JP2006126528A - Display image quality control method and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To vary display image quality by only processing on a display device side according to the screen. <P>SOLUTION: A color picture/monochromatic picture deciding circuit 10 decides whether a picture includes a color picture or a monochromatic picture and a microprocessor 7 makes the display picture quality different by making the luminance, color temperature, and gamma characteristics different among: a case wherein it is decided that a color picture is included; a case wherein it is decided that a color picture is not included and a monochromatic picture is included; and a case wherein neither picture is included. Consequently, color picture display quality, suitable for display of a picture including an image obtained by taking a color picture of a natural thing, such as a flower, monochromatic picture display quality suitable for display of an X-ray image, and text display picture quality suitable for display of a text picture created in an editor, can be switched automatically. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display image quality control method and a display device, and more particularly to a display image quality control method and a display device that can change the display image quality only by processing on the display device side according to a screen to be displayed.

2. Description of the Related Art Conventionally, a technique is known in which a host computer sends a display image quality control signal corresponding to an application or an image file to a display device through communication, and the display device that receives the display image quality control signal changes the display image quality (for example, patents). Reference 1 and Patent Reference 2).
JP 2002-341843 A Japanese Patent Laid-Open No. 2003-337581

In the above prior art, in order to change the display image quality, display image quality determination processing and communication processing on the host computer side and communication processing and display image quality change processing on the display device side are required. There is a problem that cannot be done.
Accordingly, an object of the present invention is to provide a display image quality control method and a display device capable of changing the display image quality only by processing on the display device side according to the screen to be displayed.

In a first aspect, the present invention determines whether or not a picture is included in one screen of a video signal when displaying a video based on the video signal, and includes a case where it is determined that a picture is included and a picture. Provided is a display image quality control method characterized in that the display image quality is changed depending on whether or not it is determined.
In the above configuration, a picture means an image in which pixels having a small difference in pixel value from adjacent pixels are spread two-dimensionally (an image in which pixel values are smoothly changing two-dimensionally). To do. For example, an image obtained by photographing a natural object such as a person, a human body, or a flower. On the other hand, for example, a text screen created by an editor is not a picture.
The display image quality control method according to the first aspect is suitable for displaying an image including a picture by determining whether or not a picture is included in one screen of a video signal and automatically changing the display image quality. The display image quality and the display image quality suitable for displaying an image not including a picture can be switched only by processing on the display device side.

In a second aspect, the present invention determines whether or not a color picture is included in one screen of the video signal when displaying a video based on the video signal, and a case where it is determined that a color picture is included. Provided is a display image quality control method characterized in that the display image quality is changed when it is determined that a picture is not included.
In the above configuration, a color picture is a pixel in which there is a small difference in pixel values from adjacent pixels and R (red pixel value) = G (green pixel value) = B (blue pixel value) is not two-dimensional. This means an image that is spread out (an image in which pixel values that are not monochrome change smoothly in two dimensions). For example, an image obtained by color photographing natural objects such as a person, a human body, and a flower. On the other hand, for example, a text screen or an X-ray image created by an editor is not a color picture.
In the display image quality control method according to the second aspect, it is determined whether or not a color picture is included in one screen of a video signal and the display image quality is automatically changed, so that the color picture can be obtained only by processing on the display device side. The display image quality suitable for displaying an image including the image quality and the display image quality suitable for displaying an image not including a color picture can be switched only by processing on the display device side.

In a third aspect, according to the present invention, when displaying a video based on a video signal, it is determined whether or not a monochrome picture is included in one screen of the video signal. Provided is a display image quality control method characterized in that the display image quality is changed when it is determined that a picture is not included.
In the above configuration, a monochrome picture has two pixels that have a small difference in pixel value from adjacent pixels and R (red pixel value) = G (green pixel value) = B (blue pixel value). It means an image that spreads in two dimensions (an image in which monochrome pixel values change smoothly two-dimensionally). For example, it is an image or X-ray image of a natural object such as a person, a human body, or a flower taken in monochrome. In contrast, for example, an image obtained by photographing a natural object such as a person, a human body, or a flower in color or a text screen created by an editor is not a monochrome picture.
In the display image quality control method according to the third aspect described above, it is determined whether or not a monochrome picture is included in one screen of a video signal, and the display image quality is automatically changed. The display image quality suitable for displaying an image including the image quality and the display image quality suitable for displaying an image not including a monochrome picture can be switched only by processing on the display device side.

In a fourth aspect, the present invention discriminates whether a color picture, a monochrome picture, or both are not included in one screen of the video signal when displaying the video based on the video signal, Provided is a display image quality control method characterized by changing display image quality when it is determined that a color picture is included, when it is determined that it does not include a color picture and includes a monochrome picture, and when it is determined that both are not included. .
In the above configuration, a color picture is a pixel in which there is a small difference in pixel values from adjacent pixels and R (red pixel value) = G (green pixel value) = B (blue pixel value) is not two-dimensional. This means an image that is spread out (an image in which pixel values that are not monochrome change smoothly in two dimensions). For example, an image obtained by color photographing natural objects such as a person, a human body, and a flower. A monochrome picture is a two-dimensional pixel in which there is a small difference in pixel value from adjacent pixels and R (red pixel value) = G (green pixel value) = B (blue pixel value). (An image in which monochrome pixel values change smoothly two-dimensionally). For example, it is an image or X-ray image of a natural object such as a person, a human body, or a flower taken in monochrome. On the other hand, for example, a text screen created by an editor is neither a color picture nor a monochrome picture.
In the display image quality control method according to the fourth aspect, the display image quality is automatically changed by determining whether one picture of a video signal includes a color picture, a monochrome picture, or both. Display quality suitable for displaying an image including a color picture, display quality suitable for displaying an image including a monochrome picture, and an image including neither a color picture nor a monochrome picture, only by processing on the display device side The display image quality suitable for display can be switched only by processing on the display device side.

In a fifth aspect, the present invention provides at least one of luminance, color temperature, and gamma characteristics in order to change the display image quality in the display image quality control method according to any one of the first to fourth aspects. Provided is a display image quality control method characterized by changing.
The display image quality can be changed by changing at least one of luminance, color temperature, and gamma characteristics.

In a sixth aspect, the present invention provides the display image quality control method according to any one of the first to fifth aspects, wherein the colors of all or some of the display pixels constituting one screen of the video signal are not designated colors. Providing a display image quality control method that determines whether or not a color is included, and changes the luminance when it is determined that a color that is not a specified color is included and the luminance when it is determined that a color that is not a specified color is not included To do.
In the above configuration, the color includes a grayscale gradation value.
In the display image quality control method according to the sixth aspect, for example, all the colors used in the screen saver screen are designated as designated colors, and the colors of all display pixels constituting one screen of the video signal are not designated colors. If the display brightness is included, the brightness set for normal display is set. If it is determined that the specified color is not included, the display brightness is set lower than the normal display brightness. Power consumption can be saved.

In a seventh aspect, the present invention provides a picture discriminating means for discriminating whether or not a picture is included in one screen of an input video signal in a display device that displays video based on the input video signal; There is provided a display device comprising: a display image quality changing unit that changes a display image quality depending on whether the picture determining unit determines that a picture is included or not.
In the display device according to the seventh aspect, the display image quality control method according to the first aspect can be suitably implemented.
The display device may be a liquid crystal panel or a CRT.

In an eighth aspect, the present invention provides a picture discriminating means for discriminating whether or not a color picture is included in one screen of an input video signal in a display device for displaying video based on the input video signal. There is provided a display device comprising: a display image quality changing means for changing a display image quality depending on whether the picture determining means determines that a color picture is included or not.
In the display device according to the eighth aspect, the display image quality control method according to the second aspect can be suitably implemented.

In a ninth aspect, the present invention provides a picture discriminating means for discriminating whether or not a monochrome picture is included in one screen of an input video signal in a display device for displaying video based on the input video signal. There is provided a display device characterized by comprising display image quality changing means for changing the display image quality when the picture discriminating means discriminates that a monochrome picture is included and when it does not contain a monochrome picture.
In the display device according to the ninth aspect, the display image quality control method according to the third aspect can be suitably implemented.

In a tenth aspect, the present invention relates to a display device that displays video based on an input video signal, and includes a color picture, a monochrome picture, or both in one screen of the input video signal. A picture discriminating unit that discriminates whether or not a color picture is included, a case in which the picture discriminating unit discriminates that a color picture is included, a case in which a color picture is not included and includes a monochrome picture, and a case in which both are not included. Provided is a display device comprising display image quality changing means for changing display image quality.
In the display device according to the tenth aspect, the display image quality control method according to the fourth aspect can be suitably implemented.

In an eleventh aspect, the present invention provides the display device according to any one of the seventh to the tenth aspects, wherein the display image quality changing means includes a luminance, a color temperature, and a gamma characteristic for changing the display image quality. A display device characterized by changing at least one of the above is provided.
In the display device according to the eleventh aspect, the display image quality control method according to the fifth aspect can be suitably implemented.

In a twelfth aspect, the present invention provides a display device according to any one of the seventh to eleventh aspects, wherein a color that is not a designated color is used as a color of all or part of display pixels constituting one screen of a video signal. A designated color discriminating unit that discriminates whether or not a color is included, and a luminance changing unit that changes luminance between a case where the designated color discriminating unit discriminates that a color that is not a designated color is included and a case that a color that is not a designated color is not included A display device is provided.
In the display device according to the twelfth aspect, the display image quality control method according to the sixth aspect can be suitably implemented.

  According to the display image quality control method and the display device of the present invention, the display image quality can be changed only by processing on the display device side according to the screen to be displayed.

  Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited thereby.

FIG. 1 is a block diagram illustrating a liquid crystal display device 100 according to the first embodiment.
The liquid crystal display device 100 includes a liquid crystal panel 1, a backlight 2, an inverter 3 for driving the backlight 2, a connector 4 for inputting a display signal d from a host computer PC, and a DVI (Digital Visual Interface) receiver. 5, based on the video signal and control signal output from the DVI receiver 5, the image processing unit 6 that drives the liquid crystal panel 1 based on the video signal and control signal output from the DVI receiver 5, and displays the video. A color picture / monochrome picture discriminating circuit 10 for discriminating whether or not a color picture or a monochrome picture is included in one screen, and all display pixels constituting one screen based on video signals and control signals output from the DVI receiver 5 Specified color discriminating circuit 20 for discriminating whether or not the selected color includes a color other than the designated color, and a control output from the DVI receiver 5. And a microprocessor 7 that controls the inverter 3 and the image processing unit 6 based on the determination signal output from the signal and the color picture / monochrome picture determination circuit 10 and the determination signal output from the designated color determination circuit 20. .

  The image processing unit 6 includes a color temperature adjustment pixel value conversion unit 61 and a gamma characteristic adjustment pixel value conversion unit 62.

  Note that hardware other than the color picture / monochrome picture discrimination circuit 10 and the designated color discrimination circuit 20 is originally provided in a conventional liquid crystal display device.

  FIG. 2 is a circuit diagram illustrating the color picture / monochrome picture discrimination circuit 10 according to the first embodiment. FIG. 3 is a timing chart showing signals of the respective parts in FIG.

  As shown in FIG. 3, before the start of one line, the horizontal synchronization signal H-SYNC becomes “1” in a pulse shape, the data enable signal DE becomes “1” during the display period, and the left end of one line. The pixel values d0 of the R, G, and B pixels and the R, G, and B pixel values dn of the rightmost pixel are sequentially input in accordance with the pixel clock signal CLOCK.

The color picture / monochrome picture discriminating circuit 10 discriminates whether or not a color picture is included in one screen and whether or not a monochrome picture is included according to the following determination conditions.
(1) The upper 5 bits b of G of the current pixel (currently input pixel) have the same value as the upper 5 bits of G of the left adjacent pixel (pixel input one clock before), and R of the current pixel The most significant bit is the same value as the most significant bit of R of the left adjacent pixel, and the most significant bit of B of the current pixel is the same value as the most significant bit of B of the left adjacent pixel (A1 = 1) and the current pixel If the lower 3 bits of G are not the same value as the lower 3 bits of G of the left adjacent pixel (A2 = 1), it is determined that the current pixel is a picture element (g = 1). Otherwise, it is determined that the current pixel is a non-picture element (g = 0).
(2) If the pixel value of the current pixel is R = G = B (A3 = 0), it is determined that the current pixel is a monochrome pixel (j = 0). If R = G = B is not satisfied (A3 = 1), it is determined that the current pixel is a color pixel (j = 1).
(3) A monochrome picture line (C1 = 1) including two or more (this value is merely an example) pixels that are picture elements (g = 1) and monochrome pixels (j = 0) in one line. If there are not more than 4 non-monochrome picture lines in between (this value is just an example) (C2 = 0) and 128 (this value is just an example), continue (C3 = 1). (C = 1). Otherwise, it is determined that no monochrome picture is included (C = 0). It should be noted that, for example, a monochrome thumbnail image in which 94 monochrome picture lines (C1 = 1) and no more than four non-monochrome picture lines are sandwiched between them (C2 = 0) and 94 lines continue is not regarded as a monochrome picture.
(4) A color picture line (D1 = 1) including two or more (this value is merely an example) pixels that are picture elements (g = 1) and color pixels (j = 1) in one line. If no more than 2 non-color picture lines are sandwiched between (this value is just an example) (D2 = 0) and 128 (this value is just an example), it will continue (D3 = 1). (D = 1). Otherwise, it is determined that no color picture is included (D = 0). It should be noted that, for example, 94 color thumbnail images in which the color picture line (D1 = 1) continues with no more than two non-color picture lines in between (D2 = 0) are not regarded as a color picture.

FIG. 4 is a circuit diagram illustrating the designated color discrimination circuit 20 according to the first embodiment.
The designated color decoder 21 has a first output E1, a second output E2, and a third output E3. The first output E1 is set to “0” when the pixel color is “black”, and the first output E1 is set to “1” when the pixel color is not “black”. The second output E2 is set to “0” when the pixel color is “white”, and the second output E2 is set to “1” when the pixel color is not “white”. Further, when the pixel color is “black” “red” “green” “yellow” “blue” “magenta” “cyan” or “white”, the third output E3 is set to “0”, and the pixel color is “black”. The third output E3 is set to “1” when it is not “red” “green” “yellow” “blue” “magenta” “cyan” or “white”.

The AND gate 22 passes the pixel clock signal CLOCK when the data enable signal DE is “1”, and stops the pixel clock signal CLOCK when the data enable signal DE is “0”.
The signal m becomes “1” at the falling edge of the pixel clock signal CLOCK after the vertical synchronization signal V-SYNC becomes “1” in a pulse shape before the start of one screen (frame), and the vertical synchronization signal V− It becomes “0” at the falling edge of the pixel clock signal CLOCK after SYNC returns to “0”.

The D flip-flop 23 sets the output Q to “0” when the signal m becomes “1”. Further, the output E1 of the designated color decoder 21 is read and outputted at the falling edge of the pixel clock signal CLOCK passing through the AND gate 22. Accordingly, the output Q is set to “0” when the pixel color is “black”, and the output Q is set to “1” when the pixel color is not “black”.
The D flip-flop 24 sets the output Q to “0” when the signal m becomes “1”. Further, the output E2 of the designated color decoder 21 is read and outputted at the falling edge of the pixel clock signal CLOCK passing through the AND gate 22. Accordingly, the output Q is set to “0” when the pixel color is “white”, and the output Q is set to “1” when the pixel color is not “white”.
The D flip-flop 25 sets the output Q to “0” when the signal m becomes “1”. Further, the output E3 of the designated color decoder 21 is read and outputted at the falling edge of the pixel clock signal CLOCK passing through the AND gate 22. Accordingly, when the pixel color is “black”, “red”, “green”, “yellow”, “blue”, “magenta”, “cyan” or “white”, the output Q is set to “0”, and the pixel color is “black” “ The output Q is set to “1” when it is not red, “green”, “yellow”, “blue”, “magenta”, “cyan” or “white”.

The D flip-flop 26 sets the output Q to “0” when the signal m becomes “1”. Further, the output Q is set to “1” at the rise of the output Q of the D flip-flop 23. That is, the output Q is set to “0” immediately before the start of one screen, and the output Q is maintained at “0” when the colors of all display pixels constituting the one screen do not include any color other than “black”. The output Q is changed to “1” when the color of all the display pixels constituting the pixel includes a color other than “black”.
The D flip-flop 27 sets the output Q to “0” when the signal m becomes “1”. Further, the output Q is set to “1” at the rise of the output Q of the D flip-flop 24. That is, the output Q is set to “0” immediately before the start of one screen, and the output Q is maintained at “0” when the colors of all display pixels constituting one screen do not include any color other than “white”. The output Q is changed to “1” when the color of all the display pixels constituting the pixel includes a color other than “white”.
The D flip-flop 28 sets the output Q to “0” when the signal m becomes “1”. Further, the output Q is set to “1” at the rise of the output Q of the D flip-flop 25. In other words, the output Q is set to “0” immediately before the start of one screen, and “black”, “red”, “green”, “yellow”, “blue”, “magenta”, “cyan” or “ If no color other than white is included, the output Q is maintained at “0”, and the colors of all display pixels constituting one screen are “black”, “red”, “green”, “yellow”, “blue”, “magenta”, “ When even one pixel includes a color other than “cyan” or “white”, the output Q is changed to “1”.

The D flip-flop 29 reads and holds the output Q of the D flip-flop 26 at the rising edge of the vertical synchronization signal V-SYNC.
The D flip-flop 30 reads and holds the output Q of the D flip-flop 27 at the rising edge of the vertical synchronization signal V-SYNC.
The D flip-flop 31 reads and holds the output Q of the D flip-flop 28 at the rising edge of the vertical synchronization signal V-SYNC.

  After all, the designated color discrimination circuit 20 outputs “1” as the black solid discrimination signal F1 in the next screen when the color of all the display pixels constituting one screen includes a color other than “black”. When it is determined that no color other than “black” is included, “0” is output as the black solid determination signal F1 in the next screen. Further, when the color of all display pixels constituting one screen includes a color other than “white”, “1” is output as the white solid discrimination signal F2 in the next screen, and no color other than “white” is included. If it is determined, “0” is output as the white solid determination signal F2 in the next screen. Further, if the colors of all display pixels constituting one screen include colors other than “black”, “red”, “green”, “yellow”, “blue”, “magenta”, “cyan” or “white”, the designated color discrimination signal F3 If “1” is output in the next screen, and it is determined that it contains no colors other than “black”, “red”, “green”, “yellow”, “blue”, “magenta”, “cyan” or “white”, the specified color “0” is output as the discrimination signal F3 in the next screen.

FIG. 5 is a flowchart showing display mode control processing executed by the microprocessor 7.
In step S1, it is checked whether the vertical synchronization signal V-SYNC (or horizontal synchronization signal H-SYNC) is input from the DVI receiver 5. If not, the process proceeds to step S2, and if it is input, the process proceeds to step S3. move on.

  In step S2, the inverter 3 is stopped and the backlight 2 is turned off. Then, the process returns to step S1. That is, when the display signal d is not input from the host computer PC, the display is turned off (no signal non-display mode).

  In step S3, it is checked whether the discrimination signal D from the color picture / monochrome picture discrimination circuit 10 is “1” (including a color picture). If “1”, the process proceeds to step S4, and “0” (does not include a color picture). If so, the process proceeds to step S5.

  In step S4, the inverter 3 is operated so that the output is slightly higher, the backlight 2 is set to medium luminance, the color temperature adjustment pixel value conversion unit 61 of the image processing circuit 6 is instructed to the color temperature “6500K”, and A gamma correction “γ2.2” is instructed to the gamma characteristic adjustment pixel value conversion unit 62 of the image processing circuit 6 (color picture display mode). Then, the process returns to step S1.

  In step S5, it is checked whether the discrimination signal C from the color picture / monochrome picture discrimination circuit 10 is “1” (including a monochrome picture). If “1”, the process proceeds to step S6, and “0” (no monochrome picture is included). If so, the process proceeds to step S7.

  In step S6, the inverter 3 is operated so as to obtain a high output, the backlight 2 is made bright, the color temperature adjustment pixel value conversion unit 61 of the image processing circuit 6 is instructed to the color temperature “7500K”, and the image is further displayed. The gamma correction “DICOM-γ” is instructed to the gamma characteristic adjusting pixel value converting unit 62 of the processing circuit 6 (monochrome picture display mode). Then, the process returns to step S1.

  In step S7, it is checked whether the black solid determination signal F1 from the designated color determination circuit 20 is “0” (black solid screen). If “0”, the process proceeds to step S8, and if “1”, the process proceeds to step S9.

  In step S8, the inverter 3 is stopped and the backlight 2 is turned off. Then, the process returns to step S1. That is, when a screen in which all pixels are “black” is input from the host computer PC, the display is turned off (black solid non-display mode).

  In step S9, it is checked whether the white solid determination signal F2 from the designated color determination circuit 20 is “0” (white solid screen). If “0”, the process proceeds to step S10, and if “1”, the process proceeds to step S11.

  In step S10, the inverter 3 is operated so as to obtain the highest output, and the backlight 2 is set to the maximum luminance. Then, the process returns to step S1. That is, when a screen in which all pixels are “white” is input from the host computer PC, the screen is brightest (white solid high luminance mode). As a result, as shown in FIG. 6, if the film scissors P placed on the liquid crystal panel 1 is held on the screen of the liquid crystal panel 1 with the films F1 and F2 being sandwiched, the white screen Gw is suitably used as the screen for the shaucus ten. It can be used.

  In step S11, it is checked whether the designated color discrimination signal F3 from the designated color discrimination circuit 20 is “0”. If “0”, the process proceeds to step S12, and if “1”, the process proceeds to step S13.

  In step S12, the inverter 3 is operated so that the output is extremely low, and the backlight 2 is set to an extremely low luminance. Then, the process returns to step S1. That is, when the color bar screen CB as shown in FIG. 7 is input from the host computer PC as the display signal d, the screen is darkened (power saving display mode).

  In step S13, the inverter 3 is operated so that the output is slightly low, the backlight 2 is lowered in brightness, the color temperature adjustment pixel value conversion unit 61 of the image processing circuit 6 is instructed to “no correction”, and the image A gamma correction “γ2.2” is instructed to the pixel value conversion unit 62 for gamma characteristic adjustment of the processing circuit 6 (text display mode). Then, the process returns to step S1.

  According to the liquid crystal display device 100 of the first embodiment, the display image quality can be changed only by processing on the display device side according to the screen to be displayed. For example, only by processing on the display device side, color picture display image quality suitable for displaying a screen including an image obtained by color-taking a natural object such as a person, a human body, or a flower, and suitable for displaying an X-ray image It is possible to automatically switch between monochrome picture display quality and text display quality suitable for displaying a text screen created by an editor. In addition, it is possible to save power on a black solid screen only by processing on the display device side. Also, the brightness at the time of the white solid screen can be increased only by the processing on the display device side. Furthermore, only the processing on the display device side can reduce the power consumption when a screen saver or a television broadcast is transmitting the color bar screen CB.

  If the designated color discriminating circuit 20 as shown in FIG. 8 is used, steps S7 to S10 in FIG. 5 can be skipped.

  If a designated color discrimination circuit 20 as shown in FIG. 9 is used, steps S7 to S12 in FIG. 5 can be skipped.

  The present invention can also be applied to a CRT display device. In that case, instead of controlling the backlight 2, the luminance level may be controlled.

  The display image quality control method and display device of the present invention can be used for liquid crystal display devices and CRT display devices.

1 is a configuration diagram illustrating a liquid crystal display device according to Embodiment 1. FIG. 1 is a circuit diagram illustrating a color picture / monochrome picture discrimination circuit according to Embodiment 1. FIG. 3 is a timing chart illustrating signals of respective units of the color picture / monochrome picture discrimination circuit according to the first embodiment. 3 is a circuit diagram illustrating a designated color discrimination circuit according to Embodiment 1. FIG. FIG. 6 is a flowchart illustrating a display image quality control process according to the first embodiment. It is an illustration figure of a white solid screen. It is an illustration figure of a color bar screen. FIG. 6 is a circuit diagram illustrating a designated color discrimination circuit according to a second embodiment. FIG. 10 is a circuit diagram illustrating a designated color discrimination circuit according to a third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 Backlight 3 Inverter 6 Image processing circuit 7 Microprocessor 10 Color picture / monochrome picture discrimination circuit 20 Designated color discrimination circuit 61 Pixel value conversion part for color temperature adjustment 62 Pixel value conversion part for gamma characteristic adjustment 100 Liquid crystal display device

Claims (12)

When displaying a video based on a video signal, it is determined whether or not a picture is included in one screen of the video signal, and the display image quality is determined depending on whether the picture is included or not. A display image quality control method characterized by changing. When displaying a video based on a video signal, it is determined whether or not a color picture is included in one screen of the video signal, and when it is determined that a color picture is included or not. A display image quality control method characterized by changing display image quality. When displaying a video based on a video signal, it is determined whether or not a monochrome picture is included in one screen of the video signal, and when it is determined that a monochrome picture is included and when it is determined that a monochrome picture is not included. A display image quality control method characterized by changing display image quality. When displaying a video based on a video signal, it is determined whether one screen of the video signal includes a color picture, a monochrome picture, or both. A display image quality control method characterized by changing display image quality when it is determined that a picture is not included and a monochrome picture is included and when it is determined that both are not included. 5. The display image quality control method according to claim 1, wherein at least one of luminance, color temperature, and gamma characteristics is changed in order to change the display image quality. . In the display image quality control method according to any one of claims 1 to 5, it is determined whether or not all or some of the display pixels constituting one screen of the video signal include a color other than the designated color. A display image quality control method characterized by changing a luminance when it is determined that a color other than a specified color is included and a luminance when it is determined that a color which is not a specified color is not included. In a display device that displays a video based on an input video signal, a picture discrimination unit that discriminates whether or not a picture is included in one screen of the input video signal, and that the picture discrimination unit includes a picture And a display image quality changing means for changing a display image quality depending on whether the image is included or not included. In a display device that displays video based on an input video signal, a picture determination unit that determines whether or not a color picture is included in one screen of the input video signal, and the picture determination unit includes a color picture And a display image quality changing means for changing the display image quality when it is determined that the color picture is not included. In a display device that displays video based on an input video signal, a picture determination unit that determines whether or not a monochrome picture is included in one screen of the input video signal, and the picture determination unit includes a monochrome picture And a display image quality changing means for changing the display image quality when it is determined that a monochrome picture is not included. A picture discriminating means for discriminating whether a screen of an input video signal includes a color picture, a monochrome picture, or both in a display device for displaying video based on the input video signal; Display image quality changing means for changing the display image quality when the picture discriminating means discriminates that it includes a color picture, when it discriminates that it does not contain a color picture and contains a monochrome picture, and when it discriminates that both are not included. A display device comprising the display device. 11. The display device according to claim 7, wherein the display image quality changing unit changes at least one of luminance, color temperature, and gamma characteristics in order to change the display image quality. Display device. 12. The display device according to claim 7, wherein the color of all or some of the display pixels constituting one screen of the video signal includes a color other than the specified color. And a brightness changing means for changing the brightness when it is determined that the specified color determining means includes a color that is not a specified color and when it is determined that a color that is not a specified color is not included. .

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