KR20230013833A - Apparatus for measuring visual acuity using eye tracking and spatial frequency and method thereof - Google Patents

Abstract

The present invention relates to a visual acuity measurement device using eye tracking and spatial frequency, and a method thereof. According to the present invention, the method for measuring visual acuity using a visual acuity measuring device comprises the steps of: determining whether a subject is looking at a screen of a display device by using an eye tracking device, when the subject is looking at the screen; when the subject's gaze is determined to be looking at the screen, displaying, on the screen, a mark in which a spatial frequency is gradually changed; determining whether the subject's eyes looking at the mark are twitching by using an eye tracking device, and extracting the mark at a time when the subject's eyes are not twitching; repeatedly displaying the mark at the time when the subject's eyes are not twitching; and, if the subject's eyes are not twitching for a period of time, determining the visual acuity of the subject by extracting the highest spatial frequency at the time when the subject's eyes are twitching. According to the present invention, the visual acuity of the subject can be accurately measured by measuring the visual acuity through the contrast sensitivity of the subject looking at a mark whose spatial frequency changes step by step. In addition, the eye-tracking device can be used to determine whether the subject's gaze is on the screen.

Description

Apparatus and method for measuring eyesight using eye tracking and spatial frequency

The present invention relates to an apparatus for measuring visual acuity using eye tracking and spatial frequency and a method thereof, and more particularly, to an apparatus for measuring visual acuity using an eye tracking apparatus and a target with varying spatial frequency, which measures the visual acuity of an examinee using eye tracking and visual acuity using spatial frequency. It relates to a measuring device and its method.

In general, an eye test is a test for clinically measuring visual function, and means a test for minimum reading eyesight, which is the ability to clearly recognize characters or shapes at a specific distance.

Here, the method of measuring visual acuity is expressed as the visual acuity of the subject through the degree of the target when the subject recognizes the target on the visual acuity chart.

More specifically, the subject can read the letters marked on the visual acuity chart from a distance of 5m to 6m to check his or her eyesight, and the size of the letters is marked differently for each degree of visual acuity, so the degree of the target until the subject recognizes it can be checked. can be expressed visually.

At this time, the target is in the form of numbers, alphabets, or Landolt rings on the visual acuity chart, and the visual acuity can be said to be high or low depending on the degree of discriminating the spatial difference between black and white.

Using this principle, visual acuity can be measured indirectly through spatial frequency for children who do not know numbers.

In other words, if a target with repetitive spatial frequency continuously passes horizontally in front of your eyes, you follow one target and then when the next target appears, the eyes unconsciously return to the initial position to see the new target. This is called trial run. Quantitative measurement of visual acuity is possible by using the principle of optokinetic nystagmus (OKN) according to the spatial frequency.

However, since the general eye chart is composed of a composition in which the subject sees, interprets, and reads the target according to the subject's will, it is impossible to accurately measure the visual acuity if the subject does not read or answers that he or she does not see the target despite being able to determine the target. there is.

In addition, when a young child cannot read the chart, it is difficult to accurately measure the child's visual function.

On the other hand, although a medical staff performs a malingering test such as a mirror test or an OKN test, it is not a quantitative measurement of visual acuity, but an approximate condition. Therefore, it is necessary to develop a method for objectively and quantitatively measuring visual acuity using the unconscious eye response.

The background technology of the present invention is disclosed in Korean Patent Publication No. 10-2019-0088491 (published on July 26, 2019).

A technical problem to be achieved by the present invention is to provide an eye tracking device and a method for measuring eyesight using eye tracking and spatial frequency for measuring the eyesight of an examinee using a target whose spatial frequency changes.

According to an embodiment of the present invention to achieve this technical problem, in the vision measurement method using an eyesight measuring device, when the subject looks at the screen of the display device, the eye tracking device is used to determine whether the subject's gaze looks at the screen. Determining whether or not the gaze of the examinee is looking at the screen, displaying a target in which spatial frequency gradually changes on the screen, if it is determined that the gaze of the examinee is looking at the screen, Eyes of the examinee who gaze at the target using the eye tracking device Determining whether or not tremor occurs and extracting a target at the time when the subject's eye tremor does not occur, repeatedly displaying the target at the time when the subject's eye tremor does not occur, and If it does not occur, determining the eyesight of the subject by extracting the highest spatial frequency in a state in which the subject's eye tremor occurs.

The method may further include providing a warning notification when the subject's eyes do not look at the screen.

The target has a spatial frequency that changes by using a difference in width between a white grid and a black grid having a stripe shape. The above table can be displayed.

In the step of extracting the target at the time point at which the subject's eyestrain does not occur, the subject's eye tremor that gazes at the target using the eye tracking device while sequentially narrowing the widths of the white grid and the black grid of the target Determining whether the subject's eyes tremble has occurred, and extracting a target having a specific spatial frequency at a point in time when the subject's eye trembling does not occur.

As the width between the white grid and the black grid of the target becomes narrower, the spatial frequency corresponding to the target may increase.

According to another embodiment of the present invention, in the apparatus for measuring eyesight using eye tracking and spatial frequency, when the subject gazes at a screen of a display device, it is determined whether the gaze of the subject gazes at the screen using the eye tracking apparatus. a determination unit that, if it is determined that the gaze of the subject is looking at the screen, displays a target in which the spatial frequency changes step by step on the screen, and repeatedly displays the target at a point in time when the eye tremor does not occur; a display unit; An extractor for extracting a target at a point in time when the subject's eyestrain does not occur by determining whether the subject's eyestrain occurs while looking at the target using the eyeball tracking device, and the subject's eyestrain occurs for a certain period of time. If not, a determination unit for determining the visual acuity of the subject by extracting the highest spatial frequency when the subject's eyes tremble occurs.

As described above, according to the present invention, the visual acuity of the subject can be accurately measured by measuring the visual acuity through the contrast sensitivity of the subject who gazes at the target in which the spatial frequency is gradually changed. In addition, by using the eye tracking device, it is possible to determine whether the subject's gaze is looking at the screen, so that the gaze of the subject who is looking at another subject can be detected, or the subject who lies during the vision test can be identified to accurately measure visual acuity. Visual acuity in young children can also be accurately measured.

1 is a diagram for explaining a vision measurement apparatus using eye tracking and spatial frequency according to an embodiment of the present invention.
2 is a diagram for explaining the configuration of a vision measurement apparatus using eye tracking and spatial frequency according to an embodiment of the present invention.
3 is a flowchart illustrating a method for measuring visual acuity using eye tracking and spatial frequency according to an embodiment of the present invention.
FIG. 4 is a diagram for explaining the movement of a target and a pupil in steps S330 and S350 of FIG. 3 .
FIG. 5 is an exemplary diagram for explaining a target when the subject's eyestrain occurs in step S350 of FIG. 3 .

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. In addition, in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

Then, with reference to the accompanying drawings, an embodiment of the present invention will be described in detail so that those skilled in the art can easily practice it.

Hereinafter, a visual acuity measurement apparatus 100 using eye tracking and spatial frequency according to an embodiment of the present invention will be described with reference to FIG. 1 .

1 is a diagram for explaining a vision measurement apparatus using eye tracking and spatial frequency according to an embodiment of the present invention.

As shown in FIG. 1 , the vision measuring device 100 according to an embodiment of the present invention is connected to the display device 200 and the eye tracking device 300 through a network.

First, the eyesight measuring device 100 displays a target through the screen of the display device 200 and determines whether or not the eye twitching of the subject looking at the target occurs through the eye tracking device 300 .

Here, the display device 200 is implemented as a device capable of displaying a chart having a spatial frequency and displaying a video or image transmitted from the outside through a wired or wireless network connection.

Also, the display device 200 may include devices such as a monitor, a TV, and a screen.

Next, the eye tracking device 300 is implemented in a form that can be worn by a user like glasses or is implemented in a form that is mounted in a bar form, and tracks the subject's gaze through infrared rays and transmits the extracted tracking data to the vision measurement device 100. ) is sent to

In addition, the eye tracking device 300 may detect whether or not the subject's eyes tremble occurs through the subject's gaze shaking on the screen of the display device 200 .

Hereinafter, the configuration of the vision measurement apparatus 100 using eye tracking and spatial frequency according to an embodiment of the present invention will be described with reference to FIG. 2 .

2 is a diagram for explaining the configuration of a vision measurement apparatus using eye tracking and spatial frequency according to an embodiment of the present invention.

As shown in FIG. 2 , the vision measurement device 100 according to an embodiment of the present invention includes a determination unit 110, a display unit 120, an extraction unit 130, a determination unit 140, and a notification providing unit 150. ).

First, the determination unit 110 determines whether the examinee's eyes are looking at the screen of the display device 200 .

At this time, when the examinee gazes at the display device 200, the determination unit 110 uses the eye tracking device 300 to determine the gaze position of the examinee.

That is, the determination unit 110 determines whether or not the subject's gaze is looking at the display device 200 through the eye tracking device 300 .

Next, the display unit 120 displays a table in which the spatial frequency gradually changes on the screen of the display device 200 .

At this time, the target has a spatial frequency that changes by using the difference in spacing between the white grid and the black grid having a stripe shape, and as the interval between the white grid and the black grid of the chart becomes narrower, the spatial frequency corresponding to the chart may increase. there is.

Also, the display unit 120 displays a target using contrast sensitivities for a plurality of white and black grids that appear repeatedly.

In addition, the display unit 120 repeatedly displays a target at a point in time when the subject's eye tremor, which is detected through the eye tracking device 300, does not occur.

Next, the extraction unit 130 extracts a target at a point in time at which the subject's eyes do not shake.

At this time, the extraction unit 130 determines whether or not the subject's eye trembling occurs while looking at the target using the eye tracking device 300 .

That is, the extractor 130 determines whether or not the subject gazes at the target through the eye tracking device 300 while gradually narrowing the interval between the white grid and the black grid of the target, and the subject's eye tremor occurs. A target having a specific spatial frequency at a point in time that is not used is extracted.

Next, the determination unit 140 determines the visual acuity of the subject by extracting the highest spatial frequency in the case of eye tremor.

At this time, the determination unit 140 may determine the visual acuity matching the extracted spatial frequency as the visual acuity of the subject.

Next, the notification providing unit 150 provides a warning notification when the examinee's eyes do not look at the screen.

At this time, the notification providing unit 150 may provide a warning notification that the examinee's eyes stray from the screen through a lighting signal or a sound.

Hereinafter, a visual acuity measuring method using eye tracking and spatial frequency according to an embodiment of the present invention will be described with reference to FIGS. 3 to 5 .

3 is a flowchart for explaining a method for measuring eyesight using eye tracking and spatial frequency according to an embodiment of the present invention, and FIG. 4 is a diagram for explaining the movement of a target and a pupil in steps S330 and S350 of FIG. 3 .

First, while the subject is looking at the screen of the display device 200, the optometry apparatus 100 according to the embodiment of the present invention receives the gaze data of the subject detected by the eye tracking apparatus 300 (S310). .

At this time, the eye tracking device 300 tracks the gaze of the subject gazed at on the screen of the display device 200 and transmits the detected gaze data of the subject to the vision measuring device 100 in real time.

Next, the eyesight measurement apparatus 100 determines whether the subject's gaze gazes at the screen of the display device 200 using the subject's gaze data input in step S310 (S320).

At this time, the subject's gaze data includes data on the gaze position, gaze gaze value, and gaze movement, and the optometry apparatus 100 determines the subject's gaze of the display device 200 through the subject's gaze data input in real time. It is possible to determine in real time whether or not the user is watching the screen.

That is, the eyesight measurement apparatus 100 determines whether the gaze data of the subject is located in the screen area of the display device 200 .

If it is determined that the subject's eyes are looking at the screen of the display device 200, the vision measuring device 100 according to the embodiment of the present invention displays a target whose spatial frequency changes step by step on the screen of the display device 200. is displayed (S330).

As shown in FIG. 4, the target is formed in a form in which a white grid and a black grid having a stripe shape are repeatedly arranged, and a spatial frequency is changed when the width of the white grid or the black grid is changed.

Here, the width of the white grid and the width of the black grid are set to the same length.

Also, the vision measuring device 100 repeatedly displays a target having a constant width of a white grid and a black grid on the screen of the display device 200 so as to move in a horizontal direction.

In this case, as the widths of the white grid and the black grid of the target become narrower, the spatial frequency corresponding to the target increases.

Then, if it is determined that the subject's eyes are not looking at the screen of the display device 200, the vision measurement apparatus 100 provides a warning notification to the subject (S340).

In this case, the warning notification may be provided through the vision measurement device 100 or through a user terminal receiving a warning notification request signal from the vision measurement device 100 . Here, the gongo notification may be provided to the examinee through a lighting signal or sound.

Here, the user terminal may be implemented as a device capable of exchanging information, such as a PC, a laptop computer, an iPad, and a smart phone.

On the other hand, if the eyesight measuring device 100 determines that the subject's eyes are looking at the screen of the display device 200, the eyesight measuring device 100 according to an embodiment of the present invention uses the eye tracking device 300 It is determined whether the subject's eyes tremble while looking at the target occurs (S350).

As shown in FIG. 4, when a target having a plurality of white and black grids repeatedly appearing passes in the right direction (Direction of Grating Motion), the gaze of the subject gazing at the target follows one target (Eyes Tracking Motion) , when the next target appears, he unconsciously sees a new one. Then, the subject's gaze returns to the initial position (Eyes Snap Back), and at this time, the subject's eyes tremble.

Using this principle, the vision measurement apparatus 100 according to an embodiment of the present invention sequentially narrows the widths of the white grid and the black grid of the target, while using the eye tracking device 300 to measure the subject's gaze on the target. It is determined whether there is an eye tremor.

In this case, the eye tracking device 300 may detect movement of the subject's iris and eye shaking through the subject's gaze slightly trembling on the screen of the display device 200 .

If the subject's eyes tremble while looking at the target, the vision measurement apparatus 100 repeats step S330.

Then, the vision measurement apparatus 100 displays the target on the screen of the display device 200, in which the widths of the white grid and the black grid of the target are narrower than before.

FIG. 5 is an exemplary diagram for explaining a target when the subject's eyestrain occurs in step S350 of FIG. 3 .

FIG. 5(a) is an exemplary diagram for explaining a target initially observed by the subject, and FIG. 5(b) is an exemplary diagram for explaining another target observed by the subject after eye tremor occurs.

As described above, the narrower the width of the grid inside the chart, the higher the spatial frequency, so the chart shown in FIG. 5(b) has a higher spatial frequency than the chart shown in FIG. 5(a).

When the subject gazes at the target shown in FIG. 5 (a) and the subject's eyes tremble occurs, the optometry apparatus 100 uses a target with narrower widths of the white grid and the black grid than in FIG. )) is displayed on the screen of the display device 200 to operate.

On the other hand, when the subject's eye trembling does not occur while looking at the target, the optometry apparatus 100 according to the embodiment of the present invention extracts a target at a point in time when the subject's eyes trembling does not occur (S360).

That is, the width of the target is gradually narrowed until the subject's eyestrain does not occur, and when the subject's eyestrain does not occur, the optometry apparatus 100 determines a specific spatial frequency at a point in time when the subject's eyestrain does not occur. A table with can be extracted.

Next, the vision measurement apparatus 100 according to the embodiment of the present invention repeatedly displays the target at the point in time when the subject's eyestrain does not occur, extracted in step S360 (S370).

At this time, the vision measuring device 100 displays a target corresponding to a specific spatial frequency on the screen of the display device 200 for a predetermined time.

Then, the eyesight measurement apparatus 100 checks whether or not the subject's eyes tremble occurs for a predetermined time using the eye tracking apparatus 300 (S380).

At this time, the predetermined time may be set to 5 seconds, and the set time may vary.

In addition, the eye tracking device 300 may detect the subject's gaze shaking on the screen of the display device 200 and transmit the subject's gaze data to the optometry apparatus 100 .

Then, the eyesight measurement apparatus 100 may determine whether the subject's eyestrain occurs within 5 seconds through the subject's gaze data.

Here, if the subject's eyes tremble occurs within 5 seconds, the vision measurement apparatus 100 repeats steps S320 to S370.

If the subject's eyestrain does not occur for a certain period of time, the optometry apparatus 100 according to the embodiment of the present invention extracts the highest spatial frequency when the subject's eyestrain occurs in step S330 to determine the subject's eyesight. Visual acuity is determined (S390).

Here, if the subject's eye trembling does not occur while looking at the target, it means that the subject's eye does not experience any trial movement by the target. A spatial frequency is extracted to determine the subject's visual acuity corresponding to the corresponding spatial frequency.

Here, the spatial frequency and visual acuity are matched with each other, and the visual acuity value varies according to the extracted spatial frequency.

For example, the subject's eye tremor occurred with respect to a target (spatial frequency of 200 Hz) in which the width of the white grid and the black grid were 0.15 mm, and the width of the white grid and the black grid, which were the next step, were 0.10 mm (spatial frequency 200 Hz). It is assumed that the subject's eye tremor does not occur with respect to the spatial frequency of 300 Hz).

Then, the highest spatial frequency when the subject's eyes tremble occurs is a target (spatial frequency 200 Hz) in which the width of the white grid and the black grid is 0.15 mm, and the optometry apparatus 100 has a white grid where the subject's eyes tremble occurs. and 200 Hz, which is a spatial frequency corresponding to a target having a black grid width of 0.15 mm, extracted, and a visual acuity matching the spatial frequency may be determined as the visual acuity of the subject.

In this case, the visual acuity measurement apparatus 100 according to the embodiment of the present invention may determine the visual acuity of the subject by extracting a spatial frequency at a point in time when the subject's eyes do not shake for a predetermined time in step S380.

As described above, according to an embodiment of the present invention, the visual acuity of the subject can be accurately measured by measuring the visual acuity through the contrast sensitivity of the subject watching the target in which the spatial frequency is gradually changed. In addition, by using the eye tracking device, it is possible to determine whether the subject's gaze is looking at the screen, so that the gaze of the subject who is looking at another subject can be detected, or the subject who lies during the vision test can be identified to accurately measure visual acuity. Visual acuity in young children can also be accurately measured.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is only exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims.

100: vision measurement device, 110: determination unit,
120: display unit, 130: extraction unit,
140: decision unit, 150: notification providing unit,
200: display device, 300: eye tracking device

Claims (10)

A visual acuity measuring method using a visual acuity measuring device,
When the examinee gazes at the screen of the display device, determining whether the gaze of the examinee gazes at the screen using an eye tracking device;
If it is determined that the gaze of the subject is looking at the screen, displaying a target in which the spatial frequency changes step by step on the screen;
Extracting a target at a point in time when the subject's eye tremor does not occur by determining whether the subject's eye tremor occurs while looking at the target using the eye tracking device;
Repeatedly displaying a target at a point in time when the eye tremor does not occur, and
and determining the visual acuity of the subject by extracting the highest spatial frequency in a state where the subject's eyestrain has not occurred for a predetermined period of time. According to claim 1,
The method of measuring eyesight further comprising providing a warning notification when the eyes of the subject do not look at the screen. According to claim 1,
The table above is
It has a spatial frequency that changes by using the difference in width between the white grid and the black grid having a stripe shape,
In the step of displaying the target,
A visual acuity measurement method of displaying the target using contrast sensitivity for a plurality of white and black grids that appear repeatedly. According to claim 1,
In the step of extracting a target at a point in time when the subject's eyestrain does not occur,
Determining whether or not the subject gazes at the target by using the eye tracking device while sequentially narrowing the widths of the white grid and the black grid of the target;
A method for measuring eyesight comprising extracting a target having a specific spatial frequency at a point in time when the subject's eyestrain does not occur. According to claim 4,
A visual acuity measuring method in which a spatial frequency corresponding to the target increases as the width between the white grid and the black grid of the target decreases. In the vision measuring device using eye tracking and spatial frequency,
When the examinee gazes at the screen of the display device, a determination unit for determining whether the gaze of the examinee gazes at the screen using an eye tracking device;
If it is determined that the gaze of the subject is looking at the screen, a display unit for displaying a target in which the spatial frequency changes step by step on the screen and repeatedly displaying the target at a point in time when the eye tremor does not occur;
An extractor for extracting a target at a point in time when the subject's eye tremor does not occur by determining whether or not the subject's eye tremor occurs while looking at the target using the eyeball tracking device, and
and a determination unit configured to determine visual acuity of the subject by extracting a highest spatial frequency when the subject's eyestrain does not occur for a predetermined period of time. According to claim 6,
The vision measurement device further comprising a notification providing unit configured to provide a warning notification when the subject's eyes do not look at the screen. According to claim 6,
The table above is
It has a spatial frequency that changes by using the difference in width between the white grid and the black grid having a stripe shape,
the display unit,
An optometry device for displaying the target using contrast sensitivity for a plurality of white and black grids that appear repeatedly. According to claim 6,
The extraction part,
While sequentially narrowing the widths of the white grid and the black grid of the target, it is determined whether or not the subject's eye tremor occurs while looking at the target using the eyeball tracking device, and the subject's eye tremor does not occur. A visual acuity measuring device that extracts a target having a spatial frequency. According to claim 9,
A visual acuity measuring device in which a spatial frequency corresponding to the target increases as the width between the white grid and the black grid of the target decreases.

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