JP6191018B2 - Signal processing apparatus and signal processing method - Google Patents

Description

  The present disclosure relates to a signal processing device and a signal processing method for performing signal processing on input content data.

  Patent Document 1 discloses a display device, a display control method, and a program. The display device includes a display unit that outputs an image signal and a signal processing unit that executes control of the image signal output to the display unit. The signal processing unit executes control for gradually decreasing the color temperature of the image signal according to the elapsed time from the observation start time of the display unit. By lowering the color temperature, it is possible to reduce the blue component and reduce user fatigue.

JP 2013-257457 A

  The present disclosure provides a signal processing device that can reduce fatigue of a user who views displayed content data.

  The signal processing device according to the present disclosure is based on an extraction unit that extracts a character region in which a ratio of a region occupied by characters is larger than a predetermined value in a display region where content data is displayed, and color information of characters in the character region A setting unit that sets a target color temperature for displaying the content data, and a conversion unit that changes the original color temperature of the content data to the target color temperature.

  The signal processing device according to the present disclosure is effective in reducing fatigue of a user who views displayed content data.

1 is a block diagram illustrating a configuration example of a display device having a signal processing device according to a first embodiment; The figure which shows an example of the density histogram of the character area in 1st Embodiment The figure which shows an example of the method of identifying the character in 1st Embodiment The flowchart explaining operation | movement of the setting part of the signal processing apparatus in 1st Embodiment. The figure explaining an example of the color temperature change process of the conversion part of the signal processing apparatus in 1st Embodiment Explanatory drawing of the other example of the color temperature change process of the conversion part of the signal processing apparatus in 1st Embodiment. The figure which shows an example of the color temperature change in 1st Embodiment The block diagram which shows the example of 1 structure of the display apparatus which has the signal processing apparatus in 2nd Embodiment The figure explaining an example of the color temperature setting of the setting part of the signal processing apparatus in 2nd Embodiment The flowchart explaining other operation | movement of the setting part of the signal processing apparatus in 2nd Embodiment. The figure which shows the color temperature change in 2nd Embodiment The block diagram which shows the structure of the display apparatus which has the signal processing apparatus in 3rd Embodiment. The figure which shows an example of the relationship between the contrast and color temperature in 3rd Embodiment The figure which shows an example of the color temperature change in 3rd Embodiment The block diagram which shows the structure of the display apparatus which has the signal processing apparatus in 4th Embodiment. The figure which shows an example of the relationship between the contrast and color temperature in 4th Embodiment The figure which shows the color temperature change in 4th Embodiment

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

  The inventor provides the accompanying drawings and the following description in order for those skilled in the art to fully understand the present disclosure, and is not intended to limit the subject matter described in the claims. Absent.

(First embodiment)
In recent years, there are increasing opportunities to read characters such as newspapers and magazines on the screens of monitors and tablets. If you read characters on the screen for a long time, your eyes often get tired. It has been found that this is due to a blue light emitting component (blue light) issued from the screen. In order to reduce the eyestrain of the user, it is effective to reduce the blue light emission component, that is, to lower the color temperature of the display image. Here, the blue light-emitting component is a light component having a wavelength of about 400 nm to 500 nm.

  By the way, when the background color of the content data to be displayed is a warm color system and the character color is also a warm color system, the contrast of the characters is lowered and the displayed characters are difficult to see. Here, the warm color is a red, orange, or yellow color. For example, in the hue ring of the Munsell color system, the hue ranges from 10RP (red purple) to 5YR (yellow red) to 10Y (yellow).

  Therefore, if the color temperature of content data is simply lowered to reduce the blue light emission component for content data containing warm-colored characters, the background color that is not warm-colored will become warm-colored and characters will be visible. It may be difficult. In addition, the content data originally having a warm background color has a problem that characters are more difficult to see.

  Therefore, the present disclosure describes color temperature setting when displaying content data including warm-colored characters.

  In the first embodiment, a case will be described in which the color temperature of content data is set according to whether a character is a warm color system or not.

  Hereinafter, the first embodiment will be described with reference to FIGS.

[1-1. Constitution]
FIG. 1 is a block diagram illustrating a configuration example of a display device 1 having a signal processing device according to the first embodiment.

  As illustrated in FIG. 1, the display device 1 includes an acquisition unit 100, a signal processing device 10, a display control unit 104, and a display unit 105. Further, the signal processing apparatus 10 includes an extraction unit 101, a setting unit 102, and a conversion unit 103.

  The acquisition unit 100 is an input unit for content data. Here, the content data is digital information expressed by video, images, characters, or a combination thereof. For example, it is data in a file format conforming to a standard such as MPEG, JPEG, PDF, BMP.

  The extraction unit 101 divides the display area in which the content data input from the acquisition unit 100 is displayed into a plurality of areas, and the ratio of the area occupied by characters for each divided area is a character area that is larger than a predetermined value. By determining whether or not, a character area is extracted. Here, the predetermined value is, for example, ½, and indicates that characters are displayed in an area that is ½ or more of the display area. Note that the ratio of characters or characters other than the characters that are displayed in the display region for determining the region is not limited to ½. The setting unit 102 sets a target color temperature when the extraction unit 101 displays content data based on the color information of characters in the character area. Note that the color temperature indicates a hue when a gray gradation including white is displayed. When the color temperature is low, the display is reddish, and when the color temperature is high, the display is blue. The color temperature in the present disclosure indicates not only the color on the black body radiation locus represented on the chromaticity diagram but also the color of the coordinates including the vicinity of the black body radiation locus which is the so-called correlated color temperature.

  The conversion unit 103 changes the original color temperature of the content data to the target color temperature according to the target color temperature set by the setting unit 102. The change in the color temperature can be changed immediately to the target color temperature, but it may be changed gradually over time.

  The display control unit 104 performs processing for displaying the content data whose color temperature has been changed by the conversion unit 103 on the display unit 105 in the subsequent stage.

  The display unit 105 is a display, and includes, for example, a liquid crystal display, an organic EL display, or a plasma display.

[1-2. Operation]
The operation of the signal processing apparatus 10 configured as described above will be described below.

[1-2-1. Extraction area detection]
FIG. 2 is a diagram illustrating an example of a density histogram of a character area according to the first embodiment. In FIG. 2, the horizontal axis indicates the density value, and the vertical axis indicates the frequency of each density value. As shown in FIG. 2, the density histogram of the character area is divided into two peaks, with the density values of the character portion and the background portion gathering together.

  The extraction unit 101 determines whether the display area to be determined is a character area, using the characteristics of the density histogram shown in FIG. Here, the density value may be obtained by adding and averaging the signal levels of the RGB signals, or may be a luminance value obtained from the RGB signals. The luminance value is expressed by the following (Equation 1), for example.

(Equation 1)
Luminance value = 0.3R + 0.6G + 0.1B
Here, in (Equation 1), R, G, and B indicate the signal levels of the red signal, the green signal, and the blue signal, respectively.

  Further, the extraction unit 101 may add determination based on the edge amount in the area in addition to determination of the area based on the density histogram. The extraction unit 101 determines the area using the fact that there are many large edge changes in the character area.

[1-2-2. Operation of the setting unit]
FIG. 3 is a diagram for explaining an example of a method for identifying a character in the first embodiment. FIG. 3 shows a part of the character area extracted by the extraction unit 101. FIG. 3 shows a case where the appearance frequency of the density value of one character portion which is one of the density values divided in FIG. 2 is obtained. In FIG. 3, the vertical axis Y indicates the frequency of appearance of density values in the horizontal direction, and the horizontal axis X indicates the frequency of appearance of density values in the vertical direction. FIG. 3 shows a character area in which five characters “a”, “1”, “B”, “2”, “c” are arranged in order on a white background.

  As shown in FIG. 3, the frequency of appearance of density values in the vertical and horizontal directions increases in the range where characters are present. Using the feature of the frequency of appearance of the density value, it is possible to distinguish between the background and the characters. Thus, if the character signal can be distinguished, the character color can be obtained from the RGB signal of the character signal.

  FIG. 4 is a flowchart for explaining the operation of the setting unit 102 of the signal processing device according to the first embodiment.

  The setting unit 102 determines whether or not the characters in the character area are warm colors (step S401). If the setting unit 102 determines that the character is a warm color system, the setting unit 102 sets a small decrease amount from the original color temperature to the target color temperature (step S402). If the setting unit 102 determines that the character is not a warm color system, the setting unit 102 sets a large decrease amount from the original color temperature to the target color temperature (step S403).

[1-2-3. Operation of conversion unit]
FIG. 5 is a diagram illustrating an example of the color temperature change process of the conversion unit 103 of the signal processing device according to the first embodiment. FIG. 5 shows an example in which the displayed color temperature is 5000K when the RGB signals are at the same level. When changing the color temperature, the conversion unit 103 performs a process of changing the ratio of the RGB signals by multiplying each of the RGB signals by a predetermined gain. When increasing the color temperature, the conversion unit 103 increases the level of the B signal and changes the level of the R signal to decrease. When the color temperature is lowered, the conversion unit 103 lowers the level of the B signal and changes the level of the R signal to increase.

  FIG. 6 is a diagram illustrating another example of the color temperature change process of the conversion unit 103 of the signal processing device according to the first embodiment. FIG. 6 shows an example in which the displayed color temperature is 9000K when the RGB signals are at the same level. When the color temperature is lowered, the conversion unit 103 multiplies each of the RGB signals by a predetermined gain to change the levels of the B signal and the G signal.

  FIG. 7 is a diagram illustrating an example of a color temperature change according to the first embodiment. FIG. 7 shows an example in which the conversion unit 103 gradually changes the color temperature over time with respect to the target color temperature set by the setting unit 102. FIG. 7 shows the color temperature A1 of the character area when the character is in a warm color system and the color temperature A2 of the character area when the character is not in a warm color system. If the character is not a warm color, the setting unit 102 sets the target color temperature to the color temperature K3 that is set to have a larger amount of decrease in the color temperature than the original color temperature K1. When the character color is a warm color, the setting unit 102 sets the target color temperature to the color temperature K2 that is set to be smaller than the color temperature K1. The conversion unit 103 gradually changes the color temperature A1 and the color temperature A2 to the target color temperature K2 and the target color temperature K3, respectively. As shown in FIG. 7, it can be seen that the color temperature A1 and the color temperature A2 gradually change as time elapses toward the target color temperatures K2 and K3, respectively. By gradually changing the color temperature, it is possible to prevent the user from feeling uncomfortable by using the adaptability in which the user watching the display unit 105 adapts to the color.

[1-3. Effect]
As described above, in the present embodiment, the extraction unit 101 extracts a character area in which the ratio of the area occupied by characters is larger than a predetermined value in the display area where the content data is displayed. The setting unit 102 sets a target color temperature for displaying content data based on the color information of characters in the character area extracted by the extraction unit 101. The conversion unit 103 changes the original color temperature of the content data to the target color temperature.

  The setting unit 102 sets a large decrease range from the original color temperature to the target color temperature when the color information does not indicate the warm color system, and sets the target color from the original color temperature when the color information indicates the warm color system. Set the temperature drop to small.

  Thereby, when a character is not a warm color system, the blue light emission component considered to increase a user's fatigue can be reduced significantly. Further, when the characters are warm colors, it is possible to reduce the blue light emitting component that is supposed to increase the fatigue of the user and to suppress the contrast of the warm colors characters from becoming difficult to see.

(Second Embodiment)
In the second embodiment, a case will be described in which the target color temperature is set according to the size of the character area in which warm-colored characters are displayed.

  Hereinafter, the second embodiment will be described with reference to FIGS.

[2-1. Constitution]
FIG. 8 is a block diagram illustrating a configuration example of the display device 2 including the signal processing device according to the second embodiment. As illustrated in FIG. 8, the display device 2 includes an acquisition unit 100, a signal processing device 20, a display control unit 104, and a display unit 105. The signal processing device 20 includes an extraction unit 101, a setting unit 202, and a conversion unit 203. Here, constituent elements that perform the same operations as those in the first embodiment are given the same reference numerals, and descriptions thereof are omitted. In the present embodiment, the operation of the setting unit 202 and the conversion unit 203 will be mainly described.

  The setting unit 202 sets the target color temperature in accordance with the ratio of the area where warm color characters exist in the display area in the area determined by the extraction unit 101 as the character area.

  The conversion unit 203 changes the original color temperature of the display area to the target color temperature set by the setting unit 202.

[2-2. Operation]
The operation of the signal processing device 20 configured as described above will be described below.

[2-2-1. Setting color temperature]
FIG. 9 is a diagram illustrating an example of the color temperature setting of the setting unit 202 of the signal processing device according to the second embodiment. FIG. 9 shows an image region B1, a second region B2 where the ratio of warm color characters is low, and a first region B3 where the ratio of warm color characters is high. In the second embodiment, the color temperature of the original content data is 9000K.

  (A) of FIG. 9 shows the content data comprised by image area | region B1 and 2nd area | region B2. In this case, since the first region B3 does not exist, the setting unit 202 increases the decrease range of the color temperature and sets the target color temperature to, for example, 3000K. FIG. 9B shows content data including an image region B1, a second region B2, and a first region B3. In this case, the second area B2 and the other areas are almost the same size. The setting unit 202 sets the target color temperature to 5000K, for example, by reducing the decrease amount of the color temperature smaller than the case of FIG. FIG. 9C shows content data composed of an image area B1 and a first area B3. In this case, since the ratio of the first region B3 is high, the setting unit 202 sets the target color temperature to 6500K, for example, by making the decrease amount of the color temperature smaller than that in FIG.

  As illustrated in FIG. 9, the setting unit 202 sets the color temperature higher as the ratio of the first region B <b> 3 in which warm-colored characters are present in the content data is larger. In other words, the setting unit 202 decreases the amount of decrease from the original color temperature as the ratio of the first region B3 in which warm-colored characters exist is higher.

  Note that the setting unit 202 may weight the first region B3 according to the size of the warm-colored characters in the first region B3.

  FIG. 10 is a flowchart illustrating another operation of the setting unit 202 of the signal processing device according to the second embodiment. The setting unit 202 compares the character size of the warm color with the character size that is not the warm color in the character area (step S1001). If the character size of the warm color is large, the character of the warm color exists. The first region having a high ratio is weighted (S1002). The setting unit 202 sets the target color temperature of the display area in consideration of weighting (S1003). In this case, the setting unit 202 treats the weighted character area as an area smaller than the actual area. This is because when the warm-colored character is larger in size than the non-warm-colored character, the background is easily visually recognized even when the background changes to the warm-colored character. By performing such processing, the target color temperature can be set to a lower value.

[2-2-2. Conversion unit setting operation]
FIG. 11 is a diagram illustrating a change in color temperature in the second embodiment. FIG. 11 shows an example in which the conversion unit 203 gradually changes the color temperature over time with respect to the target color temperature set by the setting unit 202. FIG. 11 shows a color temperature D1 when the first region where the ratio of warm-colored characters is high is large and a color temperature D2 when the first region is small. When the first area is small, the setting unit 202 sets the color temperature E3 having a large decrease width as the target color temperature, and when the first area is large, the setting section 202 sets the color temperature E2 having the small decrease width as the target color temperature. Set. As shown in FIG. 11, the conversion unit 203 draws gentle curves and gradually changes the color temperature D1 and the color temperature D2 toward the target color temperature E2 and the target temperature E3 over time.

[2-3. Effect]
As described above, in the present embodiment, setting unit 202 sets the target color temperature in accordance with the ratio of the first area where the ratio of warm color characters in the display area is high.

  In addition, the setting unit 202 sets the reduction range from the original color temperature to the target color temperature to be smaller as the ratio of the first region is larger.

  Thus, in the content data, when the character area that is not warm color system is large, the reduction range of the target color temperature setting is set large, and when the warm color system character area is large, the reduction range of the color temperature setting is reduced.

  Therefore, in the case of content with a large character area that is not warm colors, the blue light emission component can be greatly reduced. In addition, when the warm-colored character region is large, it is possible to reduce the blue light emission component and to suppress the contrast of the warm-colored character from being lowered and becoming difficult to see.

  The setting unit 202 sets the ratio of the first area to be smaller as the size of the warm color character in the character area is larger.

  The setting unit 202 compares the size of the warm-colored character size and the size of the non-warm-colored character size. If the warm-colored character size is large, the setting unit 202 weights the character area in a smaller direction.

  As a result, when the warm-colored character is large, it is possible to set a color temperature that is larger than the target color temperature set when there is a warm-colored character. That is, it is possible to reduce the blue light emission component and to prevent the contrast of the warm-colored characters from becoming difficult to be seen compared to the processing performed when there are warm-colored characters.

(Third embodiment)
In the third embodiment, a case will be described in which the target color temperature is set according to the contrast of warm-colored characters.

  Hereinafter, the third embodiment will be described with reference to FIGS.

[3-1. Constitution]
FIG. 12 is a block diagram showing one configuration of the display device 3 having the signal processing device according to the third embodiment. As illustrated in FIG. 12, the display device 3 includes an acquisition unit 100, a signal processing device 30, a display control unit 104, and a display unit 105. The signal processing device 30 includes an extraction unit 101, a setting unit 302, and a conversion unit 103. Here, constituent elements that perform the same operations as those in the first embodiment are given the same reference numerals, and descriptions thereof are omitted. In the present embodiment, the operation of the setting unit 302 will be mainly described.

  The setting unit 302 sets a target color temperature in consideration of the contrast state of warm-colored characters in the character area.

[3-2. Operation]
The operation of the display device 30 configured as described above will be described below.

[3-2-1. Color temperature setting in the color temperature setting section]
FIG. 13 is a diagram illustrating an example of the relationship between contrast and color temperature in the third embodiment.

  In FIG. 13, the horizontal axis indicates the color temperature, and the vertical axis indicates the contrast value of the warm color characters. As shown in FIG. 13, when the color temperature is lowered toward the left in the horizontal direction, the contrast of warm-colored characters is lowered. The contrast reaches a preset lower limit value F1 when the color temperature decreases to 5000K. The setting unit 302 sets the target color temperature to a color temperature of 5000K that reaches the lower limit value F1 so that the contrast does not decrease when the contrast reaches the lower limit value F1.

  FIG. 14 is a diagram illustrating an example of a color temperature change in the third embodiment.

  As shown in FIG. 14, the conversion unit 103 gradually lowers the color temperature to the target color temperature. When the color temperature reaches 5000K at time t1, the conversion unit 103 performs processing to keep the color temperature at 5000K.

[3-3. Effect]
As described above, in the present embodiment, setting unit 302 sets the target color temperature so that the contrast of warm-colored characters in the character area does not become smaller than a predetermined value.

  Thereby, in the content data, the color temperature can be set so that the contrast of characters of warm colors does not become smaller than a predetermined value. Therefore, it is possible to display so as to reduce the blue light-emitting component that is supposed to increase user fatigue, and to prevent the contrast of warm-colored characters from being lowered and becoming difficult to see.

(Fourth embodiment)
In the fourth embodiment, a case will be described in which a target color temperature is set according to the contrast of a warm color character and a process of increasing the contrast of a warm color character is performed.

  The third embodiment will be described below with reference to FIGS.

[4-1. Constitution]
FIG. 15 is a block diagram showing a configuration of a display device 4 having a signal processing device according to the fourth embodiment. As illustrated in FIG. 15, the display device 4 includes an acquisition unit 100, a signal processing device 40, a display control unit 104, and a display unit 105. The signal processing device 40 includes an extraction unit 101, a setting unit 402, and a conversion unit 403. Here, constituent elements that perform the same operations as those in the first embodiment are given the same reference numerals, and descriptions thereof are omitted. In the present embodiment, the operation of the setting unit 402 will be mainly described.

  The setting unit 402 sets the target color temperature in consideration of the contrast of the warm color characters in the character area, and sets the conversion contents for increasing the contrast for the warm color characters.

  The conversion unit 403 changes the color temperature of the content data to the target color temperature, and performs a conversion process related to contrast for warm-colored characters according to the conversion content.

[4-2. Operation]
The operation of the signal processing device 40 configured as described above will be described below.

[4-2-1. Operation of setting unit and conversion unit]
FIG. 16 is a diagram illustrating an example of a relationship between contrast and color temperature in the fourth embodiment. In FIG. 16, the vertical axis indicates the contrast value of warm-colored characters, and the horizontal axis indicates the color temperature. In addition, the contrast value G2 before the conversion unit 403 performs the process of increasing the contrast and the contrast value G1 of the warm-colored character after the conversion unit 403 performs the process of increasing the contrast are shown. G3 indicates a lower limit value of a predetermined contrast value.

  As shown in FIG. 16, when the color temperature is lowered toward the left in the horizontal direction, the contrast value of warm-colored characters is also lowered. The contrast value G2 reaches the lower limit G3 when the color temperature drops to 5000K. At this time, if processing for increasing the contrast of warm-colored characters is performed, the contrast value G2 becomes the value of the contrast value G1, and even if the color temperature is lowered to about 3000K, the contrast larger than the lower limit G3 of the contrast can be maintained. it can.

  In this case, the setting unit 402 sets the target color temperature to 3000K. In addition, the setting unit 402 sets the first color temperature 5000K at which the contrast value reaches the lower limit value and the conversion content that increases the contrast value.

  FIG. 17 is a diagram illustrating a change in color temperature in the fourth embodiment. The conversion unit 403 gradually decreases the color temperature of the content data toward the target color temperature of 3000K. In addition, when the color temperature reaches 5000K at time t2, the conversion unit 403 performs a process of increasing the contrast on the warm-colored characters.

  Here, as a process for increasing the contrast of the character, there is a process for changing the brightness between the character and the background, the saturation or the hue of the character, and the like.

[4-3. Effect]
As described above, in the present embodiment, setting unit 402 sets the target color temperature for displaying content data in consideration of the contrast of warm-colored characters in the character area. The setting unit 402 sets the first color temperature and the conversion content at which the contrast of the warm-colored character in the character region becomes a predetermined value. The conversion unit 403 changes the color temperature of the content data to the target color temperature. In addition, when the setting unit 402 lowers the color temperature from the first color temperature, the conversion unit 403 performs a process of increasing the contrast of warm-colored characters.

  Thus, when the color temperature when displaying the content data is lowered, the contrast value of the warm-colored character can be prevented from becoming smaller than a predetermined value.

  Therefore, it is possible to display so as to reduce the blue light-emitting component that is supposed to increase user fatigue, and to prevent the contrast of warm-colored characters from being lowered and becoming difficult to see.

  As described above, the embodiments have been described as examples of the technology in the present disclosure. For this purpose, the accompanying drawings and detailed description are provided.

  Accordingly, among the components described in the accompanying drawings and the detailed description, not only the components essential for solving the problem, but also the components not essential for solving the problem in order to illustrate the above technique. May also be included. Therefore, it should not be immediately recognized that these non-essential components are essential as those non-essential components are described in the accompanying drawings and detailed description.

  Moreover, since the above-mentioned embodiment is for demonstrating the technique in this indication, a various change, replacement, addition, abbreviation, etc. can be performed in a claim or its equivalent range.

  The present disclosure is applicable to a signal processing device with a display unit. Specifically, the present disclosure is applicable to PC displays, in-flight displays, tablet terminals, head mounted displays, smartphones, and the like.

DESCRIPTION OF SYMBOLS 100 Acquisition part 101 Extraction part 102,202,302,402 Setting part 103,203,403 Conversion part 104 Display control part 105 Display part

Claims (8)

An extraction unit that extracts a character region in which a ratio of a region occupied by characters is larger than a predetermined value in a display region where content data is displayed;
When color information of characters in the character area indicates a warm color system, a setting unit that sets a target color temperature when displaying the content data based on the color information ;
A conversion unit that changes the original color temperature of the content data to the target color temperature;
A signal processing apparatus comprising: The signal processing apparatus according to claim 1, wherein the setting unit sets a decrease width from the original color temperature to the target color temperature smaller than when the color information does not indicate a warm color system .   The said setting part extracts the 1st area | region where the warm color type character in the said display area exists, and sets the said target color temperature according to the ratio of the said 1st area | region in the said display area. A signal processing device according to 1. The signal processing apparatus according to claim 3 , wherein the setting unit sets a reduction width from the original color temperature to the target color temperature to be smaller as a ratio of the first area to the display area is larger. .   The signal processing apparatus according to claim 4, wherein the setting unit sets the ratio of the first region to be smaller as the size of the warm color character in the first region is larger.   The signal processing apparatus according to claim 1, wherein the setting unit sets a target color temperature so that a contrast of a warm color character in the character region does not become smaller than a predetermined value. The setting unit sets a first color temperature at which a contrast of a warm color character in the character region becomes a predetermined value;
2. The signal processing device according to claim 1, wherein when the color temperature of the data of the content is lower than the first color temperature, the conversion unit performs a process of increasing a contrast of a warm color character in the character region. . In the display area where the content data is displayed, a character area in which the proportion of the area occupied by the characters is larger than a predetermined value, and when the color information of the characters in the character area indicates a warm color system, based on the color information And setting a target color temperature for displaying the content data, and changing the original color temperature of the content data to the target color temperature.

Images