Image set for testing visual characteristics, method for testing visual characteristics, method for determining characteristics of correction filter and correction filter

Abstract

This invention provides a method for examining visual characteristics with minimal burden on the test subject, an examination image set for examining visual characteristics, a method for determining the characteristics of a correction filter based on the examination results of the visual characteristics, and a correction filter manufactured according to this method. The examination image set of this invention includes multiple examination images for examining the visual characteristics of the test subject. Each of the multiple examination images has a background area and an examination area located within the aforementioned background area. The examination area contains a graphic showing that at least one of the R, G, and B components in the RGB color space has a color different from that of the background area. In the multiple examination images, at least one color of the background area and the examination area are different from each other.

Description

Technical Field

[0001] This invention relates to an image set for examining visual characteristics, a method for examining visual characteristics, a method for determining the characteristics of a corrective color filter, and a corrective color filter. Prior Technology

[0002] As visual impairments related to human vision, color blindness or color weakness (low sensitivity to specific wavelengths of light) and photosensitivity (glare at specific wavelengths of light) are well-known. Examples of photosensitivity include Irlen syndrome. These visual impairments are caused by the higher or lower sensitivity of the three types of cone cells (S-cones, M-cones, and L-cones) or rod cells in the retina compared to healthy individuals. S-cones, M-cones, and L-cones are cells that respond to blue, green, and red light, respectively. Rod cells are cells that respond to the intensity of light. Furthermore, human sensitivity to light varies with ambient brightness; sensitivity in bright light is called photopic vision, and sensitivity in dark light is called scotopic vision. Photopic vision is primarily handled by cone cells, while scotopic vision is primarily handled by rod cells (see Figure 3). Sensitivity in the bright area between these two is called mesopic vision. Mesopic vision is handled by both cone cells and rod cells. As a method for correcting the vision of patients with visual impairments, the use of optical filters with individually adjusted light transmission properties is known. Patients wear glasses with optical filters whose properties are adjusted to alleviate their visual abnormalities.

[0003] In order to create a custom optical filter for a patient, it is necessary to examine the patient's visual characteristics (sensitivity) to various colors of light. However, there are countless combinations of sensitivity to different colors of light, so examining visual characteristics places a great burden on both the examiner and the patient.

[0004] Methods for manufacturing patient-specific optical filters are known in the past. For example, Japanese Patent Application Publication No. 6-18819 discloses a method for manufacturing eyeglasses that classifies a patient's color vision characteristics. In the eyeglass manufacturing method described in Patent Document 1, color vision characteristics are classified into 32 types based on the examination results of multiple patients. In Patent Document 1, the patient's color vision characteristics are examined to determine which of the 32 color vision characteristics they match. The characteristics of the optical filter are determined based on the examination results, thereby mitigating the patient's color vision abnormalities.

[0005] [Previous Technical Documents][Patent Documents] [Patent Document 1] Japanese Patent Application Publication No. 6-18819 Summary of the Invention

[0006] [The problem that the invention aims to solve] In the color vision testing method described in Patent Document 1, the patient's color vision characteristics are determined to fall within a predetermined classification. Therefore, for patients with color vision characteristics that do not fall within the predetermined classification, or for patients with color vision characteristics falling between multiple classifications, there is a problem that accurate test results cannot be obtained. Furthermore, the color vision testing method described in Patent Document 1 classifies color vision characteristics according to the wavelength range in which cone cells are sensitive, without considering the sensitivity of rod cells. Therefore, the color vision testing method described in Patent Document 1 has the problem of being unable to detect visual characteristic abnormalities caused by the influence of rod cells. Moreover, Patent Document 1 does not consider the combined influence of cone cell sensitivity and rod cell sensitivity on photopic vision, scotopic vision, and mesovision.

[0007] The present invention was made in view of the above circumstances, and its purpose is to provide a method for examining visual characteristics that is less burdensome to the test subject and can examine the visual characteristics of the test subject, an examination image group for examining visual characteristics, a method for determining the characteristics of a correction filter based on the examination results of visual characteristics, and a correction filter manufactured according to the method.

[0008] [Methods for solving problems] An embodiment of the present invention includes an examination image set comprising multiple examination images and used to examine the visual characteristics of a subject. Each of the aforementioned examination images has a background area and an examination area disposed within the aforementioned background area. Within the aforementioned examination area, there is a graphic in which "at least one of the R, G, and B components in the RGB color space is different from the color of the aforementioned background area". In the aforementioned multiple examination images, at least one color of the aforementioned background area and the aforementioned examination area is different from each other.

[0009] One embodiment of the present invention is a method for examining visual characteristics, which is a method for examining the visual characteristics of a subject, wherein the examination images included in the aforementioned examination image set are used. The method for examining visual characteristics includes: a prompting step, in which the subject is sequentially prompted with the aforementioned examination images included in the aforementioned examination image set; and a first determination step, in which, when the subject sees the aforementioned examination images prompted in the prompting step, a determination is made as to whether predetermined examination conditions are met.

[0010] One embodiment of the present invention provides a method for determining the characteristics of a corrective color filter, comprising: a determination step, which determines the transmittance of a corrective color filter for adjusting the intensity of transmitted light based on the color of the aforementioned examination image that meets the predetermined examination conditions in the aforementioned visual characteristic examination method.

[0011] One embodiment of the present invention provides a corrected color filter having the aforementioned transmittance determined by the method for determining the characteristics of the corrected color filter.

[0012] [Effects of the Invention] According to an embodiment of the present invention, a method for examining visual characteristics that is less burdensome to the test subject and can examine the visual characteristics of the test subject, an examination image set for examining visual characteristics, a method for determining the characteristics of a correction filter based on the results of the visual characteristic examination, and a correction filter manufactured according to the method are provided. Simple Explanation of the Diagram

[0013] Figure 1 is a schematic diagram of a visual inspection system according to an embodiment of the present invention. Figure 2 shows an example of the absorption spectra of human cone cells (S cone cells, M cone cells, L cone cells) and rod cells. Figure 3 shows human photopic and scotopic vision. Figure 4 is a diagram showing an example of an inspection image of an embodiment of the present invention. Figure 5 is a flowchart of the visual inspection method of an embodiment of the present invention. Figure 6 is a diagram showing an example of a modified color filter according to an embodiment of the present invention. Figure 7 shows the frequency band of the modified color filter of the embodiment of the present invention. Figure 8 is a diagram showing one example of the characteristics of the corrected color filter according to an embodiment of the present invention. Figure 9 is a diagram showing one example of the characteristics of the corrected color filter according to an embodiment of the present invention. Figure 10 is a diagram showing one example of the characteristics of the corrected color filter according to an embodiment of the present invention. Figure 11 is a diagram showing an example of an inspection image of an embodiment of the present invention. Implementation

[0014] The embodiments of the present invention are described below with reference to the drawings.

[0015] [Visual Inspection System] Figure 1 is a schematic diagram of a visual inspection system 1 for visual inspection in one embodiment of the present invention. The visual inspection system 1 includes a display device 100 and a light shield 200, and is used to inspect the visual characteristics of a subject 500.

[0016] The display device 100 is, for example, a liquid crystal display (LCD) or a cathode ray tube (CRT) display. The display device 100 displays the examination image 110. Furthermore, the display device 100 is only required to allow the subject 500 to see the examination image 110; it is not limited to a device that displays an image corresponding to an image signal, such as an LCD. For example, the display device 100 may also have a thin film printed with the examination image 110 and a backlight that illuminates the film, thereby presenting the examination image 110 to the subject 500 by illuminating the film.

[0017] A light shield 200 is provided on the display device 100. The light shield 200 prevents external light from shining on the inspection image 110 and causing changes in the brightness or color of the inspection image 110 seen by the subject 500. In order to prevent light reflection and prevent it from affecting the visual inspection, the inside of the light shield 200 is preferably black to absorb light.

[0018] During the visual examination, subject 500 viewed examination image 110 with one or both eyes. Then, the degree of glare that subject 500 felt for examination image 110 (i.e., the degree of photosensitivity of subject 500) and the perception of color of examination image 110 (i.e., the color vision of subject 500) were examined.

[0019] If the visual characteristics of subject 500 are examined through visual inspection, corrective color filters can be made to modify the visual characteristics of the subject based on the examination results. In addition, the examination results can not only be used to make corrective color filters, but also to adjust the brightness and color of lighting devices or screens such as televisions or mobile terminals used by subject 500 to match the visual characteristics of subject 500.

[0020] Figure 2 shows an example of the absorption spectra of human cone cells (S cone cells, M cone cells, L cone cells) and rod cells. The horizontal axis of Figure 2 represents the wavelength of light, and the vertical axis represents the absorptivity of each cone and rod cell. In Figure 2, "S", "M", "L", and "Rod" represent the absorption spectra of S cone cells, M cone cells, L cone cells, and rod cells, respectively. The absorption spectra shown in Figure 2 are normalized to the maximum absorptivity. For each cone and rod cell, the higher the absorptivity, the higher the sensitivity to that light. S cone cells have maximum sensitivity around 420 nm. M cone cells have maximum sensitivity around 534 nm. L cone cells have maximum sensitivity around 564 nm. Rod cells have maximum sensitivity around 498 nm. Furthermore, there are individual differences in the wavelengths at which each cone and rod cell has maximum sensitivity.

[0021] Figure 3 illustrates human photopic and scotopic vision. The horizontal axis represents the wavelength of light, and the vertical axis represents human sensitivity at each wavelength. Solid lines represent photopic vision, and dashed lines represent scotopic vision. Human sensitivity to light differs between bright and dark environments. Photopic vision is primarily controlled by cone cells; therefore, in bright environments, humans use M-cone cells and L-cone cells to perceive color, and the remaining S-cone cells to perceive brightness. Conversely, scotopic vision is primarily controlled by rod cells; therefore, in dark environments, humans use these rod cells to perceive brightness. Thus, individuals with high sensitivity of the S-cone cells and rod cells used to perceive brightness may experience photosensitivity, a condition characterized by glare. Furthermore, individuals with differences in the sensitivity of their M-cone cells and L-cone cells (i.e., sensitivity to green light versus sensitivity to red light) may experience color weakness or color blindness. Color weakness includes, for example, type 1 color weakness, which has low sensitivity to red light, and type 2 color weakness, which has low sensitivity to green light.

[0022] [Inspection Imaging Team] Next, we will describe the examination image group. The examination image group is a combination of multiple examination images. The examination images are displayed on the display device 100. Figure 4 shows an example of examination image 110.

[0023] The inspection image 110 has an inspection area 120 disposed near the center of the inspection image 110 and a surrounding background area 130. In Figure 4, the inspection area 120 is enclosed by a dashed line. This dashed line is drawn for illustrative purposes only and is not included in the inspection image 110. A graphic 121 is disposed in the inspection area 120. The graphic 121 has a different color from the background area 130. Furthermore, the area of ​​the inspection area 120 other than the graphic 121 has the same color as the background area 130. In the example shown in Figure 4, the background area 130 is circular. Furthermore, the outermost peripheral area 140 of the background area 130 is black.

[0024] Furthermore, in the example of Figure 4, graphic 121 is the Landolt ring commonly used in vision testing, but the implementation of this case is not limited to this. Graphic 121 can be any shape that can be recognized by humans; for example, it can be text, numbers, circles, or squares. Also, graphic 121 can be a combination of multiple texts and graphics.

[0025] The examination area 120 corresponds to the fovea on the human retina. The size of the examination area 120 is set such that light emitted from the examination area 120 forms an image within the fovea. For example, the size of the examination area 120 is set such that the apex angle θIN (see Figure 1) of a cone with the examination area 120 as its base and the subject's eye as its apex corresponds to approximately 2 degrees. This approximately 2-degree apex angle θIN corresponds to the visual field width (i.e., visual field angle) produced by the fovea. Furthermore, the diameter of the examination area 120 varies depending on the distance between the subject 500 and the display device 100 in the visual examination system 1. Also, the size of the examination area 120 only needs to be set such that light emitted from the examination area 120 forms an image within the fovea; the apex angle θIN does not necessarily need to be precisely 2 degrees.

[0026] Background region 130 corresponds to the area surrounding the fovea on the human retina. The size of background region 130 is set such that light emitted from background region 130 is imaged outside the fovea of ​​the human retina. For example, the size of background region 130 is set such that the apex angle θOUT (see Figure 1) of a cone with background region 130 as the base and the eye of the subject 500 as the apex is approximately 40 degrees. When the fovea is used as the center of the visual field (0 degrees), rod cells are mostly positioned around ±20 degrees. Therefore, background region 130 is preferably set such that the apex angle θOUT is 40 degrees or more so that light emitted from background region 130 is imaged on the rod cells. Furthermore, the shape of background region 130 is not limited to circular. When the display screen of display device 100 is rectangular, the area outside examination area 120 in the display screen can also be entirely background region 130.

[0027] The fovea of ​​the human retina contains a large number of M cone cells, which are sensitive to green light, and L cone cells, which are sensitive to red light. However, the fovea contains almost no S cone cells or rod cells. On the other hand, S, M, L cone cells and rod cells are arranged in the lateral region of the fovea.

[0028] Human vision improves when using the fovea. When viewing objects, images, and text, humans primarily use the M and L cone cells located in the fovea to identify the shape and color of the observed object. That is, humans can identify color using only the M and L cone cells. Furthermore, humans use the S and M cone cells or rod cells surrounding the fovea to identify not only color but also brightness. Therefore, by performing visual examinations focusing on the M and L cone cells of the fovea, human color vision can be assessed. Additionally, by examining the fovea and the surrounding S and rod cells, the degree of photosensitivity can be assessed.

[0029] The pattern 121 within the examination area 120 is used to examine the color vision produced by the M and L cone cells in the fossa, and this pattern 121 contains chromatic colors. Furthermore, in this embodiment, the background area 130 is an achromatic color. That is, in the background area 130, the R, G, and B components in the RGB color space are of equal magnitude. This is because if a chromatic color were used in the background area 130, it might affect the color vision examination performed using the examination area 120. Additionally, the color of the background area 130 must contain colors that rod cells are sensitive to. For example, the color of the background area 130 can be any color other than black (i.e., the R, G, and B components are zero). The color of the background area 130 can also be white. Furthermore, the background area 130 does not need to be entirely the same color; it can also include areas with lower and higher luminance.

[0030] The examination image set includes multiple examination images 110, each with a different color in either image 121 or background area 130. For example, in this embodiment, the examination image set includes 345 different examination images 110. Specifically, relative to the background area 130, there are 115 examination images 110B with different blue components, 115 examination images 110R with different red components, and 115 examination images 110G with different green components. Examination image 110B is used to examine the subject 500's sensitivity to blue light. Examination image 110R is used to examine the subject 500's sensitivity to red light. Examination image 110G is used to examine the subject 500's sensitivity to green light.

[0031] The colors of multiple inspection images 110B with different background areas 130 are set, for example, by changing the brightness of the background area 130 at intervals of 5% or 10%. The colors of multiple inspection images 110G with different background areas 130 are also set, for example, by changing the brightness of the background area 130 at intervals of 5% or 10%. The colors of multiple inspection images 110R with different background areas 130 are also set, for example, by changing the brightness of the background area 130 at intervals of 5% or 10%. Furthermore, the intervals for the brightness of the background area 130 are not limited to 5% or 10%.

[0032] The inspection image 110 is displayed on the display device 100, therefore the inspection image 110 is displayed after γ correction corresponding to the γ value of the display device 100. Specifically, when the input value of the image signal input to the display device 100 is set to x, the output value (luminance) is set to y, and the γ value of the display device 100 is set to γ, y = xγ holds true. Therefore, the input value used to change the luminance y on the display device 100 is calculated using x = y1 / γ. In this embodiment, the RGB components of the inspection image 110 are represented by 256 levels from 0 to 255 for each input value (xR, xG, xB) of the display device 100. Similarly, the RGB components of the background area 130 are represented by 256 levels from 0 to 255 for each input value (xRBG, xGBG, xBBG) of the display device 100.

[0033] Table 1 shows the input values ​​(xRBG, xGBG, xBBG) of the background area 130 of 115 types of examination images 110B and the input values ​​(xR, xG, xB) of the graphic 121.

[0034] [Table 1]

[0035] Table 1 shows the "Brightness [%] of the background area" as the brightness of the background area 130 when it is white (i.e., the input value is (255, 255, 255)) is set to 100%. "Color composition of the background area" represents the input values ​​(xRBG, xGBG, xBBG) in the brightness [%] of each background area 130. This embodiment has 11 background areas 130B (5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%). In this embodiment, because the background area 130B is achromatic, the RGB color components in each background area 130 are of the same value.

[0036] The "Difference of blue component of graphic relative to background area [%]" in the table represents the difference in luminance of the blue component of graphic 121 relative to the luminance of the blue component of background area 130 when the luminance of the blue component of background area 130 is set to 100%. In this embodiment, the difference [%] of the blue component of graphic 121 relative to background area 130 ranges from -60% to +60% in 10% increments, totaling 12 values. Furthermore, in this embodiment, the red / green components of background area 130 are the same size as the red / green components of graphic 121. Therefore, when the difference in blue component of graphic 121 relative to background area 130 is 0%, graphic 121 and background area 130 are the same color and are not included in the inspection image 110B.

[0037] The inspection image 110B is a combination of a background region 130 and a graphic 121 having the same input values ​​recorded in the same column as the background region 130. For example, there are six types of inspection images 110B with input values ​​of (255, 255, 255) for the background region 130. The red and green components of the graphic 121 in these six types of inspection images 110B are each the same size as the red and green components of the background region 130 (i.e., both are 255). Furthermore, the blue input value of the graphic 121 in these six types of inspection images 110B is set relative to the blue input value of the background region 130 by changing the brightness in increments of 10% from -60% to -10%. The blue input values ​​of the graphic 121 in the six types of inspection images 110B with input values ​​of (255, 255, 255) for the background region 130 are 168, 186, 202, 217, 230, and 243, respectively.

[0038] In Table 1, the input values ​​for background area 130 (255, 255, 255) are not recorded. The input values ​​for graphic 121, where the difference [%] between the blue component and background area 130 is greater than +10%, are not recorded because the maximum input value for blue in graphic 121 is 255. Similarly, in the cases where the color components of background area 130 are (243, 243, 243), (230, 230, 230), and (217, 217, 217), the input values ​​for blue exceeding 255 are also not recorded.

[0039] When the difference [%] between the blue component of graphic 121 and the background area 130 is positive (+10% to +60), the blue component is greater than the red and green components, so graphic 121 has a blue tint. Furthermore, the larger the difference [%] between the blue component and the background area 130, the stronger the blue tint, and the more pronounced the color difference between graphic 121 and the background area 130. On the other hand, when the difference [%] between the blue component of graphic 121 and the background area 130 is negative (-10% to -60), the red and green components are greater than the blue component, so graphic 121 becomes a yellow tint (a color with strong green and red tones). Furthermore, the smaller the difference [%] between the blue component and the background area 130, the stronger the yellow tint, and the more pronounced the color difference between graphic 121 and the background area 130.

[0040] Subjects with healthy color vision can easily distinguish the color difference between figure 121 and background area 130 even when the absolute value of the difference [%] between the blue component and background area 130 is small. On the other hand, for subjects with lower blue light sensitivity, the absolute value of the difference [%] between the blue component and background area 130 must be increased in order to distinguish the color difference between figure 121 and background area 130. For example, subjects with healthy color vision can distinguish figure 121 within background area 130 when the absolute value of the difference [%] between the blue component and background area 130 is 30% or more (i.e., less than -30% or more than +30%). On the other hand, for test subjects with low sensitivity to blue light, even if the absolute value of the difference [%] between the blue component and the background area 130 is 30%, they cannot recognize the pattern 121. For example, they can only begin to recognize the pattern 121 within the background area 130 when the absolute value of the difference [%] between the blue component and the background area 130 is 40% or more. Furthermore, in cases where the test subject has photosensitivity, their sensitivity to blue light is high, so even if the absolute value of the difference [%] between the blue component and the background area 130 is less than 30%, they can still recognize the pattern 121 within the background area 130.

[0041] Furthermore, for test subjects with healthy color vision, generally speaking, the higher the luminance of the background area 130 and the figure 121, the easier it is to distinguish the color difference between the background area 130 and the figure 121. On the other hand, for test subjects with high sensitivity to blue light and photosensitivity, if the luminance of the background area 130 and the figure 121 is high, they will feel glare on the examination image 110B. Therefore, for test subjects with photosensitivity, it is easier to distinguish the color difference between the background area 130 and the figure 121 when the "luminance of the background area [%]" is less than 100%. Moreover, even if a test subject has photosensitivity, if the absolute value of the difference [%] between the luminance of the background area 130 and the background area 130 is less than 30%, it may still be difficult to distinguish the figure 121 within the background area 130. In this case, if the brightness [%] of the background area 130 is reduced, in order for the test subject to be able to identify the graphic 121 in the background area 130, the absolute value of the difference [%] between the blue component and the background area 130 must be changed to 30% or more.

[0042] Thus, depending on the color vision characteristics of the test subject, the conditions under which they can distinguish the color difference between the background area 130 and the figure 121 (in other words, the conditions under which they can distinguish the figure 121 within the background area 130) vary. Therefore, by using multiple test images 110B with different luminance (luminance of the background area 130 and the figure 121) and different color differences between the figure 121 and the background area 130, it is possible to determine the color vision characteristics of the test subject for blue light. In addition, Table 1 shows examples of test images 110B with the difference [%] of the blue component of the figure 121 relative to the background area 130 ranging from -60% to +60%, but test images 110B are not limited to these. For example, test images 110B with the difference [%] of the blue component of the figure 121 relative to the background area 130 being less than -60%, or test images 110B with the difference [%] of the blue component of the figure 121 relative to the background area 130 being greater than +60%, can also be prepared.

[0043] Tables 2 and 3 show the input values ​​(xRBG, xGBG, xBBG) of the background region 130 and the input values ​​(xR, xG, xB) of the graphic 121 in the examination image 110R and the examination image 110G when the red component of the graphic 121 is different relative to the background region 130 and the green component of the graphic 121 is different, respectively.

[0044] [Table 2]

[0045] [Table 3]

[0046] In the inspection image 110R shown in Table 2, when the difference [%] between the red component of graphic 121 and the background area 130 is positive (+10% to +60), the red component is larger than the green and blue components, so graphic 121 has a reddish hue. Furthermore, the larger the difference [%] between the red component and the background area 130, the stronger the red hue, and the more pronounced the color difference between graphic 121 and the background area 130. On the other hand, when the difference [%] between the red component of graphic 121 and the background area 130 is negative (-10% to -60), the green and blue components are larger than the red component, and graphic 121 becomes cyan (a color with strong green and blue tones). Furthermore, the smaller the difference [%] between the red component and the background area 130, the more pronounced the cyan color becomes, and the more pronounced the color difference between graphic 121 and the background area 130.

[0047] In the examination image 110G shown in Table 3, when the difference [%] between the green component of graphic 121 and the background area 130 is positive (+10% to +60%), the green component is larger than the red and blue color components, thus graphic 121 has a green tint. Furthermore, the larger the difference [%] between the green component and the background area 130, the stronger the green tint, and the more pronounced the color difference between graphic 121 and the background area 130. On the other hand, when the difference [%] between the green component of graphic 121 and the background area 130 is negative (-10% to -60%), the red and blue color components are larger than the green component, thus graphic 121 becomes magenta (a color with strong red and blue tints). Furthermore, the smaller the difference [%] between the green component and the background area 130, the more pronounced the magenta color, and the more pronounced the color difference between graphic 121 and the background area 130.

[0048] Similar to examination image 110B, in examination images 110R and 110G, the subject 500 with healthy color vision can easily distinguish the color difference between image 121 and background area 130 when the absolute values ​​of the difference [%] of the red component of image 121 relative to background area 130 or the difference [%] of the green component relative to background area 130 are small (i.e., the colors of image 121 and background area 130 are similar). On the other hand, for the subject 500 with lower sensitivity to red or green light, in order to distinguish the color difference between image 121 and background area 130, the absolute values ​​of the difference [%] of the red component of image 121 relative to background area 130 and the difference [%] of the green component relative to background area 130 must be increased. For example, a subject 500 with healthy color vision can recognize the figure 121 located within the background area 130 if the absolute value of the difference [%] between the red component of the figure 121 and the background area 130 or the green component of the figure 121 and the background area 130 is 30% or more (i.e., less than -30% or more than +30%). On the other hand, for a subject 500 with low sensitivity to red or green light, even if the absolute value of the difference [%] between the red component of the figure 121 and the background area 130 or the green component of the figure 121 and the background area 130 is 30%, the subject cannot recognize the figure 121. Instead, the subject can only recognize the figure 121 when, for example, the absolute value of the difference [%] between the red component and the background area 130 or the green component of the figure 121 and the background area 130 is 50% or more.

[0049] Furthermore, for test subjects with healthy color vision, generally speaking, the higher the luminance of the background area 130 and the figure 121, the easier it is to distinguish the color differences between the background area 130 and the figure 121. On the other hand, if a test subject has photosensitivity with high sensitivity to blue light, a high luminance of the background area 130 and the figure 121 will cause glare to the examination image 110B. Therefore, for test subjects with photosensitivity, it is easier to distinguish the color differences between the background area 130 and the figure 121 when the "luminance of the background area [%]" is less than 100%.

[0050] Thus, depending on the color vision characteristics of the test subject, the conditions under which the color difference between the background region 130 and the figure 121 can be distinguished (in other words, the conditions under which the figure 121 within the background region 130 can be distinguished) differ. Therefore, by using multiple test images 110R and 110G with different luminance (luminance of the background region 130 and the figure 121) and color differences of the figure 121 relative to the background region 130, it is possible to determine the test subject's color vision characteristics for red or green light. In addition, Table 2 shows examples of test images 110R with a difference [%] of the red component of the figure 121 relative to the background region 130 ranging from -60% to +60%, but test images 110R are not limited to these. For example, an examination image 110R can be prepared where the difference [%] between the red component of graphic 121 and the background area 130 is less than -60%, or an examination image 110R can be prepared where the difference [%] between the red component of graphic 121 and the background area 130 is greater than +60%. Table 3 shows examples of examination images 110G where the difference [%] between the green component of graphic 121 and the background area 130 ranges from -60% to +60%, but examination images 110G are not limited to these. For example, an examination image 110G can also be prepared where the difference [%] between the green component of graphic 121 and the background area 130 is less than -60%, or an examination image 110G can be prepared where the difference [%] between the green component of graphic 121 and the background area 130 is greater than +60%.

[0051] [Visual Inspection Methods] Next, a visual inspection method using a visual inspection system 1 that includes inspection image 110 will be described. Figure 5 shows a flowchart of the visual inspection method using inspection image 110.

[0052] [Processing step S101 in Figure 5] In S101, the luminance [%] of the background area 130 of the examination image 110 suitable for the test subject 500 is identified, that is, the appropriate luminance BCENTER.

[0053] In step S101, firstly, while changing the luminance [%] of the background area 130, inspection images 110B with a difference [%] of -30% between the blue component of graphic 121 and the background area 130 are sequentially displayed on the display device 100. The displayed inspection images 110B can be displayed sequentially starting from the lowest luminance [%] of the background area 130, or sequentially starting from the highest. Alternatively, inspection images 110B can be displayed sequentially starting from the lowest luminance [%] of the background area 130, and then sequentially starting from the highest luminance [%] of the background area 130. The luminance [%] of the background area 130 can also be changed randomly. If the luminance [%] of the background area 130 changes, the color component of graphic 121 also changes accordingly, while maintaining a -30% difference between the blue component of graphic 121 and the blue component of the background area 130. The display time of an examination image 110B is, for example, the time it takes for the subject 500 to confirm whether the examination image 110B is glaring and whether they can recognize the graphic 121. For example, after an examination image 110B is displayed for more than 1 second, a next examination image 110B with a different brightness [%] of the background area 130 is displayed. In the case of graphic 121 being a Randall's ring, whether the subject 500 can recognize graphic 121 can be confirmed by whether they can identify the location of the interruption of the Randall's ring (the right side in the example of Figure 4).

[0054] If subject 500 has healthy visual characteristics regarding blue light, they are highly likely to be able to recognize the pattern 121 within the background area 130 regardless of its luminance percentage. If subject 500 has photosensitivity, they will experience glare from the examination image 110B when the luminance percentage of the background area 130 is high. Therefore, subject 500 with photosensitivity will have difficulty recognizing the pattern 121 in the examination image 110B with a higher luminance percentage in the background area 130, but will easily recognize the pattern 121 in the examination image 110B with a lower luminance percentage in the background area 130. On the other hand, if subject 500 has low visual sensitivity to blue light, they will have difficulty recognizing changes in the blue component of the pattern 121, and may be unable to recognize the pattern 121 in the examination image 110B where the difference in the blue component of the pattern 121 relative to the background area 130 is -30%. Therefore, by checking whether the test subject 500 can identify the pattern 121 within the background area 130, the test subject 500's sensitivity to blue light can be checked, or the difference between the test subject 500's sensitivity to blue light and that of a healthy person.

[0055] If subject 500 can recognize the difference [%] between the blue component of image 121 and the background area 130 in image 110B as -30%, it indicates that subject 500's sensitivity to blue light is at least the same as that of a healthy person. On the other hand, if subject 500 cannot recognize the difference [%] between the blue component of image 121 and the background area 130 in image 110B as -30%, it indicates that subject 500's sensitivity to blue light is lower than that of a healthy person. In addition, subject 500, who has photosensitivity, has a high sensitivity to blue light. Therefore, when the luminance of the background area 130 is less than 100%, the difference in the blue component of the pattern 121 relative to the background area 130 is greater than -30% (that is, the color of the pattern 121 is closer to the color of the background area 130). This makes it possible to identify the pattern 121 of the examination image 110B.

[0056] Subject 500 observes the examination image 110B showing the changes in luminance [%] of the background region 130, while simultaneously identifying the luminance [%] of the background region 130 containing the recognizable image 121. Then, the central value (or a value close to the center) of the range of luminance [%] of the background region 130 containing the recognizable image 121 is designated as the appropriate luminance BCENTER. Alternatively, the appropriate luminance BCENTER can also be the highest luminance value within the range of luminance [%] of the background region 130 containing the recognizable image 121. Furthermore, if subject 500 can recognize the image 121 regardless of the luminance [%] of the background region 130, 100% can be designated as the appropriate luminance BCENTER. Additionally, subject 500's ability to recognize the image 121 is an example of the first examination condition.

[0057] If the test subject 500 cannot distinguish the difference [%] between the blue component of graphic 121 and the background area 130 in examination image 110B, which is -30%, then examination image 110B will display an examination image with a difference [%] of -40% between the blue component of graphic 121 and the background area 130. Then, it will be checked whether the test subject 500 can distinguish graphic 121 within the background area 130 of the displayed examination image 110B. At this time, the luminance [%] of the background area 130 of the displayed examination image 110B can also be changed sequentially. If the test subject 500 cannot distinguish the difference [%] between the blue component of graphic 121 and the background area 130 in examination image 110B, which is -40%, then examination image 110B will further set the difference [%] between the blue component of graphic 121 and the background area 130 to an even lower value and display it. Thus, the difference [%] between the blue component of graphic 121 and the background area 130 is changed until the subject 500 can recognize graphic 121. This allows us to examine how much lower the subject 500's sensitivity to blue light is compared to that of a healthy individual. Additionally, examination images 110B can also display images of graphic 121 where the difference [%] between the blue component of graphic 121 and the background area 130 is -30%, or images 110B where the difference [%] is closer to 0 (e.g., -20% or -10%), to determine whether the subject 500 can recognize graphic 121.

[0058] Furthermore, in the processing of S101, the inspection image 110B initially displays an inspection image 110B where the difference [%] between the blue component of graphic 121 and the background area 130 is -30%. Then, based on the inspection results, the difference [%] between the blue component of graphic 121 and the background area 130 is changed to be even lower. However, the embodiments of the present invention are not limited to this processing. For example, the inspection image 110B initially displays an inspection image 110B where the difference [%] between the blue component of graphic 121 and the background area 130 is +30%. Then, based on the inspection results, the difference [%] between the blue component of graphic 121 and the background area 130 in the displayed inspection image 110B is changed to be even higher. Alternatively, the inspection image 110B can be initially displayed with the absolute value of the difference [%] between the blue component of graphic 121 and the background area 130 being small (e.g., -10% or +10%), and then changed to increase the absolute value of the difference [%] between the blue component of graphic 121 and the background area 130 according to the inspection results. Or, the inspection image 110B can be initially displayed with the absolute value of the difference [%] between the blue component of graphic 121 and the background area 130 being large (e.g., -60% or +60%), and then changed to decrease the absolute value of the difference [%] between the blue component of graphic 121 and the background area 130 according to the inspection results.

[0059] [Processing step S102 in Figure 5] In S102, the red component of the graphic 121 within the background region 130 of the image 110R that the subject 500 can recognize is measured, namely, the specific red component RVALUE. Specifically, the difference [%] between the red component of the graphic 121 within the background region 130 that the subject 500 can recognize and the background region 130 is identified. The graphic 121 within the background region 130 is recognizable, possessing a systematic recognizable color difference between the graphic 121 and the background region 130, and the graphic 121 within the background region 130 is recognizable. Furthermore, the recognizable graphic 121 by the subject 500 is an example of the second examination condition.

[0060] In S102, the inspection image 110R is sequentially displayed on the display device 100 while changing the difference [%] of the red component of the graphic 121 relative to the background area 130 from -10% to -60%. At this time, the brightness [%] of the background area 130 of the inspection image 110R can be set to the appropriate brightness BCENTER identified in S101.

[0061] In examination image 110R where the difference [%] between the red component of graphic 121 and the background area 130 is -10%, the size of the red component of graphic 121 is only 10% smaller than the size of the green component. As the red component of graphic 121 decreases (as the difference [%] between the red component and the background area 130 moves towards -60%), the difference between the red and green components of graphic 121 increases, and the color difference between graphic 121 and the background area 130 increases. When subject 500 has healthy visual characteristics for both red and green light, subject 500 is highly likely to be able to identify graphic 121 within the background area 130 in examination image 110R where the difference [%] between the red component of graphic 121 and the background area 130 is less than -30%. On the other hand, if subject 500 has lower sensitivity to red light, they may not be able to identify graphic 121 in examination image 110R where the difference [%] between the red component of graphic 121 and the background area 130 is -30%. Therefore, by examining whether the subject 500 can recognize the pattern 121 within the background area 130, the subject 500's sensitivity to red light, or the difference between the subject 500's sensitivity to red light and that of a healthy individual, can be examined. In other words, the sensitivity of the subject 500's L-cone cells, or the difference between the subject 500's sensitivity to L-cone cells and that of a healthy individual, can be examined.

[0062] If subject 500 can recognize the image 121 of examination image 110R where the difference [%] between the red component of image 121 and the background area 130 is -30%, it indicates that subject 500's sensitivity to red light is at or above the same level as that of a healthy person. On the other hand, if subject 500 cannot recognize the image 121 of examination image 110R where the red component of image 121 is -30%, it indicates that subject 500's sensitivity to red light is lower than that of a healthy person.

[0063] If the test subject 500 cannot distinguish the difference [%] between the red component of graphic 121 and the background area 130 in the examination image 110R, which is -30%, then the difference [%] between the red component of graphic 121 and the background area 130 in the examination image 110R is changed to -40% and displayed. Then, it is checked whether the test subject 500 can distinguish graphic 121 within the background area 130 of the displayed examination image 110R. At this time, the brightness [%] of the background area 130 of the displayed examination image 110R can also be changed sequentially. If the test subject 500 cannot distinguish the difference [%] between the red component of graphic 121 and the background area 130 in the examination image 110R, which is -40%, then the red component of graphic 121 is further set to a lower value and the examination image 110R is displayed. Thus, while changing the difference [%] of the red component of graphic 121 relative to the background area 130 from -10% to -60%, the examination images 110R are sequentially displayed on the display device 100. Among the differences [%] of the red component of graphic 121 relative to the background area 130 that the test subject 500 can recognize, the difference [%] of the red component relative to the background area 130 with the smallest absolute value can be identified. In other words, among the examination images 110R of graphic 121 that the test subject 500 can recognize, the background area 130 with the color closest to graphic 121 can be identified. In this way, the degree of difference between the test subject 500's sensitivity to red light and that of a healthy person can be examined.

[0064] Furthermore, in the processing of S102, an inspection image 110R is initially displayed where the difference [%] between the red component of graphic 121 and the background area 130 is -10%. Then, based on the inspection results, the difference [%] between the red component of graphic 121 and the background area 130 is changed to be lower. However, embodiments of the present invention are not limited to this processing. For example, an inspection image 110R may initially be displayed where the difference [%] between the red component of graphic 121 and the background area 130 is +10%. Then, based on the inspection results, the difference [%] between the red component of graphic 121 and the background area 130 in the displayed inspection image 110R may be changed to be higher. Alternatively, the inspection image 110R may initially be displayed with a large absolute value of the red component of graphic 121 (e.g., -60% or +60%). Then, based on the inspection results, the difference may be changed in such a way that the absolute value of the difference [%] between the red component of graphic 121 and the background area 130 in the displayed inspection image 110R is reduced. [Processing step S103 in Figure 5]

[0065] In S103, the green component, i.e., the specific green component GVALUE, of the graphic 121 within the background area 130 of the examination image 110G is measured by the subject 500. Specifically, in S103, while changing the difference [%] between the green component of the graphic 121 and the background area 130 from -10% to -60%, the examination image 110G is sequentially displayed on the display device 100. At this time, the luminance [%] of the background area 130 of the examination image 110R is set to the appropriate luminance BCENTER identified in S101.

[0066] In S103, the same as the examination in S102, the examinee 500 is checked to see if he / she can identify the graphic 121 in the background area 130 of the examination image 110G. Specifically, the examinee 500 is checked to see if he / she can identify the color difference between the graphic 121 and the background area 130, and if he / she can identify the shape of the graphic 121.

[0067] In the examination method of S103, examination image 110G is used instead of examination image 110R, and the difference [%] of the green component relative to the background area 130 is changed instead of the difference [%] of the red component of pattern 121 relative to the background area 130. Otherwise, it is the same as the examination in S102. Specifically, while changing the difference [%] of the green component of pattern 121 relative to the background area 130 from -10% to -60%, examination image 110G is sequentially displayed on display device 100. Among the differences [%] of the green component of pattern 121 relative to the background area 130 that the subject 500 can recognize, the difference [%] of the green component relative to the background area 130 with the smallest absolute value is identified. By this examination, the subject 500's sensitivity to green light, or the difference between the subject 500's sensitivity to green light and the sensitivity of a healthy person to green light, can be detected. In other words, it can detect the sensitivity of 500 M cone cells in the subject or the difference between the sensitivity of 500 M cone cells in the subject and the sensitivity of M cone cells in healthy individuals.

[0068] Through the processing steps S101 to S103 above, the subject's sensitivity to each RGB light can be checked.

[0069] In the example shown in Figure 5, although the subject 500's sensitivity to red light and sensitivity to green light are checked in S102 and S103, the processing in this embodiment is not limited to this. For example, if it is known in advance that the subject 500 has low sensitivity to either green or red light, the check can be performed using only the check image 110 that changes the color with low sensitivity (either S102 or S103). For example, if the subject 500 has type 1 color weakness with low sensitivity to red light, the check in S102 can be performed and the check in S103 can be omitted. Or, if the subject 500 has type 2 color weakness with low sensitivity to green light, the check in S103 can be performed and the check in S102 can be omitted.

[0070] Furthermore, if only the degree of photosensitivity in subject 500 needs to be examined, examination S101 can be performed alone. Additionally, the degree of photosensitivity is determined by examining which background area 130's luminance [%] would cause subject 500 to experience glare. Therefore, when examining the degree of photosensitivity, examination image 110B is not necessary; examination image 110R or examination image 110G can also be used.

[0071] [Processing step S104 in Figure 5] In S104, using the specific red component RVALUE and the specific green component GVALUE identified in S102 and S103, the ratio of the test subject 500's sensitivity to red light to his sensitivity to green light is calculated.

[0072] When the absolute value of a specific red component RVALUE is greater than the absolute value of a specific green component GVALUE, subject 500's sensitivity to red light is less than its sensitivity to green light. In this case, the sensitivity ratio is calculated as |GVALUE / RVALUE| (the absolute value of GVALUE / RVALUE). Conversely, when the absolute value of a specific red component RVALUE is less than the absolute value of a specific green component GVALUE, subject 500's sensitivity to red light is greater than its sensitivity to green light. In this case, the sensitivity ratio is calculated as |RVALUE / GVALUE| (the absolute value of RVALUE / GVALUE). The calculated sensitivity ratio is used to determine the characteristics of the correction filter used to correct the visual characteristics of subject 500.

[0073] [Correction Filter] If the visual characteristics of subject 500 are examined using the visual examination method shown in Figure 5, the examination results are used to manufacture a corrective color filter to modify the visual characteristics of subject 500. The corrective color filter can be any material that alters the transmission spectrum, and there are no particular limitations on its material or the principle of altering the transmission spectrum. Furthermore, the corrective color filter may be worn by subject 500 in the form of eyeglasses. However, there are no particular limitations on the shape of the corrective color filter. The corrective color filter can be a contact lens or can be installed on display devices such as televisions or screens.

[0074] Figure 6 shows an example of a spectacle-shaped corrective color filter 300. The corrective color filter 300 includes, for example, a color filter 300B for light in the blue region, a color filter 300G for light in the green region, and a color filter 300R for light in the red region. Each of the color filters 300B, 300G, and 300R has frequency bands BB, BG, and BR that change the transmittance of light.

[0075] Color filter 300B alters the transmittance of light in the blue region (in other words, it absorbs or reflects some blue light), while allowing green and red light to pass through directly (in other words, it has low absorption and reflection rates for green and red light). Color filter 300G alters the transmittance of light in the green region (in other words, it absorbs or reflects some green light), while allowing blue and red light to pass through directly (in other words, it has low absorption and reflection rates for blue and red light). Color filter 300R alters the transmittance of light in the red region (in other words, it absorbs or reflects some red light), while allowing green and blue light to pass through directly (in other words, it has low absorption and reflection rates for green and blue light). Therefore, by combining three color filters (300B, 300G, and 300R), the transmittance of light in each of the three wavelength bands of RGB can be adjusted individually.

[0076] Figures 7(a) to (c) show the frequency bands BB, BG, and BR, respectively, which alter the light transmittance of three color filters: 300B, 300G, and 300R. The horizontal axis of Figures 7(a) to (c) represents the wavelength of light, and the vertical axis represents the normalized transmittance of each filter. Additionally, Figures 7(a) to (c) overlay the absorption spectra of each cone cell and rod cell; the vertical axis of Figures 7(a) to (c) represents the normalized absorption rate of each cell. The peak wavelength PS for the sensitivity of the S cone cell is approximately 420 nm, the peak wavelength PM for the M cone cell is approximately 534 nm, the peak wavelength PL for the L cone cell is approximately 564 nm, the peak wavelength PRod for the rod cell is approximately 498 nm, and the wavelength PPho, which represents the maximum sensitivity for photopic vision, is approximately 570 nm (see Figure 3).

[0077] As shown by the arrows in the solid lines of Figure 7(a), filter 300B can alter the transmittance of light at wavelengths above the peak wavelength PS (approximately 420 nm) for cone cells and below the peak wavelength PRod (approximately 498 nm) for rod cells. In other words, the lower limit of the band BB of filter 300B is PS, and the upper limit is PRod. However, the lower limit of the band BB of filter 300B is not limited to PS. The lower limit of the band BB can also be set to a wavelength band shorter than PS.

[0078] Furthermore, as long as the transmittance of light in the blue wavelength band can be changed, the upper limit of the band BB of the color filter 300B is not limited to the peak wavelength PRod (approximately 498 nm) of the rod cells. Figure 7(a) shows another example of the upper limit of the band BB of the color filter 300B, indicated by the dotted arrows, and the band BB in this case.

[0079] For example, the upper limit of the band BB of color filter 300B could also be the wavelength XRod-M (approximately 515 nm), which marks the intersection of the absorption spectra of rod cells and M-cone cells. This XRod-M wavelength is longer than the peak wavelength PRod and shorter than the peak wavelength PM (approximately 534 nm) of M-cone cells. In wavelengths longer than XRod-M, the sensitivity of rod cells becomes lower, while the sensitivity of M-cone cells becomes higher. Therefore, if the upper limit of the band BB of color filter 300B is set to be longer than the XRod-M wavelength, the transmittance of light absorbed by M-cone cells (light in the green wavelength band) changes, which may not adequately correct the visual characteristics of the subject 500.

[0080] Furthermore, the upper limit of the bandwidth BB of filter 300B can also be shorter than the peak wavelength PRod (approximately 498 nm) of rod cell sensitivity. For example, the upper limit of the bandwidth BB of filter 300B can also be the XS-Rod (approximately 453 nm), the wavelength where the absorption spectra of S-cone cells and rod cells intersect. This XS-Rod wavelength is longer than the peak wavelength PS but shorter than the peak wavelength PRod. In the band where the wavelength is shorter than the XS-Rod, the sensitivity of rod cells becomes lower, and the sensitivity of S-cone cells becomes higher. Therefore, if the upper limit of the bandwidth BB of filter 300B is set to be shorter than the XS-Rod, the proportion of light absorbed by S-cone cells increases, which may not be able to properly correct photosensitivity.

[0081] Furthermore, to appropriately mitigate the influence of rod cells on photosensitivity, it is desirable that the band BB of filter 300B includes a wavelength band close to the peak sensitivity wavelength PRod of rod cells. Therefore, the upper limit of the band BB of filter 300B can also be shorter than the peak sensitivity wavelength PRod of rod cells, but preferably not deviating too much from the peak wavelength PRod. For example, if the difference between the peak sensitivity wavelength PRod of rod cells and the wavelength XRod-M at the intersection of the absorption spectrum of rod cells and the absorption spectrum of M-cone cells is set as Δ, then by setting the upper limit of the band BB of filter 300B within the range of PRod ± Δ, the influence of rod cells on photosensitivity can be appropriately mitigated.

[0082] As shown by the solid line in Figure 7(b), filter 300G modifies the transmittance of light at wavelengths above the peak sensitivity wavelength PRod (approximately 498 nm) of rod cells and below the wavelength XM-L (approximately 548 nm), where the absorption spectra of M cone cells and L cone cells intersect. This wavelength XM-L is longer than the peak wavelength PM and shorter than the peak wavelength PL (approximately 564 nm). In other words, the lower limit of the bandwidth (BG) of filter 300G is wavelength PRod, and the upper limit is wavelength XM-L.

[0083] Furthermore, to increase the proportion of light in the wavelength bands for which M-cone cells are sensitive among the light passing through the filter 300G, the lower limit of the frequency band BG of the filter 300G can also be set to the wavelength XRod-M (approximately 515 nm) at the intersection of the absorption spectra of rod cells and M-cone cells. The frequency band BG of the filter 300G at this time is represented by a dotted line in Figure 7(b). In this way, compared to rod cells and other cone cells, only the wavelength bands for which M-cone cells have higher sensitivity are absorbed or reflected by the filter 300G.

[0084] Furthermore, rod cells are cells that respond to varying light intensity and do not affect the subject's color perception (color vision). Therefore, even if the lower limit of the band (BG) of the 300G color filter is set to the peak sensitivity wavelength (PRod) of rod cells, green light can still be corrected.

[0085] The 300R filter is a filter that alters the transmittance of red light at 500 nm for the test subject. It has the property of absorbing or reflecting light in the wavelength band that L-shaped cone cells are sensitive to.

[0086] As shown by the solid line in Figure 7(c), filter 300R allows only light with wavelengths above the wavelength XM-L (approximately 548 nm) where the absorption spectra of M cone cells and L cone cells intersect to pass through. In other words, the lower limit of the frequency band BR of filter 300R is the wavelength XM-L.

[0087] In wavelengths shorter than XM-L, the sensitivity of L-cone cells decreases, and the sensitivity of M-cone cells becomes dominant. Therefore, assuming that the lower limit of the BR band of color filter 300R is set to be shorter than the XM-L wavelength, L-cone cells may absorb or reflect not only red light but also green light.

[0088] Furthermore, the lower limit of the frequency band BR of the 300R color filter may not be the wavelength XM-L, but rather the wavelength PPho (approximately 570nm) where photopic vision achieves maximum sensitivity.

[0089] [Example 1 of a color correction filter] Next, an embodiment of the corrected color filter will be described. The transmittance of the band BB of the color filter 300B is set according to the appropriate brightness BCENTER identified in S101. For example, if the appropriate brightness BCENTER is 70%, the transmittance of the band BB is set to 70%. This corrects the photosensitivity of the subject 500.

[0090] The transmittance of band BG of color filter 300G and band BR of color filter 300R are set based on the test results of S102 and S103. For example, in the test of S102, if a specific red component RVALUE is designated as -30%, the test subject 500's sensitivity to red light is the same as that of a healthy person. Similarly, in the test of S103, if a specific green component GVALUE is designated as -50%, the test subject 500's sensitivity to green light is lower than that of a healthy person to red light. In this case, the transmittance of band BR of color filter 300R is set to be lower than the transmittance of band BG of color filter 300G only by a factor of |RVALUE / GVALUE|. This corrects for the difference between the test subject 500's sensitivity to red light and their sensitivity to green light.

[0091] Figure 8 illustrates the characteristics of the corrective color filter 300 described above. The horizontal axis of Figure 8 represents wavelength [nm], and the vertical axis represents the transmittance [%] of the corrective color filter 300. In this example, the transmittance of band BB of color filter 300B is set to 70%, the transmittance of band BG of color filter 300G is set to 100%, and the transmittance of band BR of color filter 300R is set to be lower than the transmittance of band BG of color filter 300G only by a factor of |RVALUE / GVALUE| (i.e., 30 / 50=60%). The corrective color filter 300 has characteristics that work in conjunction with those of the three color filters 300R, 300G, and 300B. By using this corrective color filter 300, glare experienced by subject 500 can be suppressed, and the difference in sensitivity to red light and green light between subject 500 and subject 500 can be corrected.

[0092] In the example shown in Figure 8, the transmittance in the region with wavelengths shorter than band BB is almost 0%. This is to reduce the glare experienced by subject 500 with photosensitivity. However, since subject 500's photosensitivity is corrected by reducing the transmittance of the correction filter 300 in band BB, the transmittance in the region with wavelengths shorter than band BB does not have to be 0%, for example, it can be the same as the transmittance of band BB. Furthermore, in the example shown in Figure 8, wavelengths XM-L (approximately 548 nm) and above in band BR are all set to 60%. However, light with wavelengths longer than approximately 650 nm has low absorption in cone and rod cells and has almost no effect on human color vision. Therefore, the transmittance of the correction filter 300 for light with wavelengths longer than approximately 650 nm can be set to any value.

[0093] [Example 2 of the corrected color filter] The transmittance of band BG of color filter 300G and band BR of color filter 300R can also be based on the transmittance of band BB of color filter 300B. For example, when the appropriate brightness (BCENTER) is 70%, the transmittance of band BB is set to 70%. Furthermore, if a specific red component (RVALUE) is designated as -30% and a specific green component (GVALUE) is designated as -50%, the transmittance of band BR of color filter 300R is set to |RVALUE / GVALUE| times the transmittance of band BB (70% × 60% = 42%). Similarly, the transmittance of band BG of color filter 300G is also set to 70% as the transmittance of band BB.

[0094] Figure 9 illustrates the characteristics of the corrective color filter 300 described above. The horizontal axis of Figure 9 represents wavelength [nm], and the vertical axis represents the transmittance [%] of the corrective color filter 300. In this example, the transmittance of band BB of color filter 300B and band BG of color filter 300G are set to 70%, and the transmittance of band BR of color filter 300R is set to 42% (70% × 60%). By using this corrective color filter 300, glare experienced by subject 500 can be suppressed, and the difference between subject 500's sensitivity to red light and green light can be corrected.

[0095] [Example 3 of the corrected color filter] Next, an example of the corrective filter 300 when subject 500 does not have photosensitivity will be explained. When subject 500 does not have photosensitivity and has low sensitivity to blue light, the transmittance of band BB of filter 300B, the transmittance of band BG of filter 300G, and the transmittance of band BR of filter 300R are set based on the examination results of S101 to S103. For example, in the examination of S101, if subject 500 can identify pattern 121 within the background area 130 of examination image 110B where the difference [%] between the blue component of pattern 121 and the background area 130 is -40%, then subject 500's sensitivity to blue light is 75% (30 / 40) of that of a healthy person. For example, in the S102 examination, if the subject 500 can distinguish the red component of graphic 121 relative to the background area 130 of the examination image 110R where the difference [%] is -30%, then the subject 500's sensitivity to red light is the same as that of a healthy person. Similarly, in the S103 examination, if the subject 500 can distinguish the green component of graphic 121 relative to the background area 130 of the examination image 110G where the difference [%] is -50%, then the subject 500's sensitivity to green light is 60% (30 / 50) of that of a healthy person. Thus, by examining the degree of difference between the subject 500's sensitivity to each RGB light and that of a healthy person, the ratio of the subject 500's sensitivity to RGB light can be determined. In the above example, the transmittance of band BB of color filter 300B is set to 75% of the transmittance of band BG of color filter 300G. Also, the transmittance of band BR of color filter 300R is set to 60% of the transmittance of band BG of color filter 300G.

[0096] Figure 10 illustrates the characteristics of the corrective color filter 300 described above. The horizontal axis of Figure 10 represents wavelength [nm], and the vertical axis represents the transmittance [%] of the corrective color filter 300. In this example, among the three RGB light sources, the subject 500 has the lowest sensitivity to green light; therefore, the transmittance of band BG of color filter 300G is set to 100%. Furthermore, the transmittance of band BB of color filter 300B is set to 75% of the transmittance of band BG of color filter 300G, and the transmittance of band BR of color filter 300R is set to 60% of the transmittance of band BG of color filter 300G. This corrective color filter 300 has higher transmittance for green light (to which the subject 500 has low sensitivity) and lower transmittance for red light (to which the subject 500 has high sensitivity, i.e., the same level as a healthy person). This corrects for the difference in the subject 500's sensitivity to RGB light.

[0097] Furthermore, the method of determining the characteristics of the corrective color filter 300 using the results of the visual inspection shown in Figure 5 is not limited to the embodiments described above. For example, it is also possible not to use all the inspection results of S101 to S103, but to use only any one or two of them to determine the characteristics of the corrective color filter 300. Alternatively, it is also possible not to use the difference or ratio of the test subject 500's sensitivity to RGB light, but to use the individual inspection results of S101 to S103 to determine the characteristics of color filters 300B, 300G, and 300R.

[0098] Furthermore, the characteristics of the corrective color filter 300 can also be designed to match the visual characteristics of the test subject 500. Alternatively, various colored filters with different characteristics can be prepared in advance and combined with the visual characteristics of the test subject 500 to create a corrective color filter 300.

[0099] Furthermore, the results of the visual examination shown in Figure 5 can also be used to determine applications other than those of the color filter 300. For example, the results of the visual examination shown in Figure 5 can also be used to adjust the brightness and hue of the display device (e.g., personal computer or mobile terminal device, television, etc.) and lighting device used by the test subject 500.

[0100] [Effect] According to this embodiment, the inspection image 110 has a background region 130 and an inspection region 120 disposed in the background region 130. The inspection region 120 is provided with a graphic 121 whose predetermined color composition is different from that of the background region 130. By using this inspection image 110, the visual characteristics of the subject 500 for light of the predetermined color composition can be inspected efficiently.

[0101] According to this embodiment, by one-dimensionally changing the luminance [%] of the background area 130 of the examination image 110, the presence or degree of photosensitivity of the subject 500 can be examined. Furthermore, by one-dimensionally changing the blue component of pattern 121 in examination image 110B, the green component of pattern 121 in examination image 110G, and the red component of pattern 121 in examination image 110R, the subject 500's sensitivity to blue light, green light, and red light can be examined. Thus, by one-dimensionally changing the luminance or a specific color component without altering multiple color components of the examination image 110, the visual characteristics of the subject 500 can be measured, thereby reducing the burden of the examination.

[0102] According to this embodiment, in the inspection image 110, the colors of the background area 130 and the graphic 121 are such that any two of the RGB components are the same size. Therefore, when inspecting the visual characteristics of the subject 500 for the remaining component of light, the difference in the subject 500's sensitivity to the other two components of light can be prevented from affecting the inspection.

[0103] According to this embodiment, an inspection image group includes multiple inspection images 110 containing background areas 130 with the same color but graphic 121 with different colors. Therefore, when using the color of graphic 121 to inspect visual characteristics, the influence of the color of the background area 130 on the inspection results of visual characteristics can be suppressed.

[0104] According to this embodiment, the examination image group includes multiple examination images 110 with different colors or brightness levels of background areas 130. Therefore, by changing the color or brightness of the background areas 130 of the examination images 110, the degree of photosensitivity of the subject 500 can be examined.

[0105] Furthermore, in this embodiment, the sensitivity of subject 500 to blue light is checked using inspection image 110B, the sensitivity of subject 500 to green light is checked using inspection image 110G, and the sensitivity of subject 500 to red light is checked using inspection image 110R. Therefore, it is possible to check only the specific color to be checked among the three RGB colors.

[0106] The above describes exemplary embodiments of the present invention. The embodiments of the present invention are not limited to those described above, and various changes can be made within the scope of the technical concept of the present invention. The embodiments of the present invention also include, for example, appropriate combinations of the explicit embodiments listed in the specification or embodiments that should be understood.

[0107] [Variation Example 1] In the above-described embodiments, the background area 130 of the examination image 110 is achromatic and the pattern 121 of the examination area 120 is chromatic. However, the embodiments of the present invention are not limited to this configuration. According to another embodiment of the present invention, both the background area 130 and the pattern 121 may be chromatic. For example, when examining whether the subject 500 has photosensitivity or the degree of photosensitivity of the subject 500, the blue component of the pattern 121 of the examination image 110B may be changed, and the blue component of the background area 130 may also be changed.

[0108] Tables 4 to 14 show the input values ​​(xR, xG, xB) of the background region 130 and graphic 121 of the inspection image 110B in another embodiment of the present invention. The background region 130 of the inspection image 110B has both achromatic and chromatic colors. The red and green components of the background region 130 are of the same size, and the blue component is of the same size as or smaller than the red and green components. Furthermore, the red and green components of the graphic 121 are each of the same size as the red and green components of the background region 130. The blue component of the graphic 121 is smaller than the blue component of the background region 130.

[0109] [Table 4]

[0110] [Table 5]

[0111] [Table 6]

[0112] [Table 7]

[0113] [Table 8]

[0114] [Table 9]

[0115] [Table 10]

[0116] [Table 11]

[0117] [Table 12]

[0118] [Table 13]

[0119] [Table 14]

[0120] Tables 4 to 14 show the luminance of the red and green components of the background region [%], which represents the luminance of the red and green components of the background region 130 when the input value of the red and green components is 255 and the luminance is set to 100%. Table 4 shows the luminance of the blue component of the background region [%], which represents the luminance of the blue component of the background region 130 when the input value of the blue component is 255 and the luminance is set to 100%. Table 4 shows the input values ​​(xR, xG, xB) in the luminance [%] of each background region 130. In this embodiment, the red and green components of the background region 130 in the inspection image 110B shown in Tables 4 to 14 are different in size. When the luminance is set to 100% with the input values ​​of the red and green components being 255, the luminance of the red and green components of the background area 130 of the inspection image 110B shown in Tables 4 to 14 are 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 5%, respectively.

[0121] Tables 4 to 14 show the "Difference of Blue Component of Graphic Relative to Background Area [%]", which represents the difference in luminance of the blue component of graphic 121 relative to the luminance of the blue component of background area 130 when the luminance of the blue component of background area 130 is set to 100%. In this embodiment, there are five different percentages of blue component of graphic 121, ranging from -50% to -10% at 10% intervals.

[0122] The inspection image 110B is a combination of a background region 130 and a graphic 121 having input values ​​recorded in the same column as the background region 130. For example, there are five inspection images 110B with input values ​​of (255, 255, 255) for the background region 130. The red and green components of the graphic 121 in these five inspection images 110B are each the same size as the red and green components of the background region 130 (i.e., both are 255). On the other hand, the blue input values ​​of the graphic 121 in these five inspection images 110B are set by changing the brightness from -50% to -10% at 10% intervals relative to the blue input values ​​of the background region 130. The sizes of the blue input values ​​of the graphic 121 in the five inspection images 110B are 186, 202, 217, 230, and 243, respectively.

[0123] In the examination images 110B recorded in Tables 4 to 14, the brightness of the background area 130 and the graphic 121 decreases from Table 4 to Table 14. Examination images 110B are selected one by one from Tables 4 to 14 and displayed sequentially on the display device 100. Then, it is checked whether the subject 500 experiences glare from the examination images 110B, thereby checking whether the subject 500 has photosensitivity or the degree of photosensitivity.

[0124] Furthermore, among the examination images 110B that do not cause eye strain for the test subject 500, the table from Tables 4 to 14 selects the examination image 110B with the highest brightness, which includes the background area 130 and the graphic 121. Then, the examination images 110B shown in the selected tables are selected one by one and displayed sequentially on the display device 100. The test subject 500 selects the examination images 110B in which the graphic 121 in the background area 130 can be identified from the sequentially displayed examination images 110B, thereby checking the test subject 500's sensitivity to blue light.

[0125] Furthermore, Tables 4 to 14 show variations of the examination image 110B, which changes the blue component of the pattern 121 relative to the colored background area 130, but the embodiments of the present invention are not limited thereto. For example, the examination image 110R, which changes the red component of the pattern 121 relative to the colored background area 130, or the examination image 110G, which changes the green component of the pattern 121 relative to the colored background area 130, can also be used to examine the visual characteristics of the subject 500.

[0126] [Variation Example 2] For example, in the above embodiment, only one graphic 121 with a single color is configured in the inspection area 120 of the inspection image 110, but the embodiments of the present invention are not limited to this configuration. Two or more graphics with different colors may also be configured in the inspection area of ​​the inspection image.

[0127] Figure 11 shows an examination image 210 in another embodiment of the present invention. The examination image 210 has an examination region 220 near the center and a surrounding background region 230. Similar to examination image 110, the examination region 220 of examination image 210 corresponds to the fovea on the human retina, and the background region 230 corresponds to the area surrounding the fovea on the human retina. The outermost peripheral region 240 of the background region 230 is expected to be black.

[0128] The inspection area 220 contains a pattern 221 with a green component of a different size relative to the background area 230 and a pattern 222 with a red component of a different size relative to the background area 230. The green component of pattern 221 and the red component of pattern 222 can be changed independently. By using this inspection image 210, the subject 500's sensitivity to both green and red light can be checked.

[0129] Furthermore, the shape and color of the graphic arranged in the inspection area 220 are not limited to those shown in Figure 11. For example, graphic 222 can also be arranged inside graphic 221. Also, any two of the following three types of graphics, or all three types of graphics, can be arranged in the inspection area 220: graphics with a different size of blue component relative to background area 230, graphics with a different size of green component relative to background area 130, and graphics with a different size of green component relative to background area 130.

[0130] [Other variations] In the above-described embodiment, the inspection image 110 is displayed on the display device 100, but the embodiments of the present invention are not limited to this configuration. The inspection image 110 can also be printed on paper or a board. In this case, multiple inspection images 110 with different brightness levels of the background area 130 and the graphic 121 are printed on different papers or boards. The multiple printed inspection images 110 are arranged sequentially at a predetermined distance from the subject 500 and illuminated with white light to alert the subject 500. This allows the visual characteristics of the subject 500 to be examined. In addition, the printed inspection images 110 are preferably placed in areas with a black background.

[0131] 1: Visual Inspection System 100: Display device 110, 110B, 110R, 110G: Examination images 120: Inspection Area 121: Graphics 130: Background Area 140: Surrounding Area 200: Sunshade 210: Examination of images 220: Inspection Area 221: Graphic 222: Graphics 230: Background Area 240: Surrounding Area 300: Correction Filter 300B, 300G, 300R: Color Filters 500: Test subjects S101~S104: Steps

Claims

1. A visual characteristic examination image set, comprising multiple examination images, wherein the aforementioned examination image set is used to examine the visual characteristics of a subject, wherein, Each of the aforementioned examination images has: a background area; and an examination area disposed within the aforementioned background area; the aforementioned examination area is configured such that when the subject views the aforementioned examination image at approximately the center, light emitted from the aforementioned examination area images the area inside the fovea of ​​the subject's retina; the aforementioned examination area contains a graphic in which at least one of the R, G, and B components in the RGB color space has a color different from that of the aforementioned background area; the color of the aforementioned background area is the same as the color of the area in the aforementioned examination area where the aforementioned graphic is not present; in the aforementioned multiple examination images, the aforementioned background area and at least one of the aforementioned graphic have different colors from each other.

2. As requested in item 1, the luminance of any one of the predetermined components of the R, G, and B components of the color of the aforementioned graphic is different from the luminance of the predetermined component of the color of the aforementioned background area.

3. In the visual characteristic inspection image group of Request 2, among the R component, G component and B component of the color of the aforementioned image, the two components other than the aforementioned predetermined components are the same size.

4. An inspection image set of the visual characteristics of any one of Request 1 to Request 3, comprising multiple of the aforementioned inspection images in which the background areas are the same color and the colors of the aforementioned graphics are different.

5. An image set of visual characteristics of any one of claims 1 to 3, comprising multiple aforementioned images of background regions with different colors.

6. The visual characteristic examination image set as requested in claim 5, which includes multiple of the aforementioned examination images in which the size of any one of the R component, G component, and B component of the aforementioned image is different from each other.

7. The visual characteristic examination image set as requested in claim 5, wherein in each of the aforementioned plurality of examination images, the magnitudes of any two of the R component, G component, and B component are the same.

8. An image set of visual characteristics of any one of Request 1 to Request 3, wherein the aforementioned background area is achromatic.

9. A set of visual characteristic examination images for any one of claims 1 to 3, wherein the aforementioned examination area is configured such that, when the subject views the aforementioned examination image at approximately the center, light emitted from the examination area is imaged within a range of 2 degrees relative to the center of the subject's retina.

10. A method for examining visual characteristics, comprising examining the visual characteristics of a subject using examination images included in an examination image set as described in any one of claims 1 to 9, the method comprising: a prompting step, sequentially prompting the subject with the aforementioned examination images included in the aforementioned examination image set; a determination step, determining whether predetermined examination conditions are met when the subject views the aforementioned examination images prompted in the prompting step; and an identification step, identifying, within the aforementioned examination image set, the aforementioned examination image that meets the aforementioned predetermined examination conditions.

11. The visual characteristic inspection method of claim 10, wherein the aforementioned predetermined inspection conditions include a first inspection condition, which is that when the subject views the aforementioned inspection image, the subject can identify the aforementioned inspection area of ​​the inspection image and the aforementioned graphic is set therein.

12. The visual characteristic inspection method of claim 11, wherein the aforementioned first inspection condition is that when the subject views the aforementioned inspection image, the subject can recognize the aforementioned graphic set in the aforementioned inspection area without feeling glare from the inspection image.

13. The method for inspecting visual characteristics as described in claim 11 or claim 12, wherein in the aforementioned identification step, when there are multiple inspection images among the multiple inspection images that satisfy the aforementioned first inspection condition, one of the multiple inspection images that satisfies the aforementioned first inspection condition is identified.

14. The visual characteristic inspection method of claim 13, wherein in the aforementioned identification step, among the aforementioned plurality of inspection images that satisfy the aforementioned first inspection condition, the aforementioned inspection image containing the central value of the luminance of the plurality of aforementioned background regions or the aforementioned background region closest to the central value is identified.

15. The visual characteristic inspection method of claim 13, wherein in the aforementioned identification step, among the aforementioned plurality of inspection images that satisfy the aforementioned first inspection condition, the aforementioned inspection image with the highest brightness in the aforementioned background area is identified.

16. A method for examining the visual characteristics of any one of claims 10 to 12, wherein the aforementioned predetermined examination conditions include a second examination condition, which is that when the subject views the aforementioned examination image, the subject can identify the color difference between the aforementioned background area and the aforementioned graphic.

17. The visual characteristic inspection method of claim 16, wherein the aforementioned second inspection condition is that when the subject views the aforementioned inspection image, the subject can identify the color difference between the aforementioned background area and the aforementioned graphic, and can identify the aforementioned graphic set in the aforementioned inspection area.

18. The visual characteristic inspection method of claim 16, wherein in the aforementioned identification step, when there are multiple inspection images among the multiple inspection images that satisfy the aforementioned second inspection condition, the inspection image whose color of the aforementioned background area is closest to the color of the aforementioned graphic is identified among the multiple inspection images that satisfy the aforementioned second inspection condition.

19. A method for examining visual characteristics, which uses an image set containing multiple examination images to examine the visual characteristics of a subject, wherein, Each of the aforementioned inspection images has: a background area; and an inspection area located within the background area; the aforementioned multiple inspection images include: multiple red inspection images, which are graphics in the aforementioned inspection area whose R component in the RGB color space is different from the color of the aforementioned background area, and the R component of each of the graphics in the multiple red inspection images is different from each other; multiple green inspection images, which are graphics in the aforementioned inspection area whose G component in the RGB color space is different from the color of the aforementioned background area, and the G component of each of the graphics in the multiple green inspection images is different from each other; the aforementioned visual characteristic inspection method includes: a red inspection image prompting step, sequentially prompting the aforementioned multiple red inspection images to the aforementioned subject; a red inspection image determination step, determining whether predetermined inspection conditions are met when the aforementioned subject views the aforementioned red inspection images prompted in the aforementioned red inspection image prompting step; a red inspection image identification step, identifying the aforementioned red inspection image that meets the aforementioned predetermined inspection conditions among the aforementioned multiple red inspection images; and a green inspection image prompting step, sequentially prompting the aforementioned multiple green inspection images to the aforementioned subject. The green inspection image determination step determines whether the predetermined inspection conditions are met when the subject views the green inspection image prompted in the aforementioned green inspection image prompting step; the green inspection image identification step identifies the aforementioned green inspection image that meets the aforementioned predetermined inspection conditions among the aforementioned multiple green inspection images; and the decision step determines the ratio of the subject's sensitivity to red light to sensitivity to green light based on the R component of the aforementioned red inspection image identified in the aforementioned red inspection image identification step and the G component of the aforementioned green inspection image identified in the aforementioned green inspection image identification step.

20. A method for determining the characteristics of a corrective color filter, comprising a determination step of determining the transmittance of a corrective color filter for adjusting the transmitted light intensity based on the color of the aforementioned inspection image that satisfies the aforementioned predetermined inspection conditions in a method for inspecting the visual characteristics of any one of claims 10 to 19.

21. A method for determining the characteristics of a corrective color filter, comprising a determination step, which determines the transmittance of a predetermined wavelength band of the corrective color filter for adjusting the transmitted light intensity based on the color of the background region of the aforementioned examination image that satisfies the aforementioned first inspection condition in the visual characteristic inspection method of any one of claims 11 to 15; the higher the luminance of the background region of the aforementioned examination image that satisfies the aforementioned first inspection condition, the higher the aforementioned transmittance determined in the aforementioned determination step.

22. A method for determining the characteristics of a corrective color filter, comprising a determination step, which determines the transmittance of a predetermined wavelength band of the corrective color filter for adjusting the transmitted light intensity based on the color of the background region of the aforementioned inspection image that satisfies the aforementioned second inspection condition in the visual characteristic inspection method of any one of claims 16 to 18; the closer the magnitude of the predetermined color component of the aforementioned background region in the aforementioned inspection image that satisfies the aforementioned second inspection condition is to the magnitude of the predetermined color component of the aforementioned pattern, the higher the aforementioned transmittance determined in the aforementioned determination step.

23. A corrective color filter having the aforementioned transmittance determined according to the characteristic determination method of a corrective color filter as described in any one of claims 20 to 22.

24. The visual characteristic inspection image set as requested in item 1, wherein the aforementioned graphic is a circle.

Images