Heterotropia determination device, heterotropia determination method, and program

Abstract

To enable determination of heterotropia to be easily performed.SOLUTION: Provided is a heterotropia determination device including: an image acquisition unit that acquires an image obtained by imaging an eye of a subject from the front of the subject; a cornea detection unit that analyzes the image and detects a cornea from the image; a heterotropia determination unit that determines a degree of heterotropia on the basis of at least one of a width and a height of the cornea.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a strabismus determination device, a strabismus determination method, and a program. [Background technology]

[0002] Strabismus is assessed by reflecting light from a light source onto the subject's eyes (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2015-525597 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the method disclosed in Patent Document 1, it is necessary to set up a light source and measure the reflection of light, which is time-consuming.

[0005] The present invention has been made in view of the above background, and has an object to provide a technique that can easily determine strabismus. [Means for solving the problem]

[0006] The main invention of the present invention for solving the above problem is a strabismus assessment device, characterized in that it comprises an image acquisition unit that acquires an image of a subject's eye taken from in front of the subject, a cornea detection unit that analyzes the image and detects the cornea from the image, and a strabismus assessment unit that determines the degree of strabismus based on at least one of the width and height of the cornea.

[0007] Other problems and solutions disclosed in this application will be made clear in the description of the preferred embodiments of the invention and the drawings. Effect of the Invention

[0008] According to the present invention, strabismus can be easily determined. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an image of a subject's eye. [Diagram 2] 2 is a diagram illustrating an example of a hardware configuration of a strabismus determination device 2. FIG. [Diagram 3] 2 is a diagram illustrating an example of a software configuration of the strabismus determination device 2. FIG. [Figure 4] 4 is a diagram illustrating a flow of processing by the strabismus determination device 2. FIG. [Diagram 5] FIG. 11 is a diagram for explaining how a subject is photographed according to the second embodiment. [Figure 6] 11 is a diagram illustrating a flow of processing by the strabismus determination device 2 according to the second embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A strabismus judgment device 2 according to one embodiment of the present invention will be described below. The strabismus judgment device 2 of this embodiment is intended to judge the degree of strabismus of a subject from an image obtained by photographing the subject.

[0011] Fig. 1 is a diagram for explaining an image of a subject's eyes. In this embodiment, it is assumed that the subject is photographed from the front using a strabismus assessment device 2. The example of Fig. 1 shows a so-called strabismus state in which the right eye 11 does not face forward.

[0012] The left eye 12 faces forward, and in this case, the cornea 121 of the left eye 12 is substantially circular. That is, the width W2 and height H2 of the cornea 121 are substantially the same.

[0013] On the other hand, the right eye 11 faces to the right of the subject (left in the drawing), and in this case, the cornea 111 of the right eye 11 has an elliptical shape. Therefore, the width W1 of the cornea 111 is smaller than the height H1.

[0014] The strabismus determination device 2 of this embodiment can determine the degree of strabismus based on the shape of the corneas 111, 121. Specifically, the degree of strabismus can be determined as a value according to the ratio (H1÷W1, H2÷W2) of the widths W1, W2 of the corneas 111, 121 to the heights H1, H2 of the corneas 111, 121. In this embodiment, the narrower the width of the cornea, the higher the degree of strabismus can be determined. The difference between the width W1 of the cornea 111 of the right eye 11 and the width W2 of the cornea 121 of the left eye 12 may be determined as the degree of strabismus. The difference between the widths (W1max, W2max) of the right eye 11 and the left eye 12 when facing forward and the widths (W1, W2) in the captured image may be determined as the degree of strabismus.

[0015] <Strabismus determination device 2> FIG. 2 is a diagram showing an example of the hardware configuration of the strabismus assessment device 2. Note that the illustrated configuration is an example, and other configurations may be used. The strabismus assessment device 2 includes a CPU 201, a memory 202, a storage device 203, a communication interface 204, a camera 205, and an input / output device 206. The storage device 203 is, for example, a hard disk drive, a solid state drive, or a flash memory that stores various data and programs. The communication interface 204 is an interface for connecting to a communication network, for example, an adapter for connecting to Ethernet (registered trademark), a modem for connecting to a public telephone line network, a wireless communication device for wireless communication, a USB (Universal Serial Bus) connector or an RS232C connector for serial communication, etc. The input / output device 206 is a device for inputting and outputting data, for example, a touch panel display. The input / output device 206 can include multiple devices, and may include, for example, a keyboard, a mouse, a touch panel, a button, a microphone, a display, a printer, a speaker, etc. Each functional unit of the strabismus judgment device 2, which will be described later, is realized by the CPU 201 reading a program stored in the storage device 203 into the memory 202 and executing it, and each memory unit of the strabismus judgment device 2 is realized as part of the memory area provided by the memory 202 and the storage device 203.

[0016] 3 is a diagram showing an example of the software configuration of the strabismus determination device 2. The strabismus determination device 2 includes an image acquisition unit 211, a cornea detection unit 212, a strabismus determination unit 213, and an image storage unit 231.

[0017] The image acquiring unit 211 acquires an image of the subject's eyes photographed from the front of the subject. The image acquiring unit 211 can, for example, output a message to the user instructing the user to photograph the face from the front, and can also acquire an image photographed by the user with the camera 205.

[0018] The image storage unit 231 stores the images acquired by the image acquisition unit 211. The image storage unit 231 can store image data in association with a user ID for identifying a user, a shooting date and time, and a shooting direction (for example, the front of the subject is set to 0 degrees, and the angle can be expressed with the surface of the subject's face (for example, between the eyebrows) as the center).

[0019] The cornea detection unit 212 analyzes the image and detects (a figure indicating) the cornea from the image. The cornea detection unit 212 detects a shape surrounding the area corresponding to the cornea using a known image processing technique, and detailed explanation of the process will be omitted here. In this embodiment, the cornea detection unit 212 detects the cornea as (approximating) a circular or elliptical shape.

[0020] The strabismus determination unit 213 determines the degree of strabismus based on at least the width of the cornea. In this embodiment, the strabismus determination unit 213 can determine the degree of strabismus according to the ratio of the corneal width W to the corneal height H. When the strabismus determination unit 213 detects the corneas 111, 121, it estimates an ellipse that approximates the shape of the corneas 111, 121. A known method can be used for the ellipse estimation process. The strabismus determination unit 213 can obtain the width W and height H from the estimated ellipse. This allows the height H to be accurately calculated even when the corneas 111, 121 are partially hidden by the eyelids or the like. Note that only the height H may be obtained from the ellipse, and the width W may be obtained from the detected corneas 111, 121.

[0021] The strabismus determination unit 213 can also determine the degree of strabismus only from the width W. For example, the cornea detection unit 212 detects the corneas 111, 121 of both the right eye and the left eye from the image, and the strabismus determination unit 213 can compare the width W1 of the right eye with the width W2 of the left eye to determine, for example, the difference (absolute value) between the width W1 of the right eye and the width W2 of the left eye as the degree of strabismus. Also, the user is instructed to move both eyes left and right, and the cornea detection unit 212 detects the corneas 111, 121 from a video of the movement of the eyes or a still image of the movement of the eyes captured multiple times in time series, and the strabismus determination unit 213 can specify the maximum values ​​W1max and W2max of the width W1 of the right eye and the width W2 of the left eye, respectively. Next, the user is instructed to look straight ahead and an image is taken from the front of the face. The cornea detection unit 212 detects the corneas 111, 121 from the image taken from the front of the user, and the strabismus determination unit 213 calculates the widths W1, W2 of the detected corneas 111, 121 and determines the degree of strabismus based on the average, larger, or smaller of the differences (W1max-W1, W2max-W2) between the maximum values ​​W1max, W2max and the widths W1, W2 of the corneas in the image taken from the front.

[0022] <Operation> FIG. 4 is a diagram illustrating the flow of processing by the strabismus determination device 2.

[0023] The strabismus judgment device 2 photographs the subject's eyes from the front using the camera 205 (S301). Note that it is up to the subject to decide whether or not the subject is photographed from the front, and the strabismus judgment device 2 itself can be configured not to judge whether the subject is photographed from the front. The strabismus judgment device 2 detects the subject's eyes from the photographed image (S302). It may be configured to detect only the right eye, only the left eye, or both eyes.

[0024] The strabismus assessment device 2 determines the detected corneal width W and height H (S303), and can assess the degree of strabismus according to the ratio of the width W to the height H (S304). As described above, the degree of strabismus can also be determined according to the difference (W1-W2) between the left and right corneal widths W1, W2, or according to at least one of the differences (W1max-W1, W2max-W2) between the maximum corneal widths W1max, W2max when the eye is moved left and right and the corneal widths W1, W2 in an image captured from the front, or the average value of the differences.

[0025] As described above, the strabismus determination device 2 of this embodiment can determine the degree of strabismus of a subject only from an image taken by the subject himself / herself.

[0026] <Second embodiment> 5 is a diagram for explaining how a subject is photographed according to the second embodiment. In the second embodiment, not only is photography performed in a direction D1 facing the front of the subject, but photography is also performed in directions D2 and / or D3 that are angled with respect to the front of the subject.

[0027] The image acquisition unit 211 acquires a first image (image taken in a shooting direction of D1) taken from the front of the subject and a second image (image taken in a shooting direction of D2 and / or D3) taken at an angle to the front of the subject, the cornea detection unit 212 detects the first and second corneas from the first and second images, and the strabismus determination unit 213 can determine the degree of strabismus based on the widths of the first and second corneas.

[0028] FIG. 6 is a diagram for explaining the flow of processing by the strabismus judgment device 2 according to the second embodiment. The strabismus judgment device 2 photographs the subject's eyes from the front (S301), and further photographs the subject's eyes at an angle (S321). The strabismus judgment device 2 detects the subject's cornea from the photographed images (S302), and detects the width W of the cornea in each image (S322). The strabismus judgment device 2 can judge the degree of strabismus according to the ratio of the width W of the cornea when photographed at an angle to the width W of the cornea when photographed from the front (S323). In this case, for example, if the width W of the cornea in the second image photographed in the photographing direction of D2 is larger than the width W of the cornea in the first image photographed in the photographing direction of D1, it can be judged that the cornea is oriented in a direction closer to a direction parallel to D2 than to D1. The degree of strabismus can be determined according to the change in size in this case.

[0029] <Third embodiment> In the first and second embodiments, strabismus with a deviation of the line of sight in the left-right direction (exotropia or esotropia) is assumed, but in the third embodiment, strabismus with a deviation of the line of sight in the up-down direction (vertical strabismus) is judged.

[0030] In the third embodiment, a value according to the ratio (W1÷H1, W2÷H2) of the height H1, H2 of the corneas 111, 121 to the width W1, W2 of the corneas 111, 121 can be determined as the degree of vertical strabismus. In the third embodiment, it can be determined that the smaller the corneal height is, the higher the degree of vertical strabismus is. Note that the difference between the height H1 of the cornea 111 of the right eye 11 and the height H2 of the cornea 121 of the left eye 12 may be determined as the degree of vertical strabismus. Also, the difference between the heights (H1max, H2max) of the right eye 11 and the left eye 12 when facing forward and the heights (H1, H2) in the captured image may be determined as the degree of vertical strabismus.

[0031] In the third embodiment, the strabismus determination unit 213 determines the degree of vertical strabismus based on at least the height of the cornea. In the third embodiment, the strabismus determination unit 213 can determine the degree of strabismus according to the ratio of the corneal height H to the corneal width W. When the strabismus determination unit 213 detects the corneas 111, 121, it estimates an ellipse that approximates the shape of the corneas 111, 121. A known method can be used for the ellipse estimation process. The strabismus determination unit 213 can obtain the width W and height H from the estimated ellipse. This allows the width W and height H to be accurately calculated even when the corneas 111, 121 are partially hidden by the eyelids or the like.

[0032] The strabismus determination unit 213 can also determine the degree of vertical strabismus only from the height H. For example, the cornea detection unit 212 detects the corneas 111, 121 of both the right eye and the left eye from the image, and the strabismus determination unit 213 compares the height H1 of the right eye with the height H2 of the left eye, and can determine, for example, the difference (absolute value) between the height H1 of the right eye and the height H2 of the left eye as the degree of vertical strabismus. Also, the user is instructed to move both eyes up and down, and the cornea detection unit 212 detects the corneas 111, 121 from a video of the movement of the eyes or from still images of the movement of the eyes captured multiple times in time series, and the strabismus determination unit 213 can specify the maximum values ​​H1max and H2max of the height H1 of the right eye and the height H2 of the left eye, respectively. Next, the user is instructed to look straight ahead and an image is taken from the front of the face. The cornea detection unit 212 detects the corneas 111, 121 from the image taken from the front of the user, and the strabismus determination unit 213 calculates the heights H1, H2 of the detected corneas 111, 121 and determines the degree of vertical strabismus based on the average, larger, or smaller of the differences (H1max-H1, H2max-H2) between the maximum values ​​H1max, H2max and the corneal heights H1, H2 in the image taken from the front.

[0033] <Fourth embodiment> In the fourth embodiment, the degree of strabismus is determined in both the left-right direction and the up-down direction.

[0034] In the fourth embodiment, the degree of strabismus can be determined based on both the ratio of the height H1, H2 of the cornea 111, 121 to the width W1, W2 of the cornea 111, 121 (W1÷H1, W2÷H2) and the ratio of the width W1, W2 of the cornea 111, 121 to the height H1, H2 of the cornea 111, 121 (H1÷W1, H2÷W2). In the fourth embodiment, the narrower the cornea width and the smaller the cornea height, the higher the degree of strabismus can be determined. Note that the magnitude of the difference between the width W1 and height H1 of the cornea 111 of the right eye 11 and the width W2 and height H2 of the cornea 121 of the left eye 12 may be determined as the degree of strabismus. In addition, the degree of strabismus can be determined by using the width and height (W1max, H1max, W2max, H2max) of the right eye 11 and the left eye 12 when they are facing forward and the width and height (W1, H1, W2, H2) in the captured image, and the sum or weighted sum of the width differences (W1max-W1, W2max-W2) and height differences (H1max-H1, H2max-H2).

[0035] In the fourth embodiment, as in the above-described embodiments, an ellipse that approximates the corneas 111, 121 can be estimated, and the degree of strabismus can be calculated using the width W and height H of the ellipse.

[0036] In the fourth embodiment, the strabismus determination unit 213 can also determine the degree of vertical strabismus only from the width W and height H. For example, the cornea detection unit 212 detects the corneas 111, 121 of both the right and left eyes from the image, and the strabismus determination unit 213 compares the width W1 and height H1 of the right eye with the width W1 and height H2 of the left eye, and can determine the degree of strabismus by, for example, adding up the difference (absolute value) between the width W1 of the right eye and the width W2 of the left eye and the difference (absolute value) between the height H1 and the height H2 of the left eye.

[0037] Also, the user is instructed to move both eyes up and down, the cornea detection unit 212 detects the corneas 111, 121 from a video of the eye movement or a still image of the eye movement captured multiple times in time series, and the strabismus determination unit 213 can specify the maximum values ​​H1max and H2max of the right eye height H1 and the left eye height H2, respectively. Next, the user is instructed to look forward, and an image is taken from the front of the face, so that the cornea detection unit 212 detects the corneas 111, 121 from the image taken from the front of the user, and the strabismus determination unit 213 obtains the heights H1, H2 of the detected corneas 111, 121, and can determine the degree of vertical strabismus according to the average value, larger, or smaller of the differences (H1max-H1, H2max-H2) between the maximum values ​​H1max, H2max and the corneal heights H1, H2 in the image taken from the front.

[0038] Although the present embodiment has been described above, the above embodiment is intended to facilitate understanding of the present invention, and is not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit of the present invention, and equivalents thereof are also included in the present invention.

[0039] For example, the degree of strabismus in the left-right direction and the degree of strabismus in the up-down direction may be calculated and output separately.

[0040] <Disclosures> The present disclosure also includes the following configurations. [Item 1] an image acquisition unit that acquires an image of the subject's eye taken from a front view of the subject; a cornea detection unit that analyzes the image and detects a cornea from the image; a strabismus determination unit that determines a degree of strabismus based on at least one of the width and height of the cornea; A strabismus assessment device comprising: [Item 2] The strabismus assessment device according to item 1, the strabismus determination unit estimates an ellipse indicating a shape of the cornea, and determines a degree of the strabismus based on a width and a height of the ellipse; A strabismus assessment device comprising: [Item 3] The strabismus assessment device according to item 2, the strabismus determination unit determines the degree of strabismus based on at least one of a ratio of the width to the height and a ratio of the height to the width; A strabismus assessment device comprising: [Item 4] The strabismus assessment device according to item 1, The images include images of the right and left eyes, the cornea detection unit detects a first cornea of ​​the right eye and a second cornea of ​​the left eye from the image; the strabismus determination unit determines a degree of the strabismus based on at least one of a width and a height of the first cornea and at least one of a width and a height of the second cornea; A strabismus assessment device comprising: [Item 5] The strabismus assessment device according to item 1, The image acquisition unit acquires a first image obtained by photographing the subject from the front and a second image obtained by photographing the subject from an angle relative to the front of the subject, the cornea detection unit detects first and second corneas from the first and second images; the strabismus determination unit determines the degree of strabismus based on at least one of the width and height of the first and second corneas; A strabismus assessment device comprising: [Item 6] acquiring an image of the subject's eye from a frontal view of the subject; analyzing the image to detect the cornea from the image; determining a degree of strabismus based on at least one of the corneal width and height; A strabismus determination method characterized by being executed by an information processing device. [Item 7] acquiring an image of the subject's eye from a frontal view of the subject; analyzing the image to detect the cornea from the image; determining a degree of strabismus based on at least one of the corneal width and height; A program for causing an information processing device to execute the above. [Explanation of symbols]

[0041] 2 Strabismus determination device

Claims

1. an image acquisition unit that acquires an image of the subject's eye taken from a front view of the subject; a cornea detection unit that analyzes the image and detects a cornea from the image; a strabismus determination unit that determines a degree of strabismus based on at least one of the width and height of the cornea; A strabismus assessment device comprising:

2. The strabismus determination device according to claim 1, the strabismus determination unit estimates an ellipse indicating a shape of the cornea, and determines a degree of the strabismus based on a width and a height of the ellipse; A strabismus assessment device comprising:

3. The strabismus determination device according to claim 2, the strabismus determination unit determines the degree of strabismus based on at least one of a ratio of the width to the height and a ratio of the height to the width; A strabismus assessment device comprising:

4. The strabismus determination device according to claim 1, The images include images of the right and left eyes, the cornea detection unit detects a first cornea of ​​the right eye and a second cornea of ​​the left eye from the image; the strabismus determination unit determines a degree of the strabismus based on at least one of a width and a height of the first cornea and at least one of a width and a height of the second cornea; A strabismus assessment device comprising:

5. The strabismus determination device according to claim 1, The image acquisition unit acquires a first image obtained by photographing the subject from the front and a second image obtained by photographing the subject from an angle relative to the front of the subject, the cornea detection unit detects first and second corneas from the first and second images; the strabismus determination unit determines the degree of strabismus based on at least one of the width and height of the first and second corneas; A strabismus assessment device comprising:

6. acquiring an image of the subject's eye from a frontal view of the subject; analyzing the image to detect the cornea from the image; determining a degree of strabismus based on at least one of the corneal width and height; A strabismus determination method characterized by being executed by an information processing device.

7. acquiring an image of the subject's eye from a frontal view of the subject; analyzing the image to detect the cornea from the image; determining a degree of strabismus based on at least one of the corneal width and height; A program for causing an information processing device to execute the above.

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