JP2008281819A - Color display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color display device that can display a color image easily recognizable by a person with defective color vision as well as recognizable by a person with normal color vision while avoiding an unnatural image. <P>SOLUTION: The color display device includes an image signal processing circuit 3 that processes input image signals. The image signal processing circuit 3 has: a basic processing circuit 10 for displaying an image recognizable by a person with normal color vision; and a correction processing circuit 11 for correcting the image signal output from the basic processing circuit 10 to display an image with enhanced only in a boundary portion to be easily recognized by a person with defective color vision, because a person with defective color vision has difficulty in recognizing a color boundary. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a color display device such as a projector, and more particularly to a color display device that displays a color image that can be easily recognized by a person with color blindness.

  In recent years, with the progress of the times, color design has been promoted in order to make it easier to attract interest to information and to convey information more accurately in various printed materials, display panels, image display devices such as images, etc. . For this reason, color display devices are common in display devices such as projectors. For example, in the education field, color presentation using a color projector has recently been frequently used in place of the previous presentation by monochrome OHP. Similarly, color images have become common in image display devices in public facilities. However, conventional color display devices are usually manufactured based on color recognition by a person with normal color vision. For this reason, there are increasing cases of inconvenience for color blind people.

  Here, the color blind person in this specification means people called a color blind person or a color blind person. In addition, as color blind people, there are many red-green color blind people who are difficult to distinguish between red and green, but there are also blue-yellow color blind people who are difficult to distinguish between blue and yellow. A person with abnormal red-green color vision is caused by an abnormality in the red or green vertebra system. An abnormal person with an abnormality in the red vertebra system is called a first color vision abnormal person, and there is an abnormality in the green vertebra system. The abnormal person is referred to as the second color blind person. Also, the blue / yellow vision abnormality is caused by an abnormality of the blue vertebra system, and the abnormal person in this case is referred to as a third color blind person. In addition, the percentage of people with color blindness is not small in many countries around the world. More specifically, in the case of the yellow race, the ratio of about 1 in 500 (about 0.2%) for women is relatively low, but about 20 in the case of men of the same yellow race. One person (about 5%) is high. In the case of blacks, males account for a high percentage of about 5%, and white males reach a high percentage of about 8%.

Therefore, in today where color is used as an important information transmission means, it is necessary to consider so as not to be disadvantageous for the color blind person.
As a color display device that makes it easy for color blind people to recognize colors under such a background of the times, a display system for color blind people described in Patent Document 1 has been proposed. This color display device replaces the display color that is difficult for red-green color vision abnormal people to recognize with other display colors that are easy for red-green color vision abnormal people to recognize, and makes it easier for red-green color vision abnormal people to recognize. is there.
JP 11-175050 A

  However, since the color display device of Patent Document 1 is only displayed in a display color that can be easily recognized by persons with abnormal red-green color vision, the color image displayed by this color display device is not recognized by those with normal color vision. It is difficult to avoid difficult images. Therefore, the color display device disclosed in Patent Document 1 is not a device that can provide recognizable images to both normal and abnormal color vision persons. This causes various inconveniences. For example, when installing a color display device as a public information means in a public facility, it is necessary to install a color display device for people with normal color vision and a color display device for people with color blindness, which increases the equipment cost. Cause problems. In addition, there is a problem that it is difficult to communicate between the color vision normal person and the color vision abnormal person regarding the image of the color display device.

  The present invention has been made by paying attention to such a problem existing in the prior art, and displays a color image that is easily recognized by a person with color blindness, can also be recognized by a person with normal color vision, and is unnatural. It is an object of the present invention to provide a color display device that can display an image that does not become.

  The present invention is a color display device including an image signal processing circuit for processing an input image signal, the image signal processing circuit, a basic processing circuit for displaying a screen that can be recognized by a normal color vision person, A correction processing circuit that corrects the image signal output from the basic processing circuit so as to display only the boundary portion so that the color boundary that is difficult for the color blind person to recognize easily is displayed. It is characterized by having.

  According to the color display device of the present invention having such a structural feature, when an input image is an image having a color boundary that can be recognized by a person with normal color vision but cannot be recognized by a person with color blindness In addition, only the boundary portion of the color boundary is displayed on the highlighted screen. For this reason, a color blind person can recognize a color boundary by emphasizing only the boundary portion of the color boundary. Further, an image in which only the boundary portion of the color boundary is emphasized in this way is not so unnatural for a person with normal color vision. Therefore, according to this display device, it is possible to display an image that can be recognized by both a color vision abnormal person and a color vision normal person, so that the usage can be diversified and the investment efficiency of equipment can be improved. In addition, the color display device can be used as a medium to deepen mutual understanding between the color blind person and the color blind person.

  Further, the image signal processing circuit can switch between outputting the image signal processed by the basic processing circuit as it is or correcting the image signal processed by the basic processing circuit by the correction processing circuit and outputting it. A signal switching circuit may be provided. If comprised in this way, the color image for color blind persons and the color image for color blind persons corrected so that a person with color blindness may recognize easily can be switched and displayed. Therefore, when displaying a color image for a person with normal color vision, it is possible to display a more natural image for the person with normal color vision.

  The correction processing circuit includes: a color conversion circuit that converts an input RGB image signal into an RGB image signal that simulates the appearance of a color vision standard for a color blind person; and a color boundary based on the converted image signal And a color edge enhancement circuit that is processed so as to enhance only the boundary portion of the color boundary that is determined to require color boundary enhancement. It shall be. In this way, since only the color boundary that cannot be identified by the color blind person is extracted and only the boundary part of the color boundary is emphasized, there is no useless enhancement of the color boundary and an image that is not unnatural for the normal color blind person is provided. Can do.

  The color edge enhancement circuit converts a RGB image signal from the basic processing circuit into a luminance color difference image signal, and converts the RGB image signal output from the color conversion circuit into a luminance color difference image signal. A luminance color difference image that is determined to be color boundary enhancement and to determine whether or not the color boundary enhancement is necessary based on the converted luminance color difference image signal It may be provided with a color edge arithmetic circuit that corrects the signal to be converted into an RGB image signal and emphasized. If comprised in this way, since it will be judged whether it is located in a color boundary based on the converted brightness | luminance color difference image signal, and the necessity of color boundary emphasis, a process becomes easy. In addition, since color boundary enhancement can be corrected based on the RGB image signal, color boundary enhancement calculation processing is facilitated.

  The color edge calculation circuit compares the luminance color difference image signal output from the first luminance color difference conversion circuit with that of the adjacent pixel, and determines whether the color difference difference with the adjacent pixel exceeds a predetermined reference value. It is determined whether or not it is located at a color boundary recognized by a normal person, the luminance color difference image signal output from the second luminance color difference conversion circuit is compared with that of an adjacent pixel, and the color difference difference and the luminance difference are determined according to respective predetermined standards. Depending on whether or not it is smaller than the value, it is determined whether or not the image is recognized at the color boundary in the image recognized by the color blind person. With this configuration, it is possible to determine in series whether or not the color boundary is positioned and whether or not color boundary enhancement is necessary, and the processing becomes simple.

  When the color edge calculation circuit determines that color boundary enhancement is necessary, the RGB value recognized by a person with normal color vision is represented by a gradation value corresponding to the number of bits. It is configured to calculate a correction amount only for the boundary portion of the color boundary determined to be emphasized using a color edge enhancement table in which RGB values are compared as correction amounts for emphasizing so as to be easy. Yes. In this way, the correction amount can be easily calculated by using the color edge enhancement table.

  The color edge emphasis circuit may include a correction amount adjustment circuit that adjusts the correction amount to a plurality of correction levels, and the user can select a level of the correction level. In this way, it is possible to perform correction that absorbs the user's view and personal differences of preference.

  In addition, the color conversion circuit represents the RGB value recognized by the normal color vision person as a numerical value of gradation according to the number of bits, and contrasts the RGB value for simulating the appearance of the color vision standard of the color vision abnormal person. The correction amount is calculated using the color conversion interpolation table, and the RGB image signal is converted by adding the correction amount. With this configuration, it is possible to easily calculate a reliable correction amount by using the color conversion interpolation table and to simulate the RGB image signal based on the color blind person.

  The correction processing circuit includes a first correction mode for a first color blind person, a second correction mode for a second color blind person, and a third color blind person as a third person. A correction mode, and the first correction mode, the second correction mode, and the third correction mode are a color conversion interpolation table for a first color blind person, a second color blind person, or a third color blind person, The color edge enhancement table may be used, and the first correction mode, the second correction mode, and the third correction mode may be alternatively selected and used according to the user's selection. Good. If comprised in this way, it can be set as the apparatus which respond | corresponds to a 1st color-blind person, a 2nd color-blind person, and a 3rd color-blind person individually, respectively, and it can be applied to any kind of color-blind person by switching It becomes possible to respond.

  The color display device can be a liquid crystal projector. When the color display device is a liquid crystal projector, presentation materials, video images, and television images created on a PC or the like can be viewed as images that can be easily recognized by people with color blindness, and can also be viewed as images for people with normal color vision. .

  According to the present invention, when an input image is an image having a color boundary that can be recognized by a person with normal color vision but cannot be recognized by a person with color blindness, only the boundary portion of the color boundary is emphasized. Is displayed. Thereby, a color blind person can recognize a color boundary. Further, an image in which only the boundary portion of the color boundary is emphasized is not so unnatural for a person with normal color vision. Therefore, according to the present invention, it is possible to display an image that can be recognized by both a color blind person and a color blind person.

  The color display device according to this embodiment is a liquid crystal projector that displays a color image that can be recognized by both a color-blind person and a color-blind person, and is configured as a liquid crystal three-plate projection projector. Hereinafter, the configuration of image processing in the liquid crystal projector according to the present embodiment will be described with reference to FIGS. FIG. 1 is a schematic functional block diagram relating to image processing of the liquid crystal projector according to the present embodiment, FIG. 2 is a detailed diagram of an image signal processing circuit of the liquid crystal projector, and FIG. 3 is a color edge of the liquid crystal projector. It is a detailed view of an emphasis circuit. FIG. 4 is a conceptual diagram of a color conversion interpolation table used in the color conversion circuit, and FIG. 5 is a conceptual diagram of a color edge enhancement table used for color boundary enhancement.

  As shown in FIG. 1, the image processing of the liquid crystal projector according to the present embodiment is roughly the same as that of a general one. That is, when an analog input image signal is input from an input device such as a personal computer or a video, it is converted to a digital signal by the A / D conversion circuit 1, and when a digital input image signal is input, the A / D The conversion circuit 1 is bypassed and input to the pixel conversion circuit 2, and the pixel conversion circuit 2 performs scaling processing. That is, the pixel conversion circuit 2 performs processing for matching the resolution of the input image signal with the resolution of the display unit. The RGB image signal scaled by the pixel conversion circuit 2 is input to the image signal processing circuit 3 so that it can be easily recognized by a general process necessary for obtaining a high-quality image or a color blind person according to the present invention. Processing for obtaining an image is performed.

  The image signal processed by the image signal processing circuit 3 is input to the digital gamma correction circuit 4 and gamma corrected. Then, the gamma corrected image signal is input to each LCD panel driver 5 that drives the LCD panel 6 for each RGB color, and the LCD panel 6 for each color is driven.

Further, in the three-plate liquid crystal projector according to this embodiment, an ultrahigh pressure mercury lamp (not shown) is used as a light source.
White light from the ultra-high pressure mercury lamp passes through the RGB dichroic mirror, is decomposed into RGB three components, and is transmitted to the LCD panel 6 for each color. The light transmitted through the LCD panel 6 is generated as RGB three-component light for image formation when an image signal that has passed through the digital gamma correction circuit 4 is input to each LCD panel driver 5 of the LCD panel 6. The RGB three-component light for image formation that has passed through the LCD panel 6 for each color is combined by an RGB combining dichroic mirror, and further projected onto a screen via an optical system device such as a projection lens, whereby a predetermined color image is displayed on the screen. Formed.

Here, the image signal processing circuit 3 that characterizes the present invention will be specifically described.
As shown in FIG. 2, the image signal processing circuit 3 includes a basic processing circuit 10 that performs image processing similar to image processing in an ordinary liquid crystal projector on an input RGB image signal. In addition, the image signal processing circuit 3 is output from the basic processing circuit 10 so as to display a screen with only the boundary portion emphasized so that the color boundary is difficult for the color blind person to recognize easily. A correction processing circuit 11 for correcting the image signal is provided. Further, the image signal processing circuit 3 can switch between outputting the image signal processed by the basic processing circuit 10 as it is, or converting the image signal processed by the basic processing circuit 10 by the correction processing circuit 11 and outputting it. The signal switching circuit 12 is provided. The above-described image processing in a normal liquid crystal projector is image processing performed in an image processing circuit in a general liquid crystal projector, and includes frequency conversion processing, color management in accordance with a color vision standard recognized by a color vision normal person, A process for obtaining a high-quality image signal such as sharpness.

  As shown in FIG. 2, the correction processing circuit 11 includes a color conversion circuit 13 that corrects the RGB input signal output from the basic processing circuit 10 so as to simulate the color vision standard of the color blind person. Further, the correction processing circuit 11 recognizes the color boundary, determines whether or not color boundary enhancement is necessary, and enhances only the boundary portion of the color boundary so that a color blind person can easily recognize when it is determined to be necessary. A color edge emphasis circuit 14 is provided for correcting as described above.

  The color conversion circuit 13 converts the RGB image signal output from the basic processing circuit 10 into an RGB image signal that simulates the appearance of the color vision standard of the color blind person. This conversion is performed using a color conversion interpolation table. As shown in FIG. 4, the color conversion interpolation table represents RGB values recognized by a person with normal color vision as gradation values according to the number of bits, and appropriately expresses these numerical values and RGB values recognized by a person with abnormal color vision. This is a step-by-step comparison. FIG. 4 is a conceptual diagram, and specific numerical values are omitted. Further, as the color conversion interpolation table, the first color conversion interpolation table 16 for the first color blind person, the second color vision, in order to correspond to the color vision standard of each color blind person depending on the type of the color blind person. A second color conversion interpolation table 17 for an abnormal person and a third color conversion interpolation table 18 for a third color blind person are prepared. These color conversion interpolation tables are connected to the color conversion circuit 13 via the first table switching circuit 15 so as to be switchable.

  As shown in FIG. 3, the color edge enhancement circuit 14 receives the image signal output from the basic processing circuit 10 and the image signal color-converted by the color conversion circuit 13. At this time, the RGB image signal from the basic processing circuit 10 is converted into a luminance color difference image signal by the first luminance color difference conversion circuit 25. The RGB image signal corrected by the color conversion circuit 13 is converted into a luminance color difference image signal by the second luminance color difference conversion circuit 26. The luminance color difference image signal converted by the first luminance color difference conversion circuit 25 is input to the color edge calculation circuit 27 as the luminance color difference image signal based on the color vision of the normal color vision person, and the luminance converted by the second luminance color difference conversion circuit 26 is obtained. The color difference image signal is input to the color edge calculation circuit 27 as a luminance color difference image signal based on the color vision of the color blind person.

  The color edge calculation circuit 27 receives the luminance color difference image signal based on the color vision of the normal color vision person input from the first luminance color difference conversion circuit 25 and the luminance color difference image signal based on the color vision standard of the color vision abnormality person input from the second luminance color difference conversion circuit 26. Based on the above, it is determined whether or not all pixels are sequentially positioned at the color boundary and whether or not the color boundary enhancement is necessary. Further, the luminance color difference image signal based on the color vision of the normal color vision person inputted from the first luminance color difference conversion circuit 25 is converted into an RGB signal, and a correction amount for enhancing only the boundary portion of the color boundary is calculated. The calculation of the correction amount is performed using a color edge enhancement table.

  As shown in FIG. 5, the color edge enhancement table expresses RGB values recognized by a normal color vision person as gradation values according to the number of bits, and emphasizes the numerical values so that a color blind person can easily recognize them. The RGB values as correction amounts to be compared are compared step by step. FIG. 5 is a conceptual diagram, and specific numerical values are omitted. In addition, the color edge enhancement table includes a first color edge enhancement table 20 for the first color blind person and a second color blind abnormality in order to correspond to the color vision standard of each color blind person depending on the type of the color blind person. A second color edge enhancement table 21 for a person and a third color edge enhancement table 22 for a person with a third color blindness are prepared. These color edge enhancement tables are connected to the color edge calculation circuit 27 via the second table switching circuit 19 so as to be switchable.

  Further, the color edge enhancement circuit 14 calculates the correction amount as an RGB value and outputs it to the correction amount adjustment circuit 28. In the correction amount adjustment circuit 28, the correction amount is adjusted by multiplying the correction amount selected by the user by this correction amount. The adjusted correction amount is output to the edge addition circuit 29, added to the RGB value of the image signal directly input from the basic processing circuit 10, and the RGB image signal with the color boundary enhanced is passed through the signal switching circuit 12. It is output to the digital gamma correction circuit 4.

  Next, the operation of the image signal processing circuit 3 will be described with reference to FIGS. FIG. 6 is a flowchart of the image signal processing, and FIG. 7 is a flowchart of determination of necessity of color boundary enhancement in the image signal processing.

  In this liquid crystal projector, the user first selects the display mode, the type of correction mode, and the degree of correction from the OSD menu of the signal switching circuit 12 displayed on the screen of the liquid crystal projector (step S1).

The selection of the display mode is to select whether the display by the color display device is the normal mode or the correction mode.
Selection of the type of correction mode is to select one of the first to third correction modes as the correction mode of the correction processing circuit 11, and when the normal mode is selected as the display mode in step S1. There is no need to select this. The type of correction mode (the type of correction mode of the correction processing circuit 11) is determined by selecting the type of color blind person to be used. When the first color blind person is selected as the color blind person to be used, this selection signal is transmitted to the first table switching circuit 15 and the second table switching circuit 19, and these table switching circuits are switched to perform the first color conversion interpolation. The table 16 is connected to the color conversion circuit 13, and the first color edge enhancement table 20 is connected to the color edge enhancement circuit 14. This is referred to as a first correction mode. Similarly, when the second color blind person or the third color blind person is selected, the first table switching circuit 15 is switched and the second color conversion interpolation table 17 or the third color conversion interpolation table 18 performs color conversion. Connected to the circuit 13. Then, the second table switching circuit 19 is switched, and the second color edge enhancement table 21 or the third color edge enhancement table 22 is connected to the color edge enhancement circuit 14. This is referred to as a second correction mode or a third correction mode. Therefore, selecting the type of correction mode is synonymous with selecting the type of color blind person to be used.

  The selection of the correction degree is to select a ratio to be multiplied by the correction amount calculated by the color edge calculation circuit 27. When the normal mode is selected, it is not necessary to select this correction degree. The selection of the correction degree is selected to absorb the user's appearance and personal differences of preference, and is usually set to have a plurality of selection stages. For example, a plurality of selection steps are given in the range of 50% to 150%. The selection signal of the selected correction degree is transmitted to the correction amount adjustment circuit 28.

  Next, the display mode selected in step S1 is confirmed (step S2). Here, when it is confirmed that the normal mode is selected as the display mode, the signal switching circuit 12 is directly connected to the basic processing circuit 10 (step S3). Therefore, the image signal processed by the basic processing circuit 10, that is, the image signal that can be recognized by a normal color vision person, is directly output to the digital gamma correction circuit 4 through the signal switching circuit 12 (step S4). As a result, an image that can be recognized by a person with normal color vision is displayed on the screen of the liquid crystal projector.

  On the other hand, when it is confirmed in step S2 that the correction mode is selected as the selected display mode, the signal switching circuit 12 is connected to the correction processing circuit 11 (step S5). As a result, the image signal from the basic processing circuit 10 is input to the correction processing circuit 11. The image signal input from the basic processing circuit 10 is input to the color conversion circuit 13. The color conversion circuit 13 is connected to a color conversion table (for the selected color blind person) selected in step S 1 via a first table switching circuit 15. Therefore, the RGB image signal input from the basic processing circuit 10 is selected from the selected color vision by an operation such as an interpolation calculation using a color conversion table (for the selected color blind person) in the selected correction mode. It is converted into an RGB image signal that simulates the appearance of the color vision standard of the abnormal person (step S6).

  The image signal converted by the color conversion circuit 13 is an RGB image signal that simulates the appearance of the color vision standard of the selected color blind person, and the image signal output from the basic processing circuit 10 is the color vision of the normal color vision person. Reference RGB image signal. Therefore, both image signals are input to the color edge enhancement circuit 14 to extract pixels that require color boundary enhancement (edge enhancement) (step S7).

Note that the necessity of color boundary enhancement necessary for this extraction is performed as follows. This will be described with reference to FIG.
The RGB image signal simulated to the appearance of the color vision standard of the color blind person input from the color conversion circuit 13 is converted into a luminance color difference image signal by the second luminance color difference conversion circuit 26 (step S21), and then for each pixel. A color difference difference (defined as UV1) and a luminance difference (defined as Y1) from adjacent pixels are calculated (step S22). Also, the color vision reference RGB image signal of the normal color vision person input from the basic processing circuit 10 is converted into a luminance color difference image signal by the first luminance color difference conversion circuit 25 (step S23), and then the adjacent pixels are detected for each pixel. Color difference (defined as UV2) and luminance difference (defined as Y2) are calculated (step S24). Note that the luminance difference Y2 may be omitted because it is not used for the determination described below.

  Next, it is determined whether or not the color difference difference UV2 with the adjacent pixel calculated from the image signal of the normal color vision person is larger than a predetermined reference value UVKA (step S25). If it is NO, it means that it is not located at the color boundary according to the color vision standard of a person with normal color vision. Therefore, there is no need for color boundary enhancement (step S26). However, if it is YES, it is determined that it is located at the color boundary according to the color vision standard of the person with normal color vision, so it is necessary to determine whether it is recognized as being located at the color boundary according to the color vision standard of the person with color vision abnormality There is.

  Therefore, in the case of YES in step S25, the color difference from the adjacent pixel calculated from the image signal of the color blind person in the next step in order to see whether or not it is located at the color boundary on the basis of the color vision standard of the color blind person. It is determined whether or not the difference UV1 is smaller than a predetermined reference value UVKB (step S27). If NO, it means that the color difference difference UV1 is larger than the predetermined reference value UVKB, and it is recognized that this pixel is positioned at the color boundary even when viewed from the color vision standard of the color blind person without any processing. It will be. Therefore, there is no need for color boundary enhancement (edge enhancement) (step S26). However, if YES, it means that a person with normal color vision is recognized as being located at a color boundary, whereas a color vision standard of a person with abnormal color vision cannot be recognized as being located at a color boundary by color difference.

  In the case of YES in step S27, it is determined whether or not the color boundary can be recognized based on the difference in luminance as seen from the color vision standard of the color blind person. Therefore, it is determined whether or not the luminance difference Y1 with the adjacent pixel calculated from the image signal of the color blind person in the next step is smaller than a predetermined reference value YK (step S28). If NO, it means that the luminance difference Y1 is larger than the predetermined reference value YK, and it is recognized that the color blind person is positioned at the color boundary according to how the color vision standard is viewed, so there is no need for color boundary enhancement. (Step S26). However, if YES, it means that there is no difference between adjacent pixels when viewed from both sides of the color difference and luminance in terms of how the color vision standard is viewed, that is, it cannot be recognized that it is located at the color boundary. Therefore, it is determined that it is necessary to emphasize only the boundary portion of the color boundary so that the color boundary can be recognized (necessity of edge enhancement) (step S29). As described above, the necessity of color boundary enhancement (edge enhancement) is determined, and pixels that need color boundary enhancement are extracted.

  Next, for a pixel that is determined to require color boundary enhancement (edge enhancement), the image signal from the basic processing circuit 10 converted into a luminance / color difference image signal is converted into an RGB image signal, and RGB of this image signal is converted. The correction amount for the value is read from the color edge enhancement table, and the correction amount is obtained through interpolation calculation (step S8). At this time, the color edge calculation circuit 27 is connected with the color edge enhancement table (for the selected color blind person) selected in step S1, so that the correction amount is determined in step S1. This is the correction amount for the correction mode selected in (the selected type of color blindness person).

  Next, the correction level adjustment circuit 28 reads the correction level selected in step S1, and multiplies the correction level calculated previously by this correction level (step S9). Using this result as the final correction amount, the correction amount is added to the RGB value of the image signal input from the basic processing circuit 10 in the edge addition circuit 29 (step S10). As described above, the necessity of the color boundary and the correction amount for color boundary enhancement are sequentially calculated for all the pixels for each pixel. Thus, an image signal for emphasizing only the boundary portion and displaying the screen so that the color boundary that is difficult for the color blind person to recognize easily is output from the image signal processing circuit 3 to the digital gamma correction circuit 4. (Step S11).

According to the color display device according to the present embodiment configured as described above, the following effects can be obtained.
(1) According to the color display device according to the present embodiment, when the input image is an image having a color boundary that can be recognized by a person with normal color vision but cannot be recognized by a person with color blindness, the color boundary Only the boundary part of is displayed on the highlighted screen. For this reason, a color blind person can recognize a color boundary by emphasizing only the boundary portion of the color boundary. In addition, an image in which only the boundary portion of the color boundary is emphasized in this way is not so unnatural for a person with normal color vision. Therefore, by correcting the image signal processed by the basic processing circuit 10 by the correction processing circuit 11, it is possible to display an image that can be easily recognized by a person with color blindness, and an image that is not unnatural for a person with normal color blindness. Can be displayed.

  (2) According to the display device according to this embodiment, an image that can be recognized by both a color vision abnormal person and a color vision normal person can be displayed, so the usage is diversified and the investment efficiency of equipment is improved. be able to. Further, by using this color display device, it is possible to deepen mutual understanding between a person with normal color vision and a person with abnormal color vision.

  (3) It is possible to switch between a color image for a normal color blind person and a color image for a color blind person corrected so as to be easily recognized by a color blind person. Therefore, when displaying a color image for a person with normal color vision, it is possible to display a more natural image for the person with normal color vision.

  (4) The input image signal is converted into an RGB image signal that simulates the appearance of the color vision standard of the color blind person, and whether or not the input image signal is located at the color boundary based on the converted image signal and the color boundary enhancement (edge enhancement) ) Is emphasized, and only the boundary portion of the necessary color boundary is emphasized. For this reason, there is no useless enhancement of the color boundary, and it is possible to minimize a portion that is likely to appear unnatural to a person with normal color vision.

  (5) Since it is determined based on the image signal converted into the luminance color difference image signal whether or not it is located at the color boundary and whether or not the color boundary enhancement is necessary, the processing becomes easy. Further, since the correction amount is calculated after converting the image signal determined to need color boundary enhancement into an RGB image signal, the color boundary enhancement calculation processing becomes easy.

  (6) After converting an RGB image signal into a luminance / color difference image signal, whether or not there is a color difference difference between adjacent pixels, whether or not it is positioned at a color boundary depending on whether or not there is a luminance difference, and whether or not color boundary enhancement is necessary Since it is determined, the process becomes simple.

  (7) When the color edge calculation circuit 27 determines that the color boundary enhancement is necessary, the RGB value recognized by the color vision normal person is represented by a numerical value of gradation according to the number of bits. Since the correction amount is calculated using the color edge enhancement table in which the RGB values as the correction amount for emphasizing so as to be easily recognized, the correction amount can be easily calculated.

(8) Since the user can select the level of the correction degree, it is possible to perform correction that absorbs the user's appearance and personal differences of preference.
(9) The color conversion circuit 13 represents an RGB value recognized by a person with normal color vision as a numerical value of gradation corresponding to the number of bits, and an RGB value for simulating the appearance of the color vision standard of the person with color vision abnormality is represented with respect to this numerical value Since the interpolated color conversion interpolation table is used, the correction amount can be easily calculated.

  (10) The correction processing circuit 11 includes a first correction mode for the first color blind person, a second correction mode for the second color blind person, and a third color blind person as the target person. Since the third correction mode is provided, it is possible to cope with any type of color blindness person by selecting these correction modes.

  (11) Since the color display device according to the present embodiment is configured as a liquid crystal projector, presentation materials, video images, and television images created on a PC or the like can be viewed as images that are easily recognized by color blind persons. At the same time, it can be viewed as an image for a person with normal color vision.

(Modification)
The above embodiment can be modified as follows.
(1) In the above embodiment, the correction amount adjustment circuit 28 is provided in the color edge enhancement circuit 14 constituting the correction processing circuit 11, and the correction amount can be adjusted according to the correction degree selected by the user. Providing such a correction amount adjustment circuit 28 can be eliminated.

  (2) The color display device according to the above embodiment is formed in a device intended for the first color blind person, the second color blind person, or the third color blind person. In view of the fact that the person is the first color blind person or the second color blind person, a simple device for the first color blind person or the second color blind person may be provided.

  (3) In the above embodiment, the color display device has been described as a liquid crystal three-plate type projection projector, but the present invention is not limited to this, and the projector has a regular grid of RGB color filters. A configuration using a single-plate liquid crystal light valve that is arranged and capable of projecting full-color modulated light with one sheet may be used. In the above embodiment, a projector using a liquid crystal panel is shown. However, a projection display device having another image light generation system, for example, DLP (Digital Light Processing) (Texas Instruments (TI), Inc. The present invention can also be applied to projectors of the registered trademark).

  (4) In the above embodiment, the color display device has been described as a projection projector, but is not limited to a projector. The color display device may be, for example, a CRT display, a plasma display, a liquid crystal display, an organic EL display, a rear projector, or the like.

  The display device according to the present invention is useful for a color display device in which a person with normal color vision and a person with abnormal color vision are users. Such a color display device may be for home use or business use. The screen size can also be applied to various types.

1 is a schematic functional block diagram of a liquid crystal projector according to an embodiment of the present invention. 2 is a detailed diagram of an image signal processing circuit of the liquid crystal projector. FIG. FIG. 3 is a detailed diagram of a color edge enhancement circuit of the liquid crystal projector. FIG. 2 is a conceptual diagram of a color conversion interpolation table used for a color conversion circuit in the liquid crystal projector. FIG. 3 is a conceptual diagram of a color edge enhancement table used for color boundary enhancement in the liquid crystal projector. 6 is a flowchart of image signal processing in the liquid crystal projector. 6 is a flowchart for determining necessity of color boundary enhancement in the image signal processing.

Explanation of symbols

  Y1 ... luminance difference, YK, UVKA, UVKB ... reference value, UV1, UV2 ... color difference difference, 3 ... image signal processing circuit, 10 ... basic processing circuit, 11 ... correction processing circuit, 12 ... signal switching circuit, 13 ... color conversion Reference numeral 14: Color edge enhancement circuit 25: First luminance color difference conversion circuit 26: Second luminance color difference conversion circuit 27: Color edge calculation circuit 28: Correction amount adjustment circuit

Claims (10)

A color display device including an image signal processing circuit for processing an input image signal,
The image signal processing circuit includes a basic processing circuit for displaying a screen that can be recognized by a person with normal color vision, and emphasizes only the boundary portion so that a color boundary that is difficult for a color blind person to recognize can be easily recognized. A color display device comprising: a correction processing circuit that corrects an image signal output from a basic processing circuit so as to display a screen. The image signal processing circuit is capable of switching whether the image signal processed by the basic processing circuit is output as it is or whether the image signal processed by the basic processing circuit is corrected by the correction processing circuit and output. The color display device according to claim 1, further comprising a circuit.   The correction processing circuit includes a color conversion circuit that converts an input RGB image signal into an RGB image signal that simulates the appearance of a color vision standard for a color blind person, and a color boundary based on the converted image signal. A color edge enhancement circuit that determines whether or not to perform color boundary enhancement and further processes only the boundary portion of the color boundary that is determined to require color boundary enhancement. The color display device according to claim 1 or 2.   The color edge enhancement circuit converts a RGB image signal from the basic processing circuit into a luminance color difference image signal, and converts the RGB image signal output from the color conversion circuit into a luminance color difference image signal. A luminance color difference image that is determined to be color boundary enhancement and to determine whether or not the color boundary enhancement is necessary based on the converted luminance color difference image signal 4. A color display device according to claim 3, further comprising a color edge calculation circuit that corrects the signal to be converted into an RGB image signal and emphasizes the signal.   The color edge calculation circuit compares the luminance color difference image signal output from the first luminance color difference conversion circuit with that of the adjacent pixel, and determines whether the color difference difference with the adjacent pixel exceeds a predetermined reference value. It is determined whether or not it is located at a color boundary recognized by a normal person, the luminance color difference image signal output from the second luminance color difference conversion circuit is compared with that of an adjacent pixel, and the color difference difference and the luminance difference are determined according to respective predetermined standards. 5. The color according to claim 4, wherein it is determined whether or not the image is recognized at a color boundary in an image recognized by a person with color blindness, and whether or not color boundary enhancement is necessary is determined based on the determination. Display device.   When the color edge calculation circuit determines that color boundary enhancement is necessary, the RGB value recognized by a person with normal color vision is represented by a gradation value corresponding to the number of bits. The correction amount of only the boundary portion of the color boundary determined to be emphasized is calculated using a color edge enhancement table in which RGB values as correction amounts to be emphasized for easy comparison are used. 5. A color display device according to 5.   The color edge emphasis circuit includes a correction amount adjustment circuit that adjusts the correction amount to a plurality of levels of correction, and is configured to allow a user to select a level of correction. 6. The color display device according to 6.   The color conversion circuit represents a RGB value recognized by a person with normal color vision as a numerical value of gradation according to the number of bits, and contrasted with this value is an RGB value that simulates the appearance of the color vision standard of a person with color blindness. The color display device according to any one of claims 3 to 7, wherein a correction amount is calculated using a color conversion interpolation table, and the RGB image signal is converted by adding the correction amount. The correction processing circuit includes a first correction mode for a first color blind person, a second correction mode for a second color blind person, and a third color blind person as a third person. Correction mode,
In the first correction mode, the second correction mode, and the third correction mode, a color conversion interpolation table and a color edge enhancement table for the first color blind person, the second color blind person, or the third color blind person are provided. The configuration to use,
The color display device according to claim 8, wherein the first correction mode, the second correction mode, and the third correction mode are selectively used by a user's selection.   The color display device according to claim 1, wherein the color display device is a projector.

Images