Patent Application
20240237892
The present disclosure relates to a test image set for testing visual characteristics, a test method for visual characteristics, a determining method for characteristics of correction filter, and a correction filter.
As impairments of a human visual sense, there has been known color blindness or color weakness, in which sensitivity to light in a specific wavelength band is low, and photosensitivity, in which people feel dazzled by light in a specific wavelength band. The photosensitivity is, for example, Irlen syndrome. These visual impairments are caused by higher or lower sensitivities of three cone cells (S, M, and L cone cells) or rod cells on a patient's retina compared to normal subjects. These S, M, and L cone cells are cells that respond to blue light, green light, and red light, respectively. The rod cells are cells that respond to the light intensity. The light sensitivity of a human depends on brightness of the environment, and the sensitivity in a bright environment is called photopic vision and the sensitivity in a dark environment is called scotopic vision. The photopic vision is mainly achieved by the cone cells, while the scotopic vision is mainly achieved by the rod cells (see
In order to make an optical filter adjusted to the patient, it is necessary to test the patient's visual characteristics (sensitivities) to various colors of light. However, since there are countless combinations of sensitivities to various lights, the test of visual characteristics is burdensome for both a testing person and the patient.
There has heretofore been known a method for making optical filters adjusted to the patient. In the method, color vision characteristics are classified into 32 types based on test results of multiple patients' color vision characteristics. Then, it is tested which of the 32 types of color vision characteristics the patient's color vision characteristics correspond to. By determining the characteristics of the optical filter based on the test results, the patient's color vision abnormality is suppressed.
In the color vision test method described in Patent Document 1, it is determined which of the predefined classifications a patient's color vision characteristic corresponds to. Therefore, there is a problem that accurate test results cannot be obtained for patients with color vision characteristics that do not correspond to any of the predefined classifications, or for patients with intermediate color vision characteristics between the multiple classifications. In the color vision test method described in Patent Document 1, color vision characteristics are classified according to the wavelength range to which cone cells are sensitive, and the sensitivity of rod cells is not taken into consideration. Therefore, the color vision testing method described in Patent Document 1 cannot test for abnormalities in visual characteristics caused by rod cells. In addition, Patent Document 1 does not take into account photopic, scotopic, and mesopic vision, which are affected by the combined sensitivity of cone cells and rod cells.
A test image set according to one embodiment of the present disclosure is a test image set for testing visual characteristics of a subject, the test image set including a plurality of test images, each of the plurality of test images including a background area, and a test area located in the background area, the test area including a figure having a color different from a color of the background area in at least one of R, G or B components in a RGB color space, and the plurality of test images are different from each other in the color of at least one of the background area or the test area.
A test method for visual characteristics according to one embodiment of the present disclosure is a test method for visual characteristics of a subject using test images included in a test image set described above. The test method for visual characteristics comprising a showing step of sequentially showing the test images included in the test image set to the subject, and a determining step of determining whether a particular test condition is specified when the subject looks at each of the test images sequentially shown in the showing step.
A determining method according to one embodiment of the present disclosure is a determining method for determining characteristics of a correction filter using the test image set described above. The determining method comprises sequentially showing the test images included in the test image set to the subject, determining whether a particular test condition is satisfied when the subject looks at each of the test images sequentially shown, specifying, among the test images, at least one test image that satisfies the particular test condition, and determining transmittance of a correction filter configured to adjust an intensity of transmitted light based on a color of the specified at least one test image.
A correction filter according to one embodiment of the present disclosure has the transmittance determined by the determining method described above.
Hereinafter, an illustrative embodiment according to aspects of the present disclosure will be described referring to the accompanying drawings.
The display 100 is, for example, a liquid crystal display or a CRT (Cathode Ray Tube) display. The display 100 displays a test image 110. The display 100 is used to show the test image 110 to the subject 500. The display 100 is not limited to the liquid crystal display that displays an image based on image signals. For example, the display 100 is equipped with a film on which the test image 110 is printed and a backlight that illuminates the film. The test image 110 may be presented to the subject 500 by illuminating the film with illumination light.
The display 100 is covered with the light shielding hood 200. The light shielding hood 200 is configured to prevent the test image 110 from being illuminated by external light and changing the luminance and color of the test image 110 as seen by the subject 500. The inside of the light shielding hood 200 should be black, which absorbs light, in order to prevent light from reflecting and affecting the test of visual characteristics.
In the test of visual characteristics, the subject 500 looks at the test image 110 with one or both eyes. The degree to which the subject 500 perceives glare in the test image 110 (i.e., the degree of photosensitivity that the subject 500 has) and the color of the test image 110 (i.e., the color vision characteristics of the subject 500) are tested.
Once the visual characteristics of the subject 500 are tested by the test of visual characteristics, a correction filter can be made to correct the visual characteristics of the subject based on the test results. The test results may be used not only to made the correction filter, but also to adjust the luminance and color of a lighting system or a monitor, such as a television or a mobile terminal used by the subject 500, to match the visual characteristics of the subject 500.
Next, test image sets will be explained. The test image set is a set of multiple test images. The test images are displayed on the display 100.
The test image 110 has a test area 120 located around a center of the test image 110 and a background area 130 surrounding the test area 120. In
In the example in
The test area 120 is an area corresponding to a fovea centralis on a human retina. The size of the test area 120 is set in such a manner that light emitted from the test area 120 forms an image within the fovea centralis. For example, the size of the test area 120 is set so that the apex angle θIN (see
The background area 130 corresponds to an area surrounding the fovea centralis on a person's retina. The size of the background area 130 is set so that light emitted from the background area 130 forms an image outside the fovea centralis on the human retina. For example, the size of the background area 130 is set so that the apex angle θOUT (see
On the fovea centralis of the human retina, M cone cells, which are sensitive to green light, and L cone cells, which are sensitive to red light are located. The fovea centralis contains few S cone cells and rod cells. On the other hand, S, M, and L cone cells and rod cells are located in the area outside the fovea centralis.
Human eyesight is higher when the fovea centralis is used. When a human see objects, images, or letters, he/she recognize the figure and color of the observed object mainly using M and L cone cells located in the fovea centralis. That is, the human can recognize colors using only M and L cone cells. In addition, people recognize not only color but also luminance by using S and M cone cells and rod cells around the fovea centralis. Therefore, it is possible to test a human's color vision characteristics by performing a visual test on the M and L cone cells in the fovea centralis. In addition, the degree of photosensitivity can be tested by testing the S cone and rod cells located in and around the fovea centralis.
The
The test image set contains a plurality of the test images 110 that differ from each other in the color of the
The colors of the plurality of test images 110B, where the colors of the background area 130 are different from each other, are set in such a manner that, for example, luminance of the background area 130 varies in 5% increments or 10% increments. The colors of the plurality of test images 110G, where the colors of the background area 130 are different from each other, are set in such a manner that, for example, the luminance of the background area 130 varies in 5% increments or 10% increments. The colors of the plurality of test images 110R, where the colors of the background area 130 are different from each other, are set in such a manner that, for example, luminance of the background area 130 varies in 5% increments or 10% increments. The increments of the luminance of the background area 130 are not limited to 5% or 10%.
Since the test image 110 is displayed on the display 100, the test image 110 is gamma-corrected according to a gamma value of the display 100 before being displayed. In detail, when an input value of an image signal input to the display 100 is x, an output value (luminance) is y, and the gamma value of the display 100 is γ, y=xγ is valid. Therefore, the input value for changing the luminance y on the display 100 is calculated by x=y1/γ. In this embodiment, the RGB components of the test image 110 are the input values (xR, xG, xB) to this display 100, and each input value is represented by 256 shading from 0 to 255. The RGB components of the background area 130 are the input values (xRBG, xGBG, xBBG) to the display 100, and each input value is represented by 256 shading from 0 to 255.
Table 1 shows the input values (xRBG, xGBG, xBBG) of the background area 130 and the input values (xR, xG, xB) of the
The “Luminance of Background Area [%]” in Table 1 represents the luminance in a case where the luminance is 100% when the background area 130 is white (i.e., the input value is (255, 255, 255)). The “Color Components of Background Area” represent the input values (xRBG, xGBG, xBBG) at the luminance [%] of the respective background area 130. In this embodiment, there are 11 types of background areas 130B (5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%). Since the background area 130B is achromatic in this embodiment, the RGB color components have the same magnitude in each background area 130.
The “Difference of Blue Component of Figure from Background Area [%]” in the table represents the luminance of the blue component of the
The test image 110B is a combination of the background area 130 and the
In Table 1, when the input value of the background area 130 is (255, 255, 255), the reason why the input value of the
When the difference [%] of the blue component of
A subject with normal color vision characteristics can easily recognize the color difference between the
In general, the higher the luminance of the background area 130 and the
Thus, depending on what color vision characteristics the subject has, the conditions under which the subject can recognize the difference in color of the background area 130 and the
Tables 2 and 3 show the input values (xRBG, xGBG, xBBG) of the background area 130 and the input values (xR, xG, xB) of the
In the test image 110R shown in Table 2, when the difference [%] of the red component of the
In the test image 110G shown in Table 3, when the difference [%] of the green component of the
Similarly to the test image 110B, in the test image 110R and the test image 110G, the subject 500 with normal color vision characteristics can easily recognize the color difference between the
In general, the higher the luminance of the background area 130 and the
Thus, depending on what kind of color vision characteristics the subject has, the conditions that he/she can recognize the difference colors between the background area 130 and the
Next, the test method for visual characteristics using a test system of the visual characteristics 1 including the test image 110 is described.
In S101, an appropriate luminance BCENTER, which is a luminance [%] of the background area 130 of the test image 110 that is appropriate for the subject 500, is determined.
In S101, at first, the test images 110B with a difference [%] of −30% from the background area 130 of the blue component of the
If the subject 500 has healthy visual characteristics for blue light, the subject 500 will be able to recognize the
If the subject 500 can recognize the
The subject 500 specifies the luminance [%] of the background area 130 that the
If the subject 500 cannot recognize the
In the process of S101, the test image 110B with a difference [%] of −30% from the background area 130 of the blue component of the
In S102, the particular red component RVALUE, which is the red component that enables the subject 500 to recognize the
In S102, the test image 110R is sequentially displayed on the display 100 with the difference [%] of the red component of the
In the test image 110R, where the difference [%] of the red component of the
If the subject 500 can recognize the
If the subject 500 cannot recognize the
In the process of S102, the test image 110R with a difference [%] of −10% from the background area 130 of the red component of the
In S103, the particular green component GVALUE, which is the green component that enables the subject 500 to recognize the
In S103, similar to the test in S102, whether the subject 500 can recognize the
The test method in S103 is the same as that in S102, except that the test image 110G is used instead of the test image 110R and that the difference [%] from the background area 130 of the green component is changed instead of the difference [%] of the red component of the
With the above processes from S101 to S103, the sensitivity of the subject to each of the RGB lights is tested.
In the example shown in
If only a degree of photosensitivity of the subject 500 is to be tested, only S101 may be performed. The degree of photosensitivity is tested by measuring which luminance [%] of the background area 130 the subject 500 feels dazzled. Therefore, when testing the degree of photosensitivity, it is not necessary to use the test image 110B, but the test image 110R or the test image 110G may be used.
In S104, the ratio of the sensitivity of the subject 500 to red light and the sensitivity of the subject 500 green light is calculated using the particular red component RVALUE and the particular green component GVALUE identified in S102 and S103.
If the absolute value of the particular red component RVALUE is greater than the absolute value of the particular green component GVALUE, the sensitivity of the subject 500 to red light is less than the sensitivity to green light. In this case, the ratio of sensitivity is calculated as |GVALUE/RVALUE| (absolute value of GVALUE/RVALUE). On the other hand, if the absolute value of the particular red component RVALUE is smaller than the absolute value of the particular green component GVALUE, the sensitivity of the subject 500 to red light is greater than the sensitivity to green light. In this case, the ratio of sensitivity is calculated as |RVVALUE/GVALUE| (absolute value of RVALUE/GVALUE). The calculated ratio of sensitivity is used to determine the characteristics of the correction filter that corrects the visual characteristics of the subject 500.
Once the visual characteristics of the subject 500 are tested by the visual testing method shown in
The filter 300B changes the transmittance of light in the blue region (in other words, it absorbs or reflects part of the blue light), but allows green and red lights to be transmitted as they are (in other words, it has low absorption and reflection for green and red lights). The filter 300G changes the transmittance of light in the green region (in other words, absorbs or reflects some of the green light), but allows blue and red lights to be transmitted as they are (in other words, it has low absorption or reflectance for blue and red lights). The filter 300R changes the transmittance of light in the red region (in other words, it absorbs or reflects some of the red light), but allows green and blue lights to be transmitted as they are (in other words, it has low absorption or reflectance for green and blue lights). Therefore, by combining the three filters 300B, 300G, and 300R, the transmittance to light in the three RGB wavelength bands can be adjusted individually.
The filter 300B can change the transmittance of light at wavelengths equal to or longer than the peak wavelength PS (about 420 nm) of sensitivity of the S cone cells, and equal to or shorter than the peak wavelength PRod (about 498 nm) of sensitivity of the, as indicated by the solid arrow in
The filter 300B can change the transmittance of light in the blue wavelength band, and the upper limit of the bandwidth BB of the filter 300B is not limited to the peak wavelength PRod (about 498 nm) of the rod cells.
For example, the upper limit of the bandwidth BB of the filter 300B may be the wavelength XRod-M (about 515 nm) at which the absorption spectrum of the rod cells intersects the absorption spectrum of the M cone cells. This wavelength XRod-M is longer than the peak wavelength PRod and shorter than the peak wavelength PM (about 534 nm) of M cone cells. Within the bandwidth longer than the wavelength XRod-M, the sensitivity of the rod cells is relatively small and the sensitivity of the M cone cells is relatively large. Therefore, if the upper limit of the bandwidth BB of the filter 300B is set longer than the wavelength XRod-M, the transmittance of light absorbed by the M cone cells (i.e., light in the green wavelength band) would be changed, and the visual characteristics of the subject 500 might not be appropriately corrected.
The upper limit of the bandwidth BB of filter 300B may be shorter than the peak wavelength PRod (about 498 nm) of the sensitivity of rod cells. For example, the upper limit of the bandwidth BB of the filter 300B may be the wavelength XS-Rod (about 453 nm) at which the absorption spectrum of the S cone cells intersects that of the rod cells. This wavelength XS-Rod is longer than the peak wavelength PS and shorter than the peak wavelength PRod. Within the bandwidth shorter than the wavelength XS-Rod, the sensitivity of the rod cells is relatively low and the sensitivity of the S cone cells is relatively high. Therefore, if the upper limit of the bandwidth BB of filter 300B is set shorter than the wavelength XS-Rod, the percentage of light absorbed by the S cone cells will be larger, and the photosensitivity may not be appropriately corrected.
In order to appropriately correct for effects of the rod cells on photosensitivity, the bandwidth BB of filter 300B should include a wavelength band that is close to the peak wavelength PRod of sensitivity of the rod cells. Therefore, the upper limit of the bandwidth BB of the filter 300B may be shorter than the peak wavelength PRod of sensitivity of the rod cell, but should not be too far from the peak wavelength PRod. For example, if the difference between the peak wavelength PRod of sensitivity of the rod cells, and the wavelength XRod-M at which the absorption spectrum of the rod cells intersects that of the M cone cells is Δ, the upper limit of the bandwidth BB of filter 300B can be set within PRod±Δ, it is possible to appropriately correct the effect of the rod cells on photosensitivity.
The filter 300G changes the transmittance of light at wavelengths equal to or longer than the peak wavelength PRod (about 498 nm) of sensitivity of the rod cells and equal to or shorter than the wavelength XM-L (about 548 nm) where the absorption spectrum of the M cone cells intersects the absorption spectrum of the L cone cells, as shown in
In order to increase the percentage of light in the wavelength band to which the M-cone cell is sensitive among the light transmitted through the filter 300G, the lower limit of the bandwidth BG of the filter 300G may be set to the wavelength XRod-M (about 515 nm) at which the absorption spectrum of the rod cells and that of M cone cells intersect. In this case, the bandwidth BG of the filter 300G is shown in
It is noted that the rod cells are cells that respond to light intensity and do not affect the color perception (color vision) of the subject. Therefore, even if the lower limit of the bandwidth BG of the filter 300G is set to the peak wavelength PRod of sensitivity of the rod cells, the green light can be corrected.
The filter 300R is a filter that changes the transmittance of the red light for the subject 500 and has the characteristics of absorbing or reflecting light in the wavelength band to which the L cone cells are sensitive.
As shown by the solid line in
In the wavelength band shorter than the wavelength XM-L, the sensitivity of the L cone cells is lower and the sensitivity of the M cone cells is dominant. Therefore, if the lower limit of the bandwidth BR of the filter 300R is set shorter than the wavelength XM-L, not only red light for the L cone cells but also green light may be absorbed or reflected.
The lower limit of the bandwidth BR of the filter 300R may be the wavelength PPho (about 570 nm) at which the photopic vision is maximally sensitive, instead of the wavelength XM-L.
Next, an example of the correction filter will be explained. The transmittance of the bandwidth BB of the filter 300B is set based on the appropriate luminance BCENTER determined in S101. For example, if the appropriate luminance BCENTER is 70%, the transmittance of bandwidth BB is set to 70%. Thus, the light sensitivity of the subject 500 is corrected.
The transmittance of the bandwidth BG of filter 300G and the transmittance of the bandwidth BR of filter 300R are set based on the results of the tests in S102 and S103. For example, if the particular red component RVALUE is identified as −30% in the test of S102, the sensitivity of the subject 500 to red light is the same as the sensitivity of a healthy subject to red light. For example, if the particular green component GVALUE is identified as −50% in the test of S103, the sensitivity of the subject 500 to green light is lower than the sensitivity of the healthy human to red light. In this case, the transmittance of bandwidth BR of filter 300R is set lower than the transmittance of the bandwidth BG of the filter 300G by |RVALUE/GVALUE| times. Thus, the difference between the sensitivity of the subject 500 to red light and the sensitivity to green light is corrected.
In the example shown in
The transmittance of bandwidth BG of the filter 300G and the transmittance of bandwidth BR of the filter 300R may be based on the transmittance of bandwidth BB of filter 300B. For example, if the appropriate luminance BCENTER is 70%, the transmittance of bandwidth BB is set to 70%. If the particular red component RVALUE is identified as −30% and the particular green component GVALUE is identified as −50%, the transmittance of bandwidth BR of the filter 300R is set to |RVALUE/GVALUE| times (70%×60%=42%) the 70% transmittance of bandwidth BB. The transmittance of bandwidth BG of the filter 300G is set to 70%, the same as the transmittance of bandwidth BB.
Next, an example of the correction filter 300 when the subject 500 does not have photosensitivity will be explained. If the subject 500 does not have photosensitivity and has low sensitivity to blue light, the transmittance of the bandwidth BB of the filter 300B, the transmittance of the bandwidth BG of the filter 300G, and the transmittance of the bandwidth BR of the filter 300R are set based on the test results of S101 to S103. For example, if the subject 500 can recognize the
The method of determining the characteristics of correction filter 300 using the results of the test of visual characteristics shown in
The characteristics of the correction filter 300 may be designed to match the visual characteristics of the subject 500. Alternatively, color filters with various characteristics may be prepared in advance, and the correction filter 300 may be made by combining multiple color filters according to the visual characteristics of the subject 500.
The results of the test of visual characteristics shown in
According to this embodiment, the test image 110 has the background area 130 and the test area 120 located in the background area 130, and in the test area 120, and the test area 120 includes a
According to this embodiment, by changing the luminance [%] of the background area 130 of the test image 110 in a one-dimensional manner, it is possible to test whether the subject 500 has photosensitive or not, or the degree of photosensitivity. In addition, by changing the blue component of the
According to this embodiment, in the test image 110, the
According to this embodiment, the test image set includes a plurality of test images 110 in which the colors of the background area 130 are the same and the colors of the
According to this embodiment, the test image set includes a plurality of test images 110 in which the color or the luminance of the background area 130 are different from each other. Therefore, by changing the color or luminance of the background area 130 of the test images 110, the degree of photosensitivity of the subject 500 can be tested.
In this embodiment, the test image 110B is used for testing the sensitivity of the subject 500 to blue light, the test image 110G is used for testing the sensitivity of the subject 500 to green light, and the test image 110R is used for testing the sensitivity of the subject 500 to red light. Thus, only the particular color to be tested among the three RGB colors can be tested.
The above is a description of an exemplary embodiment of the present disclosure. The embodiments of the present disclosure are not limited to those described above, and various modifications are possible within a scope of the technical concept of the invention. For example, the embodiments exemplary indicated in the specification or combinations of obvious embodiments as appropriate are also included in the embodiments of the present disclosure.
In the embodiment described above, the background area 130 of the test image 110 is achromatic and the
Tables 4 through 14 show the input values (xR, xG, xB) of the background area 130 and the
The “Luminance of Red and Green Components of Background area [%]” in the tables 4 through 14 represent the luminances of the red and green components of the background area 130 in a case where the luminance is 100% when the input value of the red and green components of the background area 130 is 255. The “Luminance of Blue Component of Background Area [%]” represents the luminance of the blue component of the background area 130 in a case where the luminance is 100% when the input value of the blue component of the background area 130 is 255. The “Input Value of Background Area” indicates an input value (xR, xG, xB) at the respective luminance [%] of the background area 130. In this embodiment, the test images 110B shown in the table 4 through table 14 differ from each other in the magnitude of the red and green components of the background area 130. If the luminance of the input values of the red and green components is 100% when the input value of the red and green components is 255, the luminances of the red and green components of the background area 130 of the test images 110B, which are shown in the table 4 to table 14, are 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 5%, respectively.
The “Difference [%] of Blue Component of Figure from Background Area” in the tables 4 through 14 represent the luminances of the blue component of the
The test image 110B is a combination of the background area 130 and the
The test images 110B listed in the table 4 through table 14 have the luminance of the background area 130 and the
Among the test images 110B that the subject 500 did not feel dazzled, a table containing the test images 110B with the highest luminance of the background area 130 and the
Although the tables 4 to the table 14 show modifications of the test images 110B in which the blue component of the
For example, in the embodiment described above, the test image 110 has only one shape 121 having a single color located in the test area 120, but the embodiment is not limited to this configuration. Two or more figures of different colors from each other may be arranged in the test area of the test image.
The test area 220 includes a
A shape and a color of figures to be located in the test area 220 are not limited to those shown in
In the above embodiment, the test image 110 is displayed on the display 100, but embodiments of the present disclosure are not limited to this configuration. The test image 110 may be printed on a sheet or a board. In this case, a plurality of the test images 110 with different luminances of the background areas 130 or luminance of the
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-160960 | Sep 2021 | JP | national |
This is a Continuation-in-Part of International Application No. PCT/JP2022/036133 filed on Sep. 28, 2022, which claims priority from Japanese Patent Application No. 2021-160960 filed on Sep. 30, 2021. The entire disclosures of the prior applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP22/36133 | Sep 2022 | WO |
| Child | 18621609 | US |
