Method and system for evaluating human visual acuity

Abstract

A method for assessing a person's visual acuity using a mobile device comprising at least a front camera and a screen, the method comprising: - a user positioning step, in which a user of the mobile device positions themselves in front of a mirror at a predetermined distance d / 2; - a mobile device positioning step, in which the mobile device is positioned so that the front camera of the mobile device faces the mirror; - a distance measuring step, in which a distance d between the front camera of the mobile device and a virtual image of the mobile device in the mirror is measured; - a displaying step, in which a screen of the mobile device displays an optotype; and - an assessing step, in which the user's visual acuity is assessed.

Description

[Technical Field]

[0001] This disclosure relates to the evaluation of human visual acuity. In particular, this disclosure relates to a method for evaluating human visual acuity using a mobile device. This disclosure further relates to a mobile device for measuring human visual acuity.

[0002] Furthermore, this disclosure relates to a display system used to determine a person's visual acuity. [Background technology]

[0003] Typically, a person's uncorrected or corrected visual acuity is evaluated by an eye care specialist. This requires scheduling an appointment with an ophthalmologist, which makes it difficult to have their vision checked regularly and frequently.

[0004] Traditional methods have attempted to develop solutions for checking vision without requiring the intervention of an eye care specialist.

[0005] However, these methods typically require the use of a laptop, which is usually inaccessible to some people in the population. Furthermore, most conventional methods require a calibration procedure to determine and set the distance between the laptop and the user, for example, using a credit card or shoe size, before the procedure for measuring visual acuity. Thus, the distance is not properly controlled during the procedure, which can lead to errors in visual acuity measurement.

[0006] Some conventional methods propose self-measurement solutions, such as using smartphone applications. However, since the measurement is based on the length of the arm while holding the smartphone, the evaluation of visual acuity is limited to near vision. Other smartphone applications, generally proposed for professional use, allow for the measurement of a person's visual acuity at distance, but typically require the intervention of a second person, such as an eye care professional. [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, there is a need for a solution that can easily, quickly, and accurately assess a person's vision. [Means for solving the problem]

[0008] For this purpose, this disclosure proposes a method for evaluating a person's visual acuity using a mobile device having at least a front camera and a screen, the method being: - A user positioning step in which a mobile device user positions themselves in front of a mirror located at a predetermined distance d / 2, - A mobile device positioning step in which the mobile device is positioned so that the front camera of the mobile device faces the mirror, - A distance measurement step is performed in which the distance d between the front camera of the mobile device and the virtual image of the mobile device in the mirror is measured, - The mobile device screen displays the target, display step, - An evaluation step in which the user's eyesight is assessed, Includes.

[0009] Advantageously, the method described herein makes it possible to easily and accurately evaluate a person's visual acuity.

[0010] Advantageously, this method of evaluation can be performed by the user at home. An optometrist located remotely can then check whether the examination was performed accurately.

[0011] Users no longer need to visit an eye care specialist center to undergo vision assessments. This is more convenient for users who are no longer constrained by travel or time limitations to undergo assessments.

[0012] According to further embodiments that can be conceived, either alone or in combination, - During the mobile device positioning step, the mobile device is positioned vertically above the user's eyes, and / or - During the evaluation step, the binocular vision of the user is measured, and / or - During the evaluation step, the monocular vision of the user is measured, and / or - The method further includes a distance control step in which the measured distance d is compared with a predetermined distance d / 2 before the display step, and / or - The method further includes a notification step in which a notification is sent to the user based on the comparison between the measured distance d and the predetermined distance d / 2, and / or - The notification indicates that a person is too close to the mirror when the measured distance d is less than or equal to 2×(d / 2)-Δ1, and / or - The notification indicates that a person is too far from the mirror when the measured distance d is greater than or equal to 2×(d / 2)+Δ2, and / or - The size of the optotype displayed during the display step is adapted based on the measured distance d, and / or - The angular size of the optotype displayed during the display step is adapted based on the measured distance d, and / or - The distance d / 2 between the front camera and the mirror is measured periodically during the display step and the evaluation step, and the size and / or angular size of the optotype displayed during the display step is adapted in real time based on the measured distance d / 2, and / or - The method further includes a mobile device data reception step in which mobile device data is received, the mobile device data includes at least screen data related to the physical size of the screen of the mobile device and at least camera data related to the angular resolution of the pixels of the front camera, the distance d is measured based at least on the mobile device data, and / or - The method further includes a camera data reception step in which the front camera of the mobile device acquires data of the scene and the distance d is measured based at least on the camera data, and / or - The predetermined distance d / 2 is 1.5 m or more, preferably 2.0 m or more, and the visual acuity is evaluated for the distant vision state, and / or - The predetermined distance d / 2 is 0.5 m or less, preferably 0.25 m or less, and the visual acuity is evaluated for the near vision state, and / or - The method further includes an input reception step in which an instruction is received from the user according to the displayed optotype, and the visual acuity of the user is evaluated based on the instruction received from the user, and / or - The optotype displayed on the screen of the mobile device during the display step includes a single Landolt C whose direction / orientation changes, and the instruction received from the user is related to the direction / orientation of the opening of the Landolt C perceived by the user, and / or - The perceived direction of the opening of the Landolt C is indicated by the user using voice recognition and / or gesture recognition, and / or the operation of the mobile device, and / or - The displayed optotype further includes a movable cursor, and the perceived direction of the Landolt C on the screen of the mobile device is indicated by the position of the movable cursor, and / or - The mobile device has physical plus and minus volume buttons, and the movable cursor is controlled manually using the physical plus and minus volume buttons of the mobile device, and / or - The mobile device can be held in one hand and can be, for example, a smartphone, a phablet, or a tablet.

[0013] The present disclosure further relates to a computer-readable storage medium having a program recorded thereon, the program causing a computer to execute the method according to the present disclosure.

[0014] [[ID=二十一]] [[ID=二十二]]The present disclosure also relates to a non-transitory program storage device that is readable by a computer and tangibly embodies a program of instructions executable by a computer to execute the method, the method comprising: - measuring the distance d between the front camera of the mobile device and a mirror facing the front camera of the mobile device, and - Displaying visual targets on the screen of a mobile device, - Receiving input from mobile device users, - Evaluate the user's visual acuity based on the received input, Includes.

[0015] This disclosure further states that -Screen and, - At least one front camera, -Memory configured to store a sequence of instructions, - A processor coupled to memory, a screen, and at least one camera, -Measure the distance d between the front camera and the mirror facing the front camera. - Display the target on the screen of the mobile device, -Receive input from mobile device users, and - Evaluate the user's eyesight based on the received input. A processor configured to execute a sequence of instructions, This relates to mobile devices that are equipped with the following features.

[0016] Furthermore, this disclosure relates to a display system used to determine a person's visual acuity, the display system is: - A control means for identifying and processing input data, wherein the input data is received from a person, - A display means for displaying at least one target and at least one movable cursor, wherein the target is oriented in a direction selected from a predetermined list of orientations, and the movable cursor is displayed in any of the predetermined directions, and the orientation of the displayed movable cursor is based on an input processed by a control means, It is equipped with.

[0017] Advantageously, the display system provides a simple and accessible method for implementing a method for evaluating a person's visual acuity.

[0018] A mobile device system may include a display system. The display means may be formed by the screen of the mobile device. The mobile device may further include control means for the display system, which is configured to identify and process input data, and the input data is received from a person.

[0019] Herein, several embodiments of the present invention will be described with reference to the following drawings, as just one example. [Brief explanation of the drawing]

[0020] [Figure 1] This diagram shows a flowchart embodiment of a method for evaluating a person's vision using a mobile device. [Figure 2] This figure shows a person measuring their own eyesight according to one embodiment of the present disclosure. [Figure 3a] This figure shows a person measuring their own eyesight according to one embodiment of the present disclosure. [Figure 3b] This figure shows a person measuring their own eyesight according to one embodiment of the present disclosure. [Figure 4] This figure shows an example of a mobile device according to one embodiment of the present disclosure. [Figure 5] This figure shows a person measuring their own eyesight according to one embodiment of the present disclosure. [Figure 6] This figure shows a display system used to determine a person's visual acuity according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0021] The components in the drawings are shown for simplification and clarity and are not necessarily drawn to an accurate scale. For example, the size of some elements in the drawings may be exaggerated compared to others in order to make embodiments of the present invention easier to understand.

[0022] This disclosure relates to a method for evaluating a person's visual acuity using a mobile device 2. Visual acuity generally refers to the clarity of vision, but technically it evaluates a person's ability to accurately perceive details. Visual acuity can be evaluated for a user with or without glasses.

[0023] In the sense of the present invention, a mobile device is a portable computer device that can be used independently and is small enough for a user to easily carry and operate by hand. For example, a mobile device may be a smartphone, a phablet, or a tablet.

[0024] For clarity and simplicity, a mobile device will be illustrated using a smartphone in the following disclosure. However, those skilled in the art will be able to readily adapt the following examples to any other mobile device as defined herein.

[0025] As shown in Figure 4, the mobile device 2 comprises at least a screen 4 and a front camera 6. The screen 4 and the front camera 6 are located on the same surface of the mobile device 2.

[0026] The mobile device 2 further comprises a memory 8 configured to store a sequence of instructions, and a processor 12 coupled to the memory 10 and configured to execute the sequence of instructions stored in the memory 10.

[0027] As shown in Figure 1, the method for evaluating a person's visual acuity includes a user positioning step S2. During the user positioning step S2, the user of the mobile device positions themselves in front of a mirror at a predetermined distance d / 2 from the mirror.

[0028] As shown in Figures 2 and 3, the user is positioned at a predetermined distance d / 2 facing the mirror 20 and views a virtual image generated by light reflected off the surface of the mirror. Preferably, the mirror 20 is a planar mirror. When the user is positioned at the predetermined distance d / 2, the distance between the user and the virtual image the user is viewing in the mirror can be defined as equal to twice the predetermined distance d / 2.

[0029] According to one embodiment of the present invention, the predetermined distance d / 2 is 1.5 m or more, preferably 2.0 m or more. Advantageously, the predetermined distance d / 2 is 2.5 m or more for better relaxed accommodation. Under such conditions, the method of the present disclosure evaluates the user's visual acuity relative to distance visual acuity.

[0030] Alternatively, the predetermined distance d / 2 may be 0.5 m or less, preferably 0.25 m or more. Under such conditions, the method of this disclosure evaluates the user's visual acuity relative to near visual acuity.

[0031] As shown in Figure 1, the method for evaluating a person's visual acuity further includes a mobile device positioning step S4. During the mobile device positioning step S4, the user positions the mobile device 2 so that the front camera 6 faces the mirror.

[0032] As shown in Figures 2 and 3, the user positions the mobile device 2 so that the front camera 6 faces the mirror 20. Preferably, the mobile device 2 is positioned perpendicularly so as to be substantially parallel to the plane of the mirror 20. More preferably, the mobile device 2 is positioned as close as possible to the user's head.

[0033] According to one embodiment of the present disclosure, the mobile device 2 is positioned vertically above one of the user's eyes, and the visual acuity of the other eye is evaluated. Advantageously, having a mobile device covering the user's eye facilitates the evaluation of the monocular visual acuity of the user's uncovered eye.

[0034] As shown in Figure 1, the method for evaluating a person's visual acuity further includes a distance measurement step S8. During the distance measurement step S8, the distance d between the front camera of the mobile device and the virtual image of the mobile device is measured.

[0035] The distance d between the front camera of mobile device 2 and the virtual image 2' created by the mirror 20 on which the mobile device is reflected can be measured using mobile device 2 itself.

[0036] According to one embodiment of the present disclosure shown in Figure 1, a method for evaluating a person's visual acuity may include a mobile device data receiving step S0, in which mobile device data is received. The mobile device data includes screen data relating to at least the physical size of the mobile device's screen and at least camera data relating to at least the angular resolution of the pixels of the front camera.

[0037] Screen data enables the display of visual targets, and more specifically, the positioning and dimensionality of visual targets based on the physical size of the mobile device's screen.

[0038] The screen data allows for the determination of the size of the displayed element, which has known dimensions, during the distance measurement step S8.

[0039] In one embodiment, the element displayed during the distance measurement step is a target.

[0040] As shown in Figure 4, the physical width of the screen is w s , the physical height of the screen h s As, w s ×h s The physical size of the screen represented by m is the screen resolution. s ×n s and the pixel density of the screen (expressed as dots / inch or dpi) p,sIt can be obtained from any mobile device 2 based on this. The screen resolution and pixel density can be easily obtained from the operating system (OS) of the mobile device or the manufacturer's data.

[0041] m s 、n s 、and D p.s By knowing the values of, the following formula can be used to determine the values of w s and h s can be determined.

Number

[0042] As a non-limiting example, the calculation of the physical size of the screen of the mobile device 2 is for a specific smartphone S with a screen resolution m s ×n s and a pixel density D p,s equal to 550 dpi. By using formula (1), a physical screen width ws equal to 66.5 mm and a physical screen height equal to 140.4 mm can be obtained.

[0043] Alternatively, the physical size of the screen can be calculated from the physical size of the diagonal of the screen and the resolution.

[0044] The angular resolution of the pixels p c、θ of the front camera can be obtained from the pixel size p c of the front camera (expressed in meters) and the focal length f c Similarly, the pixel size and focal length of the front camera can be obtained from the operating system (OS) of the mobile device or the manufacturer's data.

[0045] By knowing the values of p c and f c the value of p c、θ can be determined using the following formula. [[ID=

[0046] By displaying elements with known dimensions on the screen of a mobile device having a front camera facing a mirror, it becomes possible to estimate the distance d during the distance measurement step S8 based on the angular resolution of the front camera.

[0047] In one embodiment, the element displayed during the distance measurement step is a target.

[0048] As a non-limiting example, the calculation of the angular resolution of the pixels of the front camera of mobile device 2 is based on the size p of the front camera pixels. c This is illustrated for a specific smartphone S in which the angle is equal to 1.22 μm and the focal length is equal to 3.34 mm. By using equation (2), the angular resolution p of the front camera pixels is equal to 0.021°. c,θ I obtained it.

[0049] To simplify things, the physical size of the camera's pixels is p. c It is assumed that has the same value in the horizontal and vertical directions. However, if this condition is not true, the inference can be easily extended. Since the specified working distance of the front camera is likely not set to infinite, to improve accuracy, the value f c This can be replaced with the actual distance between the lens of the mobile device and the camera sensor. However, the inventors have observed that equation (2) yields sufficient accuracy. Alternatively, the actual distance between the lens and the camera sensor can be calculated by assuming that the camera is set to a finite distance of 0.5m to 1.0m, preferably 0.8m.

[0050] The distance d between the front camera of mobile device 2 and the virtual image created by the mirror 20 on which the mobile device is reflected can be measured based on mobile device data and data received by the front camera 6 of mobile device 2. Advantageously, the distance measurement according to this disclosure does not require a calibration step.

[0051] Advantageously, in distance measurement step S8, the distance d is estimated based on mobile device data and the dimensions of elements displayed on the mobile device screen during distance measurement step S8, thereby avoiding the need for a distance calibration step.

[0052] The calibration step, in which elements displayed on the mobile device screen are first seen at a known distance from the mirror, is no longer necessary. Alternatively, it is no longer necessary to use an object other than the mobile device (e.g., a credit card) to calibrate the mobile device screen.

[0053] The direct measurement of the distance d between the front camera and the virtual image of the element is performed based on the known size of the element displayed on the screen and data from the mobile device.

[0054] In one embodiment, the distance d can be continuously estimated by knowing the width of the mobile device screen and adjusting the dimensions of the visual target displayed based on the width of the mobile device screen during the visual acuity evaluation method.

[0055] In one embodiment, while a visual acuity target is displayed on the screen, the distance d can be continuously estimated during the visual acuity evaluation method because the dimensions of the displayed target and the mobile device data are known. For example, the target size may be defined based on the width of the mobile device screen.

[0056] In one embodiment, if the unique parameters of the mobile device used to determine mobile device data are known, the accuracy and / or robustness of image processing are improved.

[0057] Therefore, a method for evaluating a person's vision may further include a camera data receiving step S6, during which the front camera 6 of the mobile device 2 acquires data related to the scene it is facing. Typically, the front camera 6 of the mobile device 2 captures images and / or videos of the scene, particularly of mirrors, and virtual images formed by the mirrors facing the front camera. The images and / or videos may be further processed to extract data related to the size of the virtual image of the mobile device screen reflected by the mirrors. For example, the width of the virtual mobile device screen reflected by the mirrors is the number of pixels m on the photo / video recorded by the front camera. c,d It can be expressed as follows. Similarly, the height of the virtual mobile device screen reflected by the mirror is the number of pixels n in the photo / video recorded by the front camera. c,d It can be expressed as follows.

[0058] The distance d between the front camera of mobile device 2 and the virtual image generated by mirror 20 can be determined using the following formula.

number

[0059] Furthermore,

number

[0060] Alternatively, the distance d can be measured by displaying different shapes of predetermined known dimensions on the screen 4 of the mobile device 2. By knowing the dimensions of the displayed shapes, the distance d can be measured using equations (2) to (4).

[0061] A method for evaluating a person's visual acuity may further include a parallelism measurement step in which the parallelism of the mobile device 2 to the mirror 20 is measured. If the mirror is perpendicular, the parallelism of the mobile device can be measured using the IMU of the mobile device. Alternatively, the parallelism of the mobile device 2 can be measured by displaying a predetermined shape, such as a rectangle, on the screen 4 of the mobile device 2 and comparing the displayed shape with the shape of a virtual image created by the mirror 20. For example, if the mobile device 2 is not parallel to the mirror 20, the rectangle displayed on the screen and reflected by the mirror 20 will produce a trapezoidal shape.

[0062] As shown in Figure 1, the method for evaluating a person's visual acuity may further include a distance control step S10. During the distance control step, the distance d measured between the front camera of the mobile device 2 and the virtual image created by the mirror 20 is compared with a predetermined distance d / 2.

[0063] Similarly, a method for evaluating a person's visual acuity may further include a parallelism control step in which the shape of a virtual image generated by the mirror 20 is compared with a predetermined shape displayed by the screen 4.

[0064] A method for evaluating a person's visual acuity may further include a notification step S12. During the notification step, a notification is sent to the user based on a comparison of a measured distance d with a predetermined distance d / 2.

[0065] For example, if the measured distance d between the front camera of the mobile device 2 and the virtual image generated by the mirror 20 is less than twice a given distance d / 2, a notification may indicate that the user is too close to the mirror. In addition, a deviation Δ1 may be considered. The deviation Δ1 represents an acceptable value for the given distance d / 2. If the measured distance d is less than (2 × (d / 2) - Δ1), a notification may indicate that the user is too close to the mirror. For example, the deviation Δ1 can correspond to a variation of 20%, preferably 10%, of the given distance d / 2.

[0066] For example, if the measured distance d between the front camera of the mobile device 2 and the virtual image generated by the mirror 20 is greater than twice a given distance d / 2, the notification may indicate that the user is too far from the mirror. In addition, a deviation Δ2 may be considered. The deviation Δ2 represents an acceptable value for the given distance d / 2. If the measured distance d is less than (2 × (d / 2) + Δ2), the notification may indicate that the user is too close to the mirror. For example, the deviation Δ2 can correspond to a variation of 20%, preferably 10%, of the given distance d / 2.

[0067] Alternatively, a maximum deviation ΔD from a given distance d / 2 can be defined. If the measured distance d is less than (2 × (d / 2) - ΔD), the notification may indicate that the user is too close to the mirror. Similarly, if the measured distance d is greater than (2 × (d / 2) + ΔD), the notification may indicate that the user is too far from the mirror. The maximum deviation ΔD can correspond to a variation of 20%, preferably 10%, of the given distance d / 2.

[0068] In addition, during notification step S12, a notification may be sent to the user based on a comparison between the shape of the virtual image generated by the mirror 20 and a predetermined shape displayed by the screen 4. For example, if the variation between the compared shapes is too significant, e.g., a variation of about 10%, the notification may indicate that the mobile device 2 is not parallel to the mirror 20.

[0069] As shown in Figure 1, the method for evaluating a person's visual acuity further includes a display step S14. Preferably, the display step is performed after the distance control step and the notification step. During the display step, the visual target is displayed on the screen 4 of the mobile device 2. In the sense of this disclosure, the visual target refers to a standardized symbol commonly used to test a person's visual acuity.

[0070] As shown in Figures 2 and 3b, the target displayed on the screen 4 of mobile 2 is reflected on a mirror that generates a virtual image of the target. Preferably, symmetry is applied to the displayed target. Advantageously, the user perceives the virtual image of the displayed target in the correct orientation.

[0071] The displayed targets may be Landolt C or Snellen E, or other standardized targets, letters, or figures. Targets may be displayed one at a time on the mobile device screen 4 during the display step. Alternatively, multiple targets may be displayed, one per line. The size and / or orientation and / or contrast of each target may change during the display step. Alternatively, multiple lines of targets may be displayed simultaneously, with targets of different sizes and / or orientations and / or contrasts in each line, for example, an ETDRS chart-like or two lines of VR800 procedures. Alternatively, the displayed targets may correspond to words or short sentences.

[0072] During the display step, the size of the displayed target may be adjusted based on a measured distance d. Alternatively, the size of the displayed target may be determined based on a predetermined distance d / 2 from the mirror.

[0073] Similarly, the angular size of the target displayed on the screen 4 of the mobile device 2 can be adjusted based on the measured distance d.

[0074] As a non-restrictive example, the target considered for the following calculations is a Landolt ring with an aperture such that the virtual image at a distance d of the displayed Landolt ring has an angular size Δθ. The physical size Δs of the aperture displayed on the screen is given by the following equation. (5) Δs = d × tan(Δθ)

[0075] For example, if the measured distance is 4.0m, the aperture Δθ of the Landolt ring displayed for a visual acuity of 10 / 10 should be equal to 1'. Using equation (5), the physical size Δs of the aperture displayed on the screen is approximately equal to 1.16mm. For a mobile device 2 corresponding to a specific smartphone S, the physical size Δs of the aperture displayed on the screen being equal to 1.16mm means that the number of pixels (Δs / p s This corresponds to the fact that ) is approximately equal to 25 pixels on the screen.

[0076] According to one embodiment of the present disclosure, the distance d between the front camera and the mirror is measured frequently during the display step. For example, the distance d can be measured before displaying different targets or a series of targets. Preferably, the distance d between the front camera and the mirror is measured in real time.

[0077] Advantageously, it becomes possible to periodically update the size and / or angle of the visual target displayed on the mobile device screen, for example in real time, thereby providing a more accurate assessment of a person's visual acuity.

[0078] As shown in Figure 1, the method for evaluating a person's visual acuity further includes evaluation step S18. During the evaluation step, the user's visual acuity is evaluated.

[0079] A method for evaluating a person's visual acuity may further include an input reception step S16 prior to the evaluation step. During the input reception step, instructions are received from the user in accordance with the displayed target. User instructions may be received using voice recognition and / or gesture recognition, and / or the operation of a mobile device.

[0080] If the visual target displayed on the screen 4 of mobile device 2 is a word or a short sentence, the user may identify the character or read the sentence. These instructions received from the user may be acquired, for example, using speech recognition via the microphone of the mobile device.

[0081] Furthermore, if the visual target displayed on screen 4 of mobile device 2 is a Landolt C with a different opening direction, the user can indicate the opening direction they perceive. Instructions regarding the user's perceived opening direction can be obtained through voice recognition using the mobile device's microphone, movement of the mobile device using the mobile device's IMU or front camera, and head and / or arm movements using the mobile device's front camera.

[0082] As shown in Figure 4, the mobile device 2 may further include physical volume up buttons 8a and volume down buttons 8b. Preferably, the volume up buttons 8a and volume down buttons 8b are located on the side of the mobile device 2, for example, on the left side of the mobile device 2 when facing the screen. The volume up buttons 8a and volume down buttons 8b may be used by the user to provide instructions during the input receiving step S16.

[0083] As shown in Figure 5, the displayed target may be a Landolt C having openings in different directions. The displayed target may further include a movable cursor 50. The movable cursor may be, for example, a circular art that moves along different possible directions of the openings of the Landolt C. In such a case, the user can use the physical plus buttons 8a and minus buttons 8b of the mobile device to align the direction of the movable cursor 50 with the perceived openings of the Landolt C. The selected position of the cursor can then be activated after a short waiting time, preferably 1.0 second, consisting of, for example, 0.5 seconds to 2.0 seconds.

[0084] The user's visual acuity may be assessed during the evaluation step based on instructions received from the user.

[0085] According to embodiments of the present disclosure, during the display step, a first series of various randomized targets corresponding to, for example, a first level of visual acuity is presented to the user. During the evaluation step S18, the instructions received by the user are evaluated, and a score corresponding to the accuracy of the instructions may be assigned to the user. If the user achieves a sufficient score, the display step S14, the input reception step S16, and the evaluation step S18 may be repeated with a second series of various randomized targets corresponding to a second level of visual acuity.

[0086] This disclosure further relates to a computer-readable storage medium having a program recorded thereon, wherein the program causes a computer to execute the method according to this disclosure.

[0087] The disclosure also relates to a non-temporary program storage device that is computer-readable and tangibly embodies a program of instructions that can be executed by a computer to perform the method according to the disclosure. For example, the method includes the steps of measuring a distance d between the front camera of a mobile device and a mirror facing the front camera of the mobile device; displaying a visual target on the screen of the mobile device; receiving input from the user of the mobile device; and evaluating the user's visual acuity based on the received input.

[0088] As shown in Figure 4, the disclosure further relates to a mobile device 2 comprising at least a screen 4, at least one front camera 6 such that the screen and the front camera are located on the same surface of the mobile device, a memory 10 (not shown) configured to store a sequence of instructions, and a processor 12 (not shown) coupled to the memory 10, the at least one screen 4, and the at least one front camera 6.

[0089] The processor 12 is configured to measure the distance d between the mobile device's front camera and a mirror facing the mobile device's front camera, display a visual target on the mobile device's screen, receive input from the mobile device's user, and execute a sequence of commands to evaluate the user's visual acuity based on the received input.

[0090] As shown in Figure 6, the disclosure further relates to a display system used to determine a person's visual acuity. For example, the display system is a system that includes a graphical user interface.

[0091] The display system includes control means. The control means enables the identification and processing of input data received from the user of the display system.

[0092] The display system further comprises display means, which enable the display of at least one target and at least one movable cursor. The at least one target is oriented in a direction selected from a predetermined list of orientations. The movable cursor is configured to be positioned and displayed in one of the predetermined directions from the list of orientations. The position of the displayed movable cursor is determined based on input received from the user and is identified and processed by control means.

[0093] As will become clear from the following considerations, unless otherwise specified, any use of terms such as “computing,” “calculating,” or “generating” throughout this specification is correctly understood to refer to the operation and / or processing of a computer or computing system, or similar electronic computing device, that manipulates and / or converts data, which is represented as an electronic or other physical quantity within the registers and / or memory of a computing system, into other data, which is similarly represented as a physical quantity within the memory, registers, or other such information storage device, transfer, or display device of a computing system.

[0094] Embodiments of the present invention may include an apparatus for performing the operations described herein. This apparatus may be specifically constructed for a desired purpose, or may include a general-purpose computer or digital signal processor ("DSP") that is selectively invoked or reconfigured by a computer program stored in the computer. Such computer programs may be stored in computer-readable storage media, including, but not limited to, floppy disks, optical disks, CD-ROMs, magneto-optical disks, read-only memory (ROM), random access memory (RAM), electrically programmable read-only memory (EPROM), electrically erasable and programmable read-only memory (EEPROM), magnetic or optical cards, or other types of media suitable for storing electronic instructions and capable of being coupled to a computer system bus.

[0095] The processes and representations presented herein are essentially independent of any particular computer or other device. Various general-purpose systems may be used with programs that follow the teachings herein, or it may be convenient to construct a more specialized device to perform the desired method. Desired structures for various such systems will emerge from the following description. In addition, embodiments of the present invention are not described with reference to any particular programming language. It will be understood that various programming languages ​​may be used to carry out the teachings of the present invention as described herein.

[0096] Many further modifications and variations will become apparent to those skilled in the art by referring to the exemplary embodiments described above, but these are provided for illustrative purposes only and are not intended to limit the scope of the present disclosure as determined solely by the appended claims.

[0097] In the claims, the word “contains” does not exclude other elements or steps, and the indefinite articles “a” or “an” do not exclude plurals. The fact that different features are cited in different dependent claims does not mean that combinations of these features cannot be used advantageously. No reference numeral in the claims should be construed as limiting the scope of this disclosure.

Claims

1. A method for evaluating a person's vision using a mobile device equipped with at least a front camera and a screen, - A user positioning step in which a mobile device user positions themselves in front of a mirror located at a predetermined distance d / 2, - A mobile device positioning step in which the mobile device is positioned such that the front camera of the mobile device faces the mirror, - A distance measurement step in which the distance d between the front camera of the mobile device and the virtual image of the mobile device in the mirror is measured, - A display step in which the screen of the mobile device displays a target, - An input reception step in which instructions are received from the user in accordance with the displayed target, - An evaluation step in which the mobile device evaluates the user's visual acuity based on the instructions received from the user, - A mobile device data reception step in which mobile device data is received, - A parallelism measurement step in which the parallelism of the mobile device to the mirror is measured by using an IMU or by displaying a predetermined shape on the screen of the mobile device and comparing the displayed shape with the shape of a virtual image created by the mirror, The mobile device data includes at least screen data relating to the physical size of the screen of the mobile device, and at least camera data relating to the angular resolution of the pixels of the front camera. The distance d is measured based at least on the mobile device data, The distance d / 2 between the front camera and the mirror is measured periodically during the display step and the evaluation step. A method wherein the size and / or angular size of the target displayed during the display step is adapted in real time based on the measured distance d / 2.

2. The method according to claim 1, further comprising a distance control step in which the measured distance d is compared with a predetermined distance d / 2 before the display step.

3. The method according to claim 1 or 2, further comprising a notification step in which a notification is sent to the user based on a comparison of the measured distance d with the predetermined distance d / 2.

4. The method according to any one of claims 1 to 3, wherein the size and / or angular size of the target displayed during the display step is adapted based on the measured distance d.

5. During the display step, the target displayed on the screen of the mobile device includes a single Landolt C whose orientation changes, The method according to any one of claims 1 to 4, wherein the instructions received from the user relate to the direction of the opening of the Landolt C as perceived by the user.

6. The method according to any one of claims 1 to 5, wherein the perceived direction of the opening of the Landolt C is indicated by the user using voice recognition and / or gesture recognition and / or the operation of the mobile device.

7. The method according to claim 5 or 6, wherein the displayed target further includes a movable cursor, and the perceived direction of the Landolt C on the screen of the mobile device is indicated by the position of the movable cursor.

8. The aforementioned mobile device is equipped with physical plus and minus volume buttons, The method according to any one of claims 1 to 7, wherein a movable cursor is controlled by the user using the physical plus and minus volume buttons of the mobile device.

9. The method according to any one of claims 1 to 8, wherein the mobile device can be held in one hand.

10. A non-temporary program storage device that is readable by a computer and tangibly embodies a program of instructions that are executable by the computer in order to perform a method, wherein the method is - Measuring the distance d / 2 between the front camera of the mobile device and the mirror facing the front camera of the mobile device, - Displaying a visual target on the screen of the aforementioned mobile device, - Receiving input from the user of the mobile device, - Based on the received input, the mobile device evaluates the user's visual acuity, - Includes evaluating the parallelism of the mobile device to the mirror, which is measured by using an IMU or by displaying a predetermined shape on the screen of the mobile device and comparing the displayed shape with the shape of a virtual image created by the mirror, The distance d / 2 between the front camera and the mirror is measured periodically during the display and evaluation process. A non-temporary program storage device in which the size and / or angular size of the target displayed during the aforementioned display are adapted in real time based on the measured distance d / 2.

11. A mobile device comprising a non-temporary program storage device as described in Claim 10, The aforementioned mobile device further, - The screen and, - At least one front camera, - A memory configured to store a sequence of instructions, - A processor coupled to the memory, the screen, and the at least one camera, -Receive mobile device data which includes at least screen data relating to the physical size of the screen of the mobile device and at least camera data relating to the angular resolution of the pixels of the front camera, -Measure the distance d / 2 between the front camera and the mirror facing the front camera. - Display the target on the screen of the mobile device, -Receive input from the user of the mobile device, and - Based on the received input, evaluate the user's visual acuity. A processor configured to execute a sequence of instructions, Equipped with, A mobile device in which the distance d is measured at least based on the mobile device data.

12. A display system for determining a person's visual acuity, comprising a non-temporary program storage device as described in Claim 10, The aforementioned display system further, - A control means for identifying and processing input data, wherein the input data is received from the person, - A display means for displaying at least one target and at least one movable cursor, wherein the target is oriented in a direction selected from a predetermined list of orientations, and the movable cursor is displayed in any of the predetermined directions, and the orientation of the displayed movable cursor is based on the input processed by the control means, A display system equipped with the following features.

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