CN112315423A

CN112315423A - Eye movement measuring equipment

Info

Publication number: CN112315423A
Application number: CN202011231069.7A
Authority: CN
Inventors: 杜煜
Original assignee: Shanghai Qingyan Technology Co ltd
Current assignee: Shanghai Qingyan Technology Co ltd
Priority date: 2020-11-06
Filing date: 2020-11-06
Publication date: 2021-02-05
Anticipated expiration: 2040-11-06
Also published as: CN112315423B

Abstract

The purpose of the invention is: an apparatus capable of measuring eye movement is provided. In order to achieve the above object, an aspect of the present invention provides an eye movement measuring apparatus, including: the left eye semi-transparent semi-reflective module; a movable left eye and eyeball tracking module; the right eye semi-transmitting and semi-reflecting module; and the movable right eyeball tracking module. The invention has the beneficial effects that: the eyeball motion can be automatically and quantitatively measured, the method is rapid, visual and accurate, and the time of doctors and examinees is saved.

Description

Eye movement measuring equipment

Technical Field

The invention relates to the technical field of eyeball motion measurement, in particular to eyeball motion measurement equipment based on image processing.

Background

The eyeball is approximately spherical and can rotate around the center of the sphere to perform eyeball movement (eye movement), the eyeball can perform horizontal rotation movement around a vertical axis, perform vertical rotation movement around a horizontal axis, and perform clockwise or anticlockwise rotation movement around an anterior-posterior axis.

The eye movement is examined medically, mainly based on the experience of doctors and mainly observed by naked eyes. Strabismus is a disease closely related to eyeball movement, taking strabismus as an example, one method commonly used for clinically examining strabismus at present is a covering test, namely, a single eye is covered in sequence and then covered or two eyes are alternately covered, a doctor observes the movement condition of the eyes and the eyeball of a detected person in the covering test process, judges whether strabismus exists or not, estimates the strabismus degree according to the amplitude of the eyeball movement by experience, and then verifies by using a triangular prism, and the method is time-consuming. Another commonly used method for examining strabismus is corneal reflection, which is a method of determining whether strabismus exists by observing whether the corneal light reflection is located at the center of the pupil and estimating the strabismus degree according to the distance of the corneal light reflection from the center of the pupil, which can only be roughly estimated and is affected by the Kappa angle, and therefore the accuracy is low.

Disclosure of Invention

The purpose of the invention is: an apparatus capable of measuring eye movement is provided.

In order to achieve the above object, an aspect of the present invention provides an eye movement measuring apparatus, including:

the left-eye semi-transparent and semi-reflective module is in a plane sheet shape, can transmit visible light and reflect near infrared light;

the movable left eye eyeball tracking module comprises at least one near infrared camera which is a left eye camera; comprises at least one near infrared light source as a left eye light source; the relative positions of the left-eye camera and the left-eye light source are fixed; the left-eye camera can shoot images of a left-eye area through the left-eye semi-transparent semi-reflective module; and calculating the center coordinates of the pupils of the left eye; the left-eye camera can shoot the reflective point of the left-eye light source on the left-eye cornea through the left-eye semi-transparent and semi-reflective module; and calculating the central coordinates of the left eye cornea reflecting points; the left eye eyeball tracking module can move to a corresponding position, so that the central coordinate of a left eye light source at a reflection point of a left eye cornea is superposed with the central coordinate of a left eye pupil in an image shot by the left eye camera;

the right eye semi-transparent semi-reflective module is in a plane sheet shape, can transmit visible light and reflect near infrared light;

the movable right eye eyeball tracking module comprises at least one near infrared camera called a right eye camera; comprises at least one near infrared light source, called right eye light source; the relative positions of the right-eye camera and the right-eye light source are fixed; the right-eye camera can shoot the image of the right-eye area through the right-eye semi-transmitting and semi-reflecting module; and can calculate the pupil center coordinate of the right eye; the right eye camera can shoot the reflection point of the right eye light source on the right eye cornea through the right eye semi-transparent and semi-reflective module; and calculating the central coordinate of the reflecting point of the cornea of the right eye; the right eye eyeball tracking module can move to a corresponding position, so that in an image shot by the right eye camera, the center coordinate of the reflection point of the right eye light source on the right eye cornea coincides with the center coordinate of the right eye pupil.

Preferably, the left eye eyeball tracking module moves along the left spherical surface, and the center position of the left spherical surface is the position of a virtual image of the center of the left eye eyeball reflected by the left eye semi-transparent semi-reflective module; the radius R1 of the left spherical surface is a fixed value; the position of the left eye eyeball tracking module can be represented in a spherical coordinate system taking a virtual image of the spherical center of the left eye eyeball as the spherical center and R1 as the radius;

the right eye eyeball tracking module moves along the right spherical surface, and the sphere center position of the right spherical surface is the position of a virtual image of the sphere center of the right eye eyeball reflected by the right eye semi-transparent semi-reflective module; the radius R2 of the right spherical surface is a fixed value; the position of the right eye eyeball tracking module can be represented in a spherical coordinate system taking a virtual image of the sphere center of the right eye eyeball as the sphere center and R2 as the radius.

Preferably, the radius R1 of the left spherical surface and the radius R2 of the right spherical surface are equal.

Preferably, when the left eye eyeball tracking module moves along the left spherical surface, the axis of the left eye camera always faces the virtual image of the center of the left eye eyeball;

when the right eye eyeball tracking module moves along the right spherical surface, the axis of the right eye camera always faces the virtual image of the center of the right eye eyeball.

Preferably, according to the angle of the left eye eyeball tracking module moving along the left spherical surface, the angle of the left eye eyeball rotating in the horizontal direction and the angle of the left eye eyeball rotating in the vertical direction can be calculated;

according to the angle of the right eyeball tracking module moving along the right spherical surface, the angle of the right eyeball rotating in the horizontal direction and the angle of the right eyeball rotating in the vertical direction can be calculated.

Preferably, the horizontal viewing angle at the left eye is θ_l1And the vertical viewing angle is

When the sighting target is used, the spherical coordinates of the left eye eyeball tracking module at the moment are recorded

Calculating Delta theta_l1＝θ_l1’-θ_l1，

After the left eye eyeball moves, respectively subtracting delta theta from the measured horizontal direction angle value and the measured vertical direction angle value in the spherical coordinate of the left eye eyeball tracking module_l1And

the horizontal visual angle and the vertical visual angle of the left eye can be obtained;

horizontal viewing angle theta at right eye_r1And the vertical viewing angle is

When the optotype is viewed, the spherical coordinates of the right eyeball tracking module at the moment are recorded

Calculating Delta theta_r1＝θ_r1’-θ_r1，

After the right eye eyeball moves, respectively subtracting delta theta from the measured horizontal direction angle value and the measured vertical direction angle value in the spherical coordinate of the right eye eyeball tracking module_r1And

a horizontal viewing angle and a vertical viewing angle for the right eye can be obtained.

Preferably, the left eye eyeball tracking module is movable along a left plane; when the left eye looks straight ahead, and the horizontal direction visual angle and the vertical direction visual angle are both 0 degrees, the left plane is vertical to the visual axis of the eye eyeball virtual image; the vertical line of the left plane passing through the point of the left plane (0,0) is intersected with the virtual image of the sphere center of the eyeball of the left eye; the distance between the left plane and the virtual image of the center of the eyeball of the left eye is D1;

the right eyeball tracking module can move along the right plane; when the right eye looks straight ahead and the horizontal direction visual angle and the vertical direction visual angle are both 0 degrees, the right plane is vertical to the visual axis of the eyeball virtual image of the right eye; the vertical line of the right plane passing through the point of the right plane (0,0) is intersected with the virtual image of the sphere center of the eyeball of the right eye; the distance between the right plane and the virtual image of the spherical center of the right eye is D2.

Preferably, the distance D1 between the virtual images of the left plane and the center of the left eye eyeball sphere is equal to the distance D2 between the virtual images of the right plane and the center of the right eye eyeball sphere.

Preferably, when the left eye eyeball tracking module moves along the left plane, the axis of the left eye camera always faces the virtual image of the center of the left eye eyeball;

when the right eye eyeball tracking module moves along the right plane, the axis of the right eye camera always faces the virtual image of the center of the right eye eyeball.

Preferably, according to the angle of the left eye eyeball tracking module moving along the left plane, the angle of the left eye eyeball rotating in the horizontal direction and the angle of the left eye eyeball rotating in the vertical direction can be calculated;

according to the angle of the right eyeball tracking module moving along the right plane, the angle of the rotation of the right eyeball in the horizontal direction and the angle of the rotation of the right eyeball in the vertical direction can be calculated.

Preferably, the horizontal viewing angle at the left eye is θ_l2And the vertical viewing angle is

When the sighting target is used, the left plane coordinate of the left eye eyeball tracking module at the moment is calculated

And calculateΔθ_l2＝θ_l2’-θ_l2，

After the left eye eyeball moves, respectively subtracting delta theta from the measured horizontal direction angle value and the measured vertical direction angle value in the left plane coordinate of the left eye eyeball tracking module_l2And

horizontal viewing angle theta at right eye_r2And the vertical viewing angle is

When the optotype is viewed, the right plane coordinate of the right eyeball tracking module at the moment is calculated

And calculates Delta theta_r2＝θ_r2’-θ_r2，

After the right eye eyeball moves, respectively subtracting delta theta from the measured horizontal direction angle value and the measured vertical direction angle value in the right plane coordinate of the right eye eyeball tracking module_r2And

Preferably, the left eye eyeball tracking module can identify the characteristics of the left eye iris and calculate the rotation angle of the left eye according to the change of the characteristics of the left eye iris; the right eye eyeball tracking module can identify the characteristics of the right eye iris and calculate the rotation angle of the right eye according to the change of the characteristics of the right eye iris.

Preferably, the system also comprises a display and control module; the display and control module comprises a display device which can be switched among the following three display modes:

the first display mode is as follows: displaying a optotype visible only to the left eye;

and a second display mode: displaying a visual target visible only to the right eye;

and a third display mode: and displaying the visual target visible to both eyes.

Preferably, the LCD device comprises a left liquid crystal shutter device which is positioned between the left transflective module and the display device in the display and control module and can switch the transparent state and the opaque state;

the display device comprises a right liquid crystal shutter device which is positioned between the right semi-transparent semi-reflecting module and the display device in the display and control module and can switch transparent and opaque states.

Preferably, the system further comprises a squint measurement module configured to perform the following steps,

(a) the display and control module is switched to a first display mode, two eyes are set as an F eye and a G eye respectively, and firstly, only the F eye can see the strabismus measurement sighting target displayed on the display device; when the F eye watches the sight, the central coordinate of the light source of the F eye on the reflecting point of the cornea of the F eye is coincided with the central coordinate of the pupil of the F eye, and the position EF of the eyeball tracking module of the F eye is recorded₁Enabling the central coordinates of the reflecting point of the G eye light source on the G eye cornea to coincide with the central coordinates of the G eye pupil, and recording the position EG of the G eye eyeball tracking module₁(ii) a Two thresholds TH are set₁And TH₂Wherein TH is₂≥TH₁；

(b) The display and control module is switched to a display mode III, the F eye and the G eye can both see the squint measurement sighting target displayed by the display device, and the display position of the sighting target is unchanged; when the eyes watch the sight, the center coordinates of the reflecting point of the F eye light source on the cornea of the F eye and the center coordinates of the pupil of the F eye coincide, and the position EF of the F eye eyeball tracking module is recorded₂(ii) a The central coordinates of the reflecting point of the G eye light source on the G eye cornea are coincided with the central coordinates of the G eye pupil, and the position EG of the G eye eyeball tracking module is recorded₂；

Such as | EF₂-EF₁|＜TH₁And | EG₂-EG₁|＜TH₁The result was recorded as B1;

such as | EF₂-EF₁|＜TH₁And | EG₂-EG₁|≥TH₂Knot ofMarking the fruit as B2;

such as | EF₂-EF₁|≥TH₂And | EG₂-EG₁|≥TH₂The result was recorded as B3;

(c) the display and control module is switched to a second display mode, only the oblique vision measurement sighting marks displayed on the G-eye visible display device are visible, and the display positions of the sighting marks are unchanged; when the G eye watches the sight, the central coordinate of the reflecting point of the G eye light source on the cornea of the G eye is coincided with the central coordinate of the pupil of the G eye, and the position EG of the G eye eyeball tracking module is recorded₃The center coordinates of the light reflecting point of the F eye light source on the F eye cornea are coincided with the center coordinates of the F eye pupil, and the position EF of the F eye eyeball tracking module is recorded₃；

Such as | EF₃-EF₂|＜TH₁And | EG₃-EG₂|＜TH₁The result was denoted as C1;

such as | EF₃-EF₂|≥TH₂And | EG₃-EG₂|＜TH₁The result was denoted as C2;

such as | EF₃-EF₂|≥TH₂And | EG₃-EG₂|≥TH₂The result was denoted as C3;

(d) the display and control module is switched to a display mode III, the F eye and the G eye can both see the squint measurement sighting target displayed by the display device, and the display position of the sighting target is unchanged; when the eyes watch the sight, the center coordinates of the reflecting point of the F eye light source on the cornea of the F eye and the center coordinates of the pupil of the F eye coincide, and the position EF of the F eye eyeball tracking module is recorded₄(ii) a The central coordinates of the reflecting point of the G eye light source on the G eye cornea are coincided with the central coordinates of the G eye pupil, and the position EG of the G eye eyeball tracking module is recorded₄；

Such as | EF₄-EF₃|＜TH₁And | EG₄-EG₃|＜TH₁The result was recorded as D1;

such as | EF₄-EF₃|≥TH₂And | EG₄-EG₃|＜TH₁The result was recorded as D2;

such as | EF₄-EF₃|≥TH₂And | EG₄-EG₃|≥TH₂The result was recorded as D3;

(e) after the steps are completed, the requirements of B1, C1 and D1 are met at the same time, and the condition shows that no strabismus exists and no heterophoria exists;

if B1, C3 and D1 are satisfied simultaneously, it is judged that there is alternative strabismus, and the strabismus degree is | EF₃-EF₂The prism degree converted by the angle corresponding to the | is calculated;

when B3, C1 and D1 are satisfied simultaneously, it is judged that there is monocular strabismus, F eye is strabismus, and strabismus is | EF₂-EF₁The prism degree converted by the angle corresponding to the | is calculated;

when B1, C3 and D3 are satisfied simultaneously, it is judged that there is monocular strabismus, G eye is strabismus, and strabismus is | EG₄-EG₃And | is converted into a triangular prism degree by the corresponding angle.

Preferably, after the direction and the degree of strabismus are measured, the prism with the corresponding degree is placed in front of the strabismus, and the measurement is carried out again; if the measurement is carried out again, the moving angles of the left eye eyeball tracking module and the right eye eyeball tracking module in each step are all less than TH₁Then, the prism power at this time was confirmed to be the squint power.

Preferably, a rotational strabismus measurement module is also included, arranged to perform the steps of,

(a) the display and control module is switched to a first display mode, two eyes are respectively J eyes and K eyes, and firstly, the squint measuring sighting marks displayed on the display device can be seen by only the J eyes; when the eye is gazed at the sighting mark, the characteristics of the iris of the eye and the corresponding iris angle HJ of the eye are recorded₁And recording the characteristics of the K eyes iris at the moment and the corresponding K eyes iris angle HK₁(ii) a Two angle thresholds TH are set₃And TH₄Wherein TH is₄≥TH₃；

(b) The display and control module is switched to a display mode III, the squint measurement sighting marks displayed by the display device can be seen by J eyes and K eyes, and the display positions of the sighting marks are unchanged; recording the characteristics of the J-eye iris at the moment and the corresponding J-eye iris angle HJ₂(ii) a Recording the characteristics of the K-eye iris at the moment and the corresponding K-eye iris angle HK₂；

Such as | HJ₂-HJ₁|＜TH₃And | HK₂-HK₁|＜TH₃The result was recorded as B4;

such as | HJ₂-HJ₁|＜TH₃And | HK₂-HK₁|≥TH₄The result was recorded as B5;

such as | HJ₂-HJ₁|≥TH₄And | HK₂-HK₁|≥TH₄The result was recorded as B6;

(c) the display and control module is switched to a second display mode, the squint measurement sighting marks displayed on the display device can be seen by only K eyes, and the display positions of the sighting marks are unchanged; recording the characteristics of the K-eye iris at the moment and the corresponding K-eye iris angle HK₃Recording the characteristics of the J-eye iris at the moment and the corresponding J-eye iris angle HJ₃；

Such as | HJ₃-HJ₂|＜TH₃And | HK₃-HK₂|＜TH₃The result was denoted as C4;

such as | HJ₃-HJ₂|≥TH₄And | HK₃-HK₂|＜TH₃The result was denoted as C5;

such as | HJ₃-HJ₂|≥TH₄And | HK₃-HK₂|≥TH₄The result was denoted as C6;

(d) the display and control module is switched to a display mode III, the squint measurement sighting marks displayed by the display device can be seen by J eyes and K eyes, and the display positions of the sighting marks are unchanged; recording the characteristics of the J-eye iris at the moment and the corresponding J-eye iris angle HJ₄(ii) a Recording the characteristics of the K-eye iris at the moment and the corresponding K-eye iris angle HK₄；

Such as | HJ₄-HJ₃|＜TH₃And | HK₄-HK₃|＜TH₃The result was recorded as D4;

such as | HJ₄-HJ₃|≥TH₄And | HK₄-HK₃|＜TH₃The result was recorded as D5;

such as | HJ₄-HJ₃|≥TH₄And | HK₄-HK₃|≥TH₄The result was recorded as D6;

(e) after the steps are completed, as B4, C4 and D4 are satisfied at the same time, the condition that the rotational strabismus is not dominant and the rotational strabismus is not recessive is indicated;

if B4, C6 and D4 are satisfied simultaneously, it is judged that there is alternately dominant rotational strabismus and the rotational strabismus is | HJ₃-HJ₂The angle corresponding to | is;

when B6, C4 and D4 were satisfied simultaneously, it was judged that there was monocular dominant rotational strabismus, J eye was a strabismus eye, and rotational strabismus was | HJ₂-HJ₁The angle corresponding to | is;

when B4, C6 and D6 were satisfied simultaneously, it was judged that there was monocular dominant rotational strabismus, K eye was a strabismus eye, and rotational strabismus was | HK₄-HK₃The angle corresponding to | is calculated.

Preferably, the left eye eyeball tracking module and the right eye eyeball tracking module use an automatic pupil center tracking algorithm, and the calculation method of the automatic pupil center tracking algorithm is as follows: and if the central coordinates of the cornea reflecting point and the central coordinates of the pupil are not overlapped, the eyeball tracking module corresponding to the eyeball moves along the vector direction of a connecting line from the central coordinates of the cornea reflecting point to the central coordinates of the pupil, the distance between the center of the cornea reflecting point and the center of the pupil is gradually reduced in the moving process, and the movement is stopped until the center of the cornea reflecting point and the center of the pupil are overlapped again.

Preferably, head fixing device contains the chin strap of liftable, and head fixing device contains left side post and right side post, has standard height scale mark on left side post and the right side post, and adjustment chin strap makes examinee's eye height and standard height scale mark height during the test.

Preferably, the device also comprises a three-dimensional coordinate measuring device which can measure the three-dimensional coordinates of the sphere center of the eyeball of the left eye and the sphere center of the eyeball of the right eye; adjusting the position of a left spherical surface where the left eye eyeball tracking module is located or adjusting the position of the left eye semi-transparent and semi-reflective module according to the three-dimensional coordinates of the virtual image of the left eye eyeball center to enable the left spherical center to coincide with the virtual image of the left eye eyeball center; and adjusting the position of a right spherical surface where the right eyeball tracking module is located or adjusting the position of the right eye semi-transmitting and semi-reflecting module according to the three-dimensional coordinates of the virtual image of the sphere center of the right eyeball to enable the sphere center of the right spherical surface to coincide with the virtual image of the sphere center of the right eyeball.

Preferably, the device also comprises a three-dimensional coordinate measuring device which can measure the three-dimensional coordinates of the sphere center of the eyeball of the left eye and the sphere center of the eyeball of the right eye; adjusting the position of a left plane where the left eye eyeball tracking module is located or adjusting the position of the left eye semi-transparent and semi-reflective module according to the three-dimensional coordinates of the virtual image of the left eye eyeball center to enable a left plane (0,0) point to be intersected with the vertical line of the left plane and the virtual image of the left eye eyeball center to enable D1 to be equal to the distance between the left plane (0,0) point and the virtual image of the left eye eyeball center; and adjusting the position of a right plane where the right eyeball tracking module is located or adjusting the position of the right eye semi-transparent and semi-reflective module according to the three-dimensional coordinates of the virtual image of the sphere center of the right eyeball, so that the right plane (0,0) point is intersected with the virtual image of the vertical line of the plane and the sphere center of the right eyeball, and D2 is equal to the distance between the right plane (0,0) point and the virtual image of the sphere center of the right eyeball.

Preferably, the three-dimensional coordinate measuring device comprises two cameras and two light sources; the relative positions of the two cameras, the two light sources and the display device, the left eye semi-transparent and semi-reflective module and the right eye semi-transparent and semi-reflective module are fixed;

the display device can display the sighting mark at two different positions;

enabling the examinee to respectively see the two sighting marks by the left eye in the display mode, and calculating the three-dimensional coordinates of the eyeball center of the left eye through the images shot by the binocular camera;

and enabling the right eye of the examinee to respectively see the two sighting marks in the second display mode, and calculating the three-dimensional coordinates of the sphere center of the eyeball of the right eye through the images shot by the binocular camera.

Preferably, a baffle plate which is used for transmitting near infrared light and not transmitting visible light is arranged between the left eye eyeball tracking module and the left eye; a baffle plate which can transmit near infrared light and can not transmit visible light is arranged between the eyeball tracking module of the right eye and the right eye.

The invention has the beneficial effects that: the eyeball motion can be automatically and quantitatively measured, the method is rapid, visual and accurate, and the time of doctors and examinees is saved.

Drawings

FIG. 1 is a schematic diagram of the components of the apparatus in which the eye tracking module moves along a spherical surface;

FIG. 2 is a principle of measuring eye movement by movement of an eye tracking module;

3(a) through 3(c) are changes in the eye region images during the use of an automatic pupil center tracking algorithm;

FIG. 4 is a schematic diagram of the components of the apparatus with the eye tracking module moved along a plane;

FIG. 5 is a schematic diagram of the relative positions of a binocular camera, two light sources, a display and two eyes in a three dimensional coordinate measuring apparatus;

fig. 6 is a schematic diagram of a three-dimensional coordinate measuring apparatus calculating a boresight line.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Example one

As shown in fig. 1, the eye movement measuring device disclosed in this embodiment includes a left eye transflective module 101, a movable left eye tracking module 102, a right eye transflective module 103, a movable right eye tracking module 104, a display and control module (including a display 105 and a control device), a left liquid crystal shutter 106 between the left eye transflective module 101 and the display 105, a right liquid crystal shutter 107 between the right eye transflective module 103 and the display 105, and a head fixing device. Wherein:

the left eye eyeball tracking module 102 includes a near infrared camera (left eye camera) and a near infrared LED point light source (left eye light source), the wavelength of the near infrared light source is 940nm, and the relative positions of the left eye camera and the left eye light source are fixed. In this embodiment, the left eye light source is located 4cm directly above the left eye camera. The left-eye transflective module 101 is a piece of planar sheet-shaped optical glass, which can transmit visible light and reflect near-infrared light. In this embodiment, the left-eye transflective module 101 forms an angle of 45 ° with the line of sight of the left eye looking straight ahead. Accordingly, the left eye can see the display 105 through the left eye transflective module 101, and the near-infrared camera in the left eye tracking module 102 can capture a virtual image reflected by the left eye through the left eye transflective module 101. The left eye light source irradiates to the left eye cornea through the reflection of the left eye semi-transparent and semi-reflective module and generates a left eye cornea reflection point, and the left eye camera can shoot a virtual image of the left eye cornea reflection point reflected by the left eye semi-transparent and semi-reflective module.

In this embodiment, the left eye tracking module 102 can move along a spherical surface, which is called a left spherical surface, where the center of the left spherical surface is the position of the virtual image of the center of the left eye eyeball reflected by the left eye transflective module 101, and the radius of the left spherical surface is 50cm in this embodiment. The position of the left eye and eyeball tracking module 102 can be defined by a spherical coordinate system with a virtual image of the spherical center of the left eye and eyeball as the spherical center and a radius of 50cm

Denotes, theta and

the unit of (d) is an angle. In the present embodiment, on the spherical coordinate system of the left eye and eyeball tracking module 102: (50,0,0) is located directly to the left of the virtual image of the center of the eye's eyeball. Because the eye rotation range of the human eye is limited, in this embodiment, the angle range of the left eye tracking module 102 moving on the left spherical surface is-60 ° -theta ≤ 60 °,

the left eye tracking module 102 may move along the spherical surface by a guide rail or a mechanical arm. In order to center the eye image and achieve a better shooting effect, when the left eye eyeball tracking module 102 moves along the left spherical surface, the axis of the left eye camera always faces the direction of the virtual image of the center of the left eye eyeball sphere.

The right eye eyeball tracking module 104 includes a near infrared camera (right eye camera) and a near infrared LED point light source (right eye light source), the wavelength of the near infrared light source is 940nm, the relative positions of the right eye camera and the right eye light source are fixed, in this embodiment, the right eye light source is located 4cm directly above the right eye camera. The right-eye transflective module 103 is a piece of planar sheet-shaped optical glass, and can transmit visible light and reflect near-infrared light. In this embodiment, the right eye semi-transparent and semi-reflective module 103 forms an included angle of 45 ° with the line of sight of the right eye when looking straight ahead. Therefore, the right eye can see the display 105 through the right eye transflective module 103, and the near-infrared camera in the right eye eyeball tracking module 104 can shoot a virtual image reflected by the right eye through the right eye transflective module 103. The right eye light source irradiates to the cornea of the right eye through the reflection of the right eye semi-transparent and semi-reflective module and generates a right eye cornea reflection point, and the right eye camera can shoot a virtual image of the right eye cornea reflection point reflected by the right eye semi-transparent and semi-reflective module.

In this embodiment, the right eye eyeball tracking module 104 can move along a spherical surface, which is called a right spherical surface, the center position of the right spherical surface is the position of the virtual image of the center of the right eye eyeball reflected by the right eye semi-transparent and semi-reflective module 103, and the radius of the right spherical surface is 50cm in this embodiment. The position of the right eye eyeball tracking module 104 can be defined by a spherical coordinate system with the virtual image of the sphere center of the right eye eyeball as the sphere center and the radius of 50cm as the radius

Denotes, theta and

the unit of (d) is an angle. In this embodiment, the point (50,0,0) on the spherical coordinate system of the right eye eyeball tracking module 104 is located right to the virtual image of the center of the right eye eyeball. Because the eyeball rotation range of the human eyes is limited, in the embodiment, the angle range of the movement of the right eyeball tracking module 104 on the right spherical surface is more than or equal to minus 60 degrees and less than or equal to theta 60 degrees,

the right eye tracking module 104 can move along the spherical surface by means of a guide rail or a mechanical arm. In order to center the eye image and achieve a better shooting effect, when the right eye eyeball tracking module 104 moves along the left spherical surface, the axis of the right eye camera always faces the direction of the virtual image of the center of the right eye eyeball sphere.

In this embodiment, the left eye eyeball tracking module 102 and the right eye eyeball tracking module 104 use an automatic pupil center tracking algorithm to make the center coordinates of the light reflecting point of the left eye light source on the left eye cornea coincide with the center coordinates of the left eye pupil, and make the center coordinates of the light reflecting point of the right eye light source on the right eye cornea coincide with the center coordinates of the right eye pupil; the moving direction of the camera is the vector direction of a connecting line from the central coordinate of the cornea reflecting point to the central coordinate of the pupil, and the camera stops moving until the camera is overlapped again. The movement of the camera is automatically controlled by a program. Considering that the eyeball may slightly shake, a certain noise may exist in image acquisition, and the "coincidence" may be set such that the distance between the central coordinate of the corneal reflection point and the central coordinate of the pupil in the image is smaller than a certain pixel value, and in this embodiment, it is considered that the distance is smaller than 2 pixels.

The display 105 in the display and control module is positioned directly in front of the visual field of the subject, and the distance can be adjusted according to the test requirement. The display device in the display and control module may be a projector, a television, a printed pattern, an object, or the like, in addition to the display 105 described in this embodiment. A left liquid crystal shutter 106 is positioned between the left eye transflective module 101 and the display 105, and a right liquid crystal shutter 107 is positioned between the right eye transflective module 103 and the display 105. The left liquid crystal shutter 106 is transparent when not energized and is opaque when energized; the right liquid crystal shutter 107 is transparent when not powered and opaque when powered. In this embodiment, the display and control module can switch the following three display modes, namely, the first display mode: the left liquid crystal shutter 106 is transparent, the right liquid crystal shutter 107 is opaque, and only the left eye can see the content displayed by the display device, and the display mode two: the right liquid crystal shutter 107 is transparent, the left liquid crystal shutter 106 is opaque, and only the right eye can see the content displayed by the display device at this time, and the display mode three: the left liquid crystal shutter 106 and the right liquid crystal shutter 107 are both transparent, and the left eye and the right eye can both see the content displayed by the display device.

Head fixing device contains the chin strap of liftable, and head fixing device contains left side post and right side post, has eyes standard height scale mark on left side post and the right side post. In order to achieve the effect of fixing the head position more stably, the forehead fixing device further comprises a clamping band for fixing the forehead, the chin of the examinee is placed on the chin rest, the forehead leans against the clamping band, and the height of the eyes of the examinee is equal to the height of the standard height scale lines on the left side column and the right side column when the chin rest is adjusted during testing to enable the examinee to look straight ahead. A three-dimensional space coordinate system is established by taking the middle point of a connecting line of standard height scale lines on a left side column and a right side column as an origin (approximately the position of the eyebrow center of a detected person), the coordinates of the upper direction and the lower direction of the spherical centers of the eyes of two eyes are 0, the positions of the left horizontal direction and the right horizontal direction of the centers of the eyes of the left eye and the right eye can be determined by measuring the interpupillary distance of the detected person or adopting the average reference interpupillary distance of 6cm, in addition, the positions of the front and back directions of the centers of the eyes of the left eye and the right eye are basically equal to the front and back positions of the middle point of a chin rest, and therefore, for the detected. When the eyeball rotates around the vertical axis in the horizontal direction, or rotates around the horizontal axis in the vertical direction, or rotates around the front-back axis clockwise or counterclockwise, the position of the eyeball center is kept unchanged. Meanwhile, since the spatial positions of the left eye transflective module 101 and the right eye transflective module 103 are fixed, the virtual image reflected by the left eye eyeball center through the left eye transflective module 101 is also fixed and remains unchanged when the left eye eyeball moves, and the virtual image reflected by the right eye eyeball center through the right eye transflective module 103 is also fixed and remains unchanged when the right eye eyeball moves. The head restraint is not shown in fig. 1.

The left spherical center of the left eyeball tracking module 102 and the virtual image of the left eyeball center coincide, and the right spherical center of the right eyeball tracking module 104 and the virtual image of the right eyeball center coincide.

In order to prevent the examinee from seeing the camera and other devices in the eyeball tracking module and disturbing attention, the embodiment further uses two near infrared light-opaque baffles made of black acrylic material, one of which is located between the left eyeball tracking module 102 and the left eye and the other is located between the right eyeball tracking module 104 and the right eye. The baffles are not shown in fig. 1.

The device in this embodiment further includes an electronic computer configured to run an automatic pupil center tracking algorithm in the eye tracking module, run a program for controlling display contents, run a program for controlling a liquid crystal shutter switch, run a program for controlling movement of the camera and calculating a movement angle of the camera, and the like.

The following illustrates the principle of the present device for measuring eye movement by movement of the eye tracking module. For convenience of presentation, only the left-eye relevant portion is drawn, as shown in FIG. 2, at T₁At the moment, the left eye eyeball watches the visual target at a certain specified position in front of the eye, and the horizontal visual angle is marked as theta₁At a vertical viewing angle of

The left eye eyeball tracking module 102 makes the central coordinates of the light reflecting point of the left eye light source on the cornea of the left eye coincide with the central coordinates of the pupil of the left eye through an automatic pupil center tracking algorithm. Because the included angle between the eye visual axis and the optical axis, i.e., the Kappa angle, exists, and the Kappa angle varies from person to person, the spherical coordinate of the left eye tracking module 102 may not completely coincide with the actual left eye viewing angle, and the recording of the left eye tracking module at this time is performedSpherical coordinates of

The position of the left eye and eyeball tracking module 102 is θ in fig. 2₂Because of the top view, only the horizontal projection of the position can be seen. Then, at T₂At that time, the left eye eyeball moves to the right upper direction and moves to the horizontal direction viewing angle theta₃Angle of view in the vertical direction

The left eye and eyeball tracking module 102 makes the central coordinates of the light reflecting point of the left eye light source on the left eye cornea coincide with the central coordinates of the left eye pupil through an automatic pupil center tracking algorithm, and records the spherical coordinates of the left eye and eyeball tracking module at the moment

At θ in FIG. 2₄Because of the top view, only the horizontal projection of the position can be seen. The angle of rotation of the left eye eyeball and the angle of rotation of the virtual image of the left eye eyeball are the same, so θ₄-θ₂＝θ₃-θ₁，

Therefore, the left eye tracking module 102 is calculated at T₂Time and T₁Difference theta of horizontal angle of spherical coordinates of time₄-θ₂The angle theta of the horizontal movement of the left eye eyeball can be obtained₃-θ₁(ii) a By calculating the left eye tracking module 102 at T₂Time and T₁Difference in vertical angle of spherical coordinates of time

The angle of the vertical movement of the left eye eyeball can be obtained

Since the left eye tracking module captures the left eye image through the virtual image reflected by the transflective module, the left eye image is capturedThe horizontal rotation direction is opposite to the horizontal rotation direction of the left eye eyeball tracking module on the left spherical surface, for example, when the left eye eyeball rotates clockwise as viewed from the top, the left eye eyeball tracking module rotates counterclockwise on the left spherical surface. Therefore, the value of the angle change of the left eye eyeball in the clockwise direction in the horizontal direction when the angle difference is calculated should be equal to the value of the angle change of the left eye eyeball tracking module in the counterclockwise direction in the horizontal direction.

In this example, the automatic pupil center tracking algorithm works as follows: the left camera in the left eye tracking module 102 captures an image of a left eye region through reflection of the left eye transflective module 101, and the left eye light source generates a corneal reflection point through reflection of the outer surface of the left eye cornea. Setting a gray threshold value which is higher than the gray of a pupil and lower than the gray of surrounding iris and skin areas according to the characteristic that the gray of a pupil area is lower, and marking the area lower than the gray threshold value as a possible pupil area; then, an area threshold value for eliminating interference of small black objects such as eyelashes is set, so that an accurate region where the pupil is located is determined, and coordinates of the center of the pupil region are calculated. Because the left eye cornea reflective point has high brightness and the gray level can reach 255, the position of the cornea reflective point can be found according to the characteristics (if more than one bright point with the gray level of 255 exists in the image, for example, if some interference reflective points exist on the sclera, one of the bright points which is closest to the pupil area is selected as the cornea reflective point), and the coordinate of the center of the cornea reflective point is calculated. If the central coordinate of the corneal reflection point at the initial position is not overlapped with the central coordinate of the pupil, the left eye eyeball tracking module 102 is moved along the vector direction of the connecting line from the central coordinate of the corneal reflection point to the central coordinate of the pupil, and the distance between the center of the corneal reflection point and the center of the pupil is gradually reduced in the moving process until the corneal reflection point and the pupil are overlapped again. At T₁At the moment, the center of the cornea reflection point of the left eye coincides with the center of the pupil, as shown in fig. 3(a), the left eye and eyeball tracking module 102 is located at the spherical coordinate

The position of (a). At T₂At all times, the horizontal direction of the left eye eyeball moves rightwardsMove theta₃-θ₁At an angle of (1), vertically moves upwards

The angle of (c). Because the eyeball rotates at a fast speed, the left eye and eyeball tracking module still stays at the new position when the eyeball just rotates to the new position

The center of the cornea reflection point and the center of the pupil are not overlapped any more, because the left-eye image shot by the left camera is a virtual image reflected by the plane mirror image of the left-eye transflective module 101, and the center of the pupil is positioned at the upper right side of the center of the cornea reflection point in the image, as shown in fig. 3 (b); then, the automatic pupil center tracking algorithm detects that the pupil center is located at the center of the corneal reflection point and does not coincide with each other, so that the left eye and eyeball tracking module 102 is controlled to move in the right-up direction (where "upper right" is a viewing angle from the center of the left spherical surface to the virtual image of the left eye and eyeball) until the center of the corneal reflection point of the left eye and the pupil center of the left eye coincide with each other again, as shown in fig. 3(c), at this time, the left eye and eyeball tracking module 102 is located at the spherical

The position of (a).

Similarly, the eye movement of the right eye can also be calculated by the movement of the eye tracking module of the right eye.

Thus, the device can realize that: according to the angle of the left eye eyeball tracking module 102 moving along the left spherical surface, the rotation angle of the left eye eyeball in the horizontal direction and the rotation angle of the left eye eyeball in the vertical direction can be calculated; according to the angle of the right eyeball tracking module 104 moving along the right spherical surface, the angle of the horizontal rotation and the angle of the vertical rotation of the right eyeball can be calculated.

In addition, the visual angle of the eyeball can be calculated through single-point calibration. The method comprises the following steps:

horizontal view angle theta is seen by the left eye_l1And the vertical viewing angle is

The sphere coordinates of the left eye and eyeball tracking module 102 at this time are recorded

Calculating Delta theta_l1＝θ_l1’-θ_l1，

a horizontal viewing angle and a vertical viewing angle for the left eye can be obtained.

Horizontal viewing angle theta at right eye_r1And the vertical viewing angle is

The sphere coordinates of the right eye sphere tracking module 104 at this time are recorded

Calculating Delta theta_r1＝θ_r1’-θ_r1，

After the right eye eyeball moves, the measured horizontal direction angle value and the measured vertical direction angle value in the spherical coordinate of the right eye eyeball tracking module 104 are respectively subtracted by delta theta_r1And

In this embodiment, taking the left-eye single-point calibration as an example, the calibration optotype is an optotype with a horizontal viewing angle of 0 ° and a vertical viewing angle of 0 ° on the display. Recording the spherical coordinates (50,4 degrees, 3 degrees) of the left eye eyeball tracking module at the moment, and then delta theta_l1＝4°，

After the left eye moves, subtracting 4 ° from the horizontal direction angle value and subtracting 3 ° from the vertical direction angle value in the spherical coordinate of the left eye tracking module 101, so as to obtain the horizontal viewing angle and the vertical viewing angle of the left eye.

In addition, each eye tracking module of the present embodiment only uses one near-infrared camera and one near-infrared light source. In other embodiments, multiple near-infrared light sources may be used in some cases, for example, multiple light sources may all generate corneal reflection points, and the central coordinates of the corneal reflection points may be averaged to obtain central coordinates of the corneal reflection points, which are coincident with the pupil center. In some cases, a plurality of near infrared cameras can be used, and the eye image of only one camera is taken to calculate whether the pupil center and the cornea reflection point center are coincident.

Example two

In this embodiment, the left eye tracking module 102 and the right eye tracking module 104 can also move along a plane. Other apparatus components and principles of operation are similar to the embodiments.

As shown in fig. 4, the left eye tracking module 102 can move along the left plane. When the left eye looks straight ahead, the horizontal direction visual angle and the vertical direction visual angle are both 0 degrees, the left plane is vertical to the visual axis of the eye eyeball virtual image. The perpendicular to the left plane passing through the point of the left plane (0,0) intersects the virtual image of the center of the eye globe of the left eye. The distance between the left plane and the virtual image of the center of the left eye eyeball is D1.

In this embodiment, the distance D1 between the virtual images of the left plane and the center of the eyeball is 50cm, equal to the distance D2 between the virtual images of the right plane and the center of the eyeball.

When the left eye eyeball tracking module 102 moves along the left plane, the axis of the left eye camera always faces the virtual image of the center of the left eye eyeball; when the right eye eyeball tracking module 104 moves along the right plane, the axis of the right eye camera always faces the virtual image of the center of the right eye eyeball.

According to the angle of the left eye eyeball tracking module 102 moving along the left plane, the angle of the left eye eyeball rotating in the horizontal direction and the angle of the left eye eyeball rotating in the vertical direction can be calculated. Calculation methodThe method comprises the following steps: and setting the vertical line of the left plane passing through the point of the left plane (0,0) as a '0-degree vertical line', wherein the vertical line is the connecting line of the point of the left plane (0,0) and the center virtual image of the eyeball of the left eye. Let the coordinates in the left plane before the left eye tracking module 102 moves be (XL)₁,YL₁) If the horizontal included angle between the connecting line of the front left eye eyeball tracking module and the left eye eyeball center virtual image and the '0-degree vertical line' is arctan (XL)₁D1) with an angle of arctan (YL) in the vertical direction₁/D1). Let the coordinates of the left eye eyeball tracking module 102 in the left plane after movement be (XL)₂,YL₂) Then, the horizontal angle between the connection line of the left eye eyeball tracking module 102 and the center virtual image of the left eye eyeball and the "0 ° vertical line" after the movement is arctan (XL)₂D1) with an angle of arctan (YL) in the vertical direction₂/D1). The horizontal movement angle of the left eye eyeball tracking module 102 after movement is arctan (XL) compared with the movement angle before movement₂/D1)-arctan(XL₁/D1), the angle of vertical movement is arctan (YL)₂/D1)-arctan(YL₁/D1)。

Similarly, the angle of the horizontal rotation and the angle of the vertical rotation of the eyeball of the right eye can be calculated according to the angle of the eyeball tracking module 104 moving along the right plane.

The visual angle of the eyeball can also be calculated through single-point calibration:

horizontal view angle theta is seen by the left eye_l2And the vertical viewing angle is

According to the angle between the left eye and eyeball tracking module 102 and the '0 degree vertical line' of the left plane, the angle coordinate of the left plane of the left eye and eyeball tracking module 102 at the moment is calculated

And calculates Delta theta_l2＝θl2’-θ_l2，

After the left eye eyeball moves, the horizontal direction angle value and the vertical direction angle value in the left plane coordinate of the left eye eyeball tracking module 102 are measured respectivelyMinus delta theta_l2And

Horizontal viewing angle theta at right eye_r2And the vertical viewing angle is

According to the angle between the right eyeball tracking module 104 and the '0 degree vertical line' of the right plane, the right plane angle coordinate of the right eyeball tracking module 104 at the moment is calculated

And calculates Delta theta_r2＝θ_r2’-θ_r2，

After the right eye eyeball moves, the measured horizontal direction angle value and the measured vertical direction angle value in the right plane coordinate of the right eye eyeball tracking module 104 are respectively subtracted by delta theta_r2And

EXAMPLE III

The apparatus in this embodiment further includes an squint measurement module based on the apparatus in the first embodiment. The strabismus measuring module is a program running on an electronic computer of the device, and can judge whether the examinee has strabismus according to the eyeball motion measurement data, and judge the type of strabismus, the direction of strabismus and the strabismus degree if the examinee has strabismus.

Medically, strabismus can be classified as follows: the control of eye deviation from the fusion function can be classified into dominant and recessive. The classification from the fixation situation can be divided into monocular strabismus and alternating strabismus. The direction of deviation of the eyeball can be divided into horizontal strabismus, vertical strabismus and rotational strabismus.

And (3) displaying strabismus: also known as dominant strabismus, is eye deviation that cannot be controlled by the fusion mechanism.

Heterophoria: also known as scotopic strabismus, or scotopic strabismus, is a potential eye deviation that can be controlled by the fusion mechanism, which occurs only when fusion is broken.

Monocular strabismus: strabismus exists only at one eye.

Alternative strabismus: both eyes can alternately fixate autonomously.

Horizontal strabismus: oblique viewing in the horizontal direction includes inward oblique viewing when the patient is inclined inward (nasal side) and outward oblique viewing when the patient is inclined outward (temporal side).

Vertical strabismus: squint in the vertical direction.

Mixed strabismus: strabismus containing two or more components.

The squint measurement module is arranged to perform the following steps:

(a) the display and control module is switched to a first display mode, and the squint measuring sighting marks displayed on the display device can be seen by the left eye only; when the left eye watches the sight mark, the central coordinate of the reflection point of the left eye light source on the left eye cornea is coincided with the central coordinate of the left eye pupil, and the position EF of the left eye eyeball tracking module is recorded₁The center coordinates of the reflecting point of the right eye light source on the right eye cornea are coincided with the center coordinates of the right eye pupil, and the position EG of the right eye eyeball tracking module is recorded₁(ii) a Two angle thresholds TH are set₁And TH₂Wherein TH is₂≥TH₁。TH₁Is a small angle threshold, since the eye may have slight jitter when looking at the optotype, and the spontaneous slight jitter changes in vision are mostly within 1 ° of the visual angle, in this embodiment the threshold TH is set₁Is 1 deg.. TH₂Is a ratio TH₁A larger angle threshold value, beyond which the visual angle deviation exceeds, is judged to have strabismus, in this embodiment, a threshold value TH is set₂Is 2 deg..

(b) The display and control module is switched to a display mode III, the left eye and the right eye can both see the squint measurement sighting target displayed by the display device, and the display position of the sighting target is unchanged; when the eyes watch the sight mark, the central coordinates of the reflecting point of the left eye light source on the left eye cornea and the central coordinates of the left eye pupil are coincided and recordedPosition EF of the left eye and eyeball tracking module 102₂(ii) a The central coordinates of the reflecting point of the right eye light source on the right eye cornea are coincided with the central coordinates of the right eye pupil, and the position EG of the right eye eyeball tracking module 104 is recorded₂；

such as | EF₂-EF₁|＜TH₁And | EG₂-EG₁|≥TH₂The result was recorded as B2;

wherein, let EF₁In the position of

EF₂In the position of

(θ₂-θ₁) The angle of horizontal movement for the corresponding eye tracking module (which also reflects the rotation angle of the horizontal direction of the eye),

the angle of vertical movement (which also reflects the angle of rotation of the eye) for the corresponding eye tracking module is defined as | EF₂-EF₁Is |

The other symbols "|" indicating the change in the rotation angle in the present embodiment have the same meaning.

(c) The display and control module is switched to a display mode II, the squint measurement sighting marks displayed on the display device can be seen by only the right eye, and the display positions of the sighting marks are unchanged; when the right eye watches the sight, the central coordinate of the reflecting point of the right eye light source on the right eye cornea is coincided with the central coordinate of the right eye pupil, and the position EG of the right eye eyeball tracking module 104 is recorded₃To make the left eye light source at the leftThe central coordinates of the reflective point of the cornea coincide with the central coordinates of the pupil of the left eye, and the position EF of the left eye and eyeball tracking module 102 is recorded₃；

(d) the display and control module is switched to a display mode III, the left eye and the right eye can both see the squint measurement sighting target displayed by the display device, and the display position of the sighting target is unchanged; when the eyes watch the sight, the central coordinates of the reflective point of the left eye light source on the left eye cornea are coincided with the central coordinates of the left eye pupil, and the position EF of the left eye eyeball tracking module 102 is recorded₄(ii) a The central coordinates of the reflecting point of the right eye light source on the right eye cornea are coincided with the central coordinates of the right eye pupil, and the position EG of the right eye eyeball tracking module 104 is recorded₄；

when B3, C1 and D1 are satisfied, it is determined that there is monocular strabismus, the left eye is strabismus, the strabismus direction is the direction of eye movement corresponding to the direction from EF1 to EF2, and the strabismus degree is | EF₂-EF₁The prism degree converted by the angle corresponding to the | is calculated;

when B1, C3 and D3 are satisfied simultaneously, the monocular strabismus is judged to exist, the right eye is the strabismus eye, and the direction of strabismus is EG₃Towards EG₄The direction of the eye movement is the direction of the oblique vision degree | EG₄-EG₃And | is converted into a triangular prism degree by the corresponding angle.

If the type of the strabismus is horizontal strabismus, the strabismus in the horizontal direction is the triangular prism converted by the moving angle of the corresponding eyeball tracking module; if the type of the strabismus is vertical strabismus, the vertical strabismus is the triangular prism converted by the moving angle of the corresponding eyeball tracking module; if the squint type is a mixed type squint in which the horizontal direction and the vertical direction are mixed, the movement angle of the corresponding eye tracking module is decomposed into a horizontal component and a vertical component, and then the horizontal component is converted into a triangular prism as the horizontal squint degree, and the vertical component is converted into a triangular prism as the vertical squint degree.

(f) After the direction and the strabismus degree of the strabismus are measured, placing a prism with corresponding degree in front of the strabismus eye, and measuring again; if the measurement is carried out again, the moving angles of the left eye eyeball tracking module and the right eye eyeball tracking module in each step are all less than TH₁Then, the prism power at this time was confirmed to be the squint power.

For example, the specific process of a strabismus subject using the apparatus to perform strabismus measurement is as follows:

the display and control module uses a projector to display an oblique vision measuring sighting mark at a position which is 6m far away and parallel to the sight line and is positioned at the middle position. Other modules and embodiments are the same. Because the distance is far away, the sight lines of the left eye and the right eye are approximately parallel, and the horizontal direction and the vertical direction of the measuring sighting target are both 0-degree visual angles.

First, the display and control module is switched to the first display mode, and only the left eye can see the squint measurement optotype, and the visual angle of the eyeball of the left eye is (0, 0). The central coordinates of the reflective point of the left eye light source on the left eye cornea are coincided with the central coordinates of the left eye pupil, and the position of the left eye eyeball tracking module 102 on the left spherical surface at the moment is recorded

Due to the Kappa angle, the position of the left eye tracking module 102 on the left spherical surface is (50,3, 2).

In the present embodiment, a positive value of θ represents a counterclockwise direction when viewed from above,

positive values of (a) indicate the upper hemisphere on the spherical surface. And simultaneously recording the position of the right eye eyeball tracking module 104 on the right spherical surface at the moment.

And then the display and control module is switched to a display mode III, the squint measuring sighting marks can be seen by two eyes, and the display positions of the sighting marks are unchanged. The left eye eyeball tracking module 102 moves to (50,9,2) using the automatic pupil center tracking algorithm, which means that the left eye eyeball tracking module 102 moves 6 ° in the counterclockwise direction, and accordingly, the left eye eyeball rotates 6 ° in the clockwise direction (in the right horizontal direction). At the same time the device records that the right eye tracking module 104 has also moved 6 counterclockwise on the right sphere, the result being noted as B3.

And then the display and control module is switched to a second display mode, only the right eye can see the squint measurement sighting target, and the display position of the sighting target is unchanged. In the process, neither the left eye tracking module 102 nor the right eye tracking module 104 moves, or both the moving angles are smaller than 1 °, and the result is denoted as C1.

And then the display and control module is switched to a display mode three, the squint measuring sighting marks can be seen by the left eye and the right eye, and the display positions of the sighting marks are unchanged. In the process, neither the left eye tracking module 102 nor the right eye tracking module 104 moves, or both the moving angles are smaller than 1 °, and the result is denoted as D1.

In summary, when B3, C1, and D1 are satisfied at the same time, it is determined that there is monocular strabismus, the left eye is an oblique eye, the direction of strabismus is an oblique view (inward strabismus) in the horizontal right direction of the left eye, and the strabismus is a prism degree converted to 6 °. The degree of strabismus is converted into the degree of strabismus in units of triangular Prism Degrees (PD) according to the formula "100 × tan (angle)", and the degree of strabismus is calculated to be 10.5 PD.

Finally, in order to verify the accuracy of the strabismus measurement, a prism with a corresponding degree is placed in front of the left eye, and the measurement is carried out again. When the measurement is carried out again, the moving angles of the left eye eyeball tracking module and the right eye eyeball tracking module in each step are all less than TH₁Then, the prism power at this time was confirmed to be the squint power.

In addition, if the strabismus is required to be measured in different directions, the strabismus can be measured by displaying the measurement sighting mark in different directions of the display device and repeating the steps. If the strabismus is required to be measured at different distances, the strabismus can be measured by adjusting the distance between the display device and the eyes, and the distance adjustment range is generally between 30cm and 6 meters; the distance of the display device is constant, and different display distances can be simulated through the adjustable lens or the lens group.

Example four

The apparatus can also measure the clockwise or counterclockwise rotational movement of the eyeball about the anterior-posterior axis. The hardware components of the device are the same as those of the first embodiment. In addition, the left eye eyeball tracking module 102 may identify characteristics of the left eye iris and calculate the angle of rotation of the left eye according to the change of the characteristics of the left eye iris; the right eye eyeball tracking module 104 may identify characteristics of the right eye iris and calculate the angle of the right eye rotation based on the change in the characteristics of the right eye iris.

In this embodiment, an automatic pupil center tracking algorithm is used to make the center of the corneal reflection point coincide with the center of the pupil, and at this time, according to the characteristic that the gray scale of the iris is larger than the pupil but smaller than the sclera, an annular region where the iris is located is found and the size and shape of the annular region are normalized. And then calculating the texture angle characteristic of the left eye iris according to the gradient of the left eye image, and calculating the texture angle characteristic of the right eye iris according to the gradient of the right eye image. When the sight is only visible by the left eye, the iris texture angle characteristic of the left eye is set to be the rotation angle of 0 degree of the left eye, and if the iris texture angle characteristic of the left eye at a certain later moment is changed, the angle difference value between the iris texture angle characteristic of the left eye and the rotation angle of 0 degree of the left eye is the rotation angle of the eyeball of the left eye around the front and rear axes. The iris texture angle characteristic of the right eye when only the right eye can see the sight is set to be a 0-degree rotation angle of the right eye, if the iris texture angle characteristic of the right eye changes at a certain later moment, the angle difference value between the iris texture angle characteristic of the right eye and the 0-degree rotation angle of the right eye is the rotation angle of the eyeball of the right eye around the front and rear axes.

The embodiment further comprises a rotating strabismus measuring module which is a program running on the electronic computer of the device and can judge whether the examinee has rotating strabismus according to the eyeball motion measurement data, and judge the type of the rotating strabismus, the direction of the rotating strabismus and the rotating strabismus degree if the examinee has the rotating strabismus.

The rotational strabismus measurement module is configured to perform the steps of:

(a) the display and control module is switched to a first display mode, and the squint measuring sighting marks displayed on the display device can be seen by the left eye only; when the left eye watches the sighting mark, the characteristics of the left iris and the corresponding left iris angle HJ are recorded₁And recording the characteristics of the right iris at the moment and the corresponding right iris angle HK₁(ii) a Two angle thresholds TH are set₃And TH₄Wherein TH is₄≥TH₃。TH₃Is a small angle threshold, since the eye may have slight rotation change when looking at the optotype, and the spontaneous slight rotation change is mostly within 1 ° of visual angle, in this embodiment, the threshold TH is set₃Is 1 deg.. TH₄Is a ratio TH₃A larger angle threshold, which is exceeded to determine that there is a rotational strabismus, in this embodiment, a threshold TH is set₄Is 2 deg..

(b) The display and control module is switched to a display mode III, the left eye and the right eye can both see the squint measurement sighting target displayed by the display device, and the display position of the sighting target is unchanged; recording the characteristics of the left iris and the corresponding left iris angle HJ₂(ii) a Recording the characteristics of the right iris and the corresponding right eyeEye angle HK₂；

wherein, | HJ₂-HJ₁And | is the absolute value of the angle change of the rotation of the iris of the eyeball. The other symbols "|" indicating the change in the rotation angle in the present embodiment have the same meaning.

(c) The display and control module is switched to a display mode II, the squint measurement sighting marks displayed on the display device can be seen by only the right eye, and the display positions of the sighting marks are unchanged; recording the characteristics of the right iris at the moment and the corresponding right iris angle HK₃Recording the characteristics of the left iris and the corresponding left iris angle HJ₃；

(d) the display and control module is switched to a display mode III, the left eye and the right eye can both see the squint measurement sighting target displayed by the display device, and the display position of the sighting target is unchanged; recording the characteristics of the left iris and the corresponding left iris angle HJ₄(ii) a Recording the characteristics of the right iris at the moment and the corresponding right iris angle HK₄；

Such as | HJ₄-HJ₃|＜TH₃And HK4-HK3 < TH |)₃The result was recorded as D4;

such as | HJ₄-HJ₃|≥TH₄And HK4-HK3 < TH |)₃The result was recorded as D5;

such as | HJ₄-HJ₃|≥TH₄And HK4-HK3| ≧ TH₄The result was recorded as D6;

when B6, C4 and D4 are satisfied simultaneously, it is judged that there is monocular dominant rotational strabismus, the left eye is a strabismus eye, and the rotational strabismus is | HJ₂-HJ₁The angle corresponding to | is HJ in the direction of oblique rotation₁Steering HJ₂The opposite direction of (because the captured image is a virtual image of planar reflection, the rotation direction is opposite, for example, the iris of the eyeball is rotated clockwise, and the captured image is rotated counterclockwise);

when B4, C6 and D6 were satisfied simultaneously, it was judged that there was monocular dominant rotational strabismus, the right eye was a strabismus eye, and the rotational strabismus was | HK₄-HK₃The angle corresponding to the angle I, the direction of the rotational strabismus is HK₃Steering HK₄Opposite to the direction of (1).

EXAMPLE five

The movable surface of the eyeball tracking module needs to be matched with the virtual image position of the eyeball center as much as possible, the more accurate the position matching is, and the more accurate the eyeball motion measurement is. In the first embodiment, the head fixing device is used, the eyeball center position is estimated according to the eye position observed by naked eyes and the empirical value of the eyeball size, the eyeball center position is basically accurate, but certain errors exist, because the eyeball movement is measured by the device mainly according to the relative angle change before and after movement, and the small error of the eyeball center position estimation generally has little influence on the measurement result.

In some situations, it may be desirable to measure eye movement and the position of the center of the eye with a high degree of accuracy. In order to eliminate the eyeball center position and eyeball movement measurement error caused by the interpupillary distance or the eyeball size which is different from person to person, the equipment can use a three-dimensional coordinate measuring device and a corresponding measuring method to measure the three-dimensional coordinates of the eyeball center of the left eye and the eyeball center of the right eye.

If the eyeball tracking module moves along the spherical surface, adjusting the position of a left spherical surface where the left eyeball tracking module 102 is located or adjusting the position of the left eye semi-transparent and semi-reflective module 101 according to the three-dimensional coordinates of the virtual image of the center of the eyeball of the left eye, so that the center of the sphere of the left spherical surface is coincident with the virtual image of the center of the eyeball of the left eye; and adjusting the position of a right spherical surface where the right eyeball tracking module 104 is located or adjusting the position of the right eye semi-transmitting and semi-reflecting module 103 according to the three-dimensional coordinates of the virtual image of the sphere center of the right eyeball to enable the sphere center of the right spherical surface to coincide with the virtual image of the sphere center of the right eyeball.

If the eyeball tracking module moves along the plane, the position of a left plane where the left-eye eyeball tracking module 102 is located or the position of the left-eye transflective module 101 is adjusted according to the three-dimensional coordinates of the center of the left-eye eyeball, so that the left plane (0,0) point is intersected with the vertical line of the left plane and the virtual image of the center of the left-eye eyeball, and D1 is equal to the distance between the left plane (0,0) point and the virtual image of the center of the left-eye eyeball; and adjusting the position of a right plane where the right eyeball tracking module 104 is located or adjusting the position of the right eye semi-transmitting and semi-reflecting module 103 according to the three-dimensional coordinate of the center of the right eyeball, so that the right plane (0,0) point is intersected with the virtual image of the vertical line of the plane and the center of the right eyeball, and D2 is equal to the distance between the right plane (0,0) point and the virtual image of the center of the right eyeball.

Taking the case of the eyeball tracking module moving along a spherical surface as an example, a specific implementation manner is as follows:

as shown in fig. 5, the three-dimensional coordinate measuring device is composed of a binocular camera and two light sources, wherein the binocular camera is a left camera 108 and a right camera 109, respectively, and the two light sources are a left light source 110 and a right light source 111, respectively, and can emit white visible light, which are point light sources, and are located at two sides of the binocular camera. The display device in the display and control module is a display, and the sighting marks can be displayed at different positions. The three-dimensional coordinate measuring device is positioned below the display, and the relative positions of all components of the three-dimensional coordinate measuring device, the display, the left-eye semi-transparent and semi-reflective module, the right-eye semi-transparent and semi-reflective module and the head fixing device are known. The three-dimensional coordinate measuring device for measuring the three-dimensional coordinates of the eyeball center comprises the following steps:

(a) taking the eyeball center measurement of the left eye as an example, first, the left liquid crystal shutter 106 is made transparent, the right liquid crystal shutter 107 is made opaque, a visual target is displayed at a point Q on the left side of the display 105, the head of the subject is placed on the head fixing stand, and the left eye watches the visual target. According to the binocular vision three-dimensional space positioning principle, the center P of the left eye pupil can be measured by a binocular camera at the moment₁Three-dimensional space coordinates of (a).

(b) As shown in fig. 6, the outer side of the pupil has a spherical corneal surface, which is regarded as a convex mirror, and the point light source forms a virtual image on the other side of the convex mirror by reflection of the convex mirror. Based on optical imaging principles, it is known that the position of the virtual image is determined by the position of the light source and the convex mirror, independent of the position of the observer (i.e. independent of the position of the camera). In addition, a spatial straight line formed by connecting the point light source and the virtual image passes through the spherical center of the spherical surface where the convex mirror is located. When the examinee gazes at the sighting mark point Q, based on the optical principle of point light source convex mirror reflection imaging and the binocular vision three-dimensional space positioning principle, the three-dimensional space position of two point light sources is set to be R₁And R₂The three-dimensional spatial position R of two virtual reflection point images on the surface of the cornea can be calculated₁' and R₂’。R₁-R₁' connection and R₂-R₂' the connecting line intersects with the spherical center O of the spherical surface on which the corneal surface is positioned_c. In addition, the pupil center P has been measured in the previous step₁Three-dimensional coordinates of (a). P₁And O_cThe connecting line of (1) is a left eye optical axis straight line and an optical axis straight line P₁-O_cPassing through the eyeball center O of the left eye_e。

(c) Then another visual target is displayed at a point S on the right side of the display, so that the head of the examinee is placed on the head fixing support, the left eye watches the visual target, the eyeball rotates only when the visual target point changes, and the position of the head is kept unchanged. The straight line of the left eye optical axis at this moment can be obtained by the same principle and also passes through the sphere center O of the left eye eyeball_eThe optical axis line and the line P obtained in the previous step₁-O_cThe intersection point of the two lines is the spherical center O of the eyeball of the left eye_eThree-dimensional coordinates of (a).

(d) The three-dimensional coordinates of the center of the eyeball of the right eye can be obtained by the same principle as in the previous steps by making the right liquid crystal shutter 107 transparent and making the left liquid crystal shutter 106 opaque and displaying the optotypes on the left and right sides of the display 105, respectively.

(e) And calculating the three-dimensional coordinates of the virtual image of the sphere center of the left eye eyeball according to the three-dimensional coordinates of the sphere center of the left eye eyeball obtained in the step and the three-dimensional space position of the left eye transflective module 101. If the three-dimensional coordinates of the sphere center of the spherical surface where the left eye eyeball tracking module 102 is located and the virtual image of the sphere center of the left eye eyeball are not consistent, the three-dimensional coordinates of the sphere center of the spherical surface where the left eye eyeball tracking module 102 is located and the virtual image of the sphere center of the left eye eyeball are made consistent by adjusting the position of the spherical surface where the left eye eyeball tracking module 102 is located or adjusting the position of the left eye transflective module 101.

(f) And calculating the three-dimensional coordinate of the sphere center virtual image of the eyeball of the right eye according to the three-dimensional coordinate of the sphere center of the eyeball of the right eye obtained in the step and the three-dimensional space position of the right eye semi-transmitting and semi-reflecting module 103. If the sphere center of the spherical surface where the right eye eyeball tracking module 104 is located is not consistent with the three-dimensional coordinates of the virtual image of the sphere center of the right eye eyeball, the sphere center of the spherical surface where the right eye eyeball tracking module 104 is located is consistent with the three-dimensional coordinates of the virtual image of the sphere center of the right eye eyeball by adjusting the position of the spherical surface where the right eye eyeball tracking module 104 is located or adjusting the position of the right eye semi-transparent semi-reflective module 103.

Claims

1. An eye movement measuring apparatus, comprising:

2. The eye movement measuring device according to claim 1, wherein the left eye tracking module moves along the left spherical surface, and the center of the left spherical surface is the position of the virtual image of the center of the left eye eyeball reflected by the left eye transflective module; the radius R1 of the left spherical surface is a fixed value; the position of the left eye eyeball tracking module can be represented in a spherical coordinate system taking a virtual image of the spherical center of the left eye eyeball as the spherical center and R1 as the radius;

3. An eye movement measurement device according to claim 2, wherein the radius R1 of the left spherical surface and the radius R2 of the right spherical surface are equal.

4. The eye movement measuring device according to claim 2, wherein when the left eye tracking module moves along the left spherical surface, the axis of the left eye camera always faces the virtual image of the center of the left eye eyeball;

5. The eye movement measuring apparatus according to claim 2, wherein the angle of rotation of the left eye eyeball in the horizontal direction and the angle of rotation in the vertical direction can be calculated according to the angle of movement of the left eye eyeball tracking module along the left spherical surface;

6. An eye movement measurement apparatus according to claim 2, wherein the horizontal viewing angle at the left eye is θ_l1And the vertical viewing angle is

Calculating Delta theta_l1＝θ_l1’-θ_l1，

horizontal viewing angle theta at right eye_r1And the vertical viewing angle is

Calculating Delta theta_r1＝θ_r1’-θ_r1，

7. The eye movement measurement device of claim 1, wherein the left eye tracking module is movable along a left plane; when the left eye looks straight ahead, and the horizontal direction visual angle and the vertical direction visual angle are both 0 degrees, the left plane is vertical to the visual axis of the eye eyeball virtual image; the vertical line of the left plane passing through the point of the left plane (0,0) is intersected with the virtual image of the sphere center of the eyeball of the left eye; the distance between the left plane and the virtual image of the center of the eyeball of the left eye is D1;

8. An eye movement measurement device according to claim 7, wherein the distance D1 between the virtual images of the left plane and the center of the left eye eyeball center is equal to the distance D2 between the virtual images of the right plane and the center of the right eye eyeball center.

9. The eye movement measuring device according to claim 7, wherein when the left eye tracking module moves along the left plane, the axis of the left eye camera always faces the virtual image of the center of the left eye eyeball;

10. The eye movement measuring apparatus according to claim 7, wherein the angle of rotation of the left eye eyeball in the horizontal direction and the angle of rotation in the vertical direction can be calculated according to the angle of movement of the left eye eyeball tracking module along the left plane;

11. An eye movement measurement apparatus according to claim 7, wherein the horizontal viewing angle at the left eye is θ_l2And the vertical viewing angle is

And calculates Delta theta_l2＝θ_l2’-θ_l2，

horizontal viewing angle theta at right eye_r2And the vertical viewing angle is

And calculates Delta theta_r2＝θ_r2’-θ_r2，

12. The eye movement measuring apparatus according to claim 1, wherein the left eye tracking module may recognize a feature of the left iris and calculate an angle of rotation of the left eye according to a change in the feature of the left iris; the right eye eyeball tracking module can identify the characteristics of the right eye iris and calculate the rotation angle of the right eye according to the change of the characteristics of the right eye iris.

13. The eye movement measurement device of claim 1, further comprising a display and control module; the display and control module comprises a display device which can be switched among the following three display modes:

14. The eye movement measuring apparatus according to claim 13, comprising a left liquid crystal shutter device, disposed between the left transflective module and the display device in the display and control module, for switching between transparent and opaque states;

15. An eye movement measurement device according to claim 13, further comprising a squint measurement module arranged to perform the steps of,

(b) The display and control module is switched to a display mode III, the F eye and the G eye can both see the squint measurement sighting target displayed by the display device, and the display position of the sighting target is unchanged; when the eyes watch the sight, the central coordinates of the reflecting point of the F eye light source on the cornea of the F eye and the central coordinates of the pupil of the F eye coincide, and the central coordinates are recordedPosition EF of the F eye tracking module₂(ii) a The central coordinates of the reflecting point of the G eye light source on the G eye cornea are coincided with the central coordinates of the G eye pupil, and the position EG of the G eye eyeball tracking module is recorded₂；

(d) the display and control module is switched to a display mode III, the F eye and the G eye can both see the squint measurement sighting target displayed by the display device, and the display position of the sighting target is unchanged; when the eyes watch the sight, the center coordinates of the reflecting point of the F eye light source on the cornea of the F eye and the center coordinates of the pupil of the F eye coincide, and the position EF of the F eye eyeball tracking module is recorded₄(ii) a The center coordinates of the light reflecting point of the G eye light source on the G eye cornea are coincided with the center coordinates of the G eye pupil, and the G eye eyeball tracking module is recordedPosition EG of₄；

16. An eye movement measuring apparatus according to claim 15, wherein after the direction and degree of strabismus are measured, a prism of a corresponding degree is placed in front of the strabismus, and the measurement is performed again; if the measurement is carried out again, the moving angles of the left eye eyeball tracking module and the right eye eyeball tracking module in each step are all less than TH₁Then, the prism power at this time was confirmed to be the squint power.

17. The eye movement measurement device of claim 13, further comprising a rotational strabismus measurement module configured to perform the steps of,

such as | HJ₃-HJ₂|≥TH₄And has aHK₃-HK₂|＜TH₃The result was denoted as C5;

18. An eye movement measurement device according to claim 1, wherein the left eye and right eye tracking modules use an automatic pupil center tracking algorithm, the calculation method of which is: and if the central coordinates of the cornea reflecting point and the central coordinates of the pupil are not overlapped, the eyeball tracking module corresponding to the eyeball moves along the vector direction of a connecting line from the central coordinates of the cornea reflecting point to the central coordinates of the pupil, the distance between the center of the cornea reflecting point and the center of the pupil is gradually reduced in the moving process, and the movement is stopped until the center of the cornea reflecting point and the center of the pupil are overlapped again.

19. The eye movement measuring apparatus according to claim 1, wherein the head fixing device comprises a lifting chin rest, the head fixing device comprises a left column and a right column, the left column and the right column have standard height marks, and the chin rest is adjusted during the test to make the height of the eyes of the subject equal to the standard height marks.

20. The eye movement measuring apparatus according to claim 2, further comprising three-dimensional coordinate measuring means for measuring three-dimensional coordinates of the center of the eyeball of the left eye and the center of the eyeball of the right eye; adjusting the position of a left spherical surface where the left eye eyeball tracking module is located or adjusting the position of the left eye semi-transparent and semi-reflective module according to the three-dimensional coordinates of the virtual image of the left eye eyeball center to enable the left spherical center to coincide with the virtual image of the left eye eyeball center; and adjusting the position of a right spherical surface where the right eyeball tracking module is located or adjusting the position of the right eye semi-transmitting and semi-reflecting module according to the three-dimensional coordinates of the virtual image of the sphere center of the right eyeball to enable the sphere center of the right spherical surface to coincide with the virtual image of the sphere center of the right eyeball.

21. The eye movement measuring apparatus according to claim 7, further comprising three-dimensional coordinate measuring means for measuring three-dimensional coordinates of a center of the eyeball of the left eye and a center of the eyeball of the right eye; adjusting the position of a left plane where the left eye eyeball tracking module is located or adjusting the position of the left eye semi-transparent and semi-reflective module according to the three-dimensional coordinates of the virtual image of the left eye eyeball center to enable a left plane (0,0) point to be intersected with the vertical line of the left plane and the virtual image of the left eye eyeball center to enable D1 to be equal to the distance between the left plane (0,0) point and the virtual image of the left eye eyeball center; and adjusting the position of a right plane where the right eyeball tracking module is located or adjusting the position of the right eye semi-transparent and semi-reflective module according to the three-dimensional coordinates of the virtual image of the sphere center of the right eyeball, so that the right plane (0,0) point is intersected with the virtual image of the vertical line of the plane and the sphere center of the right eyeball, and D2 is equal to the distance between the right plane (0,0) point and the virtual image of the sphere center of the right eyeball.

22. An eye movement measurement device according to claim 20 or 21, wherein the three-dimensional coordinate measurement means comprises two cameras and two light sources; the relative positions of the two cameras, the two light sources and the display device, the left eye semi-transparent and semi-reflective module and the right eye semi-transparent and semi-reflective module are fixed;

the display device can display the sighting mark at two different positions;

23. The eye movement measuring apparatus according to claim 1, wherein a barrier which transmits near infrared light and does not transmit visible light is provided between the left eye tracking module and the left eye; a baffle plate which can transmit near infrared light and can not transmit visible light is arranged between the eyeball tracking module of the right eye and the right eye.