated as long as the visual range can be specified.
Note that acquisition of environmental information and estimation of the visual range may be performed by different functional units.
The environmental information is not limited to the information indicating the ambient light level. For example, the environment information may be information indicating the installation location (living room, bedroom, meeting room, etc.) of the display device. When the environmental information is information other than the information indicating the environmental light level, the environmental light level may be estimated based on the environmental information.

The correction factor determination unit 123 determines the correction factor of the target brightness based on the reproduction target brightness and the maximum brightness value and the minimum brightness value of the estimated visual range. Then, the correction factor determination unit 123 outputs the determined correction factor.
The correction factor determination unit 123 determines the upper limit correction factor from the reproduction target luminance and the maximum luminance value of the estimated visual range. The upper limit correction rate is a correction rate that corrects the reproduction target luminance so that the display luminance does not greatly exceed the maximum luminance value of the estimated visual range, and the ratio of the reproduction target luminance to the maximum luminance value of the estimated visual range exceeds 1 Correction factor to reduce (reduce) the reproduction target luminance. Specifically, as shown in FIG. 6C, information (a function or a table) representing the correspondence between the ratio of the reproduction target luminance to the maximum luminance value of the estimated visual range and the upper limit correction rate is prepared in advance. The upper limit correction rate is determined using the information.
Similarly, the correction factor determination unit 123 determines the lower limit correction factor from the reproduction target luminance and the minimum luminance value of the estimated visual range. The lower limit correction rate is a correction rate that corrects the reproduction target luminance so that the display luminance does not fall far below the minimum luminance value of the estimated visual range, and the ratio of the reproduction target luminance to the maximum luminance value of the estimated visual range exceeds a threshold Correction factor which increases (expands) the reproduction target luminance. Specifically, as shown in FIG. 6C, information (a function or a table) representing the correspondence between the ratio of the reproduction target luminance to the minimum luminance value of the estimated visual range and the lower limit correction rate is prepared in advance. The lower limit correction factor is determined using the information. The threshold is, for example, a value determined based on the maximum contrast ratio and the maximum dynamic range of an image that can be displayed by the liquid crystal panel unit 103. Specifically, when the maximum contrast ratio is 1000: 1, 1/1000 is used as the threshold.
Then, the correction factor determination unit 123 calculates the correction factor by multiplying the determined upper limit correction factor and the lower limit correction factor.

The correction unit 124 corrects the reproduction light emission luminance by multiplying the reproduction target luminance by the correction factor, and outputs the corrected target luminance. The processing of the correction unit 124 can correct the reproduction target luminance so that the display luminance approaches the estimated visual range.
The method of correcting the reproduction target luminance is not limited to the above method. The reproduction target luminance may be corrected in any way as long as the display luminance can be brought close to the estimated visual range. In other words, the reproduction target luminance may be corrected in any way as long as the display luminance can be prevented from largely deviating from the estimated visual range. For example, the reproduction target luminance may be corrected such that the corrected target luminance has a value inside the estimated visual range. Specifically, the reproduction target luminance may be corrected such that the corrected target luminance matches the maximum luminance value of the estimated visual range.
In order to improve the visibility of the display image, it is preferable to correct the reproduction target luminance so that the display luminance has a value inside the estimated visual range.

It returns to the explanation of FIG.
The light emission luminance control unit 110 controls the light emission luminance of the backlight module unit 109 (the light source of the backlight module unit 109) to the target luminance (target luminance after correction) determined by the target luminance determination unit 108. Specifically, the light emission luminance control unit 110 generates a DC current control signal and a PWM signal in accordance with the target luminance determined by the target luminance determination unit 108. Then, the light emission luminance control unit 110 drives and controls each light source with the generated direct current control signal and the PWM signal. The direct current control signal is a signal indicating the value (current value) of the current supplied to the light source, and the PWM signal is a signal indicating the length of the supply period of the current supplied to the light source. In the present embodiment, processing for controlling ON / OFF of supply of current to the light source (ON / OFF control processing) is periodically performed. The PWM signal indicates the ratio (duty ratio) of the length of the current supply period to the length of one period of the ON / OFF control process.
Note that the light emission luminance of the light source can also be controlled by controlling the value of the voltage applied to the light source and the application period of the voltage.

FIG. 7 is a diagram illustrating the relationship between the PWM value (duty ratio) and the light emission luminance [cd / m ² ] of the light source when the light source is driven with the standard current value and the standard 1/10 current value. is there. The emission brightness of the light source is determined by the current value for driving the light source and the PWM value. In the present embodiment, the light emission luminance control unit 110 determines the current value and the PWM value corresponding to the target luminance based on the relationship as shown in FIG. 7, and determines the DC current control signal indicating the determined current value Generate a PWM signal indicating the selected PWM value. For example, when the target luminance is 500 [cd / m ² ], the light source may be driven at a standard current value, and the PWM value may be 50%. Further, when the target luminance is 20 [cd / m ² ], the light source may be driven at a current value of 1/10 of the standard, and the PWM value may be 20%. Although there may be a plurality of combinations of current values and PWM values for controlling the light emission luminance to the target luminance, in this case, the current value and the PWM value may be determined in consideration of control accuracy and the like. By controlling both the current value and the PWM value, it is possible to control the emission brightness more finely than in the case of controlling one. In addition, by controlling both the current value and the PWM value, it is possible to control the light emission luminance in a wider dynamic range as compared with the case of controlling one.

FIG. 8 is a diagram for explaining light emission luminance control according to the present embodiment.
The horizontal axis in FIG. 8 indicates the ambient light level at the time of shooting of the input image data, and the vertical axis indicates the light emission luminance of the backlight module unit 109. FIG. 8 shows the relationship between the ambient light level at the time of shooting of the input image data and the light emission luminance of the backlight module unit 109 for a plurality of installation environments (installation environment of the display device) having different environmental light levels. There is. Specifically, a solid line indicates a relationship (characteristic) under a visual environment of appropriate brightness, a broken line indicates a relationship under a dark visual environment, and a dashed dotted line indicates a relationship under a bright visual environment.
As shown in FIG. 8, in the present embodiment, the light emission luminance of the backlight module unit 109 is controlled such that the light emission luminance becomes higher as the ambient light level at the time of photographing of the input image data becomes higher. Furthermore, in the present embodiment, the light emission luminance is controlled in consideration of the brightness of the viewing environment (the installation environment of the display device). Specifically, as shown in FIG. 8, when the ambient light level at the time of shooting of the input image data is high, the back light module is such that the lower the ambient light level in the installation environment of the display device, the lower the light emission luminance. The light emission luminance of the unit 109 is controlled. Further, when the ambient light level at the time of shooting the input image data is low, the light emission brightness of the backlight module unit 109 is controlled such that the light emission brightness is higher as the ambient light level in the installation environment of the display device is higher. As a result, the display image can be viewed with good visual sensitivity, and image display close to the impression of the subject at the time of shooting can be realized with high accuracy.

  As described above, according to the present embodiment, since the light emission luminance of the backlight module unit 109 is controlled based on the photographing information and the environment information, the image display close to the impression of the subject at the time of photographing is accurately realized. be able to.

  In this embodiment, an example in which the light emission luminance of the backlight module unit is controlled in consideration of the ambient light level in the installation environment of the display device has been described. However, an image is considered in consideration of the ambient light level in the installation environment of the display device Data may be corrected. Specifically, the luminance of the image data may be corrected by the difference between the target luminance before correction (reproduction target luminance) and the target luminance after correction. According to such a configuration, it is easy to cause white crushing and black crushing of the image, but it is possible to perform image display close to the impression of the subject at the time of shooting.

  In this embodiment, an example in which the final target brightness is determined by the two-step process of determining the target brightness based on the shooting information and correcting the determined target brightness based on the environment information has been described. But it is not limited to this. For example, the final target brightness may be determined from the combination of the shooting information and the environment information in a one-step process using, for example, information indicating the correspondence between the combination of the shooting information and the environment information and the target brightness. . The final target brightness may be determined by a two-step process of determining the target brightness based on the environment information and correcting the determined target brightness based on the imaging information.

In the present embodiment, the visual range is estimated based on the environmental information, and the target luminance (the target luminance determined based on the imaging information) is corrected based on the estimated visual range. It is not limited to this. For example, the target brightness may be corrected without estimating the visual range. Specifically, the correction factor may be determined from the environmental information using information indicating the correspondence between the environmental information and the correction factor, and the target luminance may be corrected with the determined correction factor.

Example 2
Hereinafter, a display device according to a second embodiment of the present invention and a control method thereof will be described with reference to the drawings. In the first embodiment, an example in which the target brightness is determined based on the shooting information and the environment information has been described. However, the display luminance depends not only on the light emission luminance of the backlight module portion and the ambient light level in the installation environment of the display device but also on the image data. Thus, in the present embodiment, an example will be described in which the target luminance is determined based on the photographing information, the environment information, and the brightness of the input image data.

FIG. 9 is a block diagram showing an example of a functional configuration of the display device according to the present embodiment.
The display device according to the present embodiment includes a separation unit 101, an image processing unit 102, a display unit 111, an image determination unit 211, a target brightness determination unit 208, a backlight module unit 109, a light emission brightness control unit 110, and the like.
The operations of the separation unit 101, the image processing unit 102, the display unit 111, the backlight module unit 109, and the light emission luminance control unit 110 are the same as in the first embodiment.

  The image determination unit 211 determines the brightness of input image data. In this embodiment, the brightness of the input image data after the processing by the image processing unit 102, that is, the brightness of the display image data is determined. Specifically, the image determining unit 211 determines the total area of the area including pixels whose pixel values are equal to or less than the first threshold among the pixels of the display image data as the dark area (dark area determination). In addition, the image determination unit 211 determines the total area of the area including pixels in which the pixel value is equal to or more than the second threshold among the pixels of the display image data as the bright area (bright area determination). Then, the image determination unit 211 outputs the determined dark area and bright area. The first threshold is, for example, a pixel value at which the ratio of the obtainable pixel value of the display image data to the maximum value is 20%. The second threshold is, for example, a pixel value at which the ratio of the obtainable pixel value of the display image data to the maximum value is 80%.

The first threshold and the second threshold are not limited to the values described above. The first threshold and the second threshold may be higher or lower than the values described above. The first threshold and the second threshold may be predetermined fixed values, or may be values that can be changed by the user. The first threshold and the second threshold may be the same value.
Note that the method of determining the brightness of the image data is not limited to the above method. For example, image data to be determined may be converted into luminance data by performing gamma conversion processing or the like, and the brightness may be determined using the luminance data. Further, the brightness of the input image data before the processing by the image processing unit 102, that is, the brightness of the input image data output from the separation unit 101 may be determined. In addition, information such as a luminance histogram of image data, a representative luminance value, and luminance dispersion may be acquired as a determination result. The representative luminance value is, for example, the maximum value, the minimum value, the average value, the mode value, or the median value of the luminance values of the image data. Only one of the dark area determination and the bright area determination may be performed.

The target brightness determination unit 208 determines the target brightness of the backlight module unit 109 based on the brightness of the input image data, the shooting information, and the environment information.
The relationship between the shooting information and the target brightness, and the relationship between the environment information and the target brightness are the same as in the first embodiment.

When the brightness of the input image data is bright, the brightness of the display image may be higher than the brightness at the time of shooting. Further, when the brightness of the input image data is dark, it is conceivable that the brightness of the display image is lower than the brightness at the time of shooting. Therefore, in the present embodiment, when the brightness of the input image data is high, the target brightness determination unit 208 sets the target brightness of the backlight module unit 109 so that the target brightness is lower than when the brightness is low. Adjust the

  Specifically, when the light area is small (when the dark area is large), it is conceivable that the display brightness is lower than the brightness at the time of photographing in most of the image area. If the input image data is small, it can be said that the input image data is dark. When the dark area is small (when the light area is large), the display brightness may be higher in most image areas than the brightness at the time of shooting. Therefore, when the dark area is small, It can be said that this corresponds to the case where the brightness of the input image data is high. Therefore, in the present embodiment, as the adjustment of the target brightness based on the brightness of the input image data, the adjustment of the target brightness based on the bright area and the dark area is performed.

  The method of adjusting the target brightness based on the brightness of the input image data is not limited to the method using the bright area and the dark area. If the target brightness of the backlight module unit 109 is adjusted so that the target brightness is lower when the brightness of the input image data is bright than when the brightness is dark, the target brightness is adjusted May be As described above, since various types of information can be considered as information obtained as the determination result of the brightness of the input image data, the target luminance may be adjusted by a method according to the type of information obtained as the determination result. Alternatively, only one of the adjustment of the target brightness based on the bright area and the adjustment of the target brightness based on the dark area may be performed.

FIG. 10 is a block diagram showing an example of a functional configuration of the target luminance determination unit 208 according to the present embodiment.
The target luminance determination unit 208 includes a reproduction luminance determination unit 121, a visual range estimation unit 122, a correction factor determination unit 223, a correction unit 124, and the like.
The operations of the reproduction luminance determination unit 121, the visual range estimation unit 122, and the correction unit 124 are the same as in the first embodiment.

  The correction factor determination unit 223 determines the upper limit correction factor by performing the following process.

First, when the ratio (bright area ratio) of the bright area to the area of the image represented by the input image data (display image data) is small, the correction factor determination unit 223 compares the target luminance with that when the ratio is large. Correct the reproduction target brightness so that Thereby, the target luminance for determining the upper limit correction factor is determined.
In the present embodiment, as shown in FIG. 11, information (table or function) representing the correspondence between the bright area ratio and the bright area correction rate is prepared in advance, and the bright area correction rate is determined using the information. Ru. Then, the target luminance for determining the upper limit correction factor is determined by multiplying the reproduction target luminance by the bright area correction factor. When the information shown in FIG. 11 is used, it is determined that the brightness of the input image data is dark when the light portion ratio is smaller than the threshold, and the reproduction target luminance is lower so that the target luminance decreases as the light portion ratio decreases. It is corrected. The threshold may be any value as long as it can be determined whether the brightness of the input image data is dark.
Then, based on the target luminance (target luminance for determining the upper limit correction rate) determined above and the maximum luminance value of the estimated visual range, the correction factor determination unit 223 performs the upper limit correction in the same manner as in the first embodiment. Determine the rate. As a result, when the light area ratio is small, a higher upper limit correction rate is determined as compared to the case where the light area ratio is large.

Further, the correction factor determination unit 223 determines the lower limit correction factor by performing the following process.
First, when the ratio (dark area ratio) of the dark area to the area of the image represented by the input image data (display image data) is small, the correction factor determination unit 223 has a higher target luminance than when the ratio is large. The reproduction target luminance is corrected to be Thereby, the target luminance for determining the lower limit correction factor is determined.
In the present embodiment, as shown in FIG. 11, information (table or function) representing the correspondence between the dark area ratio and the dark area correction rate is prepared in advance, and the dark area correction rate is determined using the information. Then, the target luminance for dark area correction factor determination is determined by multiplying the reproduction target luminance by the dark area correction factor. When the information shown in FIG. 11 is used, it is determined that the brightness of the input image data is bright when the dark area ratio is smaller than the threshold, and the reproduction target brightness is corrected such that the target brightness increases as the dark area ratio decreases. Ru. The threshold may be any value as long as it can be determined whether the brightness of the input image data is bright. The threshold used in determining the dark area correction factor may be the same as or different from the threshold used in determining the bright area correction factor.
Then, based on the target luminance (target luminance for determining the lower limit correction rate) determined above and the minimum luminance value of the estimated visual range, the correction factor determination unit 223 performs the lower limit correction in the same manner as in the first embodiment. Determine the rate. Thereby, when the dark area ratio is small, a lower upper limit correction rate is determined as compared with the case where the dark area ratio is large.

  Then, the correction factor determination unit 223 determines the correction factor by multiplying the determined upper limit correction factor and the lower limit correction factor, and outputs the determined correction factor. As described above, since the upper limit correction factor and the lower limit correction are determined in consideration of the brightness of the input image data, the correction factor taking into account the brightness of the input image data (the upper limit correction factor and the lower limit correction factor are multiplied Correction factor) can be obtained. Then, it is possible to obtain the target brightness in consideration of the brightness of the input image data as the final target brightness. Specifically, it is possible to adjust the target brightness of the backlight module unit 109 so that when the dark area ratio is small, the target brightness is lower than when the dark area ratio is large. In addition, when the bright portion ratio is small, it is possible to adjust the target brightness of the backlight module unit 109 so that the target brightness is higher than when the bright portion ratio is large.

  As described above, according to the present embodiment, the light emission luminance of the backlight module unit 109 is controlled in consideration of the brightness of the input image data in addition to the photographing information and the environment information. As a result, it is possible to more accurately realize the image display close to the impression of the subject at the time of shooting.

  In the present embodiment, the final target luminance is determined by the following method. That is, the reproduction target luminance is determined based on the photographing information, and the reproduction target luminance is corrected based on the brightness of the input image data, thereby determining the correction factor determination target luminance. Then, the correction rate was determined based on the target brightness for determining the correction rate and the environmental information, and the reproduction target brightness was corrected with the determined correction rate to determine the final target brightness. However, the method of determining the final target luminance is not limited to this. For example, the target brightness is determined based on at least one of the imaging information, the environment information, and the input image data, and the determined target brightness is corrected based on the remaining information to obtain the final target brightness. May be determined. In addition, the imaging information, the environment information, and the input in one-step processing by using information representing the correspondence between the combination of the imaging information, the environment information, and the brightness of the input image data and the target luminance. The final target brightness may be determined from the combination of the brightness of the image data.

Example 3
Hereinafter, a display device according to a third embodiment of the present invention and a control method thereof will be described with reference to the drawings. In the first and second embodiments, an example has been described in which it is assumed that all pixel values of input image data are pixel values that can be processed by the display unit. However, an image file such as OpenEXR may store input image data having a very wide dynamic range. The range of pixel values of input image data may be wider than the range corresponding to the display unit. That is, input image data may include pixel values that can not be effectively used by the display unit. In this embodiment, a configuration capable of appropriately displaying even in such a case will be described.

FIG. 12 is a block diagram illustrating an example of a functional configuration of a display device according to a third embodiment.
The display device according to the present embodiment includes a separation unit 101, an image processing unit 302, a display unit 111, an image determination unit 211, a target brightness determination unit 208, a backlight module unit 109, a light emission brightness control unit 110, and the like.
The operations of the separation unit 101, the display unit 111, the backlight module unit 109, and the light emission luminance control unit 110 are the same as in the first and second embodiments. The operations of the image determination unit 211 and the target luminance determination unit 208 are the same as in the second embodiment.

The image processing unit 302 has the same function as the image processing unit 102 of the first embodiment. However, the image processing unit 302 corrects the input image data with an image correction factor that sets the maximum value of the pixel values to a value within the range of pixel values that can be processed by the display unit 111. That is, the image processing unit 302 corrects input image data by multiplying each pixel value of the input image data by the image correction rate. Then, the input image data after the correction (after the image correction processing for correcting the image data with the image correction rate) is output as display image data. Therefore, in the present embodiment, image data corresponding to the display unit 111 can be obtained as display image data by performing the image correction process. Then, in the display unit 111, light from the backlight module unit 109 is modulated based on display image data which is input image data after correction.
In the present embodiment, although an example in which input image data output from the separation unit 101 is corrected by the image correction rate will be described, the present invention is not limited thereto. For example, the input image data output from the separation unit 101 may be subjected to the predetermined image processing described in the first embodiment prior to the image correction processing. Then, the image correction processing may be performed on the image data after the predetermined image processing has been performed.
In the present embodiment, an example in which the image processing unit 302 performs predetermined image processing and image correction processing will be described, but predetermined image processing and image correction processing may be performed by different functional units. Predetermined image processing may not be performed.

  Further, the image processing unit 302 corrects the shooting information so that the final target luminance of the backlight module unit 109 becomes a value corrected by the reciprocal of the image correction rate. That is, the image processing unit 302 corrects the shooting information so that the final target brightness is a value obtained by multiplying the inverse of the image correction rate by the target brightness determined by the methods of the first and second embodiments. Then, the image processing unit 302 outputs the shooting information after correction. As a result, since the light emission luminance of the backlight module unit 109 is controlled to a value corrected by the reciprocal of the image correction rate, it is possible to prevent a change in display luminance due to the correction of the input image data by the image correction rate. it can.

FIG. 13 is a block diagram showing an example of a functional configuration of the image processing unit 302. As shown in FIG.
The image processing unit 302 includes a maximum value detection unit 312, a division unit 313, a multiplication unit 314, a display image data generation unit 315, and the like.
The maximum value detection unit 312 detects the maximum value of the pixel value of the input image data from the input image data, and outputs the detected pixel value as the maximum pixel value.
The division unit 313 divides each pixel value of the input image data by the maximum pixel value, and the division result (image data in which each pixel value is normalized so that the maximum value of the pixel value is 1) is used as corrected image data. Output. That is, in the present embodiment, the reciprocal of the maximum pixel value is the image correction rate.
The multiplying unit 314 corrects the photographing information (for example, the ambient light level) using the image correction factor, and outputs the corrected photographing information as the corrected photographing information. In this embodiment, it is assumed that the value of shooting information and the reproduction target luminance determined based on the shooting information are in a proportional relationship. Therefore, the multiplication unit 314 corrects the imaging information by multiplying the inverse of the image correction rate (that is, the maximum pixel value) by the value of the imaging information. The corrected shooting information is input to the target brightness determination unit 208, and the reproduction target brightness is determined based on the corrected shooting information.
In the division unit 313, the input image data is divided by the maximum pixel value, and in the multiplication unit 314, the value of the imaging information is multiplied by the maximum pixel value.
The display image data generation unit 315 performs predetermined image processing on the corrected image data, and outputs the image data subjected to the predetermined image processing as display image data.

  As described above, according to the present embodiment, the input image data is subjected to the image correction processing for correcting the image data at the image correction rate, and the display image data which is the input image data after the image correction processing is performed. The light from the backlight module unit 109 is modulated based on the Then, the light emission luminance of the backlight module unit 109 is controlled to a value corrected by the reciprocal of the image correction rate. Thus, all pixel values of display image data can be effectively used by the display unit 111, and appropriate display can be performed. In other words, it is possible to suppress the deterioration of the image quality due to the display image data including pixel values that can not be effectively used by the display unit 111.

  In the present embodiment, an example in which the image correction rate is the reciprocal of the maximum pixel value has been described, but the image correction rate is not limited to this. For example, the reciprocal of the average value of the pixel values of the input image data may be calculated as the image correction rate. The image correction factor may be determined based on the data luminance distribution of the input image data. The image correction rate may be any value as long as the maximum value of the pixel values can be set to a value within the range of pixel values that can be input to the display unit 111. For example, the image correction factor may not be a value determined using input image data. The image correction factor may be the reciprocal of the upper limit of the pixel value.

  In the present embodiment, an example is described in which the value of the imaging information is corrected based on the image correction factor, but the present invention is not limited to this. For example, the target brightness determined based on at least one or more of the shooting information, the environment information, and the brightness of the input image data may be corrected. In addition, the display device may have a brightness correction unit (not shown) that corrects the shooting information and the target brightness.

<Other Embodiments>
The present invention can also be implemented by a computer (or a device such as a CPU or MPU) of a system or apparatus that implements the functions of the above-described embodiments by reading and executing a program recorded in a storage device. For example, the present invention can also be implemented by a method including steps executed by a computer of a system or apparatus that realizes the functions of the embodiments described above by reading and executing a program recorded in a storage device. . To this end, the program may be, for example, through the network or from various types of recording media that can be the storage device (i.e. from computer readable recording media that hold data non-temporarily) Provided to Therefore, the computer (including devices such as CPU and MPU), the method, the program (including program code and program product), and a computer readable recording medium which holds the program non-temporarily are all It is included in the category of the invention.

Reference Signs List 100 display device 101 separation unit 108 target luminance determination unit 109 back light module unit 110 emission luminance control unit 111 display unit

Claims (16)

A display device for displaying image data;
A first acquisition unit that acquires imaging information related to imaging conditions at the time of imaging of input image data;
A second acquisition unit configured to acquire environmental information on an installation environment of the display device;
Light emitting means,
Display means for displaying an image on a screen by modulating light from the light emitting means based on the input image data;
A determination unit that determines a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired by the first acquisition unit, and the environment information acquired by the second acquisition unit When,
Control means for controlling the light emission luminance of the light emission means to the target luminance determined by the determination means;
Have
A display apparatus characterized in that the determination means adjusts the target brightness of the light emitting means so that the target brightness is lower when the brightness of the input image data is bright than when the brightness is dark. . A display device for displaying image data;
A first acquisition unit that acquires imaging information related to imaging conditions at the time of imaging of input image data;
A second acquisition unit configured to acquire environmental information on an installation environment of the display device;
Light emitting means,
Display means for displaying an image on a screen by modulating light from the light emitting means based on the input image data;
A determination unit that determines a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired by the first acquisition unit, and the environment information acquired by the second acquisition unit When,
Control means for controlling the light emission luminance of the light emission means to the target luminance determined by the determination means;
Have
When the ratio of the area of the bright portion of the pixels of the input image data to the area of the image represented by the input image data is small, the determining unit determines that the ratio is small. A display apparatus characterized in that the target brightness of the light emitting means is adjusted so that the target brightness is higher than when it is large. The shooting information includes information on ambient light level at the time of shooting of the input image data,
The environmental information includes information on the ambient light level in the installation environment of the display device,
When the ambient light level at the time of photographing the input image data is high, the determination means has a target luminance higher than when the ambient light level is low, and the ambient light level in the installation environment of the display device is 3. The display device according to claim 1, wherein the target brightness of the light emitting means is adjusted so that the target brightness is higher when the level is high than when the ambient light level is low. The said determination means determines the target brightness | luminance of the said light emission means based on the said imaging | photography information, and correct | amends the said determined target brightness | luminance based on the said environment information. The display apparatus as described in a term. The determining means is
Based on the environmental information, estimate the range of display luminance that allows good visual recognition;
5. The display device according to claim 4, wherein the determined target luminance is corrected such that display luminance approaches the estimated range. The display device according to claim 5, wherein the determination means corrects the determined target luminance such that the display luminance has a value inside the estimated range. The imaging information includes information indicating at least one of an ambient light level at the time of imaging of the input image data, an ISO sensitivity, a shutter speed, an aperture value, and an imaging mode. The display device according to any one of the items. The display device according to any one of claims 1 to 7, wherein the environment information is information indicating an ambient light level in an installation environment of the display device. A control method of a display device, comprising: light emitting means; and display means for displaying an image on a screen by modulating light from the light emitting means based on input image data,
A first acquisition step of acquiring imaging information on imaging conditions at the time of imaging of the input image data;
A second acquisition step of acquiring environment information on an installation environment of the control method of the display device;
A determination step of determining a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired in the first acquisition step, and the environment information acquired in the second acquisition step When,
Controlling the light emission luminance of the light emitting means to the target luminance determined in the determination step;
Have
A display apparatus characterized in that, in the determination step, when the brightness of the input image data is bright, the target brightness of the light emitting means is adjusted so that the target brightness is lower than when the brightness is dark. Control method. A control method of a display device, comprising: light emitting means; and display means for displaying an image on a screen by modulating light from the light emitting means based on input image data,
A first acquisition step of acquiring imaging information on imaging conditions at the time of imaging of the input image data;
A second acquisition step of acquiring environment information on an installation environment of the control method of the display device;
A determination step of determining a target luminance of the light emitting unit based on the brightness of the input image data, the photographing information acquired in the first acquisition step, and the environment information acquired in the second acquisition step When,
Controlling the light emission luminance of the light emitting means to the target luminance determined in the determination step;
Have
In the determining step, when the ratio of the area of a bright portion made up of pixels whose pixel values are equal to or larger than the threshold among the pixels of the input image data is smaller than the area of the image represented by the input image data. And adjusting the target brightness of the light emitting means so that the target brightness is higher than when it is large. The shooting information includes information on ambient light level at the time of shooting of the input image data,
The environmental information includes information on the ambient light level in the installation environment of the display device,
In the determination step, when the ambient light level at the time of capturing the input image data is high, the target brightness is higher than when the ambient light level is low, and the ambient light level in the installation environment of the display device is 11. The method according to claim 9, wherein the target luminance of the light emitting means is adjusted so that the target luminance is higher when the ambient light level is high than when the ambient light level is low. The target luminance of the light emitting means is determined based on the photographing information in the determination step, and the determined target luminance is corrected based on the environment information. The control method of the display apparatus as described in a term. In the determination step,
Based on the environmental information, estimate the range of display luminance that allows good visual recognition;
The control method of the display device according to claim 12, wherein the determined target luminance is corrected such that display luminance approaches the estimated range. The control method of a display device according to claim 13, wherein in the determination step, the determined target luminance is corrected such that the display luminance becomes a value inside the estimated range. The photographing information includes information indicating at least one of an ambient light level, an ISO sensitivity, a shutter speed, an aperture value, and a photographing mode at the time of photographing of the input image data. The control method of the display apparatus of any one statement. The control method of a display device according to any one of claims 9 to 15, wherein the environment information is information indicating an ambient light level in an installation environment of the display device.

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